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1. c ccccccesseseeeeeeeeeees 211 8 7 Throughput Expt 8 2 1 4 Parameters SettingS ccccccccsseeeeeeeeeeeeees 212 8 8 Throughput Expt 8 2 2 1 Parameters SettingS ccccccseeeeeeeeeeeeees 215 8 9 Throughput Expt 8 2 2 2 Parameters SettingS cccccccecseeeeeeeeeeeeees 216 8 10 Throughput Expt 8 2 2 3 Parameters SettingS cccccceeeeeeeeeeeeeeeees 217 8 11 Throughput Expt 8 2 2 4 Parameters SettingS ccccccccsseeeeeeeeeeeees 218 8 12 Throughput results of Iperf and network speed tool eeeeeeeeeeeees 219 8 13 Data rate vs throughput for IEEE802 119 eee eeeeeeeeeeeeeeeeeeeeeeeeeee 224 xi LIST OF ILLUSTRATIONS Page 2 1 Greenbelt Weather Station GBC_WS ce cece eee e eter ee eeeeeeeeeeeeeeeeees 8 2 2 Environmental Monitoring System in Greenbelt Corridor cceeeeeeeeeee 8 2 3 Discovery Park Weather and Soil Station DP_WS eee 10 2 4 Environmental Monitoring System in Discovery Park eeeeeeeee 11 3 1 Dataloggers Used in the Field 2 22 2 00 2 ccee cceeceeeeeeeceeeeeeeeeeeeeeeeeeeneeeees 14 3 2 Wining Panel of CRIOX gta ccn AeA rene kee ee cea 15 3 3 Wiring Panel of CR1000 cc cccccceeeeseeeeeeeeceeeceeessseeeeeeeeeeeeeeessseeeeeees 20 3 4 03001 RM Young Wind SOMUY sc ceceeic cet eexsecndsex aetderdeceddeudscedeederedcodscueeouss 24 3 5 Air Temperature and RH S
2. 27 Sample P70 1s 2 Reps PAES Loc BATT_WTHR 28 Sample P70 alee lt u Reps 22 10 Loc BATT_SM 29 Sample P70 ee ol Reps 2 1 Loc T_C 240 30 Sample P70 Les GL Reps 2 2 Loc 31 Sample P70 te aL Reps Zc Loc 32 Sample P70 Te Reps 2 4 Loc 33 Sample P70 dee I Reps 2 5 Loc 34 Sample P70 1 2 Reps 256 Loc 35 Sample P70 din CL Reps 2E 7 Loc 36 Sample P70 Loreal Reps Z8 Loc Set the Reps equal to the n 37 Sample P70 16 Reps 2 11 Loc Do two reps to r 38 Sample P70 Ls 2 Reps 2 23 Loc enable recali T 39 Sample P70 T2 Reps ZE 2T Loc 40 Sample P70 S Reps 2 43 Loc 41 End P95 RH P_mmHg SUN_W_m2 WIND_ave WIND_dir WIND_max RAIN_tot in the following instruction umber of EC 5 probes used SM1 store both CS615 readings SM_CS1 Also store the periods for each CS615 to bration if needed P ER_CS1 ET ENSIO 241 Table 2 Program 02 0 0000 Execution Interval seconds Table 3 Subroutines A Se nd current time hr min sec to weather logger Note the weather logger invokes this subroutine via P105 SDI 12 Recorder command This is done at 2 10 a m Beginning of Subroutine P85 98 Subroutine 98 SDI 12 Sensor P106 0 SDI 12 Address 0503 Time Values 32 Loc hr Put curren
3. 15 Set Active Storage Area P80 lee 3 Input Storage Area 25 8 Loc RAIN_tot 16 Totalize P72 Ls aL Reps 2 20 Loc RAIN Set port 1 high one minute prior to sampling the following sensors Port 1 controls the switched 12 volts which applies power to some sensors The T amp H sensors must be powered at least one second prior to taking a reading One minute is 7 more than ample to allow all powered sensors to stabilize 7 before measurement 17 If time is P92 1 14 Minutes Seconds into a 26 15 Interval same units as above 32 30 Then Do 18 Do P86 41 Set Port 1 High m 231 19 End P95 Sample the remaining sensors at 15 minute interval and then send all weather data to final storage and to the moisture 7 data logger 20 If time is P92 Laco Minutes Seconds into a 2 15 Interval same units as above Be 30 Then Do Read barometric pressure and store at P_mb 21 Volt Diff P2 1 1 Reps 2 24 2500 mV 60 Hz Rejection Range B26 DIFF Channel 4 24 Loc P_mb 5 1 84 Mult 6 600 Offset Convert barometeric pressure to mmHg 22 Z X F P37 1 24 X Loc P_mb 2 0 75006 F 303 Z Loc P_mmHg Read air temperature deg C and store at T_C 2 Volt SE P1 Reps 2500 mV Slow Range SE Channel Loc T_C 1 Mult 40 Offset DOF WNE W OrRN UE Read relative humidity and store at RH Volt SE P1 Reps 2500
4. IONS SILILA LILLIA ILE LAA Alias WIND_aveArray 6 BATT_W TAVVVVVAVAVAVAVAAVAVAVAAAANAANAAA OUTPUT SECTION 7 DataTable Tablel true 1 OpentInterval DataInterval 0 15 Min 10 Average 1l W_m2 FP2 0 WindVector 1 WS_mph WD_deg FP2 0 0 0 1 Maximum 1 WS_mph FP2 0 False Totalize l RAIN_tot FP2 0 Sample 1 BATT_W FP2 Sample 1 T_C FP2 Sample 1 RH FP2 Sample 1 P_mmHg FP2 Sample 1 SUN_W_m2 FP2 Sample 1 WIND_ave FP2 Sample 1 WIND_dir FP2 Sample 1 WIND_max FP2 Sample 1 RAIN_tot FP2 EndTable TAVVAVANVAAVAVAVANVANANAANANVANA SUBROUTINES 1111 717 Sub Subroutine98 Subroutine to send weather data to moisture logger P106 EndsSub PXVVVVANAVAVAVAVAVANAAVANANANANAN PROGRAM S 1 11111 1111717 BeginProg Scan 10 Sec 3 0 The following instructions ar xecuted at each execution cycle l to allow averaging over the 15 minute output period and in 7 the case of rainfall to detect each tip of the 01 bucket i ven when the data logger has been recently restarted Read pyranometer solar radiation convert to watts m 2 and i store result at W_m2 VoltDiff W_m2 1 mv7_5 3 true 0 _60Hz 200 0 Set negative values to zero If W_m2 lt 0 Then W_m2 0 EndIf Count switch closures of rainfall tipping bucket convert to inches of rain during this execution cycle and sto
5. Lees le http 129 120 9 227 speedtest cgi Done NETWORK SPEED TEST Select destination IP or specify manually User Password input manualy TESTRESULTS 129 120 9 226 Rx 1 80 Mbps V Show advanced options Direction Duration Data amount what Tx 1 54 Mbps esoe both 12582912 bytes r Internet Protected Mode Off 120 Figure 8 16 Throughput Result of Experiment 8 2 2 2 Result Throughput 1 54 Mbits sec 216 Experiment 8 2 2 3 Parameters Settings Table 8 10 Throughput Expt 8 2 2 3 Parameters settings PARAMETERS EESAT_NS2 DPWS_NS2 Iperf mode Server Client Tx power 11 dBm Data Rate 54 Mbps Rate Mode Full 20 MHz RSL 89 dBm ra r e NanoStation2 Tools SpeedTest Windows Internet Explorer le http 129 120 9 227 speedtest cgi ites pct Siow x gt NETWORK SPEED TEST Select destination IP input manually 2 TEST RESULTS or specify manually 129 120 9 226 Rx 942 24 Kbps User ubnt Tx 354 46 Kbps Password ccoo V Show advanced options Direction both Duration sec Data amount 12582912 bytes Done Internet Protected Mode Off R120 v Figure 8 17 Throughput Result of Experiment 8 2 2 3 Result Throughput 354 46 Kbits sec 217 Experiment 8 2 2 4 Parameters Settings Table 8 11 Throughput Expt 8 2 2 4 Parameters settings PARAMET
6. Nanostation2 at EESAT Table 6 5 Nanostaion2 configuration settings Site Name Discovery Park Nanostation Name EESAT_NS2 DPWS_NS2 ESSID EESAT_NS2 Wireless Mode Access Point Station IP Address 129 120 9 226 129 120 9 227 MAC Address LAN 00 15 6D AA 77 19 00 15 6D AA 77 5A MAC Address WLAN 00 15 6D A9 77 19 00 15 6D A9 77 5A Network Mode Bridge Static Tx power 26 dBm 26 dBm 160 Rate Mode Quarter 5 MHz Data Rate 13 5 Mbps Channel 3 Frequency 2 422 GHz Antenna Polarization Vertical Receive Power Level 67 dBm IEEE Standard 802 119 Rate Algorithm Conservative 6 6 Antenna Alignment After EESAT_NS2 ESSID of Nanostation2 of EESAT was selected from Link Setup page of DPWS_NS2 while operating in station mode the link between EESAT_NS2 and DPWS_NS2 was established Because both of the antennas were already adjusted though not in exact direction facing towards each other the RSL obtained at first connection was 75 dBm The EESAT DP_WS link is nei thert hat ong nor any obstacle i s obstructing the LOS signal noticeably So there is a clear line of sight for the link Otherwise in many cases there may be some obstruction or may be sites are visually unclear or link distance may be quite long All of the above mentioned scenarios make the antenna alignment task difficult One very important thing to be noted and discussed here is the antenna directivity versus complexity in antenna alignment Directivity is t
7. Or OOo OO Ore OO e a a G OOO O o OO CO OO O S OD IO On Ot OD 1 DOO GD SD IO ODO OOS ORO IO OS Or OO sO E S COCO OG OGOOGO OGOGO OOGG GO OGO OGOGO OOGOO GGO oO 236 ii Soil Moisture Station Program Code CR10X r Table 1 Program O01 5 Execution Interval seconds Read soil moisture probes every fifteen minutes Is If time is P92 aE aa 0 Minutes Seconds into a 27 T5 Interval same units as above 3 2 30 Then Do Set port 1 high to power the probes 2 Do P86 Terg Set Port 1 High Wait two execution cycles 10 sec for probe electronics to stabilize 3 Beginning of Loop P87 Lgl Delay 2 2 Loop Count 4 End P95 Measure the frequency of each CS615 probe and multiply result by 001 to convert to KHz 5 Pulse P3 il ss Gh Reps 201 Pulse Channel 1 B 2 2 1 Low Level AC Output Hz 4 25 Loc FREQ _CS1 523 OOD Mult 6 0 Offset 6 Pulse P3 dee Reps 2 2 Pulse Channel 2 82 21 Low Level AC Output Hz 4 26 Loc FREQ CS2 Bi 0 01 Mult 6 0 Offset Remove power from probes to save battery 7 Do P86 Len Sa Set Port 1 Low Convert probel fequency to period msec 237 8 Z 1 X P42 L225 X Loc FREQ CS1 25 27 Z Loc PER_CS1 Insert period of probel into polynomial which A calculates soil water content 9 Polynomial P55 Tee Reps 2s 2 X Loc
8. Administrator D Windows system32 cmd exe Client connecting to 129 120 9 238 TCP window size 8 00 KByte default 20 9 237 port 61 Transfer 4 36 MBytes 4 43 MBytes 12 0 MBytes Figure 8 14 Throughput Result of Experiment 8 2 1 4 Result Throughput 3 75 Mbits sec Observations and Analyses of Above Experiments lo L Lilx Now lets discuss about how the settings of the parameters such as Tx power and dat a r ate af fect t he t hroughput per formance o f t he sy stem The obtained throughout results for two different Tx powers and the two different data rates are summarized as follows 212 Experiment 8 2 1 1 474 Kbits sec at Tx power 11 dBm Data Rate 13 5 Mbps Experiment 8 2 1 2 1 56 Mbits sec at Tx power 26 dBm Data Rate 13 5 Mbps Experiment 8 2 1 3 422 Kbits sec at Data Rate 54 Mbps Tx power 11 dBm Experiment 8 2 1 4 3 75 Mbits sec at Data Rate 54 Mbps Tx power 26 dBm e Observation 1 Effect of change in Tx power on throughput The huge and significant difference in the results of the Experiments 8 2 1 1 and Experiment 8 2 1 2 shows that the impact of Tx power is very noticeable for longer link such as 4 74 km EESAT_NS2 DPWS_NS2 radio link e Observation 2 Effect of change in Data Rate on throughput i Effect of change in data rate on throughput at high Tx power 26 dBm From the results of the experiments Experiment 8 2 1 2 and E xperiment 8 2 1 4 it is clearly noticeabl
9. Main page of the Nanostation2 6 5 1 EESAT_NS2 Settings To establish a point to point wireless link using Wi Fi technology one site has to be an access point AP that provides wireless connection to a wireless network and another has to be client that connects to the network Here in this equipment there are two wireless modes Access point AP mode and station mode EESAT_NS2 is set as Access Point mode In order to minimize the interference the rate mode is selected as Quarter 5 MH z The output poweris settoits maximum value 26 dBm A default vertical polarization is selected The default network settings is changed to a new static one pr ovided by U NT co mputer su pport H ere s a new st atic network settings IP Address 129 120 9 226 Subnet Mask 255 255 255 240 Default Gateway 129 120 9 225 159 6 5 2 DPWS_NS2 Settings Since EESAT_NS2is settoaccess pointm ode DPWS_NS2 sh ould necessarily be set to station mode All other parameters values are setina similar manner except the network IP Address setting The network settings are as follows IP Address 129 120 9 227 Subnet Mask 255 255 255 240 Default Gateway 129 120 9 225 After setting up all the parameters the EESAT_NS2 Extended service set identification ESSID of Nanostation2 of EESAT was selected by pressing the Select button of ESSID inthe Link Setup page of DPWS_NS2 ESSID is the identifying name for a wireless access point EESAT_NS2 is an ESSID for the
10. TIME Bee 0 Mult 6 0 0 Offset If the moisture logger fails to communicate then 99999 will be stored in TIME If communication has failed then do not update the time clock 44 If X lt gt F P89 ITs 30 X Loc TIME Ze gt 32 0 F 4 30 Then Do 45 Set Real Time Clock P114 Eero Set Hr Min Sec from locations 2 30 Loc TIME 46 End P95 47 End P95 Table 2 Program 02 0 0000 Execution Interval seconds Table 3 Subroutines Subroutine to send weather data to moisture logger 234 1 Beginning of Subroutine Subroutine 98 Ls 98 23 SDI 12 Sensor SDI 12 Address Time Values Loc 30 2 0009 ae 3 End P95 End Program Input Locations T_C RH P_mmHg SUN_W_m2 WIND_ave WIND_dir WIND_max RAIN _tot BATT_W OANA BWNE nerrrrrrrrrKro COCMIDDUBWNHEO RAIN WS_mph WD_deg W_m2 P_mb WNHNNNNNNN NY COMTI ADAUO PWN EF TIM Gl A PWWW WWW WW Ww HOG S A OBPWNE gel 22 Or Or Our Ry ea IO Orit Oo OO OGOTO O O GCE REN GO O TO nOA MW ERER A O OO O O O O O Ta 5 DOO CTO O O OG OG G G AOG Oa GOH RNR O O D G OGO OGO OG OG P85 235 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 0 0 Program Security 0000 0000 0000 Mode 4 Final Storage Area 2 0 CR10X ID 0 CR10X Power Up 3 a OO
11. bandwidth and throughput are discussed It also discusses in brief about why it is worth studying and analyzing the throughput Then various types of throughput ex periments carried out by changing different parameters are discussed T hen the gist of this chapter throughput measurement of EESAT_NS2 DPWS_NS2 link and the analysis of its results are also discussed Also discussed is the various factors affecting the throughput performance of a wireless link In addition the comparison of the throughputs of different EEE Standards are reviewed T his chapter also discusses about the various ways to maximize the system throughput It introduces the throughput measuring software called Iperf Finally this chapter discusses on the throughput results of the system Throughput Throughput is the average rate of su ccessful m essage delivery over a communication channel or in other words itis the amount of data transferred successfully over a link from one end to another in a given period It is usually expressed in bi ts per se cond bps or ki lo bits perse cond kbps 83 192 total file size bits Throughput time taken for transferring seconds Throughput is a key measure of a network LAN or WLAN performance Herein this application itis ar adio link quality m easuring par ameter Iti s different than the RSL quality of the link Though the RSL value is very good throughout may not be because of interference f
12. en wikipedia org wiki Throughput K Davis September 20 WLAN Performance Available http www netqos com resourceroom articles 21_wlan_performance html BWMO Net 2006 09 05 2009 How To Accelerate Your Internet First ed Available http bwmo net pdf bwmo ebook pdf 2007 September 21 Bandwidth vs Throughput Available http courses washington edu lis549sp unit_net docs Bandwidth_vs_Throu ghput_Overview pdf Openmaniak Com September 25 Iperf Available http openmaniak com iperf php Wikipedia September 25 Iperf Available http en wikipedia org wiki lpert 258 89 90 J M Dugan 2008 September 25 Using Iperf Available http www nanog org meetings nanog43 presentations Dugan_Iperf_N43 p df Networksfirst Com September 25 Factors Affecting Wireless LAN Performance Available http www networksfirst com admin files Factors 20Affecting 20WLAN 20Performance 2007 05 08 pdf 259
13. ii Wi Fi in 3 6 GHz The EEE S tandard that uses 3 6 GHzbandi s 802 11y approved on September 2 008 Unlike other W i Fi this Wi Fiis nott he unl icensed one licensees have to pay asm all fee for a nationwide and also they have to pay additional fee for each high powered base station that they deploy 31 It is not as popular as other two 2 4 GHz and 5 G Hz Wi Fi but it operates at much higher power allowing greater transmission range The operating frequency range for 3 6 GHz band is 3 65 3 7 GHz 3650 3700 MHz The channel separation can be 5 MHz 10 M Hz or 20 MHz Some of its applications include back haul Wi Fi networks fixed point to point links fixed point to mobile links etc 31 36 iii Wi Fi in 5 GHz The IEEE Standards that use 5 GHz band are 802 11a 802 11 802 11h and 802 11n Though the operating range extends within 5 15 5 825 GHz the 5 GHz band i s divided into t hree se parate 1 00 M Hz sections The low band ranges from 5 15 5 25 GHz the middle from 5 25 5 35 GHz and the high band from 5 725 5 825 G Hz T he upper por tion of this bandis restricted al most everywhere in the world There are 23 non overlapping channels allowed in US each of which are separated by 20 MHz A list of allowed and restricted 5 GHz channels in different parts of the world is shown in Table 5 4 Although 802 11a was ratified at the same time 1999 as 802 11b it could not catch pe ople s attention in the same way 802
14. network speed test Tool Table 8 12 Throughput results of Iperf and network speed tool Throughput Link Distance Tx Power Data Rate Network Speed Test Tool 13 5 Mbps 474 Kbps 432 19 Kbps 13 5 Mbps 1 56 Mbps 1 54 Mbps 54 Mbps 422 Kbps 354 46 Kbps 54 Mbps 3 75 Mbps 3 57 Mbps 219 8 3 Maximizing the Radio Link Throughput Performance The throughputs obtained in above discussed experiments are obviously affected by various external factors which degraded the throughput performance of the system So in order to maximize the throughput of the system first all the probable factors affecting the throughput are needed to be identified and then try to avoid or at least minimize those factors 8 3 1 Various Factors Affecting Throughput Performance There are various factors affecting the throughput of the WLAN system but here only those factors affecting the present system will be di scussed The following are the probable factors that may contribute to degrade the throughput performance of the link between EESAT_NS2 and DPWS_NS2 e Interference due too ther devices There may be di fferent o ther dev ices microwave co rdless pho nes B luetooth etc occu pying sa me frequency spectrum or operating in 2 4 GHz band e Inappropriate channel selection The present system may cause interference to UNT wireless and may receive interference especially from EESAT terrace e Data rate rate algorithm settings If not ma
15. 50 C 7 Wind vane Wind cups for wind direction for wind speed Crossarm p Figure 3 4 03001 RM Young Wind Sentry 24 Wind speed sensor has 3 wires black white and cl ear used for wind speed si gnal wind speed r eference a nd w ind sp eed sh ield r espectively Similarly wind direction has 4 w ires red black white and clear used for wind directional si gnal wind direction ex citation w ind direction reference an d w ind direction sh ield r espectively The co nnections oft he se nsor t o C R10X and CR1000 dataloggers are shown below in Table 3 3 7 Table 3 3 03001 wiring with CR10X and CR1000 WIRE COLOR DESCRIPTION CR10X CR1000 Black Wind speed signal Pulse Pulse Wind Speed White Wind speed reference G A Clear Wind speed shield G Red Wind direction signal SE Analog SE Analog Wind Black Wind direction excitation Excitation Excitation Direction White Wind direction reference AG Clear Wind direction shield G gt b Air Temperature and Relative Humidity Sensor The Vaisala temperature an dr elative hu midity RH her eafter sensor HMP50 is used for measuring air temperature A typical HMP50 is shown below in Figure 3 5 i When it is installed outdoor or exposed in sunlight it must be housed in a solar radiation shield which can be mounted directly to the tripod or tower mast as shown in above Figure 3 5 ii It can measure air temperature within the range 25 to 60 C and rela
16. System unless another is specified at the time of ordering it Available operating systems for CR1000 are e PakBus table data operating system This operating system uses a packet based communication which creates final storage tables to logically separate different types of data collection such as hourly daily etc This protocol allows the C R1000 to communicate with other C R1000 dataloggers in the same network 6 21 e Modbus operating system This operating system supports Modbus protocol one of the more primitive protocols allowing the CR1 000 to interface with SCADA and MMI software packages It allows the remote setting of control ports and reading changing of memory locations 6 SDI 12 SDI 12 is the acr onym for serial data interface at 1200 baud Iti s a standard communication protocol allowing connection of multiple sensors to an SDI 12 compatible datalogger SDI 12 sensors connect to control ports C1 C3 C5 and C7 of CR1000 It communicates using a cable containing 3 wires a 12 V line a ground line and a serial data line 6 22 Table 3 2 CR1000 technical specifications FEATURE SPECIFICATION Voltage Current drain Analog inputs Digital Control ports Pulse Counter channel Communication port Data Storage Input Voltage range Switched voltage output Other output voltage Scan rate A D conversion Switched volt excitation channel Programming Datalogger support software Op
17. doing antenna alignment In this page using extra info ARP and Bridge tables can be looked at The Figure 3 16 below is asnapshot of the main page of Nanostation2 operating in station mode 21 47 Base Station SSID UBNT_AP Signal Strength 67 dBm TX Rate 54 0 Mbps RX Rate 54 0 Mbps Frequency Channel Antenna Security ACK Timeout Transmit CCQ 100 QoS Status Uptime Date LAN Cable Host Name LAN MAC LAN IP Address 192 168 1 20 Q a an PA a 4 QO oO Eea IS j 0 15 6D B5 08 60 5387038 286929795149 6863892105 261391208 Note Pp O0 po Ease ees ee 0 Sa es 0 ee ee Figure 3 16 Main Page in Station Mode 48 b Link Setup This page allows user to set various wireless settings such as transmit output power rate mode IEEE 802 11 mode etc Wireless mode feature allows choosing the appropriate mode such as station station WDS access point and access point WDS mode It also allows the device in station mode to choose EESID A 2 4 GHz band has only 11 channels used in United States so one of them can be selected This page allows user to set wireless security settings in three optional modes wired eq uivalence pr ivacy WEP hereafter Wi Fi protected access WPA and WPA2 Station and station WDS modes are client modes which can connect to access point or access point WDS The acronym WDS stands for wireless distribution system which allows equipments to
18. si milar co ndition m ay ha ppen when the strong wind sh akes the pole orthe boom and antenna which can significantly delocalize the an tenna po sitions in both horizontal an d v ertical directions resulting in huge fluctuation in RSL and even link breakdown if the delocalization of ant enna is significant Similarly t he i nappropriate t ilting o f antenna especially microwave antenna may result in the same scenario Tilting of an tenna is the way of adjusting ant enna ei ther in hor izontal or in v ertical position without affecting its position with respect to the pole or boom of tower where it is mounted or clamped Tilting of antenna plays a vital role especially when t he two r adio link sites are deployed ina si gnificant le velo f height difference 166 Improper Parameters Settings One of the causes due to which the link may breakdown is setting of improper parameters in radio equipment There are various parameters that can be set manually which may have a huge effect in the link quality For example if the Tx power is set to lower value for along radio link in order to minimize the interference where itis not that important to reduce interference the RSL and hence the link quality degrades whenever the system encounters some hostile situations as discussed above Also it is obvious that setting the data rate higher improves the speed of the system but at the cost of limitation on the link distance Interference from Other Signa
19. 1 Functional Overview Greenbelt Weather Station GBC_WS Above Figure 4 1 is the functional block diagram of GBC_WS There are two stations in Greenbelt one is a soil moisture station measuring soil moisture and soil water pressure and another is a weather station measuring various kinds 62 of environmental parameters A CR10X datalogger is used as a measurement and control module in both stations Both the stations are powered by a sealed lead acid rechargeable battery soil moisture s tation is powered by a12 V 12 Ahr battery whereas weather station is powered by a 12 V 7 Ahr battery Because electricity is not available in GBC_WS a solar panel is used as a charging source SX20 U and MSX10 are the so lar pan els used in soil m oisture an d w eather s tations respectively A charging regulator CH12R is connected to both solar panel and battery as well Different kinds of e nvironmental s ensors are co nnected w ith w eather station datalogger and soil moisture sensors and tensiometers are connected with soil moisture station datalogger Thereis alsoan SBC c onnected withthe soil moisture datalogger In the day time solar panel supplies power to the system and charges the battery as well Battery gives power to the system during night and also that time whenever the solar panel is not powering the system due to insufficient sunlight In the above Figure 4 1 you can see different colors are assigned for the lines connecting the blocks
20. 16 Technical specifications of NL120 FEATURE SPECIFICATION Voltage 12 Vdc Current drain 20 mA Loggernet 3 2 or later PC400 1 3 or Support software later Operating system PakBus Standard Temperature Range 25 C 50 C Dimension 4 0 x 2 5 x 1 1 Weight 2 35 oz 59 3 2 3 Network Switch A switcho ra n etwork sw itch is a computer net working device t hat connects multiple co mputers and p eripherals together w ithin o ne I ocal ar ea network LAN Network switches operate at d ata link layer layer 2 of Open System Interconnection OSI reference model The main function of a switch is to forward the data packets to the correct destination ports after processing them A network switch enables sharing of multiple co mputers peripherals such as printers wireless routers etc withina LAN It acts as an intermediate st ation which i nterconnects the c ommunication inks and su b networks to enable transmission of data between the end stations 23 Figure 3 25 Network Switch In this work anet work switch willbe use dt oi nterconnectt he Nanostation2 and e thernet i nterface N L120 which are use din DP_WS The Figure 3 25 24 shown above is of a typical 8 port network switch 60 CHAPTER 4 DATA COLLECTION PROCEDURE Data co llectioni s the pr ocess o f c ollecting env ironmentald ata o f a particular ar ea by deploying a weather st ation connected w ith various environmental sensors The descript
21. 2 1 Throughput Measurements Using Iperf eeeeeeeee eee 208 8 2 2 Throughput Measurements Using Network Speed Test Tool 214 8 3 Maximizing the Radio Link Throughput Performance 05 220 8 3 1 Various Factors Affecting Throughput Performance 220 8 3 2 Techniques Used to Maximize the System Throughput 221 8 4 Impact of Data Rate on Throughput ccccceeeeeeeeeeeeeeeeeeeeeeeeees 223 9 GONCLUSIONG 24 2nn terete et cee AeA ee eee ae fee A ee te 226 RP INDI at erased e E E E AE Ee ia Er aere EES Saet 228 EDLOG PROGRAM CODE FOR GBO WS ecccccceeceeeeeeeeeeeteeeetees 228 APPENDIX B s occeeencs cue eae oe eae cele g ates 244 CRBASIC PROGRAM CODE FOR DP_WGS cceeeeeeeeeeeeeeeteeees 244 REFERENCES sroti pec cee este eeeceick tau ns esc oases cae ean ewe ede amee 249 viii LIST OF TABLES Page 3 1 CR10X technical specifications ccccceceecceeeeeeeeeeeeeeeeeeeeeeeaeeneeeeeeeees 18 3 2 CR1000 technical specifications ccccccecccccceeeeeeeeeeeeeeceeeeeeeseeeeeeeees 23 3 3 03001 wiring with CR10X and CR1000 c ccceeeeeeeeeeeeeeeeeeeeeeseneeees 25 3 4 HMP50 wiring with CR10X and CR1000 ccceeeeeeeeeeeeeeeeeeeteeesneeees 26 3 5 CS106 wiring with CR10X and CR1000 c ccceeeeeeeeeeeeeeeeeeeeeeeenneees 28 3 6 LI200X wiring with CR10X and CR1000
22. 3 21 Advanced Page in Conservative Rate Algorithm Mode eeeeeeeeeeeeee 54 3 22 S6VICeS PAJE ee eE eee eE cher ence ener exer cher esceenccencecheresceenecent 56 3 23 Oystem P gen is ta a en lst Ae Set EA EA TAa A AE EE e EA EE A EEA EEA EEA EEA EEA at 58 3 24 NLI 20 ica ee ale E E E ite T E EE 59 3 25 Network Switch 25 4 3 5ct casos cols oi ea tee eee tee eee 60 4 1 Functional Overview Greenbelt Weather Station GBC_WS 62 4 2 PC208W Main WINdOW 568 cack cc8 cet a ook ek ca as ee ee i a dk ek Cee 64 4 3 CSI Input Program File 2 2 2 2 se0 eeeeeee eee ee eee eee eee 68 4 4 Ediog DLD Program File need tala te test tain as nea ee tad 69 4 5 Edlog FSL Program Fil tsiccescconcedconeceseconreeesemeneuesemeneeeceece 70 4 6 ASCII Comma Separated Input File cece eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeees 71 42 7 ASCI Pnntable Input Files siciiecis let icieste lec e cee toca 71 4 8 Field Formatted ASCII Input File cccccceeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeenees 72 4 9 Functional Overview of DP_WGS ccccccccccceeeeeeeeeeeeeeeeeeaeeeeeeeeeeeeeeeeeaes 73 4 10 PC208W Main Window ccccecccccceeeeeeeeeeeeeeeeeeeeeeseeeeeeesseeeeeeessneeees 75 4 11 Transformer Utility CSI to CR1 Input Files 0 00 0 eeeeeeee 80 4 12 Transformer Utility CSI to CR1 Output Files 0 0 0 80 4 13 CRBasic CR1 Input Program File c eceseeeeeeeseeeeeeeeeeeeee
23. 3981 W 26 dBm Required E Field 43 46 dBu m Line loss 0 5 dB Antenna gain 10 dBi 7 85 dBd Antenna gain 10 dBi 7 85 dBd Line loss 0 5 dB Radiated power EIRP 3 55 W ERP 2 16 W Rx sensitivity 5 6234 pv 92 dBm Antenna height m 25 Undo Antenna height m jf ie Undo r Net Frequency MHz EESAT DP_WS Minimum 2400 Maximum 2483 5 Figure 6 9 Simulation Result of EESAT DPWS Radio link Modeling 155 The parameters showing up in the faint green shaded region at the top of the simulation result window are the output parameters Some of the important output parameters are extracted into the Table 6 4 given below for a quick view Table 6 4 Output parameters obtained after simulation PARAMETER EESAT DPWS Azimuth 1 4 181 4 Elevation angle 0 391 0 349 RSL 69 5 dBm Path Loss 114 5 dB Link Distance 4 74 km Fade margin 22 5 dB 6 4 Installation Installation of Nanostation2 at DP_WS For the installation of Nanostation2 in DP_WS a pole of about 9 m tall was installed near about 2 m DP_WS The pole is thin whose diameter is only about 2 inch S oit wouldbea veryr isky and di fficultt ask tom ount t he Nanostation2 i ft he pole w as erected v ertically pr iort om ounting S o a Nanostation2 was mounted at the top of the pole prior to erect it vertically An ethernet ca ble Cat 5 of ength a bout1 2m was run f rom D PWS _NS2to DP_WS A lightning arrestor was also installed atthe top of the pole and a g
24. 4 Figure 4 14 Normal View Comma Separated In Expand Tabs view also data ar e aligned i n co lumns witha tab separation This format is easy to read manually The Figure 4 15 below shows a collected data from DP_WS in Expand Tabs view a a EE S o 163 8 8 94 172 1 13 48 o 0 a a 1 121 7 7 51 173 1 10 46 0 02 13 08 21 52 2 71 2 7 294 172 1 10 13 0 13 08 22 4 3 27 87 6 815 170 6 8 79 0 13 16 d 22 67 4 6 457 4 967 164 8 7 779 0 13 05 23 96 I 5 1 204 4 449 161 5 5 766 a 12 48 26 13 i 0 161 4 928 162 5 6 102 0 12 45 z 27 96 7 0 025 4 883 164 4 5 934 0 12 44 28 77 8 0 4 41 162 7 5 599 0 12 42 29 45 9 0 4 443 162 6 5 431 a 12 41 30 67 4 Figure 4 15 Expand Tabs View Field Formatted 85 In H ex v iew dat a are showed up in he xadecimal f ormat The da ta collected from DP_WS is shown below in Figure 4 16 Lo Perret e aes o as F T i et ta caine r ay EAEnvironmental_Monitoring_and_Modeling DP_WS Data LoggerNet_data CR1000 File View Help BSC Rr Maras zu o ee 00000030 31 35 22 2C 22 43 50 55 3A 53 44 49 SF 57 54 48 15 CPU SDI_WIH a 00000040 52 SF 6D 6F 64 69 66 69 65 64 2E 43 52 31 22 2C R_modified CR1 00000050 22 35 32 31 39 22 2C 22 54 61 62 6C 65 31 22 OD 5219 Tablei 00000060 OA 22 54 49 4D 45 53 54 41 4D 50 22 2C 22 52 45 TIMESTAMP RE 00000070 43 4F 52 44 22 2C 22 53 55 4E SF 57 SF 6D 32 SF CORD SUN_W m2_ 00000080 41 7
25. 8 low differential input channels F or single ended measurements H or L either of them can be used as an independent channel to measure voltage with respect to analog ground of C R1000 So there are altogether 16 single ended channels starting sequentially from 1H 1L 2H 7L 8H 8L That means the H and Lt erminals of differential ch annel 1 a re single ended ch annels 1 and 2 respectively The terminals labeled V X1 V X2 and V X3 are switched excitation 20 outputs used to s upply pr ogrammable ex citation v oltages for r esistive br idge measurements P1 and P2 terminals are the pulse counter channels They are also called control ports There is one 5 V output used to power some external sensors that require 5 V power supply The switched 12 V outputs can be used to power se nsors and dev ices whichr equireanu nregulated12V For communication between CR1000 and its external devices such as PC printers and other co mpatible se rial and par allel devices the CR1000 wiring panel is incorporated with a 9 pin serial CS I O an RS 232 port and a parallel peripheral port The peripheral port here can be used to connect Ethernet devices such as NL115 Terminals labeled as C1 C2 C8 are the digital input output ports In addition to communicating via its RS 232 and CS I O ports the CR1000 can also communicate via the digital O COM ports 6 CR1000 Operating Systems The de fault operating sy stem oaded on C R1000 is PakBus Operating
26. A 4mrr is the surface area of sphere of radius r 1 Ir Ta i 1 i oS a ii Or r hr From i and ii we have J zl iii From iii it is clearly noticeable that when we double the distance then the signal strength will be reduced to one quarter of its original value Note that 122 the signal strength is watt per unit area But it s very easy to do this type of power calculation in logarithmic expression or in dB unit From iii changing in dB unit we have 1 dB orog 4 orog 10log I dB 6 0206 iv So itis seen that the signal strength at double distance is 6 dB less than the original strength Using Equation 5 2 Table 5 9 gi ven b elow sh ows the t heoretically calculated v alues of receive signal level RSL hereafter at various distances varying transmit powers for 2 4 GHz radio signal The calculations assumed the transmit and receive antenna are of 10 dBi antenna gain The calculations are done in logarithmic units The Eq 5 2 is used for the calculation of RSL Table 5 9 Tx power vs RSL for 2 4 GHZ Receive Signal Level RSL dBm Tx power dBm g tkm d 5km d 20km d 50km 105 75 113 03 104 75 112 03 101 75 109 03 96 75 104 03 81 75 89 03 56 75 64 03 6 75 14 03 123 RSL dBm Tx power dBm Figure 5 11 Tx Power Vs RSL for 2 4 GHz The above Figure 5 11 is the plot of Tx power Vs RSL referring to the data sho
27. Client TX power 26 dBm Data Rate 13 5 Mbps Rate Mode Quarter 5 MHz RSL 66 dBm E Administrator D Windows system32 cmd exe o x 129 120 9 238 TCP port KByte default local 9 9 237 port 55915 connected with 129 120 9 238 port 5001 Interi Transfer Bandwidth 0 0 1 81 MBytes 1 52 Mbits sec 10 80 MBytes 1 Mbits sec 20 0 MBytes 53 Mbits sec 30 0 MBytes 51 Mbits sec ly ly N Nnn MMA MARANA ww 40 0 MBytes 54 Mbits sec 50 0 60 0 MBytes _ 3 Mbits sec 0 0 60 1 nw mm Nan MBytes 56 Mbits sec Figure 8 12 Throughput Result of Experiment 8 2 1 2 Result Throughput 1 56 Mbits sec 210 Experiment 8 2 1 3 Parameters Settings Table 8 6 Throughput Expt 8 2 1 3 Parameters settings PARAMETERS EESAT_NS2 DPWS_NS2 Iperf mode Server Client Tx power 11 dBm Data Rate 54 Mbps Rate Mode Full 20 MHz RSL 89 dBm E Administrator D Windows system32 cmd exe lol x 120 9 237 port 62284 connected with 129 120 9 Transfer Bandwidth sec 544 K 446 Kbits sec 0 sec Ad Bytes ec 0 sec 0 sec sec 5 0 sec 112 4 sec 3 04 D Iperf iperf 1 7 0 win32 gt _ Figure 8 13 Throughput Result of Experiment 8 2 1 3 Result Throughput 422 Kbits sec 211 Experiment 8 2 1 4 Parameters Settings Table 8 7 Throughput Expt 8 2 1 4 Parameters settings PARAMETERS EESAT_NS2 DPWS_NS2 Iperf mode Server Client Tx power 26 dBm Data Rate 54 Mbps Rate Mode Full 20 MHz RSL 71 dBm
28. Ground Reflected Wave lonosphere a N Pi Sky wave ge N vo SS Po Surface wave it 7 N Pa ee ee N ne i ar T Tee N N Earth s curvature Tx Rx Figure 5 6 Radio Waves Surface Wave and Sky Wave 5 2 2 Phenomenon of Radio Wave Propagation Like light waves radio waves are also electromagnetic waves and hence they are affected by different kinds of phenomenon such as reflection refraction diffraction sca ttering and absorption Understanding t hee ffects of these phenomenon onthe radio waves propagation has many practical appl ications such as designing ar eliable m obile co mmunication sy stem r adio nav igation choosing appropriate frequencies for shortwave broadcastings etc Reflection When radio waves traveling in a m edium strike on any objects such as buildings trees or surfaces such as ground surface of sea etc they are bounced back tot he sa me medium withan alteration o f 18 O d egree phas e This phenomenon is called reflection The amount of reflection depends on reflecting material Smooth metal surfaces of g ood electrical co nductivity are very good examples of efficient reflectors of radio waves Earth s surface and sea surface are also the good examples of good radio wave reflectors 54 When radio waves are reflected from flat surfaces there occurs a phase shift in the reflected wave A fter reflection the waves are approximately 180 degrees out of phase from their initial phase rel
29. However the bandwidth remains constant for a given system A quick glance of some of the differences between bandwidth and throughput is given below in Table 8 1 86 Table 8 1 Bandwidth vs throughput BANDWIDTH THROUGHPUT How fast a device is actually sending data over a single communication channel How fast a device can send data over a single communication channel Independent of link distance Varies with link distance Bandwidth 2 Throughput Throughput lt Bandwidth Also called maximum throughput Also called consumed bandwidth Theoretical case Practical case 8 1 Throughput Test Experiments As already discussed earlier that the throughput is the main metric for the performance of any wired or wireless network h ence itis worth p erforming throughput ex periments with various kinds of devices and changing v arious parameter settings In this section some throughput test experiments for various kinds of devices and their result analyses are presented All the tests are carried out using an Iperf a separate throughput measuring software and a Network speed tool throughput measuring tool of Nanostation2 194 Iperf Introduction Iperf is a modern tool for network performance measurement written in C that can create TCP and User D atagram P rotocol UDP hereafter data streams and measure the throughput of the network that is carrying them Iperf has a client and server functionality and can measure the throughput be t
30. Pressure Sensor Available http Awww campbellsci com documents manuals cs106 pdf Campbell Scientific Inc August 17 L 200X Pyranometer Available http www campbellsci com documents manuals li200x pdf Campbell Scientific Inc Auguat 17 TE525 Tipping Bucket Rain Gage Available http Awww campbellsci com documents manuals te525 pdf Decagon Devices August 18 ECH2O Probe User s Manual Available http www decagon com soil_ moisture ec5 index php pg specs UMS GmbH Munchen August 18 74 T4e Pressure Transducer Tensiometer Available http www ums muc de en products tensiometer t4 html Power Sonic August 18 Rechargeable Sealed Lead Acid Battery PS 12120 Available http www powersonic com site doc prod 93 pdf Campbell Scientific Inc August 18 MSX10 MSX10R MSX20R MSX64R and MSX128R Solar Panels Available http www campbellsci com documents manuals retired msx pdf Campbell Scientific Inc August 18 SP10 SP10R SP20 and SP20R Solar Panels Available http www campbellsci com documents manuals sp10 10r 20 20r pdf 250 17 18 19 20 21 22 23 BP Solar August 18 BP SX 20 BP SX 30 20 Watt and 30 Watt Multicrystalline Photovoltaic Modules Available http www bp com liveassets bp_internet solar bp_solar_usa STAGING loc al_assets downloads_pdfs pq product_data_sheet_bp sx_120 01 4004 v 2_en pdf Campbell Scientific Inc August 19 PS72LA PS512M CH12R CH512R Power Su
31. Rate 13 5 Mbps Tx power 11 dBm Experiment 3 15 7 Mbits sec at Data Rate 54 Mbps Tx power 11 dBm Observing t he obt ained r esults of E xperiment 1a nd E xperiment3 a significant di fference i n t he t wot hroughput v alues canbe obse rved while changing data rate from 13 5 Mbps to 54 Mbps Hence it can easily be concluded that increasing data rate of Nanostation2 can result in greater throughout of the wireless link Experiment 4 15 2 Mbits sec at Data Rate 54 Mbps Tx power 26 dBm Another obse rvation similart o O bservation 1 can bea_ nalyzed by comparing the results of Experiment 3 and E xperiment 4 No improvement in throughput performance is seen even when the Tx power is increased from 1 1 dBm to 26 dBm The reason is same as explained in Observation 1 206 8 2 Throughput Measurement of EESAT_NS2 DPWS_NS2 Link In this section the throughput m easurement of t he radio link between EESAT_NS2 and DPWS_NS2 is discussed F or measuring the throughput for this link the various results obtained using two different network performance measuring t ools are analyzed and di scussed T he tools used are Iperf and network speed test tool of Nanostation2 and then those results are compared 129 120 9 226 2 4 GHz Wi Fi link 129 120 9 227 J lt ae z 7 ee ee 474km 2 gt H el oO O O 9 EESAT_NS2 DPWS_NS2 5 3 N Server Client PC Receiver Sender 129 120 9 238 129 120 9 237 Figure 8 10 Throughput Test Setup f
32. S 0 10 0 see 640 MBytes 1 07 Gbits s f108 10 0 15 0 sec 647 MBytes 1 09 Gbits s tiog 1L5 0 20 0 See 650 MBytes 1 09 Gbits s EEO Si 20 0 25 0 S66 645 MBytes 1 08 Gbits s LOS 25 0 30 0 see 643 MBytes 1 08 Gbits s 108 0 0 30 0 656 3 77 GBytes 1 08 Gbits s The above Table 8 2 is the output displayed by Iperf when a file of 3 77 Gbytes of size is transferred There are total of four columns The leftmost is the ID just indicating that the transmission is in uplink from client to server direction the next to ID is Interval displaying time interval as set by the user otherwise 10 sec is the default one Next to Interval the column Transfer contains the data values In addition the last one is Bandwidth representing the throughput value corresponding to the value displayed in Transfer column 196 Iperf Various Optional Arguments By default the Iperf client PC connects to the Iperf server PC on TCP port 5001 and the throughput displayed by Iperf is the throughput from client side to the server However there are various optional arguments applicable according to what is to be achieved For example if UDP throughput is to be m easured rather than TCP then the argument u can be used and similarly n can be used to transmit the data specifying the number of bits rather than the time argument t Some of the important Iperf arguments are listed below in Table 8 3 87 Table 8 3 Iperf arguments and their purposes A
33. Setting CS106 has 6 wires blue y ellow red bl ack green and clear used for pressure Vout signal ground AGND 12 V supply power ground GND control port or excitation channel and shield G respectively Its connections to CR10X and CR1000 dataloggers are shown below in Table 3 5 The CS106 can be operated in two modes shutdown and normal The mode can be selected by 27 configuring se tting of the j umper ocated underneath t he plastic cover oft he barometer When the jumper is not installed the CS106 is in shutdown mode and the datalogger turns it on and off with a control port or excitation channel When the jumper is installed the CS106 is in normal mode and powered continuously The picture of CS106 shown in Figure 3 5 ii is set to shutdown mode 9 Table 3 5 CS106 wiring with CR10X and CR1000 SINGLE ENDED DIFFERENTIAL CR10X CR1000 CR10X CR1000 Pressure Blue SE7 SE7 4H 4H Signal ground Yellow AG gt 4L 4L DESCRIPTION COLOR Power supply Red 12V 12V 12V 12V Power Ground Black G G G G Control or Control Control Control Control Excitation erm port port port port Shield Clear G i G a d Solar Radiation Sensor LI COR pyranometer LI2Z00X measures solar radiation Its operating temperature range is 40 to 65 C This sensor is suitable o nly f or day light spectrum so it can t be use d under vegetation or artificial light Itis calibrated only for daylight 400 nm to 1100 nm of light wavelengt
34. Then an ethernet cable Cat 5 unshielded twisted pair UTP cable was run from EESAT_NS2 mounted on the UV pole to the router in EESAT 337 one of the labs of EESAT building The cable is approximately 20 m long The Nanostation2 at EESAT is powered by an AC power at the terrace which was installed for the UV sensor 157 i EESAT_NS2 ii DPWS_NS2 Figure 6 10 Nanostations in EESAT and DP_WS 6 5 Configuration Settings After t he i nstallationi s done t hen an otheri mportant taskt od ois configuration settings A configuration setting is nothing but just a setting up of different parameters such as channel Tx power IP address etc In many cases ar adio l ink failure may occu r beca use of inappropriate oro utof date not updated co nfiguration se ttings far adio eq uipmentis configured with in appropriate parameters initially prior to antenna alignment the link may not be established successfully And even if the link is established with those settings there m ay be a chance ofits breakdown later o n when the unusual hostile environment such as heavy rain thick fog etc attacks on it 158 To setup configuration se ttings first a login access to Nanostations2 is needed The default IP address of Nanostation2 set from Ubiquity Networks is 192 168 1 20 After setting the PC s IP in the same sub domain 192 168 1 30 and entering default username and default password as ubnt and ubnt for both we ll be directed to the
35. These four steps are Select the datalogger choose how often and which sensors you wish to measure se lect intervals or trigger conditions on which to store data and what processing to perform on the raw measurements for final storage Short Cutis not suitable for co mplex appl ications t hat require m ore control ov er measurement pr ograms and pr ograms that r equire su pporting all of the functionality in Campbell Scientific dataloggers 26 CRBasic CRBasic is also a full featured datalogger program editor that has more co ntrol ov erm easurements Thist ooli s intended especially f or experienced datalogger programmers who need more flexibility and control over the datalogger operation which can t be achieved by using Short C ut More detail of CRBasic programming is described in Section 4 2 3 Split Split is a tool used to post process the collected data from dataloggers Split allows us to sort and combine data based on time and conditions splits large data files into more easily analyzed smaller files One can also process TT data using arithmetic operators math functions and time series functions and can create the output files compatible in excel formats 26 View View is a simple file viewer that provides a way to look at the collected data files These files are saved in various formats including files from mixed array and t able based dat aloggers View can open the following f ile t ypes DLD C SI P TI F
36. after the system deployment whenever it is necessary Ar adio mobile software usedin the systemisa so ftware used for predicting receive power 74 With the response of the software first of all it can be made sure if it is possible to establish the link and if the ink is possible pre assess of the link quality can also be done Theoretical calculation also gives the feasibility but this kind of software gives greater flexibility to check the response frequently while changing various parameters saving a lot of time With this software one has to input only a few parameters such as GPS coordinates of the sites T x power ant enna g ain ant ennas heights and t he operating frequency Then it outputs important result including many important parameters such as receive si gnal evel path oss ink distance az imuth elevation angle fade margin etc If the result o btained is not satisfactory the input parameters can easily be modified and see the changes in output quickly The following is the table showing the list of input parameters that are set before simulation The Table 6 3 shows the list of input parameters set for modeling and the Figure 6 9 shows the output result window of the simulation 154 Table 6 3 Input parameters for modeling ar euas O sase Edi View Swap r Transmitter EESAT_NS2 DPws_Ns2 Role Command Role Command Tx system name EESAT_NS2 Fix system name DPwS_NS2 Tx power 0
37. another system nearby having same antenna polarization and antenna facing to either Tx or Rx antenna of another this system So this may result in interference which in turns results in the degradation of the link quality If such a case is encountered then 178 the polarization of the system can be changed That way the system canbe prevented from being interfered by other system or interfering other system 7 2 3 Use of Various Diversity Techniques Radio link communication reliability for a g iven Tx power in a m ultipath environment can be increased through diversity techniques Diversity technique is a method for improving the reliability of a radio signal by using two or more communication channels with different characteristics These techniques play a vital r ole i n co mbating against fading in multipath f ading and co channel interference The idea behind diversity techniques is that if signals are received over multiple independent c hannels the argest si gnal signal hav ing hi ghest power can be se lected for use We ll discuss here the most important t hree diversity techniques though there are few more of them 76 Space Diversity This technique also called as antenna diversity talks about using multiple transmitting antennas and or multiple receiving antennas having same frequency channel and using the strongest received signal among other signals received at the receiver with various different signal strengths
38. at each site At the weather station data collection site and the base site where there is an internet access By linking these two sites via Nanostation2 link the data collected by weather station are sent to the system server An etherneti nterface allows connecting the dataloggerand t he Nanostation2 This interface allows the datalogger to communicate over a ocal network oradedi catedi nternetco nnectionv ia Transmission Control Protocol Internet Protocol TCP IP here after 1 1 3 Motivation Before the implementation of this new Wi Fi technology in the project GPRS network has been used and hence has been paid forits services to transmit the data to the CRI web server The plan was to directly transmit the data from the field to the server and reduce cost substantially In addition the typical data throughput of GPRS net work is around 15 40 K bps while i ts maximum datarateis 171 2 Kbps 2 4 This is m uch I ower t han t he Wi Fi technology which is being used now Wi Fi technology fits both in quality transmission and in cost effectiveness for the application that this thesis talks about With Wi Fi technology one ca n achieve greater data throughput and radio link stability therefore this technology is selected this for implementing the link at the DP_WS 1 4 Contribution to the Field Using the Wi Fi technology resource a high speed radio link has been established for transmitting the environmental data from the fie
39. compiled in E dlog compiler then a DLD f ile is created automatically which is sent to datalogger later A snapshot of a DLD file 68 formed after compilation of the above CSI program is shown in the Figure 4 4 below Final storage label FSL files are also automatically created when an Edlog program is compiled Z4 Edlog CRLOX E ENVIRO 1 SM_PRO 1 CR10X_SM EC5T4 DLD View Only zy Eile Edit Search Compile Display Options Window Help O x la x T_C 5 518M1 3 SM6 55 SMii 3 1 P92 1 6 2 15 gt CRIGR 5ECST4 DLD WIND_dir 3 gt TENSIO_4 ODE 1 SCAN RATE 5 RH WIND_max SM2 SM M12 FREQ_CS2 PER_CS1 day_of_yr hr Figure 4 4 Edlog DLD Program File P_mmHg RAIN_tot SM3 SM8 SM_CS1 PER_CS2 min SUN_W_m2 WIND_ave BATT_WIHR BATT_SM SM4 SM5 SM9 8M10 SM_CS2 FREQ_CS1 year tsec thr_min I a en TENSIO_2 TENSIO_3 4 3 38 z Figure 4 5is a sn apshoto fat ypical FSL file created a fter program compilation The FSL file lists the final storage labels for each data element 69 z Edlog CRLOX E ENVIRO 1 SM_PRO 1 CR1OX_SM ECS5T4 FSL View Only iol x ea File Edit Search Compile Display Options Window Help 8 x Final Storage Label File for ECST4 CSI a Date 11 15 2067 Time 20 24 38 Output_Table 5 66 Sec 1i L year L day_of_yr L hr_min L BATT_WIHR L BATT_SM L TC L RH L P_mmHg L 10 S
40. echo response replies It has another tool known as SNMP agent for monitoring and managing other network devices SNMP agent provides an interface for device monitoring using SNMP It allows network administrators to monitor network performance find and solve problems Services page is shown in Figure 3 22 21 55 Figure 3 22 Services Page Web servercanbes etas secure Hypertext T ransfer P rotocol Secure HTTPS mode by checking ont he box of use secure c onnection HTTPS default m ode is Hypertext T ransfer P rotocol HTTP hereafter Also in telnet server enable telnet server box can be checked on to enable telnet access to the Air OS device 21 56 f System This page contains various administrative opt ions This page al lows administrator t o cu stomize various configuration andr eboott he device Administrator can upgrade a new firmware in firmware version tool Also this page allows him to change host name setandch ange the administrator s username and password In configuration management tool there are two configurations Backup configuration and upload configuration One can click on download bu tton of backup configuration tool to download the current sy stem configuration file so thatso thatt he sy stem ca nb er estored usingt hed ownloaded sy stem configuration file when the sy stem crashes or something bad happened And also if you want to change the system configuration file then browse button of upload c
41. in signal strength of a transmitted signal resulting from the distance covered while travelling from Tx to Rx over a line of sight path It is directly dependent up on two factors the first is the distance between Tx and Rx and the second is the frequency of operation This means as you increase frequency the FSL will also increase accordingly and vice versa Similarly when the Tx Rx distance is increased the FSL also increases and vice versa The free space loss is given by the following formula 67 int FSL E REE TOT RETO EA TTL MONT REE T Tene See Equation 5 6 The Equation 5 7 given below is the logarithmic form of above Eq 5 6 FSL dB 20 log f 20log d 32 45 cece cece cece eee eeee eens enone Equation 5 7 where f frequency of the signal MHz d distance between Tx and Rx km 128 From the above equation of free space loss it can easily be shown that if we double the transmission distance d keeping ev erything el se frequency unchanged FSL will be 6 dB more For example for a distance of d let s rewrite the Equation 5 7 as FSL dB 20log d K v where K 32 45 20log f constant Now on do ubling the frequency and k eeping everything else unchanged we ll have FSL at distance 2d given by FSL dB 20log 2d K vi FSL dB 20log d K 201log 2 FSL dB 20log d K 6 0206 So from v replacing 20log d K by FSL dB we get FSL dB PSL GB 5 40 02
42. is selected by default as it is widely used by the subscriber stations while connecting to access point or using WDS The device will act as a transparent bridge forwarding all the network management and data packets from one network interface to another w ithout a ny intelligent r outing WLAN and LAN interfaces belong to the same network segment so there will be no network segmentation while broadcast domain will be the same 20 21 Network Mode Bridge NETWORK SETTINGS Bridge IP Address DHCP Static IP Address 192 168 1 20 Netmask 255 255 255 0 Gateway IP 192 168 1 1 Primary DNS IP 1 1 1 1 Secondary DNS IP i112 DHCP Fallback IP Spanning Tree Protocol E FIREWALL SETTINGS Enable Firewall Iv Configure Change Figure 3 19 Network Page in Bridge Mode 51 Network Mode Router gt WLAN NETWORK SETTINGS M Vv 192 168 100 5 bara 192 168 100 250 i aes SCAT A Figure 3 20 Network Page in Router Mode 52 Router operating mode can be c onfigured to perform routing and enable network segmentation nt his mode wireless clients will be o n different P subnet Router mode will block broadcasts while it is not transparent The Air OS powered d evice Nanostation2 her e ca na ctas Dynamic Host Co nfiguration Protocol DHCP server and us e network address translation feature which is widely used by access points Figure 3 20 shows typical configuration settings of
43. km for Nanostation2 of the radio equipment In addition one has to make sure that there is no high power line transmission pole or tower The site should not be chosen in a place where there is a high power line nearby because it interferes 140 the radio signal Also the antennas should be mounted in a tower or pole at least raising a minimum necessary height Because the EESAT building of UNT is tall enough LOS is clear from DP_WS and the link distance is only 4 74 km itis chosen for all those reasons Figure 6 2 shows a snapshot of Google map of a radio link between EESAT_NS2 and DPWS_NS2 P i sie DPWS NS2 i rae he S 3 poke iy ai ee g E McKinney St i ee 4 Figure 6 2 Google Map Snapshot of EESAT DP_WS Link Le 3 pi i TAN i A R ESSN Aiu Ti Also itis important to analyze the surroundings of the installed stations andthe LOS path to m ake s ure t hat t here is no any objects such a trees buildings bushes etc nearby not exactly in the LOS path but very close to it 141 which m ay obst ruct the signal that travels in az one called 1 Fresnel z one There s a detail discussion about Fresnel zone later in Section 7 2 4 But for now this section will focus on the fact that in order to get the good receive signal at the receiver any obstacle should neither be present in LOS path nor bein the surroundings nearby either of the stations Recording Some Data During field survey it is go
44. lect pr opagation model the first one is free space p ropagation model and the second is two ray propagation model Free space model is good for short transmission di stances whereas two ray m odel b est fits for onger distances The selection of the model should be done accordingly As already discussed that the two ray model doesn t give good prediction for sh orter distances and free space model does not give good prediction for longer distances Here s a big question How long distance is considered as long and how short is considered as short in this case 143 Well to answ ert he abov eq uestion a newt erm ca lled C ross Over distance is introduced It is defined as the value of the transmission distance de beyond w hich t wo ray m odel canbe applied for b etter pr ediction It si mply determines the switch between free space and two ray model 72 For the value of cross over distance let s consider path losses of both models _ And Path loss of free space model FSL ae 4 Path loss of two ray model 5 h h tr Now equating the path losses of both propagation models we get sd A h h _ 4ah h A a Now replacing d by de justto give the good notation fora cross over distance so the formula of cross over distance is now given by a rea a ieee tutes uae Oui oan ites buen eee eee ace Equation 6 1 where h height of the transmitting antenna h height of the receiving
45. mV Slow Range SE Channel Loc RH reek Mult Offset NOP WNE A O O RMH UE Limit the maximum relative humidity to 100 25 If X lt gt F P89 thse sez X Loc RH Ze 3 gt 3 1 0 0 F 232 r 28 i Ph r 29 las r 30 30 Then Do Z F P30 100 F 0 Exponent of 10 2 Z Loc RH End P95 Set control port 1 low to remove power from some sensors Do P86 yL Set Port 1 Low Read the battery voltage and store at BATT_W Batt Voltage P10 9 Loc BATT_W Store present date time and weather data in final storage Set Active Storage Area P80 01 Final Storage Area 1 Array ID Real Time P77 1110 Year Day Hour Minute midnight 0000 Sample P70 1 Reps 9 Loc BATT_W Sample P70 1 Reps 1 Loc TC Sample P70 1 Reps 2 Loc RH Sample P70 i Reps 3 Loc P_mmHg Sample P70 1 Reps 4 Loc SUN_W_m2 Sample P70 1 Reps 5 Loc WIND_ave Sample P70 1 Reps 233 2 6 Loc WIND_dir 39 Sample P70 Ie 1 Reps 250 iT Loc WIND_max 40 Sample P70 Lh E Reps 25 38 Loc RAIN_tot 41 End P95 At 2 10 a m synchronize weather logger time with time from soil moisture logger 42 If time is P92 Le 3 0 Minutes Seconds into a 2 1440 Interval same units as above 3 30 Then Do 43 SDI 12 Recorder P105 LO SDI 12 Address PAG Start Measurement aM0 3 68 Port 4 30 Loc
46. network page in router mode 21 d Advanced This page allows userto manage and handle advanced r outing and wireless settings There are three options for selecting rate algorithm which are as follows Optimistic conservative and exponentially weighted moving average EWMA Rate algorithm has avery crucial impact on performance of outdoor links which selects data packet transmission algorithm depending upon the rate mode selected in link setup page and the data transmission throughput 21 Optimistic algorithm always tends to achieve maximum throughput at the cost of sacrifice of noise immunity and robustness It is more prone to individual packet failure It starts with the highest possible rate and then decreases till the rate can be supported while periodically transmitting packets at higher rates and computing t he t ransmission t ime Conservative a Igorithmis less prone t o individual packet failure This algorithm looks carefully at number of successful and erroneous transmission retransmission ov er ace rtain p eriod of time and accordingly it steps down toal owerrate after co ntinuous failure of packet 53 transmission and steps up to higher rate aftera number of successful p acket transmissions Ito ffers the bes t st ability a nd r obustness but at the costo f degraded t hroughput EWMA a lIgorithm is a hy brid of above t wo m entioned algorithms So it is the compromise for most of the wireless networks Below is the snapshot
47. new technology called adaptive antenna polarization AAP has already been introduced in the market With the advent of this technology 119 the undesired fluctuation of polarization of the radio waves can be minimized and controlled to some extent 5 2 4 Radio Wave Propagation Models Radio wave propagation model is an empirical mathematical formulation for the characterization of radio wave propagation It describes mathematically how the radio waves propagate how they reach up to receiver which paths do they follow and etc And by knowing these factors one can set the parameters accordingly and pr edict out the receive power by using the appropriate radio wave pr opagation model There ar e basi cally t wo pr opagation models F ree space propagation model and two ray propagation model 61 Free Space Propagation Model The term free sp ace here is the sp ace or path be tween t ransmitting antenna Tx and receiving antenna Rx where there is supposed to be nothing obstacle and hence the radio wave can travel freely without being obstructed by any obst acle or i nfluenced by any phe nomena l ike r eflection r efraction diffraction etc In another word we can say free space propagation is a LOS propagation So it is only the T x Rx distance that influences the receive signal strength at the receiving site S atellite co mmunication sy stem and microwave LOS radio links undergo free space propagation The free sp ace pr
48. obvious that everyone wants a higher data rate But it can t be simply set as higher as we want because of other detrimental effects associated with that Data rate is inversely proportional to the RSL and hence the link distance as well In some cases if the data rate is set higher in order to have a greater speed then the link connection may be lost due to significant decrease of RSL which results the RSL go below the threshold value Also when data rate is increased the receiver sensitivity decreases So there should always be tradeoff between data rate and RSL as well as between data rate and Rx sensitivity For example the available data rates along with their corresponding Rx sensitivities are shown in Table 3 15 is shown in the Figure 7 4 below 65 70 75 Rx Sensitivity dBm 90 95 100 Data Rate Mbps Figure 7 4 Data Rate Vs Rx Sensitivity from Table 3 15 173 The graph of above Figure 7 4 tells us that when the datarateis set higher then the Rx sensitivity decreases and vice versa But having higher data rate is always desired and at the same time Rx sensitivity is also desired to be higher as well But both can t be achieved at the same time because they are mutually exclusive With higher Rx sensitivity the link distance can be extended and hence a good fade margin level canbe designed Also higher d ata r ate means higher speed of data transmission So it s very important to choose the data rate accord
49. of the system Interference from other systems which are already operating on same frequency is inevitable but of course could be minimized by appropriately setting different parameters of the system 221 Channel selection Since one of the nanostations is installed on the terrace of EESAT b uilding it m ay ca use interference t o or r eceive f rom o ther U NT wireless systems Therefore it is extremely important to select the channel which hasn t been used or least used Channel 4 turned out to be the best channel to be selected for the system after analyzed by a Wi Fi spectrum analyzing tool called AirView2 Data rate rate algorithm selection Depending upon the link quality condition the Nanosation2 has the capacity to select the rate mode controlled by Rate Algorithm automatically That means if the link quality is good then it selects the higher rate mode and switches to lower rate mode when itis poor 21 But of course higher rate mode can be set to have greater throughput but at the cost of probabilistic poor quality of link But as far as the link EESAT_NS2 DPWS_NS2 is concerned the rate mode can be set higher in order to get a greater t hroughput b ecause t he ink is pretty st able a nd r obust hav ing sufficient amount of fade margin Spectral width selection The spectral width selection can significantly affect the system throughput performance Higher spectral width results in a greater throughput and vice ve
50. of throughput Similarly it reports the results every 1 second and finally when the transfer is complete it shows the total aggregate throughput along with the total size of transferred file Here in this experiment the total size of file transferred is 111 MBytes in 10 sec with the aggregate throughput of 93 2 Mbits sec 199 8 1 2 Test for Wireless Router Fort he throughput test of awireless router a n Actiontec GI704WG router w hich use s Verizonh igh speedi nternet service isch osen A n experimental set up is shown in Figure 8 3 below GT704WG Actiontec Wireless Router 192 168 1 65 192 168 1 67 Client Sender Server Receiver Figure 8 3 Throughput Test Setup for Wireless Router As shown in Figure 8 3 an experiment was carried out to test the actual throughput of a wireless router being served by Verizon high speed internet A GT704WG wireless DSL m odem m anufactured by Actiontec is used for t his experiment The two PCs are in WLAN connection connected by the wireless router The W LAN IP ad dress set toP C1i s 192 168 1 65 andP C2 is 192 168 1 67 Iperf is running in Client mode in PC1 and Server mode in PC2 Now for the test the following command is entered in command prompt of PC2 iperf s Using the following command in PC1 a video file of size 111 MBytes is sent from PC1 to PC2 200 iperf c 192 168 1 67 F sg_video mpg i 1 t 60 E Administrator D Windows system32 cmd exe oO x D
51. oints in between EESAT_NS2 and DPWS_NS2 For this a formula for the radius of the 184 zone is needed Referring to the Figure 7 7 the radius of Fresnel zone is given by the following equation 79 i i isd RT A ee EE Cen A er Equation 7 1 d d where fn Fn The n Fresnel Zone radius m d distance of P from one end m d2 distance of P from the other end m wavelength of the transmitted signal in m For n 1 1 Fresnel zone Eq 7 1 becomes FC aos spss hae acllee oboe E enn ieee Equation 7 2 The cross section radius of the 1 Fresnel zone is maximum in the center of direct path AB Let s P be at the center of the pat AB then d d2 There is a simplified version of above formula for calculating the radius of the 1 Fresnel zone in the center of direct path given by rna Fe 17 32 T RE Brn ce EE e TEPER E PROT renee Equation 7 3 where D link distance km f frequency of the transmitted signal GHz 185 i Calculation Near EESAT_NS2 The equation Eq 7 2 gives the formula for the radius of 1 Fresnel zone at distance d from the Tx Here EESAT_NS2 is Tx The nearest possible obstacle that may lie within in the 1 Fresnel zone is at 5 m from the antenna We have di 5 m dit d2 4 74 km and d2 4 735 km f 2 422 GHz r F ery 0 7867 m 2 6 fi 3x108 x5x4735 2 422x10 x 4 74 10 Now 60 of 2 6 ft 1 56 ft Conclusion From the field survey at EESAT_NS2
52. pin male CS I O Size 1 6 x 0 9 x 3 0 Weight 45 4g 42 3 2 Radio Components Once the data collection is done in the field they need t o be carried to system server for analyzing and other necessary processing So a wireless link between the w eather st ation andi nternet so urce sh ould bee stablished To accomplish this task various components are used which are described in this section Nanostation2 ethernet interface and switch are the radio components used for establishing the link and transferring data 3 2 1 Nanostation2 Nanostation2 is a radio eq uipment m anufactured by U biquity Networks that operates in 2 4 GHz frequency The letter 2 is assigned just to indicate that the operating frequency of Nanostation2 is 2 4 GHz Actually there are also other pr oducts fromt he same manufacturer su chas Nanostation3 a nd Nanostation5 op erating in3G Hzand5G Hz frequencies respectively Nanostation2 is a cheap and reliable product of the manufacturer with a hi gh gain 4 antenna system advanced radio architecture and highly researched and developed firmware technology Supporting the standards IEEE 802 11 b g of Institute of Electrical and Electronics Engineers IEEE hereafter it is commonly used for es tablishing t he w ireless link between any t wor emotely ocated applications In the present work application it is used to link the DP_WS and the internet source in EESAT It has a built in directional antenna of 10 dBi
53. sg pc iperf 1 7 0 win32 gt iperf c 192 168 1 67 F sg_video mpg i 20 t 200 Client connecting to 192 168 1 67 TCP port 5001 TCP window size 8 00 KByte default local 192 1 65 port 54397 connected with 192 168 1 67 port 5001 Interval Transfer Bandwidth 0 0 20 0 19 5 MBytes 8 17 Mbits sec 20 0 40 0 19 2 MBytes 8 07 Mbits sec 40 0 60 0 sec 20 2 MBytes 8 47 Mbits sec 60 0 80 0 sec 21 5 MBytes 9 01 Mbits sec 80 0 100 0 sec 21 3 MBytes 8 93 Mbits sec 0 0 108 5 sec 111 MBytesc 8 57 Mbits sec D sg pc iperf 1 7 0 win32 gt _ Figure 8 4 Throughput Result of Wireless Router while Transferring Video File After entering the above command a time stamped output as shown in above Figure 8 4 was outputted Here in this experiment the total size of file transferred is 111 MBytes with the aggregate throughput of 8 57 Mbits sec for which the total transfer time of 108 5 sec 8 1 3 Test for Nanostation2 For testing the throughput of Nanostation2 there are two options Change in throughput can be observed one by varying the Tx power and another by varying data rate of Nanostation2 The following are the experiments carried out for the measurement of throughput of N anostation2 An ex perimental se tup is shown in Figure 8 5 201 192 168 1 31 192 168 1 35 4 m Wi Fi link f 9 lO 8 E E o ro Client Server PC1 PC2 Sender Receiver 2 192 168 1 10 192 168 1 11 Figure 8 5 Throughput Test Setup for Nanostation2 IP a ddresses
54. the el ectromagnetic spectrum 48 Electromagnetic waves are se lf propagating waves consisting of electric and magnetic field components which oscillate in phas e per pendicular to eac h ot her and al so perpendicular t o t he direction of energy propagation According to Maxwell s equation a time varying electric field generates a magnetic field and vice versa Therefore an oscillating electric field generates an oscillating magnetic field the magnetic field in turn generates and oscillating el ectric field a nd so on These osci llating f ields together form an electromagnetic wave 49 The Figure 5 4 50 shows a typical pictorial view of electromagnetic wave propagation in which blue and red waves denote magnetic and electric field respectively 107 4 Electric Magnetic field field Figure 5 4 Electromagnetic Wave Propagation Radio frequency spectrum ranges from 3 Hz 300 GHz which covers the lower bound ary o f extremely lo wf requency ELF and upper bo undary o f extremely high frequency EHF The Table 5 8 27 given below shows the entire electromagnetic spectrum highlighting microwave frequency range Within radio frequency range radio wave occurring in ultra high frequency UHF SHF and EHF bands is called microwave Microwave frequency highlighted in shaded green color ranging from 0 3 GHz to 300 GHz covers UHF SHF and EHF bands of electromagnetic spectrum however different sources use different boundaries fo
55. the frequency of the propagating radio signal Depending upon how t her adiosi gnals propagate they ar ecl assifiedi nto following categories direct waves ground reflected waves surface waves sky waves etc Direct and ground reflected waves are shown in Figure 5 5 whereas Figure 5 6 shows surface and sky waves Direct Waves Radio si gnals thatt ravel alonga straight path inaf ree space from transmitter T x to re ceiver Rx are called direct w aves or of ten called LOS signals These waves are always supposed to be away from any obstacles in between Tx and Rx so it is only the transmission distance that affects these waves Examples are satellite communication and microwave link point to point communication occurring in UHF SHF and EHF bands Ground Reflected Waves Radio si gnals that reach t he r eceiver af ter g etting r eflected from t he Earth s surface are called ground reflected w aves Even an LO S path has adequate Fresnel zone clearance it may still su ffer ad ditional path loss other than thatis occurred from straight transmission di stance T his is the case of multipath pr opagation ca used by g round r eflection Ins uch typeo f LOS propagation the two rays direct wave and ground reflected wave travel from Tx 110 to Rx reaching the receiver at different times with different amplitude and phase So depending u pon the r elative a mplitude and phase di fference o f the two propagated signals t he multipath pr opagat
56. used for the new system significantly So channel 3 is chosen for the system Figure 6 6 is a snapshot taken from output charts produced by AirView2 after Nanostation2 is connected OW Oa a9 AM Figure 6 7 EESAT 2 4 GHz Channel Study Nanostation2 NOT Connected 152 Gy Aiview Spectrum Analyzer sa se File View Help Device Ai View2 USB 0123456789 on COM4 budt 2009 02 23 14 12 43 CST range 2399 2485 MHz 500 0 KHz stege Total RF Frames 367 FPS 3 5 Reset Ai Data a arrel Usage View 2400 2 460 Figure 6 8 EESAT 2 4 GHz Channel Study Nanostation2 Connected From t he o utput ch art o f a bove F igure 6 7 when N anostation2 is not connected itis seen that the 2 4 GHz channel in DP_WS is relatively crowded than the one in DP_WS There is no single channel left unoccupied But it can be noticed that the Ch 3 and Ch 4 are relatively less crowded Hence either one of them should be chosen Since Ch 3 is selected in DP_WS channel 3 is chosen The Figure 6 8 is the snapshot t aken f rom the output charts produced by AirView2 after Nanostation2 is connected 153 6 3 3 Radio Link Modeling It is always good to design a radio link model when deploying a new radio link sy stem Basically the modeling t ells us aboutt he i mpacts o f ch anging different parameters on the system performance That way the behavior of the system can be understood in a better way and can take action accordingly before and
57. w e should not forget the fact that due to reflections there are a lot of radio waves not only one w ave travelling from Tx to Rx following different paths when a signal is transmitted Neither all the waves reach the receiver at the same time nor do they retain same phase Multiple signals arrive at the receiver at different times and different phase This causes either the addition or the subtraction of signal strength atthe r eceiver dependi ng upo n t heir r elative phase s f t wo signals reach the receiver at the same time with same phase then they will add up themselves which is called constructive interference and if they reach with out of phase phase difference of 180 then the signal strength will be subtracted which is called destructive interference When we have destructive interference then the signal received at the receiver is the weakened or attenuated or the faded one and since signal was weakened due to multiple paths that the signals follow hence signal loss due to this cause is known as multipath fading 52 64 69 Diffraction Loss The loss which occurs due to an encounter of radio wave signal with an Opaque object in its path is called diffraction loss Though the signal can diffract around the object aninevitable oss occurs anyway The ratio of the si gnal strength without obstacle to the signal strength with obstacle is referred to as diffraction loss 56 135 _ signal _ strength _ without _ obstacle a
58. wireless index php top Wikipedia August 22 Wi Fi Available http en wikipedia org wiki Wi fi Netgate August 23 Primer on WIFi Range Available http www netgate com info antennas tutorial_on 20_link_budgets pdf Wikipedia August 23 IEEE 802 11y 2008 Available http en wikipedia org wiki IEEE_802 11y 2008 Wikipedia August 23 IEEE 802 11 Available http en wikipedia org wiki 802 11 Wikipedia August 23 List of WLAN Channels Available http en wikipedia org wiki List_of_WLAN_channels 252 34 35 36 37 38 39 40 41 CISCO August 25 Channel Deployment Issues for 2 4 GHz 802 11 WLANs Available http www cisco com en US docs wireless technology channel deployment guide Channel pdf Federal Communications Commission September 28 Before the FEDERAL COMMUNICATIONS COMMISSION Washington D C 20554 Available http Awww sbe org FCCLiaison 03 108 SBE_all pdf Sensible Radio August 23 The sensible guide to 802 11y Available http www sensibleradio com 1 1y pdf WNN Wi Fi Net News August 23 5 GHz or Bust Available http wifinetnews com archives 2007 01 5_ghz_or_bust html Federal Communications Commission August 20 Before the Federal Communications Commission Washington D C 20554 Available http fjallfoss fec gov edocs_public attachmatch FCC 03 110A1 pdf Xirrus August 25 Wi Fi Best Practices 5 GHz vs 2 4GHz Spectrum Available http www aserdiv com p
59. 0 20 0 sec MBytes 15 0 Mbijts se 0 0 23 7 sec 42 9 MBytes 2 Mbits sec D Iperf iperf 1 7 0 win32 gt Figure 8 9 Throughput Result of Experiment 4 Observations of Above Experiments e Observation 1 Effect of change in Tx power on throughput The two obtained throughout results for two different Tx powers are as follows Experiment 1 4 94 Mbits sec at Tx power 11 dBm Data Rate 13 5 Mbps Experiment 2 4 99 Mbits sec at Tx power 26 dBm Data Rate 13 5 Mbps The results didn t showa significant di fference i n t he t wo t hroughput values The rationale behind this may be because the two nanostations are kept only at a distance of 4 mand 11 dBm of Tx power is quite enough to provide 205 sufficient amount of RSL 16 dBm which obviously affect the throughout That s why only asm allimprovementin RSL 1 dBm as well as in throughput is obtained even after a huge increment of Tx power i e from 11 dBm to 26 dBm But this is for sure that if the experiment is carried out with a longer link distance let s say about 5 km the results will show a significant difference in RSL as well as in throughput values Hence it can be concluded that increasing Tx power of Nanostation2 can definitely result in greater throughout of the wireless link e Observation 2 Effect of change in data rate on throughput The two obt ained throughout results for two different data rates are as follows Experiment 1 4 94 Mbits sec at Data
60. 00 ened oid eee eave ees eee Equation 5 8 So it can be concluded that the relationship between the path loss and the transmission di stance is such t hatt he path oss increases by 6 dB octave Similarly it can also be shown that the path loss increases by 20 dB decade which is equivalent to 6 dB octave 129 Path Loss Vs Distance for 2 4 GHz and 5 GHz Since the path loss is one of the major reasons that influences the receive power at the receiving site it s important to know at what conditions the path loss is greater and howitcan be minimized One of the parameters that di rectly influence the path loss is the frequency of operation So it s also important to know how the various frequency bands affectthe path loss The Table 5 10 below shows the theoretically calculated path loss values at various transmission distances for 2 4 GHz and 5 GHz frequency bands The table is calculated using the formula for path loss given by Equation 5 7 Table 5 10 Path loss vs transmission distance Transmission Path Loss FSL d B cistance Sa Hie Gere 5 GHz 130 O 2 4 GHz 5 GHz Path Loss dB 20 30 40 50 60 70 80 90 100 110 Transmission distance km Figure 5 13 Path Loss Vs Transmission Distance Above F igure 5 12isthe plotof path oss Vs transmission di stance referring to the Table 5 9 From the graph it is seen that the loss is increasing as the transmission distance increases but it is not lin
61. 1 29 Table 5 1 IEEE standards Comparison IEEE Standard 802 11a 802 11b 802 11g 802 11n Operating frequency 5 GHz 2 4 GHz 2 4 GHz 2 4 or 5 GHz Net Bit Rate max 54 Mbps 11 Mbps 54 Mbps 600 Mbps Throughput typical 27 Mbps 5 Mbps 22 Mbps 144 Mbps 91 Modulation CCK or CCK DSSS CCK DSSS OFDM Technique DSSS or OFDM or OFDM Channel Bandwidth 20MHz 22MHz 22 MHz ve 20 Range Indoor 35m 38 m 38 m 70m Release Date 1999 1999 2003 Not released 5 1 2 Advantages and Challenges of Wi Fi Advantages Wi Fi one of the WLAN technologies allows users to connect two or more computers or devices using D SSS or O FDM m odulation t echnique within a limited area without the need of using cables Because Wi Fi uses an unlicensed radio spectrum it has become very popular in houses offices universities and other places because of its mobility and ease of installation This feature allows users to move around freely and remain connected to the network These days most of the laptops come with built in Wi Fi card Wi Fi has a set of global standards Unlike cellular carriers Wi Fi us ers can work in different co untries around the world at all time Challenges Interference is the main challenge of Wi Fi system The use of Wi Fi is totally f ree w hich al lows any one t o use it anyw here without a ny r egulatory approval So this allows interference to occur very easily within Wi Fi users using the same frequency band In
62. 1 the instability of a radio link may result in its breakdown at the worst condition For a r adio link to be robust enough to encounter any unfavorable conditions and counteract accordingly it should be very well designed A well designed radio link is capable of facing any probable unpleasant circumstances and continues functioning well evenin that kind of adverse surroundings A robust design of a radio link includes both a detail excellent f ield survey and a powerful t echnical desi gn A properly pr epared design includes adjustment of antennas perfectly setting of all the parameters 169 values properly keeping ample fade margin especially design to counteract the effect o f interference ch oosing various diversity techniques to co unteract t he effect of multipath fading etc 7 2 1 Adjustment of Antennas Perfectly As discussed a ittle ear lieri n Section 7 1 about how t he i mproperly adjusted ant ennas can result ther adio link instability ande ven the lin k breakdown So it is very important to do the antenna alignment as perfectly as it could be done Antenna adjustment includes basically three things adjustment of antenna with respect to pole or boom of tower tilting of antenna and properly tightening of knots and bolts of antenna clamps or the screws used in tilting Adjustment of Antenna Position Relative to Pole This is simply to fix the antenna position onthe pole which is called antenna mounting This is very impo
63. 10 10 113 65 lt P dBm 67 65 dBm In general for radio link design theoretically calculating formula and many other related materials can be used to predict the result of the system a fter implementation B ut in addition to these there are various so ftware available which can predict the result in a q uick way with higher accuracy Using one of such software to design a model for a radio link will be discussed a little later in Section 6 3 3 6 3 2 Channel Selection The selection of channel significantly influences the system performance so in order to minimize interference from and t o other sy stems t he ch annel should be selected very carefully when deploying a new system As 2 4 GHz Wi Fi technology is widely used by many of us it s obvious that it is very crowded There are a total of 11 channels Ch 1 Ch 11 allowed to use in 2 4 GHz Wi Fi in US among which only 3 non overlapping channels are available 34 146 3 Non overlapping Channels Ch 1 Ch 6 Ch 11 v V V 2412 2417 2422 2427 2432 2437 2442 2447 2452 2457 2462 2483 JY 5 MHz 22 MHz ee _ _ 0 O 0 83 5 MHz Figure 6 3 US 2 4 GHz Channel System In US 2 4 GHz channel system there are 11 channels spanning over a total band of 83 5 MHz ranging 2 4 2 4835 GHz Each channel having 22 MHz of channel bandwidth is separated by 5M Hz of channel sp acing The ch annel allocation is as shown in Figure 6 3 Because the channels ar
64. 11b did despite of the fact that it offered a much higher data rate One of the main reasons behind this was that it operated in 5 97 GHz ISM band which made the chips more expensive Another reason is the shorter transmission range because of higher frequency However this band is very appropriate when high performance is required 29 32 33 37 38 Table 5 4 Channels allowed in 5 GHz band nenncl Center Frequency USA Europe Japan MHz 20 MHz 20 MHz 20 MHz 183 4915 No No No 184 4920 No No Yes 185 4925 No No No 187 4935 No No No 188 4940 No No Vos 189 4945 No No No 192 4960 No No Yes 196 4980 No No Yes 7 5035 No No No 8 5040 No No No 9 5045 No No No 11 5055 No No No 12 5060 No No No 16 5080 No No No 34 5170 No No No 36 5180 Yes Yes Yes 38 5190 No No No 40 5200 Yes Yes Yes 42 5210 No No No 44 5220 Yes Yes Vee 46 5230 No No No 48 5240 Yes Yes Vos 52 5260 Yes Yes Yes 56 5280 Yes Yes Yes 98 60 5300 Yes Yes Yes 64 5320 Yes Yes Yes 100 5500 Yes Yes Yes 104 5520 Yes Yes Yes 108 5540 Yes Yes Yes 112 5560 Yes Yes Yes 116 5580 Yes Yes Yes 120 5600 Yes Yes Yes 124 5620 Yes Yes Yes 128 5640 Yes Yes Yes 132 5660 Yes Yes Yes 136 5680 Yes Yes Yes 140 5700 Yes Yes Yes 149 5745 Yes No No 153 5765 Yes No No 157 5785 Yes No No 161 5805 Yes No No 165 5825 Yes No No 2 4 GHz Wi Fi Vs 5 GHz Wi Fi When comparing 2 4 GHz and 5 GHz Wi Fi the first few important things which are to be not iced are the throu
65. 11b was the first protocol of Wi Fi released in 1999 and became the first widely accepted wireless networking standard Transmitting at 11 M bps of data rate its operating frequency is 2 4 GHz At the meantime 802 11a was also developed w ith hi gher dat a r ate 54 Mbps which use s orthogonal f requency 90 division multiplexing OFDM her eafter modulation technique whereas 802 11b uses DSSS Direct sequence spread spectrum and CCK Complementary code keying Despite of its higher data rate 802 11a could not reach up to that height where 802 11b has already started to establish its market because of its 5 GHz operating frequency Because path loss at higher frequencies is huge 802 11a couldn t su fficiently ex tend i ts mobility range as 802 11 did Later i n 2003 802 11g came with higher data rate 54 Mbps which uses OFDM modulation technique and op erates in 2 4 G Hzf requency band Then m ost dual band 802 11a b products becamed ual band tri mode su pporting 802 11aan d 802 11b g in a single mobile adapter card or access point Now there is a new 802 11n protocol proposed recently which operates in 2 4 GHz and or 5 GHz at a speed of 600 Mbps This protocol is supposed to be released in S eptember 2009 This protocol has its maximum throughput of 144 Mbps This new 802 11n protocol us es three CCK D SSS and O FDM m odulation t echniques The comparison table of above discussed various IEEE 802 11 protocols is given below in Table 5
66. 5 0 4 296 7 4 0 686 4 590 8 62 82 1 felt nata ex ne a nce n ja aae a A a oe scan o er E ioe AQ 19 A 7 CA AC A CEC N l PR l Y a a N COC A CANA O 9 LE 49 Figure 4 6 ASCII Comma Separated Input File In ASCll printable format data are aligned in columns and preceded by a 2 digit I D indicating the array position This formatis easiest to read m anually and hence it is user friendly for viewing and analyzing the collected data But it is difficult to import into spreadsheets and other applications SPLIT can be use d for converting to other formats This data format is not reliable for data arrays of about 100 or more 25 01 0001 01 0001 01 0001 01 0001 01 0001 01 0001 01 0001 01 0001 02 2008 02 2008 02 2008 02 2008 02 2008 0242008 0242008 02 2008 03 0060 03 0060 03 0060 03 0060 03 0060 03 0060 03 0060 03 0060 0442045 04 2100 0442115 0442130 0442145 04 2200 0442215 0442230 05 11 55 05 11 55 05 11 54 05 11 53 05 11 52 05 11 52 05 11 51 05 11 50 06 12 09 06 12 08 06 12 07 06 12 07 06 12 06 06 12 06 06 12 05 06 12 05 Figure 4 7 ASCIll Printable Input File 07 12 6 07 11 79 07 10 71 07 9 76 07 9 56 07 9 91 07 9 51 07 8 76 08 83 4 08 86 4 08 88 3 08 89 7 08 88 9 08 88 3 08 88 6 08 915 Binary format is the most compact and hence the size of the file is much smaller than for the above mentioned A SCII bas ed files Because the bi nary format is not
67. 6 67 22 2C 22 57 53 SF 6D 70 68 SF 57 56 63 Avg WS_mph WVc 00000090 28 31 29 22 2C 22 57 53 SF 6D 70 68 SF 57 56 63 1 WS_mph WVc 000000A0 28 32 29 22 2C 22 57 53 SF 6D 70 68 SF 4D 61 78 2 WS_mph Max 000000B0 22 2C 22 52 41 49 4E SF 54 6F 74 SF 54 6F 74 22 RAIN Tot Tot 000000C0 2C 22 42 41 54 54 SF 57 74 68 72 22 2C 22 54 65 BATT Wthr Te le See Figure 4 16 Hex View Hexadecimal Format PC208W Vs LoggerNet Table 4 1 PC208W vs LoggerNet FEATURE PC208W LOGGERNET CR500 CR510 CR10 CR10X CR10 CR10X 21X CR23X CR7 Supported Campbell iver CR500 CR510 CR200 205 CR1000 Scientific dataloggers 21X CR7 CR23X CR3000 CR800 CR5000 CR9000 Programming language Edlog Edlog CRBasic DID esi FSi DED CSI FSL FAR LBR Supported file types PAR EBR PI sak a 2 TXT DAT LOG CR2 CR5 CR1 f a CR3 CR8 CR9 DAT Program file to run CSI DLD CR1 datalogger Output file type DAT DAT Program file creating options Short Cut Edlog CRBasic Pnom eur E deg Transformer Utility 86 4 2 4 Inter connection of Datalogger and Nanostation2 This section includes short term future work at DP_WS Configuring the CR1000 datalogger is needed for making it possible communicates via ethernet port using a serial cable that connects PC COM port to CR1000 RS 232 port IP address subnet mask and IP gateway could be entered under TCP IP tab which is displayed only when NL120 is con
68. ERS EESAT_NS2 DPWS_NS2 Iperf mode Server Client Tx power 26 dBm Data Rate 54 Mbps Rate Mode Quarter 5 MHz RSL 71 dBm G NanoStation Tools SpeedTest Windows Internet Explorer foo E http 129 120 9 227 speedtest cgi NETWORK SPEED TEST Select destination IP input manually 2 TEST RESULTS or specify manually 129 120 9 226 Rx 5 74 Mbps User ubnt T 3 57 Mbps Password ecce V Show advanced options Direction both a Duration jas Data amount bytes 4 w Done Internet Protected Mode Off R120 Figure 8 18 Throughput Result of Experiment 8 2 2 4 Result Throughput 3 57 Mbits sec 218 Observations and Analyses of Above Experiments The obtained throughout results for two different Tx powers and the two different data rates are summarized as follows Experiment 8 2 2 1 432 2 Kbits sec at Tx power 11 dBm Data Rate 13 5 Mbps Experiment 8 2 2 2 1 54 Mbits sec at Tx power 26 dBm Data Rate 13 5 Mbps Experiment 8 2 2 3 354 46 Kbits sec at Data Rate 54 Mbps Tx power 11 dBm Experiment 8 2 2 4 3 57 Mbits sec at Data Rate 54 Mbps Tx power 26 dBm e Observations All t he t hroughput r esults are ex actly sim ilaras ther esults o ft he experiments done with Iperf discussed in Section 8 2 1 The only tiny difference is the numeral values which differ in some magnitudes Table 8 12 given below shows the throughout r esults ob tained from usi ng perf and Nanostation2
69. Faint red line indicates the flow of power faint blue line is for indicating the flow of collected data and gray line indicates the line connecting the blocks of sensors and other devices connected to the datalogger To indicate that the flow of current is bidirectional both ended arrow headed faint red lines are used 63 Every 15m inutes data ar eco llected by dataloggers via se nsors connected to botht he st ations After th at the co llected dat ao f Weather datalogger are transferred to soil moisture datalogger via SDI 12 sensor All the data collected from both the dataloggers are stored in soil moisture datalogger data storage module Then the data are transmitted to CRI system server via SBC and GPRS modem 4 1 2 PC208W Datalogger Support Software for CR10X PC208W is a datalogger support so ftware for C R10X datalogger that facilitates programming communication and reliable exchange of data between a PC and a CR10X datalogger When a C R10X datalogger is connected with a PC208W installed PC then after clicking the software icon the main window will be ope ned whichis shown in F igure 4 2 given bel ow T here are 8 different buttons in P C208W toolbar having t heir di fferent u nique functions which are discussed below 25 08W 3 3 Datalogger Support Software PC208 loj x 8 r fea ee Mies Setup Connect Status Program Report View Stg Module Help Figure 4 2 PC208W Main Window e Setup
70. INTEGRATING ENVIRONMENTAL DATA ACQUISITION AND LOW COST WI FI DATA COMMUNICATION Sanjaya Gurung B E Thesis Prepared for the Degree of MASTER OF SCIENCE UNIVERSITY OF NORTH TEXAS December 2009 APPROVED Miguel F Acevedo Major Professor Xinrong Li Committee Member Shengli Fu Committee Member Murali Varanasi Chair of the Department of Electrical Engineering Costas Tsatsoulis Dean of the College of Engineering Michael Monticino Dean of the Robert B Toulouse School of Graduate Studies Gurung Sanjaya Integrating environmental data acquisition and low cost Wi Fi data communication Master of Science Electrical Engineering December 2009 259 pp 45 tables 101 illustrations references 90 titles This thesis describes environmental data collection and transmission from the field to a server using Wi Fi Also discussed are components radio wave propagation received power calculations and throughput tests Measured receive power resulted close to calculated and simulated values Throughput tests resulted satisfactory The thesis provides detailed systematic procedures for Wi Fi radio link setup and techniques to optimize the quality of a radio link Copyright 2009 by Sanjaya Gurung ACKNOWLEDGEMENTS First of all would like to take this opportunity to express my gratitude towards Dr Miguel F Acevedo for his full support and supervision throughout the two years time spent formy entire work I
71. PER_CS1 32 23 F X Loc SM_CS1 4 187 co Df S037 onl 6 335 C2 Pee AO C3 8 0 C4 9 0 C5 Convert probe2 fequency to period msec 10 Z 1 X P42 dL 26 X Loc FREQ _CS2 2 28 Z Loc PER_CS2 Insert period of probe2 into polynomial which calculates soil water content 11 Polynomial P55 dys ad Reps 2 28 X Loc PER_CS2 3 24 F X Loc SM_CS2 4 187 co Dt O37 el 62 4335 G2 he 20 G3 8 0 C4 9 0 C5 Take readings from all EC 5 probes and apply factory calibration equation For multiple EC 5 probes increase the Reps in the following instruction e 12 Excite Delay SE P4 AES Reps 22 5 2500 mV Slow Range See AL SE Channel 4 1 Excite all reps w Exchan 1 SS I Delay units 0 01 sec 6 2500 mV Excitation Pee asl Loc SM1 8 1 ult 9 0 Offset 238 take readings from four tensiometer 13 Ex Del Diff P8 Tsa Reps 2 4 250 mV Slow Range 3 4 DIFF Channel 4 1 Excite all reps w Exchan 1 Ssa Delay units 0 01 sec 6 2500 mV Excitation 7 43 Loc TENSIO g 4 22 12 lt 9 00 Offset Read the battery voltage and store at BATT_SM 14 Batt Voltage P10 1 10 Loc BATT_SM Read current date time and store in input storage starting at year 15 Time P18 Lees Store Year Day Hr Min Sec in 5 consecutive locations 22 0 Mod By 32 30 Lo
72. PWS_NS2 129 120 9 227 as Rx That means the tests result the two throughputs Tx and Rx throughputs where Tx throughput means the throughput from EESAT_NS2 to DPWS_NS2 and the RX throughput means the throughput from DPWS_NS2 to EESAT_NS2 A data size of 12 MBytes 12582912 Bytes is sent for 60 seconds from PC2 to PC1 and the throughput results are recorded 214 Experiment 8 2 2 1 Parameters Settings Table 8 8 Throughput Expt 8 2 2 1 Parameters settings PARAMETERS EESAT_NS2 DPWS_NS2 Iperf mode Server Client Tx power 11 dBm Data Rate 13 5 Mbps Rate Mode Quarter 5 MHz RSL 86 dBm Pp nancctationd Toot Speadient Wardous bnamet Explorer foe http 129 120 9 227 speedtest cgi NETWORK SPEED TEST Select destination IP input manualy amp TEST RESULTS or specify manually 129 120 9 226 Rx 1 02 Mbps User ubnt x 432 19 Kbps Password eo ee V Show advanced options Direction both Data amount 12582912 bytes 4 m Done Internet Protected Mode Off 120 v Figure 8 15 Throughput Result of Experiment 8 2 2 1 Result Throughput 432 19 Kbits sec 215 Experiment 8 2 2 2 Parameters Settings Table 8 9 Throughput Expt 8 2 2 2 Parameters settings PARAMETERS EESAT_NS2 DPWS_NS2 Iperf mode Server Client Tx power 26 dBm Data Rate 13 5 Mbps Rate Mode Quarter 5 MHz RSL 66 dBm 7 NanoStation Took SpeedTaat Windows itemet Beptorer
73. SL L OG C R2 C R5 C R1 C R3 C R8 C R9 This toolbar allows us to view or graph the data files which are originally saved in comma separated tabular field formatted or hexadecimal format 26 RTMC dev The Real time monitor and control R TMC hereafter so ftware provides the ability to create and run graphical screens to display real time data as Loggernet collects it from the dataloggers RTMC can combine data from m ultiple d ataloggers on a si ngle di splay RTMC has two oper ating modes Development RTMC Dev and Run Time RTMC RT Development mode allows users to create and edit a real time graphic display screen to display the collected form dataloggers Then the screen is built and saved as a file Different types of graphical components can be combined to create an attractive real time display 26 RTMC RT The real time graphic screen the screen which was created in RTMC D ev mode ca n be di splayed usi ng R TMC Run t ime S o once a project file has been created the display screen can be run without starting 78 the R TMC D ev mode window I n R TMC Run time m ode also the image displayed in the RTMC display screen can be printed 26 e PB graph PakBus PB Graph provides a visual representation of the devices depicting the connections in a Loggernet PakBus datalogger network and lets you edit PakBus device settings PakBus Graph window is divided into three parts the list of PakBus devices a graph
74. This toolbar allows you to configure devices including d ataloggers COM ports modems and other communication devices In this toolbar you 64 can also configure other se ttings such as data collection and sch eduled communications settings 25 Connect After successfully setting up your datalogger you can now access the d atalogger just by clickingon Connect button H ereinthis Connect window you can do many tasks such as setting data logger s clock sending programs from PC t o dat alogger co llecting dat a from storage m odule viewing and making graph measurements etc 25 Status Status toolbar is used for displaying information for all the dataloggers on the device map at one glance Also itis used for checking the status of data collection including scheduled calls errors retries and how much data was collected 25 Program Program toolbar is used for creating and editing the d ata ogger program w ith E DLOG edi ting t oolbar Ital so allows the use rs toi nsert comments in between the program codes 25 Report Report allows us to so rt a nd co mbine data bas ed o n t ime and conditions splits large data files into smaller files that can be analyzed more easily O ne ca n also perform data processing using arithmetic operators math f unctions and time series functions and ca n cr eate the output f iles compatible in excel formats 25 65 e View This toolbar allows us to view or graph the data file
75. Thus this scheme improves the quality and reliability of a wireless link Each receiving antenna experiences a different interference environment T hus if one ant enna is experiencing fading very badly it is often likely that another antenna may be receiving a better signal 77 That way the receiving antenna always get chance to receive the signal 179 having st ronger st rength andh ence m aintaining r eliable connection This is illustrated with the help of the Figure 7 5 given below Tx antenna Figure 7 6 Space Diversity Using Two Antennas in Receiver Let s take an example of two antennas used in receiver site separated by one wavelength of the frequency used as shown in above figure When the Tx antenna transmits then its signal reach at the receiver antennas Rx 1 and Rx 2 at di fferent si gnal st rengths S ometimes Rx 1 has_ the st rongest si gnal and sometimes Rx 2 and other times signals at both receivers are around the same level At all cases the strongest signal is chosen In this way effects of fading can be minimized using t wo phy sically se parated ant ennas The reliability can be even m ore i ncreased by i ncreasing t he num ber o f an tennas Multiple r adio 180 system is not implemented inthis work since there s no significant multipath fading in this case Frequency Diversity The use of multiple frequency channels to transmit a signal and choosing the strongest received signal among many other s
76. Tx to Rx For the Rx to receive t he si gnal transmitted by T x i tsh ould h ave t hes ame a ntenna polarization as Tx has So the polarization is set same for both the sites B ut there exists some cases when anot her sy stem ocated ne arby interferes the present system bec ause oft he sa me polarization S ot his may r esulti n interference which in turns results in the degradation of the link quality Disrupted Fresnel Zone In many LOS radio link applications Fresnel zone plays a very important role especially when the transmission distance is longer In this type of radio link a line of sight doesn t only mean that there is only one cl ear line of sight path between Tx and R x but there exists an ellipsoidal region called Fresnel zone around t he LOS p ath which sh ould al so be cl earo f any ob stacles If any 168 obstacles do exist in the region between Tx and Rx even if itis not in the direct LOS path the RSL may be degraded in a significant amount The Fresnel zone effectis due to ani nsufficient raised hei ght of t ransmitting an d or r eceiving antennas The Figure 7 1 75 shows the picture of Fresnel zone being disrupted even when the line of sight path is clear The trees lying within the Fresnel zone are being obstacles for the radio link given in the picture lt d Tx AY r we RX wt pe Figure 7 1 Disrupted Fresnel Zone 7 2 Remedies of Radio Link Instability As discussed above in Section 7
77. UN_W_m2 11 WIND_ave 12 WIND_dir 13 WIND_max 14 RAIN_tot 15 SMi L 16 SM2 L 17 SM3 L x 35 61 Fi Help Alt Letter to Select Menu WO WNnnhwonee ol oH 3 Figure 4 5 Edlog FSL Program File PC208W su pports three file formats for the co llected data which are ASCll coma separated ASCll printable and binary ASCll coma separated is the best selection for most applications where data values are separated by commas with no eading zeros and with each array ona newline This is the easiest format for importing into other software and can be viewed directly 25 70 lo File View Help SETAn a B of a me e 2 3 4 5 6 7 8 9 10 11 12 13 14 15 1 2008 60 2045 11 1 2008 60 2100 11 1 2008 60 2115 11 1 2008 60 2130 11 1 2008 60 2145 11 1 2008 60 2200 11 1 2008 60 2215 11 1 2008 60 2230 11 1 2008 60 2245 11 1 2008 60 2300 11 1 anna 0 9970 44 55 12 09 12 6 83 4 755 0 4 295 4 eee 55 12 08 11 79 86 4 755 0 4 295 4 4 0 686 1 590 6 64 81 54 12 07 10 71 68 3 755 0 4 295 4 4 0 686 1 590 6 65 47 1 53 12 07 9 76 69 7 755 0 4 295 4 4 0 686 2 590 6 66 81 1 52 12 06 9 56 68 9 755 0 4 296 7 4 0 686 2 590 7 63 48 1 52 12 06 9 91 66 3 755 0 4 296 7 4 0 686 3 590 7 61 48 1 51 12 05 9 51 68 6 755 0 4 296 7 4 0 686 3 590 8 62 682 1 5 12 05 8 76 91 5 755 0 4 296 7 4 0 686 4 590 8 60 15 13 49 12 04 8 49 93 3 75
78. a 9m tall pole Another Nanostation2 is installed atthe top of EESAT building of UNT and co nnected 11 with an internet source These two nanostations are installed facing each other so that they are in a line of sight LOS hereafter as shown in above Figure 2 4 Because the antenna inside the Nanostation2 is directional the direct wave is the one whichis of matter of concern and so both of the nanostations should be visible to each other or in other words there should not be any obstruction in the LOS path The more detailed description of Nanostation2 is given in Chapter 3 Once both of the nanostations are installed properly so that they lie along the LOS path the link could be established a fter pow ering them and configuring some settings The detailed description of the link set up is given in Chapter 6 12 CHAPTER 3 COMPONENTS OF ENVIRONMENTAL MONITORING SYSTEMS The environmental monitoring system consists of various components For the present work these all components fall under two different categories i weather station components and ii radio components This section contains a description of all of these components 3 1 Weather Station Components 3 1 1 Datalogger A datalogger is an electronic programmable instrument or d evice t hat records environmental data ov er time via its builtin or external sensors Itis generally powered by a lead acid rechargeable battery which is recharged by an AC adapter wherever av
79. able da ta o perating sy stem OS10XPB U A llows the C R10X to communicate w ith C R200 series dataloggers int he s amen etwork F inal storage data are stored in table format 5 Modbus operating system OS10XMB U Supports Modbus protocol allowing the CR10X to interface with supervisory control and data acquisition SCADA and MMI software packages Some earlier CR10X operating systems OS10X versions older than 1 3 included Modbus in the standard operating systems 5 OS10X ALERT operating sy stem Allows the CR10X to store and transmit data in the ALERT format flood warning system 5 SDI 12 SDI 12 is the acr onym for serial dat a interface at 1200 baud Iti s a standard communication protocol allowing connection of multiple sensors to an SDI 12 compatible datalogger SDI 12 sensors connect to control ports C1 C8 of CR10X It communicates using a cable containing 3 wires a 12 V line a ground line and a s erial data line 5 SDI 12 can also be used to connect two CR10X dataloggers for making it possible to communicate between the two dataloggers Once they are co nnected v ia S DI 12 i nterface t he pr ogram transfer d ata transfer etc between them is possible 17 Table 3 1 CR10X technical specifications FEATURE SPECIFICATION Voltage Current drain Analog inputs Digital Control ports Pulse Counter channel Communication port Data Storage Input Voltage range Switched voltage
80. ailable and by a solar panel Generally they are small and hence portable It has an internal memory for data storage and is based on a digital processor Dataloggers come in two types The first type of dataloggers needs aPC for activating dow nloading so ftware v iewing and a nalyzing t he collected data The second type of dataloggers has a local interface device and can be used as a stand alone device Between the above mentioned two types of dataloggers the first type has been used because these are appropriate for recording dat a automatically and c ontinuously f rom t he environment once deployed and activated in the field Campbell S cientific dataloggers of CR1 0X 13 and C R1000 s eries are use din this work Pictures oft ypical CR10X and CR1000 dataloggers are given below i CR10X ii CR1000 Figure 3 1 Dataloggers Used in the Field a CR10X Itis a fully programmable datalogger with a no n volatile memory widely used in meteorological research routine weather measurement applications and other kinds of network applications Upon activation it can be left unattended in the field to continuously record data over time It performs a high resolution 13 bit A D conversion A detachable ke yboard display that can be carried to multiple stations can be connected via its CS I O serial port Running any co mpatible datalogger support software on the PC connected to CR10X the program can be written in apr ogram editor called Edl
81. am very grateful to Dr Ermanno Pietrosemoli for the brilliant ideas and suggestions he shared with me during the Wi Fi link setup am very much indebted towards him also for his dedication and cooperation in the field work including installation of radio equipment during his visit to the University of North Texas in December 2008 would also like to thank my committee members Dr Xinrong Li and D r Shengli Fu for their in valuable suggestions and su pport which helped clear hurdles that encountered w hile doing my thesis work would also like to acknowledge my friend Jue Yang Ph D student of Department of Computer Science at University of North Texas who helped me in every way that a student or researcher can be helped wouldn t have been able to advance my thesis work ata good pace without his precious assistance would also like to thank my colleagues Chengyang Zhang Shu Chen Kalyan Pathapati Ma rtin Xu and Rakesh Rao fort heir kind c cooperation an d act ive involvement in radio installation at Discovery Park am thankful to Carlos Jerez Rajan Rijal Vivek Thapa Dr Bruce Hunter and Heinrich Goetz for their help during radio installation at Discovery Park and the EESAT building would al so like to thank my colleague Mr Kiran L amichhane for his extensive support in the network throughput measurement Last but not least would like to thank Dr Ram Vasudevan for helping me to prepare this thesis And finally in case
82. and and hence free to use anywhere and by anyone Because 2 4 93 GHz band is open for use globally without having to have license to operate the devices that use Wi Fi such as laptops can be used anywhere in the world i Wi Fi in 2 4 GHz The I EEE Standards that use 2 4 GHz band are 802 11b 802 11g and 802 11n The operating range for 2 4 GHz band is 2 4 2 4835 GHz 2400 2483 5 MHz This total of 83 5 MHz of Industrial scientific and medical ISM hereafter band is divided i nto 14 channels which are se parated by 5M Hz with the exception of 12 MHz separation between channel 13 and 14 The graphical representation of Wi Fi channels in 2 4 GHz band i s shown in Figure 5 1 As specified by 802 11 WLAN standards the channel bandwidth is 22 MHz But the channel separation for 2 4 GHz Wi Fi is only 5 M Hzalthough the specified standard is 25 MHz 32 35 3 non overlapping channels in US Channel System Pa a 2 3 4 5 6 7 8 9 10 11 12 13 14 2 412 2 417 2 422 2 427 2 432 2 437 2 442 2 447 2 452 2 457 2 462 2 467 2 472 2 484 22 MHz Figure 5 1 2 4 GHz Wi Fi Channels From the above Figure 5 1 it is clearly seen that the 14 channels occupy entire range of 802 11 Wi Fi in 2 4 GHz band The channel bandwidth is 22 MHz 94 and each channel is separated w ith i ts adjacent ch annel by 5M Hz e xcept channel 14 which is separated from channel 13 by 12 MHz The corresponding 14 frequencies are the central frequencies ranging fr
83. annel to measure voltage with respect to AG Analog Ground of CR10X So there are altogether 12 single ended channels starting sequentially from 1H 1L 2H 5L 6H 6L That means the H and L terminals of differential channel 1 are single ended channels 1 and 2 respectively The terminals labeled E1 E2 and E3 ar e sw itched ex citation ou tputs used to su pply pr ogrammable ex citation voltages for resistive bridge measurements The terminals P1 and P2 are the pulse co unter ch annels T erminals labeled as C1 C 2 C8 a re t he di gital input output ports They are also called control ports There are two 5 V outputs used t o pow er so me ex ternal se nsors that require 5 V pow er su pply The switched 12 V outputs can be used to power sensors and devices which require an unregulated 12 V There is one 9 pin serial 1 O port used for communication between CR10X and external devices such as PC printers and other compatible serial devices 5 CR10X Operating Systems The default op erating sy stem oaded on CR10Xis the Array Based Operating System unless another is specified at the time of ordering it Available operating systems for CR10X are e Mixed array oper atings ystem standard Contains 48m easurement instructions 52 processing math i nstructions an d2 0 pr ogramco ntrol instructions 5 16 Table data operating system OS10XTD U Allows the CR10X to store the final storage data in the form of a table 5 PakBus t
84. antenna A wavelength of the propagating signal Now choose t he r adio m odel for y our system as stated by t he t wo conditions given below 72 144 Condition I f d lt de then go for free space model Condition Il _ f d gt de then go for two ray model Checking for value of cross over distance for the link _ 4Aahh 4ah h f _ 42 25 9 2 422 x10 A c 3 0x 108 d 22 83km where h height of Tx antenna EESAT_NS2 25 m h height of Rx antenna DPWS_NS2 9 m f operating frequency 2 422 GHz 2 422x10 Hz c velocity of light 3 0x10 m sec From Table 6 1 we have d 4 74 km Comparing the two distances we have d lt de so free space propagation model is chosen to predict out the receive power Equation 5 2 gives us receive power prediction formula for free space model which is P dBm P dBm G dB G dB FSL dB where P Tx power of EESAT_NS2 26 dBm G Tx antenna gain of EESAT_NS2 10 dBi G Rx antenna gain of DPWS_NS2 10 dBi FSL Free Space Loss path loss between EESAT and DP_WS Adding transmission line loss in both Tx and Rx sites total loss is then given by Total _ Loss FSL dB L dB 145 Eq 5 7 gives the free space loss for free space model which is FSL dB 20 log f 20log d 32 45 20log 2 422 x 10 20log 4 74 32 45 113 65 dB Now putting the values of all the parameters in Equation 5 2 we get P dBm 26
85. ationship The radio waves that keep their phase relationships after reflection produce a stronger signal at the receiver and those that are received out of phase produce a w eaker signal or fading signal A reflection of very high frequency VHF and higher frequencies is important for radio transmission and for radar communication 54 55 113 Refraction When radio waves traveling in one medium enter into another medium the bending of waves occur which is known as refraction of radio waves After refraction the velocity of the propagation changes The velocity of radio waves is faster i n rarer medium t han in denser medium The b ending ca used by the refraction i s al ways t owards the denser medium wheret he v elocity o f propagation is lower One v ery important type of refraction of radio waves is atmospheric refraction where the radio waves get reflected back to the earth after entering into ionosphere as shown below in Figure 5 7 The reflection is actually caused by the refraction in the highly ionized layer of the atmosphere 54 56 lonosphere Earth s curvature TX Rx Figure 5 7 lonospheric Refraction Diffraction When a radio wave meets an object of size comparable or smaller than the wavelength of the wave it naturally tends to bend around the object due to which direction of part of wave energy is changed from the normal line of sight path This bending phenomenon of wave is called diffraction of radio wave Du
86. aves and their importance in radio wave propagation Available http www radio electronics com info propagation em_waves electromagnetic wave polarisation php Wikipedia September 1 Radio propagation model Available http en wikipedia org wiki Radio_propagation_model Wikipedia September 07 Friis transmission equation Available http en wikipedia org wiki Friis_transmission_equation Wikipedia September 07 Radio propagation Available http en wikipedia org wiki Radio_propagation Ryszard Struzak September 2 Radio wave propagation basics Available http wireless ictp it school_2006 lectures Struzak RadioPropBasics ebook pdf September 08 Two ray ground reflection model Available http www isi edu nsnam ns doc node218 html T S Rappaport Wireless Communications Principles and Practice 2nd ed Prentice Hall 1996 Wikipedia September 07 Free space path loss Available http en wikipedia org wiki Free_space_loss T Manabe and T Yoshida Rain attenuation characteristics on radio links NTT Adv Technol Corp Kanagawa pp 77 80 10 25 1995 1995 256 69 70 71 72 73 74 75 76 77 D Tummala Ed INDOOR PROPAGATION MODELING AT 2 4 GHZ FOR IEEE 802 11 NETWORKS Engineering Technology Denton University of North Texas p 4pp Pages Radio Electronics September 10 Radio Signal Path Loss Available http www radio electronics com info propagation path los
87. battery should be fully charged before deploying in the field Due to self discharge characteristics of this type of battery it is required to charge them after 6 9 months of storage otherwise permanent loss of capacity might occur as a result of sulfation 14 Some technical specifications of the battery PS 12120 are given below in Table 3 10 14 Table 3 10 Technical specifications of PS 12120 DESCRIPTION SPECIFICATIONS Name PS 12120 Nominal Voltage 12V Nominal Capacity 12 Ahr Max Discharge current lt 7 min 36 Amp Max short duration Discharge current lt 10 sec 120 Amp Approximate weight 3 86 kg Operating temperature range 20 C to 50 C 37 b Solar Panel Solar panel is one of the charging sources for rechargeable batteries It is an ess ential c harging so urce for those sy stems which are set upinanarea where source of electricity is not available Solar panel is a photovoltaic power source t hat converts solar ener gyi nto el ectrical ener gy In ot her w ords i t converts the sunlight into direct current Solar panel operates in both direct and diffuse light cloudy days but not at night MSX10 and SX 20 U solar panels are used in GBC Weather S tation and S P20 solar panel is usedin DP Weather Station Figure 3 12 below sh ows the pictures of different kinds of the so lar panels used in this project i MSX10 ii SX 20 U iii SP 20 Figure 3 12 Solar Panels Among the three solar panels s
88. be set higher lets say about 75 dBm at 3 Mbps That way even if the heavy rainfall occurs the RSL value still lies above the Rx sensitivity and the link remains connected Also if the obtained RSL of 50 dBm was not the maximum value as suggested by design one should try to attain that value and that way the system will have large fade margin For the present system Rx sensitivity 92 dBm 13 5 Mbps RSL 68 0 dBm Therefore fade margin 92 68 24 dBm 7 2 6 Use of Repeaters Arepeateris an electronic device used for the ex tension of radio link Repeaters are generally of two types Firstone known as passive repeater is used for rerouting the transmitted signal towards the receiver when LOS path is obstructed a nd the another which is usedto extendt hel ink distance by retransmitting the signal at a higher power level is known as active repeater 82 Use of a repeater for rerouting a LOS blocked signal Repeater Station 7 gt f 189 J Rx Figure 7 9 Use of a Passive Repeater for Rerouting a LOS Blocked Signal Even if the link distance is not far the transmitted signal may be blocked by a hug e obstacle as shown in above Figure 7 9 lying in between transmitter and receiver such as a giant hill a hug e tall building etc A repeater station is used in such case Since transmitter and receiver both are in LOS withthe repeater as shown in figure it is linked with both of them and hence can forward the transmi
89. bits sec 25 0 30 0 sec MBytes 98 Mbits sec 0 35 0 sec 7 MBytes 98 Mbits sec 0 40 0 sec MBytes 99 Mbits sec 0 45 0 sec MBytes 99 Mbits sec 0 50 0 sec MBytes 98 Mbits sec 0 55 0 sec MBytes 92 Mbits sec sec MBytes 94 Mbits sec sec MBytes 93 Mbits sec sec MBytes 97 Mbits sec sec 42 9 MBytes 94 Mbits sec o 0 0 0 0 0 0 0 0 0 0 0 ae 0 8 ANNNNNNNNNNNNNN 4 D Iperf iperf 1 7 0 win32 gt Figure 8 6 Throughput Result of Experiment 1 Experiment 2 Parameters Settings Tx power 26 dBm Data Rate 13 5 Mbps Rate Mode Quarter RSL 1 dBm 203 D Iperf iperf 1 7 0 win32 gt iperf c 192 168 1 11 F video3 wmv i Client connecting to 192 168 1 11 TCP port 5001 TCP window size E Administrator D Windows system32 cmd exe 8 00 KByte default 5 t 100 local 192 168 1 10 port 64510 connected with 192 168 1 11 port 5001 Bandwidth 99 01 90 01 OF 02 98 98 02 02 90 02 Interval 0 0 5 5 0 10 10 0 15 15 0 20 0 25 0 30 0 35 0 40 0 45 0 50 0 55 0 60 0 65 0 70 0 72 Wi okeololololololololelolelese sec sec sec ile sec sec sec sec sec sec sec sec sec sec sec Transfer ANNNNNNNNNNNNNN 98 MBytes 98 MBytes 92 MBytes 98 MBytes MBytes MBytes MBytes MBytes MBytes MBytes MBytes MBytes MBytes MBytes MBytes 4 99 Mbits sec D Iperf iperf 1 7 0 win32 gt 5 01 Mbits sec Mbits se
90. bridge wireless traffic between devices which are operating in access point mode 21 Network Advanced Services System BASIC WIRELESS SETTINGS Wireless Mode Station A 7 MAC Clone ESSID usent ae Select Lock to AP MAC i O Country Code United States of America l IEEE 802 11 Mode B G mixed Channel Spectrum Width 20mHz z Max Datarate 54Mbps Channel Shifting Disabled v Channel Scan List Output Power Data Rate Mbps Figure 3 17 Link Setup Page in Station Mode 49 In IEEE 802 11 mode there are 3 options B only B G mixed and G only If set to B only mode then the device can connect to an 802 11b network only Similarly if set to G only mode the device can connect to an 802 11g network only and if set to B G mixed mode then the device can connect to an 802 11b or 802 11g network Another feature called rate mode has also three options for selecting spectral width of the radio channel which are quarter half and full This page also allows us to configure maximum output power of the device 21 NanoStation2 UBIQUIT J NS2_EESAT 3 2422 MHz United States of Amd Figure 3 18 Link Setup Page in Access Point Mode 50 c Network This page allows user to configure network settings At the very top of this page operating network mode can be selected for the device either as bridge or router Bridge operating mode
91. broutine HElse k via P105 SDI 112 Recorder command This is done Elself a at 2 10 a m Endlf pi P106 Hit Put current date and time into input locations amp year day of yr hr min sec H RealTime P18Time a si year P18Time 1 I I day of yr P18Time 3 lt hr P18Time 4 S min P18Time 5 lt gt sec P18Time 6 EndSub gt gt gt gt ABS AAAY VAAN ARR ALAA VLAN PROGRAM SSSSSSSSSSSSSSSSLSLSSSSASS SS AcceptDataRecords ACOS ee ae AddPrecise Alias AM25T Scan 5 Sec 3 0 AND Read soil moisture probes every fifteen minutes AngleDegrees If TimeInToInterval 0 15 Min Then ArgosD ata Set port i high to power the probes Pricer a PortSet 1 1 ArgosSetup nee JE 2 ArgosTransmit m ASIII 7 Line 1 Col 1 E Environmental_Monitoring_and_Modeling SM_Programs Conver Insert Figure 4 13 CRBasic CR1 Input Program File 83 Figure 4 13 shows a snapshot of atypical CR1 program file written in CRBasic editor The programming language is similar to structured Beginner s All purpose Symbolic Instruction Code BASIC programming language in syntax program flow and logic The variables data tables and subroutines should be declared before they can be used and this can be accomplished by outing all the variables declarations and out put table definitions at the beginning Comments can be easily inserted in this programming language either by putting apostrophe mark at the beginning of the line containin
92. by implementing a low cost and high data rate unlicensed Wi Fi technology 1 2 Hardware Description Background This section includes a brief description of the hardware components used int his work Ana utomated station deployed inap articular ar ea collects environmental d ata A t ypical w eather st ation comprises various devices A datalogger is a programmable electronic device that records environmental data from various kinds of environmental sensors Its main functions are data collection and storage The datalogger used in this work is a product of Campbell Scientific Inc Sensors wired with the datalogger are the other important components of the station They measure environmental parameters such as air temperature air pressure w ind sp eed an d w ind d irection rainfall solarr adiation relative humidity soil moisture etc The remaining components relate to power supply battery solar panel charging regulator etc The datalogger battery and charging regulator arec ontained inside a weatherproof enclosure w hile allt he environmental sensors and solar panel remain outside of the enclosure In or derto transmit t he co llected da ta to thes erver a Wi Fi lin k is established using a N anostation2 which is a radio equipment manufactured by Ubiquity Networks and operates at 2 4 GHz It has a built in directional antenna which radiates the si gnalinline of sight LOS direction Two Nanostation2 devices were installed one
93. c year Multiply hour by 100 to move over two places and then add 7 minutes to hour to get four digit time format 16 Z X F P37 Le 32 X Loc hr 2 100 F 339 Z Loc hr_min Te Z X Y P33 Le 35 X Loc hr min 2333 Y Loc min 328 lt 35 Z Loc hr min 18 End P95 Wait one minute for collection of weather data to be completed and then receive weather data from weather logger 19 If time is P92 dese Minutes Seconds into a Zr L5 Interval same units as above B 30 Then Do 20 SDI 12 Recorder P105 1 0 SDI 12 Address 239 270 Start Measurement aM0 3 8 Port Aes T Loc TC 5 120 Mult 6 0 0 Offset 21 End P95 Wait an additional minute before storing all A data in final storage Any time discrepancies between the two loggers is easily accomodated 7 by this timing 22 If time is P92 th Se 2 Minutes Seconds into a 22 15 Interval same units as above 3 2 30 Then Do Store date time battery voltages weather data and soil moisture data in final storage 23 Do P86 Li LO Set Output Flag High Flag 0 24 Set Active Storage Area P80 1 004 Final Storage Area 1 2201 Array ID Store year day in final storage two reps for two consecutive locations 25 Sample P70 Tes2 Reps 2 30 Loc year Store hour minute in final storage 26 Sample P70 Reps 22 39 Loc hr_min m m Store all of the remaining data
94. c Mbits sec Mbits sec Mbits sec Mbits sec Mbits sec Mbits sec Mbits sec Mbits sec Mbits sec Mbits sec Mbits sec Mb ec KI Figure 8 7 Throughput Result of Experiment 2 Experiment 3 Parameters Settings Tx power 11 dBm Data Rate 54 Mbps Rate Mode Full RSL 22 dBm EA Administrator D Windows system32 cmd exe 0 x D Iperf iperf 1 7 0 win32 gt iperf c 192 168 1 11 F video3 wmv i 5 t 100 Client connecting to 192 168 1 11 TCP port 5001 TCP window size local 192 Interval 0 0 5 5 0 10 10 0 15 15 0 20 0 0 22 112 112 0 0 sec 0 sec 0 sec 9 sec 8 00 KByte default 1 10 port 65466 connected with 192 168 1 11 port 5001 Bandwidth Transfer 9 33 MBytes 9 38 MBytes 9 37 MBytes 9 41 MBytes 42 9 MBytes 15 6 Mbits sec 15 7 Mbits sec 15 7 Mbits sec Figure 8 8 Throughput Result of Experiment 3 204 Experiment 4 Parameters Settings Tx power 26 dBm Data Rate 54 Mbps Rate Mode Full RSL 4 dBm Administrator D Windows system32 cmd exe O x L D Iperf iperf 1 7 0 win32 gt iperf c 192 168 1 11 F video3 wmv i 5 t 100 Client connecting to 192 168 1 11 TCP port 5001 TCP window size 8 00 KByte default local 192 1 10 port 49709 connected with 192 168 1 11 port 5001 Interval Transfer Bandwidth 0 0 5 0 9 23 MBytes 15 5 Mbits sec 5 0 10 0 sec MBytes 1 Mbits sec 10 0 15 0 sec MBytes 4 Mbits sec 15
95. cceeeeeeeeeeeeeeeeeeeeeeeseneeees 29 3 7 TE525 wiring with CR10X and CR1000 ccccceeeeeeeceeeeeeeeeeeeeeeeseneeees 31 3 8 EC 5 wiring with CR10X and CR1000 s osccccscxdaveddordscxdcendsvedderdsnedeandenuteoebs 33 3 9 T4 wiring with CR10X and CR1000 ccceeeeeeeeeeeeeeeeeeeeeeeeeeeetsenneees 35 3 10 Technical specifications of PS 12120 ccccccccceeeeeeeeeeeeeeeeeeeeeseeeeeeeees 37 3 11 Technical specifications of solar panels eeeeeeeeeeeeeeeeeeeeeeeeeeeeees 39 3 12 Technical specifications of charging regulator ceeeeeeeeeeeeeeeeeeeeeeeee 41 3 13 Technical specifications Of SC32B cccccecccccceeeeeeeeeeeeeeeeeeaaeeeeeeeeeeees 42 3 14 Technical specifications of Nanostation2 ccccccccceeseeeeeeeeseeeeeeesnaeeeees 45 3 15 Data rate vs Rx SeNSIlViVinnc 22 t tenet n Rane k ee 46 3 16 Technical specifications Of NL120 cccccceccccceeeseeeeeeeeeeeeeeeeeesseeeeeeees 59 4 1 PC208W vs LoggerNet c ccc cceeseeseeteseedeeteseesesteserseeteseesesteneeteeeeess 86 5 1 IEEE standards CompaliSOMmsscs ao ccadisstnsecdsaesieln keine noe 91 5 2 2 4 GHz channel allocation 2 22 2 2 02 c ce esse eect 95 5 3 Channels allowed in 2 4 GHZ band eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee 96 5 4 Channels allowed in 5 GHZ band eee eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee 98 5 5 Comparison table 2 4 GH
96. ce to achieve better throughput of the system So 802 11g is selected as 802 11 IEEE mode in the present system Tx Power Settings As the RSL is directly pr oportional to Tx power itis always good to transmit at higher power to make the link robust but staying within the limitation 177 fixed by the country regulation In the link EESAT_NS2 to DPWS_NS2 since the link is 4 74 km not very near and the radiation is directional also the signal is transmitted atits highest power i e at 26 dBm Higher T x power is always desired b ecause o ft he fact t hat h igher t ransmitted power y ields ag reater throughput Because the beam radiated is directional and at a significant height it doesn t interfere other signal that much Rate Algorithm Settings Appropriate s election of Rate algorithm allows clients to drop to ower connection r ates data rates as signal q uality or R SL drops to maintain t he stability of the link In Nanostation2 there are three options for choosing rate algorithm Optimistic Conservative and EWMA Among the three Conservative rate algorithm is selected bec ause it allows to automatically switch bet ween higher and lower data rates depending upon the link quality condition and hence maintaining the stability of the link almost all the time 21 Antenna Polarization Settings As discussed a bove the R x ant enna sh ould have the same antenna polarization as Tx But there may be some cases when there is
97. channels do not overlap at all with each other So if a system is to be deployed in the radio environment where any two of the three non overlapping channels are occupied then the new system can use the third unused channel hence it won t interfere the o ther t wo ch annels O rt ruly sp eaking i t will hav e onl y av ery ittle interference which should be within tolerable region for all the system 176 However the channels in 2 4 GHz are too much cr owded and hence almost all of the channels are already occupied by at least one system In this case there s no question of non overlapping channel So the channel which has been least crowded should be chosen It will be even better if the channel having less strength could also be identified These can be achieved by using spectrum analyzer Using AirView2 as discussed in Section 6 3 2 the best channel for the system is identified as Ch 3 2422 MHz since this is relatively less crowded with less signal strengths IEEE 802 11 Mode Selection There are already a lot of Wi Fi devices available in today s market which are compatible for many IEEE standards For example the device that is easily found in today s marketi s compatible for 802 11g and also compatible f or 802 11b networks This is good for interoperability but not always especially for those applications where 802 11b is not needed and want to exclude it from the network in order to avoid unnecessary interference and hen
98. d DP_WS It also introduces radio link modeling software used to pre assess t he link quality and aW i Fi spectrum analyzer tool kn own as AirView2 for choosing the appropriate channel Chapter 7 describes various techniques for Wi Fi link quality optimization It also includes received power calculation comparison of results using different approaches sucha s theoretical ca Iculation radiom obile so ftware and Nanostation2 builtin tool Also discussedis the importance of Fresnel z one calculation for optimizing the link quality Chapter 8 deals with the various throughput tests using the Iperf tool and Nanostation2 Network Speed tool and analysis of their results This chapter also discusses some techniques to improve the throughput of the link established between DP_WS and EESAT Chapter 9 concludes the thesis with a summary and providing guidelines for possible future extensions of this work CHAPTER 2 WEATHER MONITORING SYSTEM OVERVIEW Work has been do nein two weather and so il monitoring systems GBC_WS and DP_WS Each one consists of an environmental data collecting electronic device known as datalogger environmental sensors pow ering equipments like bat tery charging device such as solar panel and ach arging regulator The datalogger pressure sensor battery and charging regulators are inside an enclosure mounted on a tripod Except the barometric pressure sensor all other environmental sensors and solar panels are outsid
99. d interoperability within its own few 5 GHz compatible devices H owever now there are many frequency compatible devices available in the market Table 5 5 Comparison table 2 4 GHz Wi Fi Vs 5 GHz Wi Fi FEATURE 2 4 GHz Wi Fi 5 GHz Wi Fi IEEE Standards 802 11b g n 802 11a n Frequency Operating Range 2 4 2 4835 GHz 5 15 5 825 GHz Data Rate max 54 Mbps 600 Mbps Throughput typ 27 Mbps 144 Mbps Range of Transmission Longer Shorter Interference Severe Less severe 100 No of Non Overlapping Channels 3 23 Deployment Cost Cheaper Expensive Channel Bandwidth 22 MHz 20 MHz Channel Spacing 5 MHz 20 MHz Entire band 83 5 MHz 675 MHz Security Fair Good Flexibility to deploy High Low Signal adsorption Low High Power Limits directional ant 30 dBm 30 dBm Power Limits omni directional ant 29 dBm 36 dBm 1 W Antenna gain limits omni directional ant 9 dBi 23 dBi Interoperability Higher Lower 5 1 4 Interference in 2 4 GHz ISM Band Any type of communication systems is subject to noise or interference It is impossible to remove them completely but of course could be tried to minimize them T alking about Wi Fi communication sy stem the more concerned is the interference rather than noise Interference has been one of the main issues as well as challenges in the field of wireless communication Depending upon t he type of sy stem interference degrades the per formance in a v arying deg ree Interference may occur when
100. dfs wireless 5GHZ 20vs 202 4GHz pdf J Geier August 25 2 4GHz vs 5GHz Deployment Considerations Available http www wi fiplanet com tutorials article php 156927 1 Wikipedia August 25 Electromagnetic interference at 2 4 GHz Available http en wikipedia org wiki Electromagnetic_interference_at_2 4_ GHz 253 42 43 44 45 46 47 48 49 50 R Pachhiano August 26 Bluetooth vs Wi Fi Technology Available http www smallbusinesscomputing com webmaster article php 3331421 Mobilecomms technology com August 25 CDMA IS 95 Code Division Multiple Access Digital Mobile Telephone Standard Available http www mobilecomms technology com projects cdma_is95 CDMA Development Group August 27 Welcome to the World of CDMA Available http Awww cdg org technology cdma_technology a_ross cdmarevolution as p Wikipedia August 27 GSM Available http en wikipedia org wiki Gsm R Eelctronics August 27 GPRS Technology Tutorial Available http www radio electronics com info cellulartelecomms gprs gprs_tutorial php Wireless Communications Solutions Septemebr 1 General Packet Radio Service GPRS Available http Awww nuntius com solutions22 html Wikipedia September 1 Radio waves Available http en wikipedia org wiki Radio_waves Wikipedia September 1 Maxwell s equations Available http en wikipedia org wiki Maxwell s_ equations August 27 The Electric amp Magnetic Wave a
101. e to this ch ange energy can be r eceived ar ound the edges of the object This means that a signal may be received from a transmitter even though it is shaded by large object between them The ratio of signal strengths without obstacle and with obstacle is referred to as diffraction loss 56 This phenomenon of radio wave is particularly noticeable i n ong w ave br oadcast t ransmissions This diffraction phenomenon is used to send radio signal over a mountain range when a LOS path is not available Diffraction depends on the relationship be tween the wavelength and the size of the obstacle Lower frequencies diffract ar ound arge sm ooth o bstacle such as hill more easily than higher frequencies do For example in many cases where V HF or hi gher frequencies Cc ommunicationi s not possible du e t o shadowing by hill itis still possible to communicate using upper portion of HF band 52 54 56 Scattering When radio waves traveling in a m edium strike on any objects such as particles bubbles droplets s urface roughness etc then t hey are diffused or deflected in all direction from their straight trajectory This phenomenon is called 115 scattering of radio waves Scattering occurs when incoming signal hits an object whose size is in the order of the wavelength of the signal or less 57 Scattered waves are produced by rough surfaces small objects or by other irregularities in the channel Absorption When radio waves
102. e dat alogger via T CP IP T hen the datalogger data can directly be acce ssible via HTTP web server T he picture shown above in Figure 4 17 is the connections of radio components datalogger Nanostation2 and switch with the ethernet interface NL120 that will be used in DP_WS 88 CHAPTER 5 WI FI TECHNOLOGY AND RADIO WAVE PROPAGATION THEORY In this chapter some ke yf acts about Wi Fi technology and its theory focusing on 2 4 GHz Wi Fi are discussed A br ief ev olution of Wi Fi is also discussed Some advantages of Wi Fi over ot her technologies are discussed particularly in this application As the communication medium of Wi Fi is the air its performance obviously is affected with the characteristics of radio environment that encompasses air and other obstacles such as tall buildings trees rain etc Aco mprehensive focus onthe theory of radio w ave pr opagation is also discussed in this chapter The discussion includes types and n ature of radio wave propagation radio signal interference in various channels especially in 2 4 and 5 GHz channels hostile nature of radio environment and its influences in Wi Fi operating frequencies and etc 5 1 Wi Fi Technology Introduction Wi Fiis oneo ft hel atest andw idely used unlicensed wireless technologies certified under EEE 80 2 11 S tandard int he world of wireless communication Its operating frequencies are 2 4 GHz 3 6 GHzand5G Hz which fall under Ultra high frequency UHF hereafte
103. e of width 22 MHz and separated by only 5 M Hz there exists overlapping of channels with their adjacent c hannels A s shownin above F igure 6 3 C h 1 leftmost r ed is overlapped with its adjacent channel Ch2 left green Also Ch 1 is overlapped with other channels Ch 3 left blue Ch 4 left yellow and Ch 5 left pink But of course Ch 2 is the channel having highest overlapping with Ch 1 Ch1 is not overlapped with Ch 6 and Ch 11 So they are called non overlapping channels 147 Of course there are other non overlapping channels such as Ch 1 and Ch 7 Ch 1 and Ch 8 Ch 1 and Ch 9 Ch 1 and Ch 10 Ch 1 and Ch 11 Ch 2 and Ch 7 and etc These are two non overlapping channels Belowis the table sh owing 11 channels and their respective overlapping and non overlapping channels 34 Table 6 2 Overlapping and non overlapping channels Non overlapping channel Channel Center Frequency Number MHz Overlapping channels Ch 1 Ch 3 Ch 4 Ch 5 Ch6 Ch 1 Ch 2 Ch 4 Ch 5 Ch 6 Ch 7 Ch 1 Ch 2 Ch 3 Ch 5 Ch 6 Ch 7 Ch 8 Ch 1 Ch 2 Ch 3 Ch 4 Ch 6 Ch 7 Ch 8 Ch 9 Ch 3 Ch 4 Ch 5 Ch 6 Ch 8 Ch 9 Ch 10 Ch 11 Ch 4 Ch 5 Ch 6 Ch 7 Ch 9 Ch 10 Ch 11 Ch 5 Ch 6 Ch 7 Ch 8 Ch 10 Ch 11 Ch 6 Ch 7 Ch 8 Ch 9 Ch 11 148 Because it is always desired to have more non overlapping channels it is certain to gofor 3 rather than2 non overlapping ch annels However t he channels in 2 4 GHz are to
104. e that the throughput is improved significantly when the data rate is increased from 13 5 Mbps to 54 Mbps keeping the Tx power constant at 26 dBm ii Effect of change in data rate on throughput at low Tx power 11 dBm There is no significant difference in the obtained throughput results of the experiments Experiment 8 2 1 1a nd E xperiment 8 2 1 3 evenw hent he experiments are carried out at two contrasting data rates one low and anot her high The rationale behind this is the fact that insufficient Tx power always results ave rylow RSL which results lower throughput As longas the RSLis not 213 obtained at sufficient am ount there s no use of increasing the data rate to get greater throughput e Observation 3 Effect of simultaneous change in Tx power and data rate on throughput From the results of the experiments Experiment 8 2 1 1 and Experiment 8 2 1 4 itis clearly noticeable that the throughput is significantly increased from 474 Kbps to 3 75 Mbps when the Tx power is increased from 11 dBm to 26 dBm and the data rate is increased from 13 5 Mbps to 54 Mbps simultaneously 8 2 2 Throughput Measurements Using Network Speed Test Tool In this section also at first the two tests at two different Tx powers One at 11dBmanda nother at 26 dB m are p erformed T hen the two tests at two different data rates One at 13 5 Mbps and another at 54 Mbps are performed All the tests are done setting EESAT_NS2 129 120 9 226 as Tx and D
105. e the enclosure 2 1 Environmental Monitoring System in Greenbelt Corridor GBC_WS The GBC_WS is located in the midst of the forest of Greenbelt Corridor State P ark situated at U S 380 Denton T X USA The U NT E COPLEX pr oject deployed the system in 2004 Figure 2 1 is the picture of GBC_WS taken on September 20 09 Them ain objectivew as tom onitor different kinds of environmental phenomena by measuring different weather parameters such as air temperature air pressure relative hu midity rainfall wind sp eed and w ind direction solar radiation etc and the soil moisture around the weather st ation Figure2 2 shows the functional block diagramo fG BC WS Figure 2 1 Greenbelt Weather Station GBC_WS RS 232 CSI O Soil Moisture Station Weather Station RS 232 GPRS link Internet Pe woes Se 900 1800 MHz CRI System Web Server Figure 2 2 Environmental Monitoring System in Greenbelt Corridor There are two systems in GBC_WS O ne st ation m easures weather parameters like air temperature relative humidity air pressure wind speed and direction so lar radiation and rainfall The other st ation is for measuring so il moisture and soil pressure around the station For the sake of simplicity they will be referred to as weather station and soil moisture station respectively There is a datalogger in each station for collecting and storing data The data are collected at an interval of 15 minu
106. e when t he w eather st ation i s installed in an area such as desert forest etc where there s no electricity Battery is a power backup when there s no other power source to run the system The batteries used in this project are from Power Sonic There are various types of batteries available in the market Some batteries are non rechargeable some are rechargeable some are of low capacity some are of high capacity etc Selection of an appropriate battery type and capacity is also one of the important tasks in power system design perspective ve terminal ve terminal i PS 12120 ii Battery installation inside enclosure Figure 3 11 12 V 12 Ahr Sealed Lead Acid Rechargeable Battery A 12 V 7 Ahr and 12 V 12 Ahr sealed lead acid rechargeable batteries are chosen for the two stations in Greenbelt Corridor Weather Station A 12 V 7 Ahr battery of same kind is chosen for DP_WS A picture of a typical 12 V 12 Ahr 36 sealed lead acid rechargeable battery PS 12120 is shown in above Figure 3 11 It should be always connected to charging source through a charging regulator In this work battery is connected to solar panel through a charging regulator in every weather station So in the day time when there s sunlight it is charged by the solar panel and it supplies power to the system during whole night But of course it should be charged enough in the daytime in order to supply power for whole night The
107. ear The rate of increment of loss is higher in lower distances than in greater distances As the transmission distance goes on increasing the path loss tends to saturate Also it is seen that the path loss at every distance is relatively higher in 5 GHz than in 2 4 GHz For example the path losses for 2 4 and 5 GHz are 134 03 dB and 140 41 dB at 50 km So it can be inferred from the table and the graph that the path loss at 5 GHz is always every distance about 6 dB more than at 2 4 GHz The pink line denotes the 5 GHz line and blue the 2 4 GHz 131 Signal Attenuation The loss ofsi gnalst rength duet oat mospheric absorption during transmission as it propagates through a m edium is referred to as attenuation Attenuation does not include the FSL Attenuation is measured in dB or more precisely dB km During transmission the signal gets attenuated ex ponentially with t he di stance it traverses In so me applications especially applications requiring higher frequencies or in which signal has to travel through the medium where high absorption takes place it plays a vital role in the design perspective Attenuation is just a reciprocal of a system gain So it is given by the ratio of signal power at the transmitting end Pin to the power at receiving end Pout of a system Here Pin gt Pout Pin Attenuation Pout From definition attenuation is given by or A dB totog 2 E E E A eeeect Equation 5 9 out Attenuation is d
108. eeeeeee 125 5 13 Path Loss Vs Transmission DistanCe eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee 131 5 14 Attenuation Vs DistanCe c usccccc ucdeucccusceusdetaceuddeusceucdebacenddebdcenccebdceuddcetdee 133 6 1 BESANT DP WS rerien iea L ttre es ance ences A AAEL Et 137 6 2 Google Map Snapshot of EESAT DP_WS Link aassssssssseeesennnrreereeennnnnn 141 6 3 US 2 4 GHz Channel System cc cceeccccceeececeeeeeesseeeeeeeeeeeeeeessseeeeeeees 147 6 4 AirView2 A 2 4 GHz Wi Fi Spectrum Analyzer 149 Xiv 6 5 DP_WS 2 4 GHz Channel Study Nanostation2 NOT Connected 151 6 6 DP_WS 2 4 GHz Channel Study Nanostation2 Connected 151 6 7 EESAT 2 4 GHz Channel Study Nanostation2 NOT Connected 152 6 8 EESAT 2 4 GHz Channel Study Nanostation2 Connected 153 6 9 Simulation Result of EESAT DPWS Radio link Modeling 0 155 6 10 Nanostations in EESAT and DP_WS cccccceceeeeeeeeeeeeeeeeeeeeneeeeeeees 158 6 11 Antenna Radiation Pattern cee eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee 162 6 12 Snapshot of DPWS_NS2 Main Page ccccceeeeeeeeeeeeeeeeeeeeeeeeeeeeeeees 163 7 1 Disrupted Fresnel Zone cccccccccseeeeseeeeeeeeeeeeeeeasseeeeeeeeeeeeeaassseeeeeeess 169 7 2 Waste of Energy Due to Improper Antenna Adjustment 05 170 7 3 Vertical Tilting of Antenna 00000 eee ee eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeteeeeeee
109. eeeeeeeee 171 7 4 Data Rate Vs Rx Sensitivity from Table 3 15 00 eeeeeeeeeeeeeeeeeeeeeeee 173 7 5 A 2 4 GHz North American Channel System cecceeeeeseeeeeeeeeeeees 176 7 6 Space Diversity Using Two Antennas in Receiver ccccseeeeeeeeeeeees 180 TI AE PESIE ZONG eh ices es tret eae aches eres has ea 183 7 8 Fresnel Zone being Obstructed in Various WaYS eeeeeeeeeeeeeeeeeeeeee 184 7 9 Use of a Passive Repeater for Rerouting a LOS Blocked Signal 190 7 10 Use of an Active Repeater to Retransmit the Weakened Signal 190 8 1 Throughput Test Setup for Cat5 Cable 00 cc cceeeeeeeeeeeeeeeeeeeeeeeeeeeeeeees 198 8 2 Throughput Result of Cat5 while Transferring Video File 199 8 3 Throughput Test Setup for Wireless Router 0 ceeeeeeeeeeeeeeeeeeeeeees 200 8 4 Throughput Result of Wireless Router while Transferring Video File 201 XV 8 5 Throughput Test Setup for Nanostation2 cccececeeeeeeeeeeeeeeeeeeeeeeeees 202 8 6 Throughput Result of Experiment 1 ccccccsseseeeseeeeeeeeeeeeeeesseeeeeeees 203 8 7 Throughput Result of Experiment 2 ccccccccseeeeeeeeeeeeeeeeeeeeeeeeeeeeeeees 204 8 8 Throughput Result of Experiment 3 ccccccccceeeeeeeeeeeeeeeeeeeeeeeeeeeeeeees 204 8 9 Throughput Result of Experiment 4 cccccccseeeeeeeeeeeeeeeeeeeeeeeeeeeeeeees 205 8 10 Through
110. eeeneeseeenteestoeeeeseeenceeacese 158 6 5 1 EESAT INS2 Setting S 5 0cc ccneercintescindeneisetesaisdiseeisdasaceeeeds 159 6 5 2 DPWS NS2 SeUINGS serene i eso og foes oe be ceca 160 6 6 Antenna Alignment te ee ane rr eee re ae Pr ane er ae Pe Pe 161 7 QUALITY OPTIMIZATION OF A WI FI RADIO LINK 2 eeeeeeeees 164 7 1 Causes of Radio Link Instability 2 0 0 0 cece cece eee eeeeeeeeeeeeeeeeeeees 165 7 2 Remedies of Radio Link Instability 02 0 0 nn 169 7 2 1 Adjustment of Antennas Perfectly eeeeeeeeeeeeeeeeees 170 7 2 2 Appropriate Settings of Various Parameters ccccceee 172 vii 7 2 3 Use of Various Diversity Techniques 0eeeeeeeeeeeeeeeeees 179 7 2 4 Mounting of Antennas at Sufficient Heights 0 eee 182 7 2 5 Design of Ample Fade Margin cceeeeeeeeeeeeeeeeeeeeeeeeeeeeeees 188 7 2 6 Use of Repeaters nucc cscdssienci eect eS 189 8 THROUGHPUT PERFORMANCE MEASUREMENT e00ee 192 8 1 Throughput Test Experiments cccccceccececeeseseeeeeeeeeeeeeeeeeeeees 194 8 1 1 Test for 100 Mbps Cat5 Cable cccccccccccseeeeeeeeeeeeeeeeeeees 198 8 1 2 Test for Wireless Router lt cccsceeeeeeeeteeteeeteeeeeeeseeeteeeeeeees 200 8 1 3 Test for Nanostation2 s eeeeeseeeeeeeeeeeeeeeseeeeeeeeeeeeeeeees 201 8 2 Throughput Measurement of EESAT_NS2 DPWS_NS2 Link 207 8
111. een shaded region to be 1 Fresnel zone we should have ACB AB NIRS Let s consider any point P on direct path AB then the blue dotted circular section of radius r is the 1 Fresnel zone at point P The cross section of the 1 Fresnel zone is circular Subsequent Fresnel zones are annular in cross section and concentric with the first 79 183 The following are the two pictures shown below in F igure 7 8 80 81 showing how the Fresnel zone can be disrupted even when there s a clear direct path b etween Tx an dR xant ennas Also even w hen t here s not hing for obstructing the signal in between Tx and Rx there s still a ch ance of Fresnel zone being disrupted due to earth s surface and insufficient antenna heights i p Figure 7 8 Fresnel Zone being Obstructed in Various Ways In both of the pictures of Figure 7 7 the exact direct paths are clear But the Fresnel zones are not clear in either case They are somewhat blocked by trees in first and by buildings in latter pictures In either cases the signal will get obstructed some amount and hence RSL will be decreased The reason behind the zone being uncleared is insufficient antenna heights So a g ood design tells us to raise the antenna heights up to that point where we ll have at least 60 of 1 Fresnel zone cleared Calculation for the Radii of 1 Fresnel Zone at Different Locations Here lets calculate the radii of 1 Fresnel zone at different p
112. ensor and Radiation Shield c0cee 26 3 6 CS106 and Its Jumper Setting 0 eee eee eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeees 27 3 7 LI200X Pyranomeplerstadactavlan tailed aul ae teu led taal ag teled taal a tele tau ats 29 3 8 TE525 Tipping Bucket Rain Gage cccccceccceceeeseeeeeeeeeeeeeeeeeesseeeeeeees 30 3 9 EC 5 Soil Moisture Sensor 2 2 2 c 2 cccececeeesececeeeeececeeeeececeeeeeeeceeeeneneees 32 3 10 TA TEMSIOMELC ss ccaketacs fase tece tots a Atal fae toes Nee cold Nese case 34 3 11 12 V 12 Ahr Sealed Lead Acid Rechargeable Battery cece 36 eS eal ATO fe e cS CC eR 38 3 13 Charging Regulator Circuit Diagram cccccceccseeeeeeeeeeeeeeeeeeaeeeeeeeeeeeess 40 3 14 SC32B Optically Isolated RS 232 Interface cceccceeeeeeeeeeeeeeeeeeeeeeees 42 Oe Or NANOS AUIONZ 27 j2 22 toy 2 top to into Noh ini Ant io inh inl Ant to An bal Ant ho Jans bid 44 3 16 Main Page in Station Mode c cceeececece eee eee eeeetcneeceeteneeeneeenecetcneneue 48 xii 3 17 Link Setup Page in Station Mode eee eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee 49 3 18 Link Setup Page in Access Point Mode eee eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee 50 3 19 Network Page in Bridge Mode 0 eee eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee 51 3 20 Network Page in Router Mode cece eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeees 52
113. ental Education Science and Technology Environmental Education Science and Technology Nanostation2 Extremely high frequency Extremely low frequency Extended Service Set Identification Exponentially weighted moving average xvii FCC FSL GBC_WS GPRS GPS GSM HF Hi Fi HTTP HTTPS ICMP IEEE ISM Kbps KBps LAN LF LOS MAC Mbps MBps Federal Communications Commission Free space loss Greenbelt Corridor Weather Station General packet radio service Global positioning system Global system for mobile communications High frequency High fidelity Hypertext Transfer Protocol Hypertext Transfer Protocol Secure Internet Control Message Protocol Institute of Electrical and Electronics Engineers Internet Protocol Industrial scientific and medical Kilo bits per second Kilo bytes per second Local area network Low frequency Line of sight Media access control Mega bits per second Mega bytes per second xviii NFC NHC OFDM OSI PSD RH RSL RTMC RTMC Dev RTMC RT RTS SBC SCADA SDI SE SHF SNMP SNR SSID SWAP TCP IP UDP Near field communication Natural Heritage Center Orthogonal frequency division multiplexing Open System Interconnection Power spectral density Relative humidity Receive signal level Real time monitor and control Real time monitor and control Development Real time monitor and control Run Time Request to send Single board c
114. eps w Exchan 2 ee Delay units 0 01 sec 6 2500 mV Excitation T 22 Loc WD_deg 8 0 142 ult 9 3 0 Offset Compute statistics and totals for some weather variables and store results into input storage locations so that they can later be sent to the moisture data logger If on a 15 minute interval then set the output flag high i to enable storing results in input storage area 8 If time is P92 des 0 Minutes Seconds into a 2 L5 Interval same units as above 3 10 Set Output Flag High Flag 0 Average all solar radiation readings and store the result A at Sun_W_m2 9 Set Active Storage Area P80 Les Input Storage Area 2 4 Loc SUN_W_m2 10 Average P71 Te 1 Reps 230 23 23 Loc W_m2 Compute the net wind vector and the average wind speed Store the average wind speed at WIND_ave and store the net wind vector direction at WIND_dir 11 Set Active Storage Area P80 1g 33 Input Storage Area 208 D Loc WIND_ave 12 Wind Vector P69 Ten L Reps 2 0 Samples per Sub Interval 3 O01 S l Polar 4 21 Wind Speed East Loc WS_mph 5 22 Wind Direction North Loc WD_deg Compute the maximum wind velocity and store at WIND_max 13 Set Active Storage Area P80 3 Input Storage Area Be F Loc WIND_max 14 Maximum P73 Le T Reps 2220 Value Only Se AL Loc WS_mph Total all rainfall for 15 minute interval and store at RAIN_tot
115. er systems nearby such as Wi Fi 28 33 41 5 1 5 Wi Fi Vs other WLAN Technologies Like Wi Fi there are other WLAN technologies such as GSM 900 1800 code division multiple access CDMA hereafter Bluetooth hiperLAN WiMAX UWB Zigbee wibree WRAN DECT and HomeRF S WAP universal mobile telecommunication system UMTS etc But here this thesis is focused on Wi Fi versus cellular technologies such as global system for mobile co mmunications GSM hereafter CDMA UMTS etc Depending upon the type of technologies used different system has their own mobility range and sp eed For ex ample cellular technologies such as GSM CDMA UMTS etc can cover a large distance whereas Wi Fi Bluetooth etc cover a very small range But the speed at what Wi Fi Bluetooth etc is relatively very high as compared to cellular technologies which have very low data transmission speed So there is a trade of between speed and mobility Figure 5 3 shows a graphical representation of Speed versus Mobility for different WLAN Technologies 29 42 103 Speed Mobility Figure 5 3 Speed Vs Mobility WLAN Technologies From the above figure it can be noticed that Wi Fi has the highest speed and lowest mobility range GSM has the lowest speed but highest mobility range and W iMAX is the t rade o ff o f those t wo t echnologies Other d issimilarities between Wi Fi and cellular technologies are operating frequency bands channel bandwidth number of cha
116. erating system Communication protocol Standard Temperature Range Dimension Weight 9 6 16 Vdc optimum 12 V 0 6 mA Sleep mode 1 16 mA w o RS 232 comm 17 28 mA w RS 232 comm 16 Single Ended 8 Differential 8 I Os C1 C8 or 4 RS 232 COM 2 P1 P2 1 CS I O 1 RS 232 1 parallel peripheral port Internal memory 2 Mbytes SRAM available up to 4 Mbytes 5 0 V one 12 V one 5 V and two 12 V 100 Hz 13 bits 3 VX1 VX2 VX3 CRBasic LoggerNet 3 4 x PC400 etc PakBus PakBus 25 C 50 C 9 4 x 4 0 x 2 4 2 1 Ibs 23 3 1 2 Environmental Sensors Environmental se nsors aret heel ectronic components to measure physical quantities of environment such as light intensity air temperature so il moisture etc and c onvert them i nto si gnals that ca n b e easi lyr ead by an observer There are many environmental sensors used for measuring different environmental phenomena but only some of them are used in this project and discussed here in this section a Wind Speed and Direction Sensor For measuring wind speed and wind direction 03001 RM Young Sentry is used A typical 03001 RM Young Sentry is shown in below Figure 3 4 It can be mounted directly to the mast or to the cross arm as shown in above figure It can measure the wind speed within the range of 0 112 mph and wind direction 360 mechanical a nd 355 electrical The t emperature r ange w ithin w hich i t ca n operate is 50 to
117. eteeeeeeeeeeee 83 xiii 4 14 Normal View Comma Separated ccccceeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeseeeaeeeeees 85 4 15 Expand Tabs View Field Formatted ccccsseeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeaes 85 4 16 Hex View Hexadecimal Format ccceeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeees 86 4 17 nter connections of Radio Equipments of DP_WS ceeeeeeeeeeeees 87 5 1 2 4 GHz Wie INGMANING Soc foe tng foe Send fone te te fd So to Se ood be bd ot ad dd od 94 5 2 A Pictorial View of 2 4 GHz Technology Applications eee 102 5 3 Speed Vs Mobility WLAN TeChnologies c eeeeeeeeeeeeeeeeeteeeeeeeeeeeeeee 104 5 4 Electromagnetic Wave Propagation ceeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee 108 5 5 Radio Waves Direct Wave and Ground Reflected Wave eee 112 5 6 Radio Waves Surface Wave and Sky Wave ccc eeeeeeeeeeeeeeeeeeeeeeeeeeeeeee 112 5 7 lonospheric Refraction wick teties oes a Gas sti aaa 114 5 8 Vertical Polarization 1 2 2 22 22 s cc0 sccecetestee steer 118 5 9 Horizontal Polarization 2ee taunt tang taal a tn Dante ann Bante ann al ne 118 5 10 Free Space Propagation Model ccccccccccceeeeeeeeeeeeeeeeeeeeeeseeeeeeees 121 5 11 Tx Power Vs RSL for 2 4 GHZ 2 c0 c ccccccrsescetececesecedecesedscecesegedectseesdsacceness 124 5 12 Two Ray Propagation MOdel cece eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee
118. for Edlog Transformer ut ility i s not i nstalled i n L oggernet w indow i nstead i tis installed in a s eparate window which can be opened from Windows start menu following the track Start Programs LoggerNet Utilities Transfomer 26 So you can t see this wizard in Loggernet main window shown in Figure 4 10 File Types For CR1000 datalogger toop erate fordat a collection a CR1000 compatible program file is needed to be sent to the datalogger which can be accomplished eitheri n Connectt oolbar or in EZSetup w izard T he onl y compatible program file that can be sent to the CR1000 datalogger is in CR1 format A CR1 file canbe created by 3different ways writing program in CRBasic editor generating program using Short Cut or converting from E dlog program code to CRBasic program code using Transformer Utility 26 81 Talking about the file formats that are supported by LoggerNet 3 4 1 it can support almost all the file types that are supported by PC208W suchas CSI DLD PTI FSL DAT etc and it supports other file types such as CR2 CR5 CR1 CR3 CR8 CR9 etc 26 Data Collection After su ccessful co nnection of a C R1000 datalogger with a P C having LoggerNet 3 4 1 installed data can be transferred to the PC from dat alogger storage module simply by clicking on Collect Now button in Connect toolbar in main w indow of LoggerNet 3 4 1 N ormally dat alogger is configured w ith a LoggerNet to collect the data f
119. forgot to mention the names of those people who helped me directly or indirectly n this work would like to thank all of them also TABLE OF CONTENTS Page ACKNOWLEDGEMENT Se aa a ae aana a aa ao aAa a aa E a A E a aii iii LIST OF TABLES cataason ce eee eine E see ae ae aon ix LIS TOR IELUST RATIONS 223 03 foe nd ood ned lend fet onde col fot od e e xii LIS TOP ACRONYMS r nck Cones E anes iuce thes Souucnecaseeahectoceeneeee ieee xvii Te INTRODU C TION 22 8 sc teoS cat erlcte a a e Aa E rA N A ETE 1 TAI ODjECtVES enaner EE E E E E EEA 2 1 2 Hardware Description BACKQrOUNG ccccecceeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeees 2 Ales a IVIL ALVOM Weisciet tontcned tonbccetdonbcced tendered er eeni tend cced devdened deubcceddeutecettenbecebeentens 4 1 4 Contribution to the Field ccccccccccecceeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeees 4 1 5 Organization of the TNe SIS 2 c ceccecceceeeeeeeneeneeeeneeeeeeeneeneeeeneneeeeneeenenes 5 2 WEATHER MONITORING SYSTEM OVERVIEW cceeeeeeeeeeeeees 7 2 1 Environmental Monitoring System in Greenbelt Corridor GBC_WS 7 2 2 Environmental Monitoring System in Discovery Park eseese 9 3 COMPONENTS OF ENVIRONMENTAL MONITORING SYSTEMS 13 3 1 Weather Station Components cccccceceeceeeeeeeeeeeeeeeeeeaaeeeeeeeeeeees 13 3 We MVD AOC SE atest eee eeehe eieae eheee eaae ekienak aaeh 13 3 1 2 Environmental Sensors c cce
120. ft ravel which is characteristics o f transverse wave On the basis of the direction in which the radio w aves move t he p olarization ca n be cl assified i nto t wo types inear polarization and circular or elliptical polarization 59 Linear Polarization The polarization of w avein which electric field is oriented ina single direction as the w ave t ravels i s called inear pol arization The w ave can be thought of as vibrating in one plane either up and down or side to side Linear polarization ca n be further cl assified i nto two t ypes which ar e v ertical and horizontal polarizations 58 e Vertical p olarization The pol arization where the E field component of t he radiated wave propagates ina plane perpendicular to the Earth s surface is called v ertical pol arization and sucha radiation i s said t o be v ertically polarized 59 117 e Horizontal p olarization The pol arization where t he E field c omponent propagates in a pl ane parallel tothe E arth s surface i s called horizontal polarization and such a radiation is said to be horizontally polarized 59 Electric field Electric field component Magnetic field Earth s surface A A Figure 5 8 Vertical Polarization Magnetic field Electric field component Electric field Earth s surface p E A Figure 5 9 Horizontal Polarization 118 e Circular or elliptical p olarization When radio waves propa
121. g comments or after program code 26 After compilation o f C RBasic program and having sentt o C R1000 datalogger data can be viewed in three different views using LoggerNet 3 4 1 These are Normal Comma s eparated Expand Tabs field formatted and Hex hexadecimal format The first two Normal and Expand Tabs views are exactly similar to previously discussed Comma separated and Field formatted file types of Figure 4 6 and Figure 4 8 of Section 4 1 3 except than that they don t bear headlines at the top whereas Loggernet facilitates data view of CR1 file with headlines which makes easier to read the collected data 26 The Figure 4 14 below shows a collected data from DP_WS in Normal view 84 IMESTAMP RECORD SUN E m2_Avg WS mph WVe 1 WS_mph We 2 WS mph Max RAL 16 30 00 0 163 8 8 94 172 1 13 48 0 0 0 0 0 143 9 0 165 1 a 16 45 00 1 121 7 7 51 173 1 10 46 8 24 5 21 52 449 6 3 82 22 4 450 3 47 4 3 21 22 67 481 6 11 22 34 23 96 515 7 3 21 1 2 1 0 02 13 0 17 00 00 2 71 2 7 294 172 1 10 13 0 13 08 23 0 13 16 2 2 3 17 15 00 3 27 87 6 815 170 6 8 79 3 17 30 00 4 6 457 4 967 164 8 7 779 0 13 05 22 17 45 00 5 1 204 4 449 161 5 5 766 0 12 48 21 12 26 13 530 4 0 16 00 00 6 0 161 4 928 162 5 6 102 0 12 45 20 32 27 96 537 0 0 18 15 00 7 0 025 4 883 164 4 5 934 0 12 44 19 85 28 77 540 0 0 16 30 00 8 0 4 41 162 7 5 599 0 12 42 19 51 29 45 539 3 0 0 16C 2008 11 19 AAT ears b 3 8 0 4 4
122. g of Antennas at Sufficient Heights As already discussed in Section 7 1 due to an uncleared Fresnel zone the signal may get degraded in a significant amount even there s a clear visual line of sight between Tx and Rx To better understand this let me introduce the term Fresnel zone Fresnel Zone Fresnel zone is the area around the visual line of sight that radio waves spread o uti nto after t hey eave t he ant enna forming al ong el lipsoid t hat stretches between the two Tx and R x antennas Receive signal strength and hence system performance not only depends on LOS signal alone butis also affected by the obstacles lying within the 1 Fresnel zone If there s an obstacle near the LO S path reflections from the ob stacle m ay ca use the reduction of power r eceived at t he r eceiver In or der t o av oid such obstacles and t heir detrimental effect on RSL a minimum of 60 of 1 Fresnel zone sh ould be cleared Such a cleared path can be treated as a clear free space path 56 79 182 The 1 Fresnel zone is such that the difference between the direct path and an indirect path that touches a single point on the border of the Fresnel zone is half the wavelength as shown in Figure 7 6 below 80 Figure 7 7 1 Fresnel Zone In the above figure AB is the direct path and ACB is indirect path that touches a single point C on the border of the Fresnel zone So according to the definition of 1 Fresnel zone in order the gr
123. gain An external ant enna can also be connected for onger t ransmission r ange The transmit power of 26 dBm max allows it to cover the range of 15 km The power 43 supply required for operation is 12 V 1 A with a potential of 4 W maximum power consumption It can transmit upto 54Mbps ofdatarateand 25M bps of throughput Maximum receiver sensitivity is 97 dBm The unit can be pow ered via the same Ethernet through which it is connected to other devices like PC router or SBC etc A picture of Nanostation2 is shown in different views in the below Figure 3 15 20 Front View Side View Back View Figure 3 15 Nanostation2 Because t he a ntennai nside the uni t is di rectional itsr adio si gnal propagates only in one direction from transmitter Tx to receiver Rx and this type of transmission is called LOS transmission Nanostation2 uses commonly used vertical and horizontal polarization but besides thatit also uses anew adaptive antenna polarity AAP technology which can improve the link quality This new AAP technology allows Nanostation2 software switch antenna polarities statically or dynamically It has a 3 dB horizontal beam width of 60 and vertical beam width of 30 20 44 Table 3 14 Technical specifications of Nanostation2 DESCRIPTION Wireless Operating frequency range IEEE Standard Processor Memory Networking interface Antenna gain Antenna polarity 3 dB Beamwidth Data Rate Throughput TCP IP R
124. gate electric field may rotate rightward or leftward in the direction of propagation This type of polarization is called circular or elliptical polarization Circular polarization can be thought of as a signal propagating from an antenna that is rotating 58 The choice of polarization may play a vital role in some applications This means thereis performance di fference o ft ype of pol arizationont ype of applications For example in some applications horizontal polarization best suits while vertical polarization may be t he best choice in another application While medium w ave br oadcast s tations generally use v ertical p olarization b ecause ground wave propagation is considerably better using vertical polarization rather than using horizontal polarization horizontal polarization proves to be best fit for long distance communications where ionospheric reflections take place Circular polarization is appropriate choice in satellite communications 60 Polarization is very important factor in radio wave communication In order to get the good reception at the receiver site it is always needed to match the polarization of transmitting and receiving antennas In many applications one the signalhas been t ransmitted p olarization will r emain nor mally t he sa me However polarization can be slightly changed by the influence of reflections from the objects in the path Reflections from ionosphere can cause a greater change in the polarization A
125. ghput mobility interference etc Since 5 GHz is greater than 2 4 GHz band throughput is higher in 5 GHz band The 2 4 GHz channel is widely used and also it has only 3 non overlapping channels and hence itis crowded too much So the interference is quite severe in 2 4 GHz channel The case of 5 GHz channel is different many users do not use it and it has 23 non overlapping channels So even if there is interference in the channel selected for use then one can move to different non overlapping channel to 99 avoid or at least minimize the interference Talking about the mobility generally higher f requency app lication has relatively lower m obility t han t he sm aller frequency appl ication has T his is because 5G Hz signal coversa_ smaller transmission range than 2 4 GHz signal does The rationale behind this is the higher the frequency the lower is the transmission range because of the fact that Free space loss FSL hereafter is greater in higher frequencies So 2 4 GHz offers better mobility 33 37 39 40 Beside above mentioned aspects t here ar em any other comparison criteria between them One of them is the cost of operation which is relatively higher in 5 G Hz band b ecause eq uipments of higher frequency 5 GHz are costlier than of 2 4 GHz The 2 4 GHz band is more widely used than the 5 GHz band This allows 2 4 GHz compatible devices to interoperate with each other and other co mpatible dev ices while 5G Hz has a very limite
126. h Current consumption of LI200X solar radiation sensor is proportional to the incoming solar radiation A LI200X should be mounted such that itis never shaded by anything like tower tripod or any other instruments For accurate measurement the LI200X should 28 be mounted using LI2003S Li COR leveling base 10 A picture of at ypical LI200X pyranometer is shown in Figure 3 7 Se LI200X LI2003S ee Crossarm Figure 3 7 LI200X Pyranometer LI200X has 4 wires red black white and clear used for signal si gnal reference signal ground and shield respectively Its connections to CR10X and CR1000 dataloggers are shown below in Table 3 6 11 Table 3 6 LI200X wiring with CR10X and CR1000 DESCRIPTION COLOR CR10X CR1000 Signal Red Signal reference Black Signal ground White Shield Clear 29 e Rain Gage TE525 tipping bucket rain gage is used for measuring rainfall Its operating temperature range is 0 to 50 C This sensor is factory calibrated and itis not recommended to calibrate again in the field The rain gage should be mounted at least 30 cm above the ground The ground surface where rain gage is installed should be natural vegetation or gravel and not the paved one The picture of a typical TE525 tipping bucket rain gage is shown in Figure 3 8 11 S TE525 gt a a Mounting pole Ground level a Figure 3 8 TE525 Tipping Bucket Rain Gage TE525 has 3 wires black white and cl ear
127. h sufficient solar energy to power the sy stem C onsequently the environmental infrastructure of DP_WS is somewhat different from that of GBC_WS where there is tree cover all the way around The functional block diagram of DP_WS is shown below in Figure 2 4 Figure 2 3 Discovery Park Weather and Soil Station DP_WS 10 Wi Fi link l pons l NS2 gt O i lt NS2 T 2 4 GHz i Ethernet Ethernet l d i Ethernet i Router Router Interface 40 pin parallel Router peripheral port 9 ok ai i 3 i e5 I a oO U l 1 gt P Q WwW I Environmental gt Si Sensors A a i pe s a i A CRI System L L L LLL LLL LL LLL o Internet S Web Server a j Internet a Figure 2 4 Environmental Monitoring System in Discovery Park All the environmental sensors are deployed in a single weather station As in the previous case the data collected via environmental sensors are stored in the datalogger However at DP_WS there is no need to transfer data between dataloggers because it has only one datalogger collecting the environmental data and the station will be using an ethernet interface instead of a SBC But the main difference between GBC_WS and DP_WS is that DP_WS uses Wi Fi technology to transmit the data to the CRI system web server instead of using GPRS The Ubiquity Networks product named Nanostation2 links DP_WS and the internet The Nanostation2 is installed at the topof
128. he ability of an antenna to focus energy in a particular direction when transmitting or to receive energy from a particular direction when receiving A highly directive antenna is 161 always sought for minimizing interference to and from other channels and for obtaining ample receive power at the receiving site But what should also be considered i s the fact t hat fora ong p oint to point r adio link i f using h ighly directive antenna it may be difficult to receive the optimum RSL while doing antenna alignment because of the highly directive nature of the antenna The Figure 6 11 20 below shows a radiation pattern having 60 deg ree of horizontal beamwidth and 30 degrees of vertical beamwidth i Azimuth 60 i Elevation 30 Figure 6 11 Antenna Radiation Pattern The N anostation2 being used has its 3 dB horizontal b eamwidth of 60 degrees and 3 dB vertical beamwidth of 30 degrees 20 This means that the antenna of Nanostation2 can radiate its energy in 60 degree width in horizontal plane and in 30 degree width in vertical plane After getting 75 dBm the Nanostation2 pole was slightly rotated and kept watching the difference in RSL value using builtin antenna alignment tool of 162 Nanostation2 After few minutes of trying an RSL of 66 dBm could be achieved Knowing that the obtained RSL value was in close proximity with the theoretically calculated value 67 65 dBm further rotating the pole was stopped and fixed
129. hen P114 EndIf EndIf NextScan EndProg 248 1 2 3 4 5 6 7 REFERENCES Campbell Scientific Inc August 15 NL120 Ethernet Module Available http www campbellsci com documents manuals nl120 pdf S Chevul et al Measurement of application perceived throughput of an E2E VPN connection using a GPRS network pp 255 268 M Freitas 2003 August 15 What is GPRS Available http www geekzone co nz content asp contentid 207 Radio Eelctronics August 17 GPRS technology tutorial Available http www radio electronics com info cellulartelecomms gprs gprs_tutorial php Campbell Scientific Inc August 15 CR10X Measurement and Control Module Operator s Manual Available http www campbellsci com documents manuals retired cr10x pdf Campbell Scientific Inc August 17 CR1000 Measurement and Control System Operator s Manual Available http www campbellsci com documents manuals cr1000 pdf Campbell Scientific Inc August 15 03001 R M Young Wind Sentry Set 030101 R M Young Sentry Anemometer 03301 R M Young Wind Sentry Vane Available http www campbellsci com documents manuals retired 03001 pdf 249 8 9 10 11 12 13 14 15 16 Campbell Scientific Inc August 17 HMP50 Temperature and Relative Humidity Probe Available http www campbellsci com documents manuals hmp50 pdf Campbell Scientific Inc August 17 CS106 Barometric
130. hown above in Figure 3 12 the MSX10 delivers a peak power of 10 W whereas the remaining two SX 20 U and SP 20 solar panels deliver a peak power of 20 W 15 17 Like battery selection of a solar panel is also an important task Solar panel should be chosen such that it can charge the battery enough even within a short interval of sunlight especially during winter rainy days and foggy days etc Solar panels connect directly to 38 charging regulator whose 12 V output goes to datalogger input power supply terminal In order to get maximum amount of su nlight s olar panel should be mounted facing south if located in the northern hemisphere or facing north if in the southern hemisphere Also the tilt angle should be adjusted correctly which makes a lot difference in the output Other technical specifications of these solar panels are given below in Table 3 11 15 17 Table 3 11 Technical specifications of solar panels SPECIFICATIONS SX 20 U SP 20 DESCRIPTION Output power peak 20 W Output Voltage peak voltage 171V from solar panel before regulator i Output current peak 1 17 Amp Guaranteed minimum peak 18 W power Approximate weight 2 95 kg c Charging Regulator A charging regulator must be used to connect rechargeable batteries with a ch arging source The charging r egulator co ntrols the current flowing to the battery and pr events the ba ttery cu rrent f rom flowing to the charging source Charging r egulato
131. ical depiction of the PakBus network and the og messaged for P akBus communication P akBus Graph can be opened from the Status Monitor the Troubleshooter or from the LoggerNet toolbars Tool menu 26 Transformer Utility Transformer ut ility is a stand alone u tility designed for co nverting an existing dat alogger pr ogram cr eated in Edlog i nto aC RBasic program Iti s installed as one ofthe ut ilities with LoggerNet that canbe aunched from Windows start menu Transformer utility is offered in Log gernet esp ecially for those users of C R10X or C R23X dat aloggers who ar e switching t o C RBasic dataloggers such as CR800 CR1000 and C R3000 26 For example in this present work when switching from CR10X to CR1000 datalogger T ransformer utility successfully transformed an Edlog program file CSI DLD into a CRBasic file CR1 79 nitoring_and_Modeling SM_Programs CR10X _SM EC5T4 CSI Program File jitoring_and_ Modeling SM_Programs CR10X _SM EC5T 4 cAI Target Datalogger type C CR800 CR1000 momoo C Lance Source File Figure 4 11 Transformer Utility CSI to CR1 Input Files File Edit Options Help a Line 1 of 162 Source staid ld 1 Program EC5T4 CR1 Ba da ld 1 Put current date and time into input a year day of yr hr min sec RealTime P18Time year P18Time 1 day of yr P18Time 9 hr P18Time 4 min P18Time 5 sec P18Time EndS
132. ich are discussed below 26 9B LoggerNet 3 4 1 sfx File Tools Options Help amp ee d ARE ie Ss S ES a ES EZSetup Setup Connect Status Short Cut CRBasic Split View RTMC Devy RIMCRT PBGraph Figure 4 10 PC208W Main Window e EZSetup This is the first wizard used to set the CR1000 datalogger to make it able to communicate with PC This is the primary wizard which allows you to setup and configure devices including dataloggers COM ports modems and other communication devices In this toolbar you can also send program files to the datalogger set datalogger clock test communication link between PC and CR1000 dat alogger configured ataco Ilectiona ndsch eduled communications settings 26 e Setup Setup screen is divided into two parts Device map in the left and Set up tabs in the right side of the screen If you want to add a COM port just click on Add Root and select ComPort or alternatively right click within the white space of the Device map and choose ComPort from the list of options 15 for root devices Devices can be added j ust by clicking Add button in this screen When you highlight any device on the network shown on the left side of the S etup window configuration tab ap pears on the right side with the relevant settings 26 Connect After successfully setting up y our datalogger you can now access the datalogger j ust b y clicking o n Co nnect button The co nnect scr een provides area
133. idea is to setup a wireless connection to the already installed DP_WS The station is collecting environmental data and storing them in the datalogger storage module And for the data to be processed and refined they need to be transferred from the station to the system web server Because due to distance it is not possible to setup a wired connection from server to the station it is decided to go for wireless But the station area is not facilitated with internet connection So a wireless connection is needed which can connect the station to the internet Thus after a field survey the EESAT building was chosen as a source of internet Next ar adio link between E ESAT_NS2 and D PWS_NS2 was se tup usi ng Nanostation2 from Ubiquity Networks that uses Wi Fi technology 6 2 Field Survey For any co mmunication sy stem prior to implementa desi gn into r eal world itis very important to doa field survey Field survey not only helps to figure o ut w hether t he real world implementation of t he pr oposed d esign is feasible or not but it also allows us modify the design making the system more robust practical and reliable Talking about radio link setup between any two remotely located stations basically the f ollowingt hings should be taken into acc ountas the pre assessment tasks before implementing the radio link design in the field 138 Selection of Antenna Type Itis very important t ask to c hoose antenna t ype H ere an tenna t ype
134. if T signal _ strength _ with _ obstacle Diffraction oss will b e m ore if t he obs tacle is round i n sh ape R adio signals tend to diffract better around the sharp edges 70 Loss Due to Transmission Line between Tx Rx and Tx Rx Antenna This type of loss is occurred in the transmission line or cable between the transmitting antenna a nd t ransmitter or r eceiving ant enna and receiver Also there may be chance of some losses in connectors The amount of loss depends upon the type and length of cable used Usually this type of loss is very small around 2 3 dB and can be neg lected in many cases 71 Itis advised better to have cable as short as possible 136 CHAPTER 6 WI FI RADIO LINK SETUP This chapter discusses thoroughly about the procedure of a radio link setup bet ween the N anostation2 of EESAT EESAT_NS2 hereafter and the Nanostation2 o f DP_WS DPWS_NS2 hereafter This includes the de tail procedure explaining how it has started and ended up with an establishment of a stable Wi Fi radio link This link was set up for the purpose of providing internet connection to the DP_WS which is located at UNT so that the data collected by this weather station can be transferred to the CRI system web server located at Department of Computer Science UNT via internet EESAT_NS2 d 4 74 km DPWS_NS2 hi 20 m 4a gt oOmm Discovery Park Ground Rx Tx Figure 6 1 EESAT DP_WS 137 6 1 Methodology The
135. ighly de veloped Ubiquity firmware t echnology t hat i s included w ith Nanostation2 AirO Sis an op erating sy stem under w hich 46 Nanostation2 is built upon 21 A very good thing about Air OS is its simplicity in using which makes it user friendly And moreover it is powerful which enables high per formance ou tdoor multi point ne tworking The Nanostation2 c anbe accessed via any web browser For the link to be established one Nanostation2 should be set as access point and another a station mode Following are the brief description of the web management pages of Nanostation2 a Main Main page displays summary of link status information current values of configuration se ttings andt raffic statistics O ther ut ilities suchas network administration and monitoring are accessible via this page This page in station mode also displays the current receive signal strength RSS Also one can test the connection speed of the link using Tools feature This tool can be used to estimate preliminary throughput between two network devices Other status such as channel selected local area network LAN hereafter media access control MAC hereafter wireless LAN WLAN hereafter MAC Tx rate Rx rate LAN IP address WLAN IP address etc are also displayed in this page Also there s one feature na med align ant enna which al lows use r to m onitor RSS o ft he lin k continuously which is updated in every 1 sec and it is very useful especially while
136. ignal received at the receiver side is known as frequency di versity Fort he same positionof TxandR x antennas the different channels receive signal at different strengths at different times But it selects the signal having highest strength every time thus increasing the av erage signal to noise ratio SNR The minimum ch annel di fference depends on the path difference Larger t he pat h di fference t he sm aller t he required difference in frequency channel Polarization Diversity The use of two different antennas of different polarization i e horizontal and vertical for capturing the received sig nal having the highest st rength to provide diversity reception is known as polarization diversity The antennas take advantage o fm ultipath pr opagation ch aracteristics tor eceive se parate uncorrelated signals 56 Due to reflections the original polarization of the transmitted signal may get altered so this characteristic of a signal can be used to create two separate signal channels Thus cross polarized antennas can be used at the receiving site only Since the orientation of the antenna is not rigidly defined in a portable 181 handheld unit such as mobile phone set the diversity technique is particularly advantageous in this kind of unit This type of technique doesn t allow to use more than two channels This technique offers relatively low performance than the other above mentioned two techniques 64 78 7 2 4 Mountin
137. igured every time when PC208W and d ataloggers are c onnected The 66 datalogger s INI files are created updated each time when it disconnects the communication with PC208W and INI files of PC208W are created updated each time it is closed The DND Datalogger network configuration files are used to keep the setup information Parameter files are in PAR ex tension which are created by SPLIT and defines which data files are read what operations are performed on the data set and where the final results will be s aved PAR files can be saved and used time to time 25 Data Collection After su ccessful c onnection of a C R10X d atalogger with a PC hav ing PC208W installed data can be t ransferred to the PC from datalogger st orage module simply by cl ickingon Collect or Collect All b uttonin manual data collection of Connect toolbar Collect b utton allows us to transfer data of a desired time frame whereas withthe Collect All button all the data canbe transferred to PC from the datalogger storage module Normally datalogger is configured with a PC208W to collect the data from the field automatically just by toggling on Schedule On in schedule tab of Setup toolbar but if it is desired then it can be configured for one time data collection also Also a PC208W can be set to enable the PC collect data automatically For this the schedule for the device CR10X her e can be co pied to ot her de vices by se lecting Apply to Other Statio
138. in readable form it should be converted by SPLIT to make itin readable format 25 SPLIT can convert these files in different other formats but they must be in compatible form for conversion The input files for SPLIT must be formatted in comma se parated ASCII final st orage binary f ormat field formatted A SCII SPLIT default output format printable ASCII or raw A D data 25 The comma separated A SCII and printable A SCII input files are shownin above figures Figure 4 6 and F igure 4 7 respectively The input file type of the field formatted ASCII is shown below in Figure 4 8 ena B i JERE SSS SSS je E Environmental_Monitoring_and_Modeling GBC Data 08April01_sm DAT a a File View Help Aa r Allarrays ao EE mE 1 2 3 4 5 6 7 8 9 1 2008 60 2045 11 55 12 09 12 6 63 4 755 E 1 2008 60 2100 11 55 12 08 11 79 86 4 755 1 2008 60 2115 11 54 12 07 10 71 88 3 755 1 2008 60 2130 17 53 12 07 9 76 89 7 755 1 2008 60 2145 11 52 12 06 9 56 88 9 755 1 2008 60 2200 11 52 12 06 9 91 68 3 755 1 2008 60 2215 11 51 12 05 9 51 88 6 755 I 2008 60 2230 11 5 12 05 8 76 91 5 755 1 2008 60 2245 11 49 12 04 8 49 93 3 755 1 2008 60 2300 11 49 12 04 8 29 93 4 755 5 al nnna cn i 33 4c 7 a e 7 CA ac a cc Figure 4 8 Field Formatted ASCII Input File 72 4 2 Discovery Park Weather and Soil Station DP_WS This section al so discusses three su b topics Functional overview of DP_WS d atalogger dupports oftware L
139. ing to the need of this application When there s a need of higher data rate rather than the transmission distance then one can go for higher data rate and vice v ersa For ex ample it as hort lets say 2 km link is tobe established for video conference the data rate could be much higher pr iority rather than Rx sensitivity When the data rate is increased the RSL value decreases accordingly Again there should be tradeoff between data rate and RSL In this work a data rate of 13 5 Mbps is selected with a receiver sensitivity of 92 dBm in Quarter rate mode 5 MHz Selection of Rate Mode Spectral Width Rate mode is also one oftheimportant p arameters to be considered Here in the currents ystem rate mode is just the selection of s pectral w idth There are 3 options for the system in Nanostation2 which are Quarter rate mode having 5 MHz spectral width half rate mode having 10 MHz spectral width and full rate mode having 20 MHz spectral width 21 174 Selecting nar rower sp ectralw idthi ncreases the nu mbero fn on overlapping channels which reduces the interference Also this increases the power spectral density PSD of the channel and enables the link distance to be increased But a major drawback in reducing the spectral width is that it reduces the throughput of the system 21 So again selection of rate mode should also be carefully done In this system q uarter rate m ode i s selected i n or der to decrease the p
140. ion a nd anotheri s duet ost rong interference from another signal Also poor installation of radio sites including antenna adjustments indoor and outdoor connectors connection etc and some inappropriate parameters settings of radio equipment may become one o f the contributors that deteriorate the link quality Herei nt his chapter v arious probable causeso fsy stem q uality deterioration and its impacts on the link quality are discussed Then the chapter 164 focuses on optimizing the link quality by presenting the v arious remedies to counteract the hostile environment contributing the instability of the link 7 41 Causes of Radio Link Instability Normally RSL of an unstable link often swings in between its maximum RSL value and the threshold R SL Rx sensitivity This instability at its worst condition m ay r esult i n t hel ink breakdown w hen r eceived R SL value g oes beyond the Rx sensitivity value In almost all of the radio link systems a small fluctuation of RSL is inevitable and considered normal Depending upon the type of radio link the tolerable fluctuation values may be within 0 5 dBm 0 10 dBm 0 16 dBm etc as suggested by the fade margin However itis always desired that the RSL value to be constant Why the link is unstable What makes the link quality so deteriorate that often results the termination of link connection There are several reasons which are discussed all of them here in brief Imperfect Anten
141. ion mayr esult destructive or constructive path loss More detail is discussed in two ray propagation model in Section 5 2 4 of this chapter 52 Surface Waves Radio si gnals that t ravel al ong t he su rface o f t he ear th following it s curvature till they reach their destination receiver are called su rface w aves Lower frequencies especially AM broadcasts in the medium wave MF and long wave low frequency LF bands travel efficiently as surface waves because these low frequency waves are more efficiently diffracted by the curvature of the Earth Surface waves die more quickly as the frequency increases 53 Sky Waves Radio signals that are reflected back to earth surface by the ionosphere are calledsky w aves Mosti ong distance highf requency HF radio communication between 3 30 MHzis a result of sky wave propagation When radio waves reach the ionized layer of the ionosphere refraction or bending of the wave occurs The amount at what angle it gets refracted depends upon three things the density of ionized layer refractive index the frequency of the radio wave and t he angle at which the radio wave enters the layer incident angle When a radio wave strikes a thin very highly ionized layer low refractive index 111 the wave may be bent back so rapidly that it will appear to have been reflected instead of refracted back to Earth 53 arth s curvature Tx Rx Figure 5 5 Radio Waves Direct Wave and
142. ion r 3 5 range 40 to 60 C 40 to 60 C Charging current limit 1 2 Amp 1 2 Amp 3 1 4 Optically Isolated RS 232 Interface SC32B The SC32B optically iso lated RS 232 i nterface is used t o co nnect a CR10X dataloggers CS I O portwitha PC s RS 232 port This interface is required f or di rect co mmunication b etweenaP Canda C R10X datalogger CR1000 has both CS I O port and RS 232 port so any PC can directly connect to it via RS 232 port It optically isolates the datalogger and RS 232 peripheral Optical isolation separates the SC32B into a datalogger section and an RS 232 41 section Signals entering from either side are electrically independent protecting against ground loops normal static discharge and noise 19 CAMPBELL SCIENTIFIC INC Logan Utah c CS I O i S RS 232 connectsto gt SC32B 2 lt connects Datalogger 8 to PC Made in USA SN Figure 3 14 SC32B Optically Isolated RS 232 Interface Figure 3 24 sh ows a pi cture o f S C32B o ptically i solated i nterface t converts CR10X datalogger s logic levels to RS 232 logic levels allowing t he direct communication between the datalogger and the PC The table 3 12 shown below gives some technical specifications of SC32B 19 Table 3 13 Technical specifications of SC32B DESCRIPTION SPECIFICATION Power 5V Powered by datalogger Operating Temperature 25 to 50 C 9 pin female RS 232 configured Ports as DCE 9
143. ions of sensors and other devices used in the system are already discussed in Section 3 1 of Chapter 3 In this chapter there is a detailed description about how those sensors and devices are wired with the weather station how they are controlled by software to collect the data from the field and how the data are transmitted to the CRI system server using two di fferent wireless technologies A br ief descr iption o f datalogger support software and programming to run the datalogger are also given in this chapter As already discussed earlier the two stations GBC_WS and DP_WS are being deal tw ith Block diagrams of overview of environmental m onitoring systems of both the stations are discussed in Figure 2 2 and Figure 2 4 4 1 Greenbelt Weather Station GBC_WS In this section focusing on dat a collection procedure mainly three su b topics will be di scussed Functional overview of GBC_WS datalogger support software PC208W and Edlog programming editor used to run the datalogger for data collection 61 4 1 1 Functional Overview Greenbelt Weather Station GBC_WS Solar Panel_1 SX20 U Solar Panel_2 MSX10 A 2a Battery Battery Backup_1 Backup_ 2 12V 12 Ahr 12V 7 Ahr Charging Regulator 2 Regulator_1 Soil Moisture Station Datalogger cR10x_1 Weather Station Datalogger CR10X 2 w Soil Moisture Sensors Tensiometers Environmental Sensors Figure 4
144. ions suchas and t arguments determine the time interval for throughput report and the total time duration for 198 E Administrator D Windows system32 cmd exe lol x Client connecting to 192 168 1 11 TCP port 5001 TCP window size 8 00 KByte default im 112 local 192 1 10 port 52442 connected with 192 168 1 11 port 5001 ID Interval Transfer Bandwidth O 1 0 MBytes 8 Mbits sec MBytes 5 Mbits sec MBytes 8 Mbits sec MBytes 8 Mbits sec MBytes 0 Mbits sec MBytes 7 Mbits sec MBytes 6 Mbits sec sec MBytes 0 Mbits sec sec MBytes 2 6 Mbits sec sec MBytes 2 Mbits sec sec sec sec sec sec sec 0 0 0 0 ORPNNNNNEFO 0 1 2 3 4 Si 6 hee 8 0 OONO WN oo0oo0oo0o0o0o000 D sg pc iperf 1 7 0 win32 gt Figure 8 2 Throughput Result of Cat5 while Transferring Video File the command to run After entering the above command a time stamped output as shown in above Figure 8 2 was output Since interval is set 1 sec the command outputs the throughput result every 1 sec and after the transfer of all 111 M Bytes it out puts the aggregate t hroughput F or ex ample in the ab ove experiment while transferring the video file of 111 M Bytes in first interval i e 0 0 1 0 se c i tsh ows the out putas 10 9 M Bytes of transferred an d 91 8 Mbits sec of throughput In addition in second interval 1 0 2 0 sec it shows the output of 11 1 MBytes of transferred and 93 5 Mbits sec
145. irectly proportional to the frequency of the signal T hat means in higher frequencies the signal gets attenuated rapidly and v ice versa For example there is a huge attenuation in frequency greater than 10 G Hz and very little in frequency less than 10 GHz 56 132 A dB f f gt f d km d d2 Figure 5 14 Attenuation Vs Distance Figure 5 8 shows a graph of signal attenuation versus travelled distance for two different frequencies From the graph as the signals travel signal having higher f requency f pink gets attenuated more rapidly t han d oes the si gnal having lower frequency f2 violet A and Az are the attenuation differences of the two discussed frequencies at distances d and d respectively It is can also be observed that the difference in attenuation is not significant at ower distance here d1 but as the distance increases the difference is also increasing So it can be concluded that when the transmission distance is very near then t he se lection o f f requency i s nott hati mportant but it becomes very important task to choose the frequency when the distance is larger So above graph of Figure 5 8 suggest us to go for low frequency in order to get the signal less attenuated B ut of co urse when low f requency is ch osen there w ill be 133 another disadvantage for example antenna gain So there should be a tradeoff between selection of frequency and other design parameters We ll discuss about
146. it tightly j ras NanoStation2 UBIOUITI NETWORKS Network Services Advanced Base Station SSID EESAT_NS2 00 15 6D A9 77 19 Signal Strength 66 dBm Align Antenna TX Rate RX Rate Frequency Channel 4 Antenna Security ACK Timeout Transmit CCQ Qos Status Uptime o22504 LAN Cable LAN MAC LAN IP Address WLAN MAC WLAN IP Address Figure 6 12 Snapshot of DPWS_NS2 Main Page The abov e F igure 6 12 i s the sn apshot o f t he m ain pag e w indow of DPWS_NS2 after the alignment of antenna is complete 163 CHAPTER 7 QUALITY OPTIMIZATION OF A WI FI RADIO LINK Establishing a wireless radio link is sometimes difficult because it has to sweep away all those hurdles of geographical and technical irregularities Once the ink has b een e stablished i ts m aintenance or the st ability of the ink sometimes becomes even harder due to unpredictable environmental changes Inm osto ft hea pplications suchas mobile co mmunication m icrowave communication etc a radio link is supposed to transmit energy all the time So it s very important to keep the link up all the time For this the system should be robust enough to counteract any probable risk of system failure Here sy stem failure means the breakdown of the radio link A well functioning radio link may suddenly br eakdown esp ecially due t ot wor easons O ne i s due to su dden change i ne nvironmental cl imatic condit
147. it later There are many causes of si gnal attenuation suchas rain fog w ind snow and trees though their effects are notso noticeable most of the time However in higher frequencies they become noticeable and hence contribute in additional path loss For example rain fog and snow become significant sources of attenuation only when the operating frequency range lies completely inside upper bands SHF and EHF of microwave range More precisely attenuation from f og and sn ow become no ticeable w hen above about 30 G Hz Rain attenuation becomes noticeable only above about 10 GHz In one experiment it was observed that an attenuation of about 0 02 dB km was recorded at 2 4 GHz due to ah eavy rainfall while in another ex periment an attenuation of 1 dB km was recorded at above 10 GHz The attenuation due to rainfall is comparably very noticeable at above 10 GHz rather than at 2 4 GHz 55 68 Trees and forests can attenuate the signal in a si gnificant manner if the frequency is high and t he signal has to pass through the dense jungle having trees with wet leaves In one experiment it was seen that signal was attenuated up to the order of 0 3 dB m at 2 GHz and 0 4 dB m at 3 GHz Whether the leaves are present or notor wetor dry a single isolated tree is not usually a m ajor problem but a dense forest can become a huge source of attenuation 55 134 Multipath Fading When a practical sc enario r adio env ironment is considered t hen
148. l time connection to a dat alogger in the dat alogger net work Here in this Connect window you can do m any tasks such as setting data logger s clock se nding pr ograms from P Ct o dat alogger viewing a nd collecting dat a fromst oragem odule v iewingandm akingg raph measurements etc 26 Status Status toolbar is used for displaying information for all the dataloggers on the device map at one glance The leftmost column of the status monitor displays the network map showing the devices in the network It provides a control ov er t he Log gernet dat a co llection pr ocess co nfigure t he di splay appearance or bring up other applications such as Log tool or PakBus graph 26 Edlog Edlog toolbar is used for creating editing and documenting programs for Campbell S cientifics mixed array dataloggers such as CR10X and et c Edlog supports all operating systems for these dataloggers including table data TD and PakBus PB versions Edlog also allows comments to be 76 inserted An E dlog compiled program file whichis in DLD format can be sent to datalogger 26 Short Cut The Shortcut is an application for generating programs for all of the Campbell S cientific dataloggers Iti s also r eferred to as SCWIN It also generates a wiring diagram for connecting the sensors the datalogger Itis especially desi gned for the beginning datalogger programmers to create a datalogger program easily and q uickly in four easy steps
149. ld to the server This avoids the necessity of paying for any third party for using their services suchas GPRS n etwork This thesis o ffers guidelines of the techniques to implement similar ki nd o f pr ojects for example developing wireless internet service in remote and rural areas especially in developing countries 1 5 Organization of the Thesis Chapter 2 is an overview of weather monitoring system with its functional block diagram The overview includes the two systems the GBC_WS and the DP_WS However the latter is describedin more detail beca use t his thesis focuses on this station for the implementation of Wi Fi technology Chapter 3 deals with the detailed description of all the components of the weather monitoring system with the wirings of all the sensors used in this project and their core functions Chapter 4 deals with the data collection procedure from the field In this chapter a functional ov erview datalogger support so ftware and datalogger programming are discussed Chapter 5 discusses Wi Fi technology its advantages and challenges It also describes radio wave pr opagation t heory f ocusing ont he free sp ace propagation model and free sp ace oss This chapter al so di scusses some advantages of Wi Fi technology over GPRS technology for this application Chapter 6 de als with the d etailed description of the Wi Fi link set up between Environmental Education Science and T echnology EESAT building of the UNT an
150. leDegrees Declare array of flags as the CR10 had Public Flag 8 as boolean CR1OX This program stores the time and al storage every fifteen minutes the entire 15 minute interval Rainfall is THRSDI CRI1 lsci LoggerNet CR10X TRN This program was converted from C PC208W CR1OX_Programs WTHRSDI CSI using Campbell Scientific s Transformer application ll weather data in final totaled for The wind vector instruction is used to store average wind speed and direction Also maximum wind speed is computed transferred to the soil moisture data logger and stored minutes one minute after it is collected of the weather logger is synchronized to tha moisture logger at 2 10 a m every morning logger time is updated via cell TVVVAVAVAAVAVAVAVAVAVAVAVAVAVAVA DECLARA Public T_C Public RH Public P_mmHg Public SUN_W_m2 Public WIND_aveArray 15 Publ Publ Publ Publ Publ Publ lic RAIN Lic WS_mph lic WD_deg lic W_m2 lic P_mb ic TIME Publ lic SUN_W_m2Array 15 Public WIND_aveArray 15 Publ lic WIND_maxArray 15 Pub Alias WIND_aveArray Alias WIND_aveArray Alias WIND_aveArray Alias WIND_aveArray lic RAIN_totArray 15 WIND_ave WIND_dir WIND_max 2 8 4 5 RAIN_tot ananasa 245 eather data are every fifteen The time clock t of the soil The soil moisture modem once a day at 2 05 a m
151. lies power to some sensors The T amp H sensors must be powered at least one second prior to taking a reading One minute is more than ample to allow all powered sensors to stabilize before measurement If TimeInToInterval 14 15 Min Then PortSet 1 1 EndIf Sample the remaining sensors at 15 minute interval and then send all weather data to final storage and to the moisture data logger If TimeInToInterval 0 15 Min Then Read barometric pressure and store at P_mb VoltDiff P_mb 1 mV2500 6 true 0 _60Hz Convert barometeric pressure to mmHg P_mmHg P_mb 0 7501 Read air temperature deg C and store at T_C VoltSE T_C 1 mV2500 2 False 0 250 0 1 Read relative humidity and store at RH VoltSE RH 1 mV2500 1 False 0 250 0 1 Limit the maximum relative humidity to 100 If RH gt 100 Then RH 100 EndIf 1 84 40 0 600 Set control port 1 low to remove power from some sensors PortSet 1 0 Read the battery voltage and store at BATT_W Battery BATT_W Store present date time and weather data in final storage EndIf At 2 10 a m synchronize weather logger time with time from soil moisture logger 247 If TimeInTolInterval 130 1440 Min Then SDI12Recorder TIME 7 0 M 1 0 If the moisture logger fails to communicate then 99999 will be stored in TIME If communication has failed then do not update the time clock If TIME gt 0 T
152. ls One of the most important causes of radio link quality degradation is the interference If ar adio link system suffers interference from any other system then its quality goes down significantly depending upon how strong the interfering signal is Interference may occur due to the system using same common channel and also due to from the system using the neighboring channels The former is known as co channel interference and the latter is known as adjacent channel interference Adverse Environmental Conditions The effecto fenv ironmental f actors may be not iceablei nhi gher frequencies applications rather than in lower frequencies but sometimes if the environmental condition is very adverse such as simultaneous heavy rain and 167 strong w ind t hen some lowerf requencies may al sog et affected Other environmental factors ike sn ow fog e tc also contributes to the link quality degradation The radio signal gets highly attenuated in all of these environmental adverse conditions and hence the RSL decreases Inappropriate Antenna Polarization Settings This cause is also one of the causes due to improper parameters settings which have just been discussed a little earlier think it is worth discussing this parameter separately in a little detail because it is also one of the very important parameters that needs to be carefully selected while configuring radio equipment Polarization of antenna is how the radio wave travels from
153. lues shown in the Table 8 12 are average data rates 225 CHAPTER 9 CONCLUSION Environmental da ta c ollection is accomplished by aw eather and so il station GBC_WS in the forest of the Greenbelt Corridor A datalogger collects various environmental variables suchas airt emperature r elative hum idity barometric air pressure solar radiation wind speed wind direction rainfall and soil moisture every 15 minutes and pass the datato an SBC This computer then transfers data to the server using a GPRS modem For transmitting data from the field to the server an innovative high speed and a low cost Wi Fi technology is used instead of the costly GPRS technology For the implementation of this technology a Nanostation2 a Wi Fi co mpatible radio eq uipment having a built in directional antenna is chosen To test this concept a Wi Fi radio link between EESAT where there is an internet s ource available and DP_WS is successfully implemented There are some future tasks recommended as a continuation of this work Short term is the interconnection of datalogger and N anostation2 in order to access the datalogger and its data via internet This will be done soon using an ethernet interface as discussed in Section 4 2 4 226 One of the future plans is to establish a Wi Fi radio link between GBC_WS and the Natural Heritage Center to collect the data of GBC WS via internet An internet source is available in the Natural Heritage Center which i
154. means that what radiation pattern does its signal follow or more simply whether itis directional or o mni directional Depending u pont he type of application antenna type is chosen to fit their design goal For example directional antennas are installed in either 3 or 6 sectors in cellular towers whereas omni directional antenna is installed in every hand hel d unit mobile phone set so thatit can receive signals coming from any cellular tower from any direction facilitating the unit a high degree of mobility In this work beca use itis a point to point or line of sight connection directional antennas are used in both the sites EESAT and DP_WS Because the goal is to link only the two mentioned sites without hampering other signals and ours also directional antennas suit far bet ter than o mni directional One advantage of using directional antenna is that it radiates its power towards only one direction which prevents the system from interfering other system and being interfered by them Another adv antage is that directional antenna has a high directivity gain and hence it can cover more distance than omni directional for the same given transmitted power Site Selection Another v ery important task is the site se lection S ite se lection is very important in ce llular communication while installing many cellular towers in an urban area The selection of site should be such that mobile users get signals 139 from everywhere and als
155. n i nt exture and el ectrical conductivity of s oil The t wo poi nted prongs design m akeit easy t oi nstall 31 anywhere even in hard or compact soil However it is better to insert the probe very carefully and g ently while inserting into hard surface soil Also the probe should be buried completely inside the ground surface as shown in F igure 3 9 ii The sensor is factory calibrated but it is recommended to perform soil specific calibration because the factory pre calibration may not be appl icable for all soil types The nominal supply voltage is 3 V DC but can intake any voltage value from 2 5 to 3 6 V A typical current consumption is about 10 mA 12 Ground level gt ae as lt EC 5 prong i EC 5 Soil Moisture Sensor ii Inserting EC 5 probe inside ground Figure 3 9 EC 5 Soil Moisture Sensor The picture of a typical EC 5 is shown in the above Figure 3 9 EC 5 has 3 wires red w hite and clear used for analog out excitation signal and s hield respectively The sensor output is fed to the single ended SE hereafter channel oft he da talogger The EC 5 pr obe connections toC R10XandC R1000 dataloggers are shown below in Table 3 9 12 32 Table 3 8 EC 5 wiring with CR10X and CR1000 DESCRIPTION COLOR CR10X CR1000 Analog out Red Excitation channel White Shield Clear EC 5 Calibration Even though the EC 5 probes come with pre calibrated for most soil types it is highly recommended
156. na Alignment Imperfect antenna alignment m eans thatthe radio a ntennas ar e no t adjusted in their optimal orientations in either of or both the sites This is one of the causes of the poor link quality often when there is a heavy rain or strong wind or any other strong environmental or technical hurdles occur It might not be that noticeable at t he timeo fal ignmento f antenna beca useo f the nor mal environmental a nd o ther co nditions In many ca ses a ntennas ar e fixed by tightening knots and bolts after doing few minutes or hours of alignment when 165 they notice that the obtained RSL is within the range between its maximum and threshold v alue At t hat t ime t hey m ight t hink that t he o btained R SLis the maximum one and hence thought that they fixed the antennas in their op timal positions But the fact may not be as what they were thinking at that time As a result even if that link is up almost all the time in normal co ndition it cannot counteract the worst environmental conditions such as heavy rain etc resulting in a link breakdown or at least so much deteriorated RSL This happened because of insufficient fade margin Due to ani mperfect alignment the maximum RSL was not achieved and hence the fade margin was apparently reduced Also sometimes the loose tightening of knots and bolts of antennas may become the cause of serious link quality deterioration and of course may also be the cause of link breakdown Again as ab ove
157. nd Challenges of WI Fi ceeeeeeeeeeeeeeeeeeeees 92 Sko VV EPIC MANION S aeecueei eee eocena hiesa eve panee ieee eea ia 93 5 1 4 Interference in 2 4 GHz ISM Band eeeeeeeeeeeeeeeeeeees 101 5 1 5 Wi Fi Vs other WLAN Technologies cceeeceeeeeeeeeeeeeeeees 103 5 1 6 Advantages of Wi Fi Technology over GPRS Technology 105 5 2 Radio Wave Propagation Theory 107 vi 5 2 1 Types of Radio Waves i2cccccetepeeeietdidiee tdi hedide etdideeentnliebed 109 5 2 2 Phenomenon of Radio Wave Propagation eeeee 113 5 2 3 Polarization Of Radio WaVe ceccccceeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeees 117 5 2 4 Radio Wave Propagation MOdels cceeeeeeeeeeeeeeeeeeeeeeeeeees 120 TA P AU EOS S24 a6 fod a hod fot tod Nog tod 15h od fo tod 1 od bods 127 6 WEF RADIO LINK SETUP icccccc cose ccsccecccesccthccaaeceuscieestuccesecevececredecenssestene 137 BST Methodology ss 2 c 5 cte fists sete hs ele AE 138 6 2 Field SUIVGY e e a e rc an eee au ele ila 138 6 3 Technical Design icccscscste cst code ee eee 143 6 3 1 Selection of Propagation Model 0 es seseeeseeeseeeseeedeeeseeetens 143 6 3 2 Channel Selection c c cceeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeees 146 6 3 3 Radio Link Modeling ccceeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeees 154 6 A nstalation hfs a Poh sh a a a cer erent Pp 156 6 5 GOnfiQuration Settings rcesccoecencvenecesesesecenteen
158. nd Wavelet Reflection Available http mysite du edu lconyers SERDP Figure5 htm 254 51 52 53 54 55 56 57 58 59 Wikipedia September 1 Microwave Available http en wikipedia org wiki Microwave Electronics Technician 09 03 2009 Wave Propagation 4 10 Available http www tpub com content et 14092 css 14092_19 htm Electrical Engineering Training Series 09 03 2009 Radio Wave Propagation 15 19 Available http www tpub com content neets 14182 css 14182_76 htm Radio Electronics August 27 Electromagnetic waves reflection refraction diffraction Available http www radio electronics com info cellulartelecomms gprs gprs_tutorial php B McLarnon 1997 2009 VHF UHF Microwave Radio Propagation A Primer for Digital Experimenters Available http www tapr org ve3jf dcc97 html Rosu 2009 Basics of Radio Wave Propagation 1 10 Available http www qsl net va3iul Antenna Basics_of_Radio_Wave_Propagation pdf Wikipedia September 1 Scattering Available http en wikipedia org wiki Scattering Wikipedia September 1 Polarization Available http en wikipedia org wiki Polarization Electrical Engineering Training Series 09 03 2009 Polarization 10 11 Available http www tpub com content neets 14182 css 14182_70 htm 255 60 61 62 63 64 65 66 67 68 Radio Electronics September 07 Polarisation of electromagnetic w
159. nected with the datalogger All these tasks can be d one in Device Configuration Utility 22 After this the next step is to configure Loggernet t o co nnect datalogger v iat he e thernet p ort Input th e datalogger s IP address and port number choosing IP port under Add Root tab of Loggernet Setup screen The CR1000 default port number is 6785 which can be changed T hen add a P akBus port andsetthe desired baud rate A dd t he datalogger CR1000 and enter its PakBus address Once the above settings are done the datalogger can now be connected via ethernet port using LoggerNet connect screen and various tasks such as datalogger program transfer editing datalogger programs data collection etc are possible 22 NL120 C Nanostation2 NL120 fhe gt Se OENE g Mae n USA CR1000 u Switch Figure 4 17 Inter connections of Radio Equipments of DP_WS 87 Once t hed atalogger N L120 a nd L oggernet have bee nse tupa s described above communications are possible over T CP IP Ethernet interface NL120 can be connected with the CR1000 datalogger in DP_WS Also a switch will be used for bridging the NL120 and the Nanostation2 A static IP address 129 120 9 228 will be set to the datalogger so that all the devices including the nanostations EESAT_NS2 and DPWS_NS2 are in the same network domain Once the switch is connected to the Nanostation2 and the datalogger via NL120 it will provide ani nternet co nnection to th
160. nelto setup Wi Fi network for optimal performance The Real time chart outputs the graph showing real time energy dBm of the 2 4 GHz signals as a function of frequency The Waveform c hart outputs the g raph showing the ag gregate e nergy dBm collected since the start of Airview2 session 73 Checking of Appropriate Channel for the System Before deploying the new sy stem the radio environment of both si tes EESAT an d D P_WSw ere anal yzed usi ng A irView2 R unning A irView2 i n DP_WS it is found that the channel is not much crowded The following are the output charts obtained in DP_WS ground and EESAT terrace 150 AView Spectrom Analyzer Te el Help View2 USS 0123456789 on COM but 2009 01 23 14 12 43 CST range 2399 2485 MHz 500 0 Kru stepe Total RF Frames 2101 FPS 3 7 Revel Al Data WIFI Channels Figure 6 5 DP_WS 2 4 GHz Channel Study Nanostation2 NOT Connected AView Spectrum Analyzer 7 eel File View Help SD 0123496789 on COMA bult 2009 01 23 14 12 43 CST range 2999 2405 Matz 900 0 KHz stepe Total RF Frames 6902 PPS 2 7 Reset Al Data 2440 Avera Figure 6 6 DP_WS 2 4 GHz Channel Study Nanostation2 Connected 151 From t he o utput ch art o f a bove F igure 6 5 when N anostation2 is not connected itis seen that the 2 4 GHz channel in DP_WS is not that crowded except the channel 7 Here there are no other channels which are interfering the channel
161. nnels modulation techniques etc which are shown in the Table 5 6 below 29 33 43 45 104 Table 5 6 Wi Fi vs cellular technologies FEATURE Wi Fi Technology GSM CDMA Standards IEEE 802 11a b g n GSM900 1800 IS 95 CDMA2000 Frequency Operating 900 1800 1900 900 1800 1900 band aap ole MHz MHz Data Rate max 600 Mbps 384 Kbps 1 23 Mbps Transmission Range 15 km 35 km 25 km 25 km Soe anil Discrete Abate Almost continuous roaming continuous Channel Bandwidth 22 MHz 25 MHz 75 MHz 1 25 MHz Channel Spacing 5 MHz 200 KHz 30 KHz No of Channels 14 42 124 374 Not fixed Modulation Technique FHSS DSSS OFDM GMSK Spread Spectrum as Wireless Application networking Cellular Cellular License Regulation Unlicensed Licensed Licensed Depends on no of Interference Severe less severe lisers Flexibility to deploy High Lower Lower Interoperability Higher Lower Lower 5 1 6 Advantages of Wi Fi Technology over GPRS Technology There are several advantages of Wi Fi over GPRS technology That s why a m odern Wi Fi technology i s use d in the present application for DP_WS instead of GPRS technology Using Wi Fi technology instead of GPRS the same task can be done more easily and more reliably at much higher speed Also Wi 105 Fi can support al ot of other applications which could not be achieved using GPRS such as applications requiring higher data rates And obviously use of Wi Fi technology is free Table 5 7 Wi Fi
162. ns in schedule tab And if PC208W is put in the windows startup group it automatically I oads when the P C is turned on and st arts to collect the data automatically 25 67 4 1 3 EDLOG Programming Editor for CR10X An ED LOG is at oolf or cr eating edi ting and d ocumenting program especially fora C R10X dat alogger However itis also av ailable in modern datalogger su pport so ftware suchas LoggerNet 3 4 1 In an E dlog editor a complete datalogger program for almost all kinds of measurement can be written and saved When an Edlog program is saved a CSI extension is automatically added after the program s name It is the only file which users can edit and save again and again zy Edlog CR10X E ENVIRO 1 SM_PRO 1 CR1OX_SM EC5T4 CSI o x gy File Edit Search Compile Display Options Window Help B a x lt CR108 gt xTable 1 Program i 5 Execution Interval seconds gt Read soil moisture probes every fifteen minutes 1 If time is P92 gt 1 Minutes Seconds gt into a 2 15 Interval same units as above 3 38 Then Do Set port 1 high to power the probes 2 Do P86 gt 1 414 Set Port 1 High 3 Wait two execution cycles 18 sec for probe electronics to stabilize 3 Beginning of Loop lt P87 gt 1 1 Delay 2 2 Loop Count Figure 4 3 CSI Input Program File Figure 4 3 shows a snapshot of a typical CSI program file written in Edlog editor When this program is
163. nt is clear So t he i nitially desi gned heights of N anostations 9 m and25m in DP_WS and EESAT in both sites are ample enough to counteract the effect of the Fresnel zone 7 2 5 Design of Ample Fade Margin Fade m argin is the amount by which an RSL can ber educed without causing sy stem per formance t o fall bel ow asp ecified t hreshold v alue Itis extremely important to keep at least some amount of fade margin in every radio link systems in or der t o c ounteractt he probable fading To illustrate how important role does the fade margin playinar adiolink system here s one example Let s take a hypothetical example of an 18 GHzradiolink established between two stations located at a distance of 16 k m say from each other Its current RSL is 50 dBm and Rx sensitivity is set to 65 dBm at 5 Mbps The link works well under normal environmental c onditions B ut when there s a heavy rainfall du e t o w hich si gnal at tenuates by 1d B km t hen the attenuation i n traversing 16 km link will be 16 dB and hence the RSL value decreases to 66 dBm which is below the pre set receiver sensitivity 65 dBm In this condition the radio link will breakdown 188 The above example clarifies that the insufficient fade margin may not work at all when there is an abnormal condition as illustrated in above example even if the radio link works very well in normal condition For the above example to be in safe side the Rx sensitivity should
164. nts of the link EESAT_NS2 DPWS_NS2 performed at different available 802 11g data rates The two right most columns show the obtained Tx and Rx throughput results of the experiments carried out on the 5 MHz channel And the Figure 8 19 is the graph of datar ate vs throughput corresponding t ot he Table 8 12 The throughput experimenti s carried out usingn etwork speed testt oolo f EESAT_NS2 223 Table 8 13 Data rate vs throughput for IEEE802 11g Rate algorithm Conservative IEEE Standard EESAT_NS2 DPWS_NS2 Server Client Access Point Station Tx power 26 dBm 802 11g RSL 62 to 69 dBm Data Rate 1 5 Mbps 2 25 Mbps 3 Mbps 4 5 Mbps 6 Mbps 9 Mbps 12 Mbps 13 5 Mbps Throughput Tx 1 03 Mbps 1 76 Mbps 1 85 Mbps 2 36 Mbps 2 83 Mbps 3 13 Mbps 3 21 Mbps 3 28 Mbps Throughput Rx 978 52 Kbps 1 66 Mbps 1 69 Mbps 1 99 Mbps 2 03 Mbps 2 12 Mbps 2 17 Mbps 2 15 Mbps Throughput Mbits sec Data Rate Mbits sec Figure 8 19 Data Rate Vs Throughput for IEEE802 11g 224 In the above Figure 8 19 the pink colored line denotes the Tx throughput throughput from EESAT_NS2 to DPWS_NS2 and the blue colored denotes the Rx throughput throughput from DPWS_NS2 to EESAT_NS2 The experiments are performed for all the available data rate settings for 802 11g For every data rate settings throughput values are measured 5 times and their average is taken All the data va
165. o much crowded and hence almost all of the channels are already occupied In sucha case it will be necessary to go for the channel which has been least crowded Also it is needed to figure out the channel having less strength So before deploying the new system in a crowded system a radio environment sh ould be examined thoroughly forse lecting t he appr opriate channel Toc hoose the a ppropriate ch annel for the new system a W i Fi spectrum analyzer called AirView2 manufactured by Ubiquiti Networks is used Output charts External antenna AirView2 device Figure 6 4 AirView2 A 2 4 GHz Wi Fi Spectrum Analyzer 149 AirView2 is a cheap tiny spectrum analyzing tool for studying of all RF energy contributors in 2 4 GHz band to optimize 2 4 GHz Wi Fi networks It has a scan range of 2 399 2 485 GHz which covers the entire 2 4 GHz channel system completely Its step size interval is 500 kHz or 3 7 frames per second FPS When plugged into PC it outputs three charts Channel usage chart Real time chart and Waveform chart The channel usage chart outputs the graph showing the relative crowdedness of that specific channel Each 2 4 GHz Wi Fi channel is represented by a bar displayinga percentage r epresentingt her elative crowdedness of that specific channel This percentage is calculated by analyzing both the popularity and the strength of RF energy in that channel since the start of aA irview session This chart determines the best chan
166. o tests are performed to figure out the effect of change of transmitted power on the throughput In addition the results of the latter two tests help how the throughput changes as the data rates are varied An audio file audio mp3 of size 12 M Bytes is sent for 60 s econds from P C2 to P C1 and the throughput results are recorded 208 The Iperf command used for the throughput measurements for all the four experiments is as follows iperf c 129 120 0 238 F audio mp3 i 10 t 60 Experiment 8 2 1 1 Parameters Settings Table 8 4 Throughput Expt 8 2 1 1 Parameters settings PARAMETERS EESAT_NS2 DPWS_NS2 lperf mode Server Client Tx power 11 dBm Data Rate 13 5 Mbps Rate Mode Quarter 5 MHz RSL 86 dBm E Administrator D Windows system32 cmd exe o x D Iperf iperf 1 7 0 win32 gt iperf c 129 120 9 238 F audio mp3 i 10 t 60 Client connecting to 129 120 9 238 TCP port 5001 TCP window size 8 00 KByte default 120 9 237 port 56286 connected with 129 120 9 238 port 5001 Transfer Bandwidth 640 KBytes 524 Kbits sec 552 KBytes 452 Kbits sec 72 KBytes 387 Kbits se 0 68 KBytes 465 Kbits se 0 0 se 600 KBytes 492 Kbit 0 60 0 se 640 KBytes 52 cb 0 0 60 1 sec 40 MBytes Figure 8 11 Throughput Result of Experiment 8 2 1 1 Result Throughput 474 Kbits sec 209 Experiment 8 2 1 2 Parameters Settings Table 8 5 Throughput Expt 8 2 1 2 Parameters settings PARAMETERS EESAT_NS2 DPWS_NS2 Iperf mode Server
167. o there s a minimum or nil if possible of interference between theirow nsi gnals andsi gnals from othersy stem also Another application where site selection plays a vital role is in microwave communication while setting up a microwave radio link Because this type of link is LOS one has to first take care of the visibility of the remote station from the local station and vice versa From the name line of sight it is clear that the two sites should be in visible range from each other Or expressing itin simpler language when the remote station antenna is looked at from local station antenna the remote station tower should be visible It should not be confused here that even if one station cannot be seen from another a radio link may still be possible as long as they are in LO S andthere s no obst acle in b etween which obst ruct t he si gnal completely and the transmitted power is sufficient enough to reach up to there The tower may not be seen from another because of the fact that it may be the range limitation of human eye or unclear atmosphere None of them prevent the electromagnetic wave to travel and reach up to the destined site So the basic ideais that when one running site is already there and if there s a need of another new site to be installed then the location of the new site should be chosen in such a way that it is in LOS with the running site The site should be chosen also ina way that itis within the transmission range 15
168. oberts State Park Denton and Discovery Park Weather and Soil Station DP_WS hereafter at the University of North Texas UNT hereafter Denton during January 2008 October 2009 The thesis provides a comprehensive description of the various steps involved i e data collection and transfer of data This work includes data collection procedure transferring of data from one data collection unit datalogger to another and finally transmitting all those combined collected data to a web server using wireless fidelity Wi Fi hereafter technology where once processed is made available for public access via internet This thesis presents an alternative method to the costly general packet radio service GPRS hereafter solution wh ich has been used for transmitting data from the GBC_WS to the computing research infrastructure CRI hereafter web server An innovative ow cost anda high data rate Wi Fi technology is employed to transmit the collected data from the weather station in the field to the web server Since the new Wi Fi technology replaces the GPRS network service charge doesn t have to pay service charge for the new system deployed in DP_WS thus cutting down the cost of transmission Wi Fi technology operates in an unlicensed frequency band and hence its use is free 1 1 Objectives e Deploy a weather and soil monitoring sy stem to collect env ironmental data from the field e Improve the data transmission quality of service
169. od to have some instruments such as global positioning system GPS measurement t apes binocular compass etc f or recording some use ful data su chas GPS position of the t owers hei ghts of towers azimuth etc that may be very helpful while designing the system Table 6 1 Field survey data FEATURE Height of antenna 25m 9m Azimuth 1 4 181 4 Elevation 242 m 217 m Latitude 33 214285 33 25689 Longitude 97 151106 97 149883 Link distance 4 74 km Line Of Sight Clear Cable length 20 m 12 m Tower type Pole Building Pole Ground 142 6 3 Technical Design After completion of field survey itis worth re examining the design and making some necessary modifications according to the result obtained from the field survey if needed Technical design is very crucial part of any project or system because overall output or performance relies on how well your system is and that rely on technical design Once the sites are chosen it is time to design the system accordingly For this work the goal was to use DP_WS EESAT was the new site chosen accordingly after a field survey 6 3 1 Selection of Propagation Model Itis not g ood deci sion to travel thousands of miles by car you rather choose airplane and itis not good either to choose airplane for a very short distance journey car might be the best choice for this As discussed earlier in Section 5 2 4 in order to pr edict out t he receive power evel there are two options to se
170. of 2 Mbytes SRAM and available optional memory extends up to 4 Mbytes Instead of 2 5 V it has 5 V input range allowing the sensors output of 5 V without the use of voltage divider For communication with other external devices in addi tion to C S I O se rial port it also offers two other additional different ports an RS 232 serial port anda 40 pin parallel p eripheral p ort CR1000 comes up with processing sp eed 4 times faster than that of retired CR10X 6 A picture of a typical CR1000 is shown above in Figure 3 1 ii Wiring Panel CR1000 has various input output ports power and g round terminals etc To power the datalogger the voltage requiredis 12 V DC but itcan intake 19 voltages within the range of 9 6 16 V 6 A picture showing terminals and I O ports of CR1000 wiring panel is given below in Figure 3 3 2 pulse counting 3 switched channels excitation channels 8 Differential RS 232 port 16 single ended if Analog inputs i mw 40 pin Parallel 3 G erie peripheral port Power and ay ground terminals wu 8 Digital 9 pin CS I O I O ports port Figure 3 3 Wiring Panel of CR1000 In C R1000 wiring panel also there is a 12 V and a pow er ground G terminals used to supply 12 V DC power to the datalogger via external 12 V battery The terminals labeled 1H to 8L are analog inputs H refers to high input and L refers to low input for differential channels So there are altogether 8 high and
171. of PC1 and P C2 ar e 192 168 1 10 and 192 168 1 11 respectively The PC1 is connected to its Nanostation2 whose IP address is 192 168 1 31 with Cat5 cable and PC2 is connected to its Nanostation2 whose IP address is 192 168 1 35 as shown in above Figure 8 5 The cables are only 3 m long The experiment is carried out inside a room where the nanostations are kept 4 m apart with a perfect line of sight Several experiments will be discussed keeping the physical positions of the nanostations unchanged but changing some parameters of N anostation2 That m eans al t he ex periments t hat w ill be discussed in this Section 8 1 3 will refer to the same experimental setup shown in Figure 8 5 Now se veral ex perimental r esults obtained by usi ng perf willb e discussed A v ideo f ile video3 wmv of size 42 9 M Bytes is transferred and recorded the output throughput every time changing data rate and Tx power 202 Experiment 1 Parameters Settings Tx power 11 dBm Data Rate 13 5 Mbps Rate Mode Quarter RSL 16 dBm Administrator D Windows system32 cmd exe O x Client connecting to 192 168 1 11 TCP port 5001 TCP window size 8 00 KByte default local 192 168 1 10 port 64054 connected with 192 168 1 11 port 5001 Interval Transfer Bandwidth 0 0 5 0 sec 92 MBytes 90 Mbits sec 5 0 10 0 sec 94 MBytes 93 Mbits sec 10 0 15 0 sec 95 MBytes 94 Mbits sec 15 0 20 0 sec 95 MBytes 95 Mbits sec 20 0 25 0 sec 92 MBytes 90 M
172. of advanced page operating in conservative rate algorithm mode 21 Conservative off Zz B miles 4 8 km Allow All No QoS Figure 3 21 Advanced Page in Conservative Rate Algorithm Mode 54 This page has antennas ettings allowing us toc hooset he antenna polarization Three op tions are vertical horizontal and adaptive pol arizations Vertical and horizontal polarization systems are quite common and hence widely used but the new adaptive polarization technique dynamically chooses the best polarity It allows beam polarities to switch dynamically to get better reception for improved performance even in heavily noisy environments also Besides these advanced page allows user to set and select different parameters such as noise immunity request to send RTS threshold multicast data and multicast rate etc 21 e Services This page covers the co nfiguration o f sy stem m anagement s ervices Simple Network Management Protocol SNMP hereafter and ping watchdog It has ping watchdog feature that includes several other features like enable ping watchdog IP address to ping ping interval startup dlay and failure count to reboot After ena bling pi ng watchdog by ch eckingon the c heckbox it continuously pings the target device whose IP address is defined in IP address to ping box The ping works by sending Internet Control Message Protocol ICMP echo request to the destination host and listening for CMP
173. og and d ownloaded to C R10X Ith as internal m emory of 12 8 Kb ytes SRAM available opt ional m emory upt o2 Mbytes which is nearly equivalent to 60 000 data points 5 A picture of a typical CR10X is shown above in Figure 3 1 i 14 Wiring Panel Wiring panel is a panel which provides terminals for connecting sensors power and co mmunication d evices It al soi ncorporates protection ag ainst lightning CR10X has various input output ports power and ground terminals etc To power the datalogger the voltage level required is 12 V DC but it can intake voltages within the range of 9 6 16 V 5 A picture showing terminals and I O ports of CR10X wiring panel is given below in Figure 3 2 6 Differential Power and 12 single ended Ground Analog Inputs Connections f Se errr E ms 9 pin CS I O 3 Switched Gier ee o CR10X WIRING PANEL A Port Excitation Channels 2 Pulse Counting 8 Digital 1 O Control Port Channels Figure 3 2 Wiring Panel of CR10X There are a 12 V and a power ground G terminals used to supply 12 V DC power to the CR10X datalogger via external 12 V battery The G terminals are directly connected to the Earth terminal The terminals labeled 1H to 6L are analog inputs H refers to high input and L refers to ow input for differential channels So there are altogether 6 high and 6 low differential input channels 5 For single ended measurements either H or L can be used as an independent 15 ch
174. oggerNet 3 4 1 and CRBasic programming editor used to run the datalogger for data collection This section also di scusses an al ternative pr ogram cr eating t ool for C R1000 kn own as transformer utility The program created using the transformer utility can directly be sent to the datalogger In addition to this this section also includes some future work such as ethernet interface installation and its configuration which will enable to connection between the datalogger and the Nanostation2 4 2 1 Functional Overview of DP_WS Solar Panel SP20 y N A gt y Ns2 EEL d gt Battery Charging Regulator Backup 12V 7 Ahr ae net Weather Station nterlace Datalogger cR1000 y Environmental gt N Sensors Figure 4 9 Functional Overview of DP_WS 73 Above Figure 4 9 is the functional block diagram of DP_WS There is one station in DP_WS measuring v arious kinds of environmental parameters A CR1000 datalogger is used as a measurement and control module As in GBC_WS the DP_WS is also powered by a 12 V 7 Ahr sealed lead acid rechargeable battery A SP20 solar panel is used as a charging source A charging regulator CH100 is connected to both solar panel and battery as well Different ki nds of environmental se nsors and so ilm oisture se nsors are connected with weather station datalogger There is also an ethernet interface connected with the datalogger and the Nanostation2 In
175. om 2 412 GHz for channel 1 and 2 484 G Hz f or channel 14 In US channel sy stem there are three non overlapping channels Channel 1 Channel 6 and Channel 11 whereas in Europe channel system there are 4 n on overlapping channels Channel 1 Channel 5 Channel 9 and Channel 13 34 Butin practice Europe also follows three non overlapping channel system Table 5 2 shows channel allocation in 2 4 GHz Table 5 2 2 4 GHz channel allocation Channel Lower Frequency Center Frequency Upper Frequency Number MHz MHz MHz 1 2 3 4 5 6 7 8 95 Because every country has its own regulation not all the 14 channels are allowed t o use in allco untries Some c ountries have restrictions ons ome channels F or ex ample F CC in U S al lowed onl y 11 ch annels for use T his channeling sy stem is also ca lled North American S ystem T hat means the 3 channels are restricted to use by public in USA 85 Similarly only 13 channels are allowed 1 channel restricted in Europe Japan allowed almost all of the 14 channels with the exclusion of that only 80 2 11b can be usedinchannel 14 Beside this 13 channels are allowed to use in Europe and most of the world 32 Table 5 3 shows channels allowed in 2 4 GHz in different countries Table 5 3 Channels allowed in 2 4 GHz band Channel Center Frequency Number MHz TA Yes Yes Yes Yes Yes Yes Yes 1 2 3 4 5 6 7 8 Yes Yes Yes Yes Yes Yes 802 11b only 96
176. omputer Supervisory control and data acquisition Serial data interface Single ended Super high frequency Simple Network Management Protocol Signal to noise ratio Service set identification Shared Wireless Access Protocol Transmission Control Protocol Internet Protocol User Datagram Protocol xix UHF UMTS UNT UTP UV UWB VHF VLF VWC WDS WEP Wi Fi WiMAX WLAN WPA WRAN Ultra high frequency Universal mobile telecommunication system University of North Texas Unshielded twisted pair Ultraviolet Ultra wide band Very high frequency Very low frequency Volumetric water content Wireless distribution system Wired equivalent privacy Wireless fidelity Worldwide Interoperability for Microwave Access Wireless local area networking Wi Fi protected access Wireless regional area networks XX CHAPTER 1 INTRODUCTION Real time environmental monitoring is the process of collecting environmental data of a particular area by deploying an automated station where different kinds of environmental sensors are connected Environmental parameters such as wind speed and wind direction rainfall solar radiation air pressure air temperature relative humidity etc can be measured with the help of those sensors deployed in the field The present thesis is based on the field work carried out at Greenbelt Weather and Soil Station GBC_WS hereafter located at the Greenbelt Corridor of the Ray R
177. onfiguration tool can be clicked to select a new system configuration file and upload button can be clicked to transfer that new configuration file That new system configuration file will take effect after appl y button is activated and the system is rebooted It is highly recommended that you keep the backup of the system configuration file before uploading a new configuration file And another important thing is use only configuration files backups of same device type for that the backup configurations file of Nanostation2 only works for Nanostation2 and doesn t work for any other device type such as Powerstation2 or Litestation2 or Nanostation5 etc The snapshot of system page is given in Figure 3 23 21 57 NS2 ar2316 v2 2 1 2476 080208 1627 Figure 3 23 System Page 58 3 2 2 Ethernet Interface Ethernet interface is used to connect those devices which don t normally have an ethernet port on it with a PC making it possi ble for communication between them The ethernet interface that will be used in this project is NL120 from Campbell Scientific Inc that allows the CR1000 datalogger to communicate over a local network or a dedicated internet connection via TCP IP 22 Pictures of a typical NL120 left and its connection to 40 pin peripheral port of CR1000 datalogger right are shown in the Figure 3 26 below r NL120 5 CAMPBELL SCIENTIFIC ii NL120 connected to 40 pin peripheral of CR1000 Figure 3 24 NL120 Table 3
178. opagation model is used to pr edict r eceived si gnal strength when the LOS path between Tx and Rx is clear 120 direct path TX Ground Rx Figure 5 10 Free Space Propagation Model A schematic diagram of free space propagation model is shown in above Figure 5 10 where d is the direct path distance and h and h are the heights of transmitting and receiving antenna respectively The receive power Pr dB of the signal at t her eceiving si tei s given by the formula 62 knownas Friis transmission formula which is as follows _ PGG X Equation 5 1 4r d 3 Po e E a ener ae ee ree eer een Tee where P Transmitted power of the signal G Transmitting antenna gain G Receiving antenna gain d distance between Tx and Rx antenna A wavelength of the propagating signal 121 Expressing the above expression in logarithmic form we get P dBm P dBm G dB G dB FSL AB o n Equation 5 2 where P Transmitted power of the signal in dBm G Transmitting antenna gain in dB G Receiving antenna gain in dB FSL Free Space Loss in dB Inverse square law states that the power density of an el ectromagnetic wave at a point is proportional to the inverse of the square of the distance from the source Let P4 be the power distributed over a large spherical surface area at a distance r from the transmitting source then power density or signal strength is given by 63 P P e a A where
179. or EESAT_NS2 DPWS_NS2 Link For the test each N anostation2 is connected to a P C in either site as shown in the Figure 8 10 above The EESAT_NS2 is connected to PC1 thatis running perf in server mode and DPWS_NS2 to P C2 thatis running perf in 207 client m ode The P addresses of EESAT_NS2 and D PWS _NS2 are setas 129 120 9 226 and 129 120 9 227 respectively Similarly I P addresses of P C1 and PC2 are setas 129 120 9 238 and 129 120 9 237 respectively The t wo nanostations are 4 74 km apart from each other EESAT_NS2 and DPWS_NS2 are connected to the PC1and PC2 by 25 m and 12 m Cat5 cables respectively Now various throughput results obtained using perf first by changing Tx power and then by changing data rate will be discussed In addition in order to tally the results for their accuracy the tests are repeated using network speed test tool For all the experiments that are going to performed all the physical set up shown in Figure 8 10 will be ke pt unchanged All the experiments discussed in this Section 8 2 will refer to the same experimental setup shown in Figure 8 9 8 2 1 Throughput Measurements Using Iperf In this section throughout measurements of EESAT_NS2 DPWS_NS2 link using Iperf are performed First two tests at two different Tx powers one at 11 dBm and another at 26 dBm will be performed Then another two tests at two different data rates one at 13 5 Mbps and another at 54 Mbps will be performed The first tw
180. order to control the rapidly increasing interference 92 there is a regulatory limit set for all devices to stay under 100 mW of output power 30 This confines the range of transmission which may be troublesome in many ap plications where range is important The 2 4 GHz Wi Fi users are even more prone to interference because they suffer interference not only from other Wi Fi users but also from other technologies sharing the same frequency spectrum suchas microwave o vens cordless phones wireless transmitters such as baby monitors and etc So Wi Fi has a great challenge to overcome this drawback to improve system performance Wi Fi p ower co nsumptioni s quite higheras comparedt o other technologies Speed of W i Fi t ypically r anging f rom 2M bps to 54M bps is relatively slower than that of the slowest common 100 Mbps wired LAN One of the encr yption methods called WEP Wired eq uivalence p rivacy has been shown to be breakable So access points can be used to steal important and personal information transmitted via Wi Fi users 5 1 3 Wi Fi Channels Wi Fi works on three different frequency spectrums which are 2 4 GHz 3 6 GHz and 5 GHz Wi Fi 802 11a operates on 5 GHz band Wi Fi 802 11b and 802 11g operate on 2 4 GHz and Wi Fi 802 11n on both 2 4 and 5 GHz band Wi Fi 802 11y operates on 3 6 GHz 31 33 Among these three channels 2 4 GHz is the most popular and widely used Wi Fi band This band of operation is an unlicensed b
181. otential interference Selection of Channel Selection of channel may be one of the most important tasks especially when the channel to be used is already crowded by other applications 2 4 GHz application here When deploying the s ystem one should carefully se lect the channel so that there s as less interference as possible from and to other running systems Significant amount of interference can degrade the performance of both the interferer and the system being interfered In or der t o ex plain how w isely t he ch annel ca n bes elected w hen deploying an ew system a picture of North American ch annel system for 2 4 GHz is shown below in Figure 7 5 34 The US system only allows 11 channels though other extra two channels are also allowed in Europe and one additional on top of that in Japan The 2 4 GHz channel system operating range is 2 4 2 4835 GHz spanning over the total band of 83 5 MHz 29 32 175 3 Non overlapping Channels Ch 1 Ch 6 Ch 11 v V V 2412 2417 2422 2427 2432 2437 2442 2447 2452 2457 2462 2483 HY 5 MHz 22 MHz So re _ v OOOO eS 83 5 MHz Figure 7 5 A 2 4 GHz North American Channel System There are 11 channels Ch 1 Ch 11 one of each separated by 5 M Hz from i ts a djacent c hannel The c hannel bandwidth i s 22 M Hz A mong 11 channels there are only 3 non ov erlapping channels as shown in the ab ove figure shaded by red color 34 They are Ch 1 Ch 6 and Ch 11 These
182. output Other voltage output Scan rate A D conversion Switched volt excitation channel Programming Datalogger support software Operating systems Communication protocol Standard Temperature Range Dimension Weight 9 6 16 Vdc optimum 12 V Quiescent 1 3 mA Processing 13 mA Active 46 mA 12 Single Ended 6 Differential 8 I Os C1 C8 2 P1 P2 1 CS I O Internal memory 128 Kbytes SRAM available up to 2 Mbytes 2 5 V two 12 V two 5 V and two 12 V 64 Hz 13 bits 3 E1 E2 amp E3 Edlog PC208W LoggerNet 2 x PC400 Mixed Array Table PakBus Modbus ALERT Modbus ALERT 25 C 50 C 7 8 x 3 5 x 1 5 2 Ibs 18 b CR1000 Like CR10X it is also a fully programmable datalogger with a non volatile memory Itis anew product of Campbell Scientific Inc designed especially for replacing the old CR10X to add upgrade and improve some of the features of CR10X I tis also widely use di nm eteorological r esearch r outine w eather measurement ap plications and ot her kinds of network applications It is also designed for unattended network applications It has a high resolution 13 bit A D conversion with higher sp eed of scan rate of 100 Hz CR1000 is compatible with various datalogger support software like LoggerNet3 x PC400 1 2 ShortCut 2 2 etc The program can be written and compiled in a program editor called CRBasic Facilitating more storage it has an internal memory
183. own in Figure 3 10 13 Reference air pressure ee Cable gland lt lt _ Ceramic cup i T4 segments ii T4 deployed in field Figure 3 10 T4 Tensiometer 34 T4 Tensiometer has 5 wires brown white bl ue black and thick bl ack used for supply signal supply signal and shield respectively This means it uses DIFF channel of the datalogger The TE525 connections to C R10X and CR1000 dataloggers are shown below in Table 3 9 13 Table 3 9 T4 wiring with CR10X and CR1000 DESCRIPTION COLOR CR10X CR1000 Supply Brown 5V Signal White 1H Supply Blue AG Signal Black 1L Shield Thick black G 3 1 3 Powering and Charging Devices In order to perform any desired operation an electrical power is required for all systems that consist of electrical and electronic devices In addition to that the power sy stem is always expected to function well and its gravity is even higher in the system applications such as mobile services and etc where even a few se conds o f pow er failure i s no tt olerable Depending u pont he t ype of application the components of a power system vary The power system for this work is composed of battery backup solar panel and ch arging regulator Other elements such as AC power power supply adapters etc are also discussed in this section 35 a Battery Backup Battery backup is an important component of power sy stem in weather monitoring appl ication and itis indispensabl
184. pplies and Charging Regulators Instruction Manual Available http www campbellsci ca Catalogue PS12LA pdf Campbell Scientific Inc August 19 SC32B Optically Isolated RS 232 Interface Available http www campbellsci com documents manuals sc32b pdf Ubiquiti Networks August 20 NanoStation2 Datasheet Available http www ubnt com downloads ns2_datasheet pdf Ubiquiti Networks August 20 AirOS Available http wiki ubnt com wiki index php AirOS Campbell Scientific Inc August 21 NL120 Ethernet Module Available http www campbellsci com documents manuals nl120 pdf Electronics Manufacturer October 02 Network Switch Available http www electronics manufacturers com products computer networking network switch 251 24 25 26 27 28 29 30 31 32 33 Netgear October 02 PROSAFE 8 PORT 10 100 DESKTOP SWITCH FS108 Available http www netgear com Products Switches DesktopSwitches FS108 aspx Campbell Scientific Inc August 21 PC208W Datalogger Support Software Instruction Manual Available http www campbellsci com documents manuals pc208w pdf Campbell Scientific Inc August 21 LoggerNet Available http www campbellsci com documents manuals loggernet pdf Wikipedia August 22 Electromagnetic spectrum Available http en wikipedia org wiki Electromagnetic_spectrum Radio Eelctronics August 23 Wireless Technologies Available http www radio electronics com info
185. put Test Setup for EESAT_NS2 DPWS_NS2 Link 207 8 11 Throughput Result of Experiment 8 2 1 1 cece eeeeeeeeeeeeeeeeeeeeeeeeeeees 209 8 12 Throughput Result of Experiment 8 2 1 2 2 0 2 cceeeeeeeeeeeeeeeeeeeteeeeeeeeeeees 210 8 13 Throughput Result of Experiment 8 2 1 3 20 0 0 ccc eeeeeeeeeeeeeeeeeeeeeeeeeeeees 211 8 14 Throughput Result of Experiment 8 2 1 4 0 cece eeeceeeeeeeeeeeeeeeeeeeeteees 212 8 15 Throughput Result of Experiment 8 2 2 1 cc cccceeeeeeceeeeeeeeeeeeteeeeeeeeeeees 215 8 16 Throughput Result of Experiment 8 2 2 2 0 ccccccceececeeeeeeeeeeeeeeeeeeeeeeeees 216 8 17 Throughput Result of Experiment 8 2 2 3 20 00 cccceceeeeeeeeeeeeeeeeeeeeeeeeeeeeees 217 8 18 Throughput Result of Experiment 8 2 2 4 ccecccccccceeeeeeeeeeeeeeeeeeeeeeeeees 218 8 19 Data Rate Vs Throughput for IEEE802 119 nnn 224 xvi AAP ASCII BASIC Cat 5 CCK CDMA CRI DECT DHCP DIFF DP_WS DPWS_NS2 DSSS EESAT EESAT_NS2 EHF ELF ESSID EWMA LIST OF ACRONYMS Adaptive antenna polarity American Standard Code for Information Interchange Beginner s All purpose Symbolic Instruction Code Category 5 Complementary code keying Code division multiple access Computing research infrastructure Digital European cordless telephone Dynamic Host Control Protocol Differential Discovery Park Weather Station Discovery Park Weather Station Nanostation2 Direct sequence spread spectrum Environm
186. r 0 3 3 0 GHz and Super high frequency SHF hereafter 3 0 30 GHz frequency bands of electromagnetic spectrum 27 Wi Fi is becoming popul arm oreand m oresi nce 89 last few years when 802 11b was first used in 1999 with 11 Mbps of maximum speed With Wi Fi i tis possible to cr eate high speed wireless local ar ea networks WLAN O ther WLAN t echnologies suchas bluetooth Worldwide Interoperability for Microwave Access WiMAX IEEE 802 16 Wibree Zigbee 802 15 4 Wireless Regional Area Networks WRAN IEEE 802 22 Ultra wide band UWB 3 1 10 6 GH z Near f ield communication NFC 13 56 MH 2 Digital E uropean c ordless telephone DECT 1880 1900 M Hz and HomeRF shared wireless access protocol SWAP 2 4 GHz etc are also developing and growing fast to make their own place in the market 28 5 1 1 History Evolution of Wi Fi In the beginning Wi Fi was called Hi Fi meaning High Fidelity Later on August 1999 the term Wi Fi was used officially for the first time Unlicensed spread spectrum was first made available in US by the Federal Communications Commission FCC in rules adopted by May 9 1985 and later FCC regulations were followed with some modifications in many other countries 29 Nowadays Wi Fi t echnologyis widely used al most everywhere i ncluding aptops P Cs smartphones printers and other peripherals Before today Wi Fi traversed many IEEE standards with technical modifications 802
187. r intakes an u nregulated pow er from solar panelor AC wall charger and charges the battery connected to it as well as supply power to the system simultaneously Itis an essential element for almost all the systems that 39 require ac onstant voltage input supply The charging regulators CH12R and CH100 are used in GBC Weather Station and DP Weather Station respectively Actually CH12R comes with PS12LA power supply which includes 12 V 7 Ahr battery and CH100 comes with PS100 which includes 12 V 7 Ahr battery Figure 3 13 below shows the circuit diagram of CH12R CH100 charging regulator 18 12 V Battery ve terminals 3 12 V Battery ve terminals Regulator Charging OUT 3 Thermal Regulator jN Fuse Fima Charging source Figure 3 13 Charging Regulator Circuit Diagram 40 The ab ove F igure 3 13 18 clearly sh ows the ci rcuit di agram o f t he charging r egulator s being used B ecause both ther egulators CH12R and CH100 has the same circuitry the figure above explains both The T able 3 11 shows the technical specifications of the charging regulator 18 Table 3 12 Technical specifications of charging regulator SPECIFICATIONS DESCRIPTION CH12R CH100 15 28 Vdc 15 28 V dc Input voltage CHG terminals 18 V ac rms 18 V ac rms 12 V unregulated 12 V unregulated Output voltage 12 terminals aaa te Gaps Se Current limited 3 Amp 3 Amp Temperature compensat
188. r rrr Tx Rx Figure 5 12 Two Ray Propagation Model 125 The direct d1 and ground reflected d2 paths are denoted by violet and pink respectively ht and h are the heights of Tx and Rx antenna The received power is given by Equation 5 3 65 66 PG G h h P d Me d L EE E E E A caval osne ou TEE Equation 5 3 It can be shown that the receive power decreases by 12 dB octave or 40 dB decade That means when the transmission distance is doubled the receive power decreases by 12 dB and when the distance is made 10 times greater it decreases by 40 dB 55 Path and Phase Difference Path difference is the difference in path length between the direct and reflected signal From the above Figure 5 12 the path difference Ad between direct and ground reflected paths can be expressed as follows 66 Ad d d h h d J h h d when d gt gt h h then using Taylor series approximation the above expression can be approximated as 2h h Ad d d 7 Phase difference A is the difference in phase of the two direct and ground reflected paths given by the following formula 66 _ 2m Aa A c A0 where w is the angular frequency of the signal 126 5 2 5 Path Loss Path loss is the reduction of signal strength of an electromagnetic wave as it propagates through the medium In wireless communication the term medium refers to space between Tx antenna and Rx antenna Path loss is ve
189. r the lower band UHF and the upper band EHF Butin all cases microwave includes the e ntire S HF band 3 30 G Hz 27 5 1 Allt he Wi Fi oper ating frequencies lie in UHF and SHF bands highlighted in blue color According to the wavelength or frequency of electromagnetic waves they are classified into several types Listing them according to descending order of wavelength longer to shorter they are as follows radio waves microwaves infrared rays visible light ultraviolet rays X rays and gamma rays 108 Table 5 8 Electromagnetic spectrum FREQUENCY 3 30 Hz 30 300 Hz 300 3000 Hz 3 30 kHz 30 300 kHz 300 3000 kHz 3 30 MHz 30 300 MHz 300 3000 GHz 3 30 THz 30 300 THz 100 10 Mm 10 1 Mm 1000 100 km 100 10 km 10 1 km 1000 100 m 100 10 m 10 1 m 1000 100 um 100 10 um 10 1 ym SYMBOL WAVELENGTH NAME Radio Wave Infra Red rays 400 790 THz 750 3000 THz 3 30 PHz 30 300 PHz 300 3000 PHz 3 30 EHz 30 300 EHz 5 2 1 Types of Radio Waves 750 380 nm 400 100 nm 100 10 nm 10 1 nm 1000 100 pm 100 10 pm 10 1 pm Visible light Ultraviolet rays X rays Gamma rays Radio waves propagating from transmitter to receiver undergo different kinds of phenomenon such as reflection refraction diffraction a nd sca ttering 109 before reaching the receiver Not all the radio signals undergo all of the above mentioned phenomenon i tdep ends upon thet ypeo fm ediumt hey ar e propagating and also
190. re y result at RAIN PulseCount RAIN_tot 1 2 2 0 0 01 0 Read wind speed sensor convert to mph and store at WS_mph PulseCount WS_mph 1 1 1 1 1 677 0 4 Read wind direction sensor convert to degrees from north and 246 0 store reult at WD_deg BRHalf WD_deg 1 mV2500 3 VX2 1 2500 False 20000 Compute statistics and totals for some weather variables and store results into input storage locations so that they can later be sent to the moisture data logger If on a 15 minute interval then set the output flag high to enable storing results in input storage area CallTable Tablel Average all solar radiation readings and store the result at Sun_W_m2 2905 399 If Tablel output 1 1 true Then GetRecord SUN_W_m2Array Tablel 1 Compute the net wind vector and the average wind speed Store the average wind speed at WIND_ave and store the net wind vector direction at WIND_dir If Tablel output 1 1 true Then GetRecord WIND_aveArray Tablel 1 Compute the maximum wind velocity and store at WIND_max If Tablel output 1 1 true Then GetRecord WIND_maxArray Tablel 1 Total all rainfall for 15 minute interval and store at RAIN_tot If Tablel output 1 1 true Then GetRecord RAIN_totArray Tablel 1 Set port 1 high one minute prior to sampling the following sensors Port 1 controls the switched 12 volts which app
191. rguments Purpose Run in server mode Run in client mode UDP tests use UDP rather than TCP Simultaneous bidirectional bandwidth test Bidirectional bandwidth test individually Time in seconds to transmit Interval seconds between periodic BW reports Data format to report TCP window size socket buffer size File input Number of bytes to transmit instead of t For UDP bandwidth to send at in bits s Help 197 8 1 1 Test for 100 Mbps Cat5 Cable For t esting the throughput o f L AN ca ble a1 00M bps Cat5 cable is chosen An experimental set up is shown in the Figure 8 1 below 192 168 1 10 OE 192 168 1 11 Data flow 3 m Cat5 Client Sender Server Receiver Figure 8 1 Throughput Test Setup for Cat5 Cable As shown in Figure 8 1 an experiment was carried out to test the actual throughput ofa 100 Mbps Cat5 cable Two P Cs are connected by 2m Cat5 cable The LAN IP address set to PC1 is 192 168 1 10 and PC2 is 192 168 1 11 Iperf is running in Client mode in PC1 and Server mode in PC2 Now for the test the following command is entered in command prompt of PC2 iperf s Using the following command in PC1 a video file of size 111 MBytes is sent from PC1 to PC2 iperf c 192 168 1 11 F sg_video mpg i 1 t 60 In abov e co mmand t he P ad dress of de stination or se rver PC2 is entered after the argument c Similarly a video file sg_video mpg is allowed to be sent using the argument F Other opt
192. rom other devices using same channel Though the manufacturers qualify their products performance by the data rates this parameter alone does not define the system performance but it s the throughput that does so For example though it is rated 100 Mbps of data rate in Cat5 LAN cable its actual speed is only around 93 Mbps which can be called as its throughput Also the maximum theoretical data rate of 802 11b WLAN is 11 Mbps while the actual speed is around 6 Mbps only 84 Therefore the throughput gives the actual speed at which the data can be transmitted Bandwidth Though a bandwidth originally refers to a measure of a width of frequency range often used quite frequently in the world of digital communication in recent years many people have been using the term bandwidth to refer to the channel capacity of a digital communication line 85 In addition the terms bandwidth and throughput are used interchangeably quite often these days But there are some key differences between these two terms Bandwidth is the total channel capacity which refers to the maximum rate at which data can be transferred over a given link Throughput is the amount of 193 the capacity that the system actually utilizes in that given period T hroughput refers to the act ual speed over the communication link Fora given sy stem depending upon the time and the physical infrastructure of the link or network throughout may differ accordingly
193. rom the field aut omatically j ust by checking on Scheduled Collection Enabled box either in EZSetup wizard or in Schedule tab of Setup wizard Alsoa Loggernnet canbe setto enable the PC collect data automatically For this the schedule for the device CR1000 here can be copied to other devices by selecting Apply to Other Stations in Schedule tab of Setup wizard A ndi f LoggerNet 3 4 1 is puti nt he Windows startup g roup it automatically oads when the P Cis turned on and st arts to collect the data automatically 26 4 2 3 CRBasic Programming Editor for CR10X A CRBasic is a tool for creating editing and documenting program that has more control over m easurements and w hich i s designed esp ecially f or dataloggers suchas C R1000and etc This toolis intended especially f or 82 experienced datalogger programmers who need more flexibility and control over the da talogger oper ation w hich ca n t be a chieved by usi ng S hort C ut Ina CRBasic editor a complete datalogger program can be written and saved When a CRBasic program is saved a CR1 extension is automatically added after the program s name It is the file which users can edit again and again eee RAAEN Aonitor d eo File Edit Search Compile Template Instruction Options Goto Window Help DAHAR ce RAR ABH Sub Subroutines8 Send current time hr min sec to weather logger Note the weather logger invokes this su
194. rounding cable was run from the lightning arrestor to the grounding connection of the DP_WS In order to make the pole sturdy it is supported by six guy wires 156 in three different directions It is very important for the pole to be sturdy or at least unaffected by strong wind Otherwise if the pole swings due to strong wind then there may be a great fluctuation in RSL and the link may break down if the RSL value goes below its threshold Rx sensitivity Here also compass was used to adjust the orientation of Nanostation2 and once it was adjusted then the pole was made st urdy by tightening t he kn ots of the guy wires The N anostation2 at DP_WS is powered by AC power installed inside DP_WS area A pole with the Nanostation2 mounted at DP_WS is shown in Figure 6 10 ii Installation of Nanostation2 at EESAT Building For the installation o f Nanostation2 in E ESAT building a pole inthe terrace which has been used for ultraviolet UV sensor is chosen The pole is around 5 m tall and the height of EESAT building from ground to the base where the UV pole has been installed is about 20 m So the total height of the antenna is about 25m Nanostation2 was mountedinthe UV pole directing towards DPWS_NS2 using compass as shown in Figure 6 10 i Because DPWS_NS2 is slightly visible from E ESAT building the orientation of Nanostation2 in E ESAT could easily be adjusted without using compass However a compass was also used for fine adjustment
195. rsa Therefore its selection should also be done wisely depending upon the system demand and condition Since there were already so much crowd in 2 4 GHz Wi Fi channel not to be severely affected and also not to affect other system severely smallest available spectral width of 5 MHz is chosen for the system 222 8 4 Selection of IEEE 802 11 mode A lot of Wi Fi devices that are compatible with various IEEE st andards are e asily available int oday s market F or example the device compatible with both 802 11g and 802 11b standards can easily be found Although this is good for interoperability it is not always required For example when 802 11b excludes from the network in order to avoid unnecessary interference and thus achieve greater throughput Tx power settings As throughput increases as Tx power is increased it is always good to transmit at high power but staying within the limit set by the country regulation Besides that it sh ould also be made sure that other systems are not being affected bythe high power used However a few amount o f interference from and to ot her sy stems should b et olerable because the common unlicensed channel 2 4 GHz is shared For the link EESAT_NS2 DPWS _NS2z2 since it is quite long 4 74 km and the radiation is directional the signal is transmitted at its highest power i e at 26 dBm Impact of Data Rate on Throughput Table 8 12 shows various results of the throughput experime
196. rtant when the link distance is long because a small disorientation of Tx antenna can result in targeting Rx antenna in a wrong direction in a great deal This is depicted in a Figure 7 2 below A waste of radiated energy Transmitting in perfect direction Figure 7 2 Waste of Energy Due to Improper Antenna Adjustment 170 In above Figure 7 2 it is noticed that only a few portion of energy denoted by dotted green line is captured by Rx antenna when antenna is fixed in position A In this case some part of energy denoted by dotted orange line is wasted due to the improper alignment of antenna A But when the antenna is fixed in position B then almost all of the energy radiated is captured by the Rx antenna Tilting of Antenna In radio link where the two sites are in different height levels there is a need of tilting of antenna It s sometimes necessary to tilt the antenna especially when one site is at much higher or lower altitude relative to the other In such a situation one cannot establish a r adio link without tilting of antenna So tilting should be done in such a way that the receiving antenna gets almost all of the radiated energy There are two types of tilting v ertical and hor izontal t ilting Mostly vertical tilting is widely used in most of the radio link system Down tilting Up tilting Transmitting in perfect direction Figure 7 3 Vertical Tilting of Antenna 171 Tightening of Knots and Bol
197. ry important element in the design of any radio communication systems or wireless system Path loss determines many other elements of the system such as Tx power frequency of operation ant enna si ze ant enna g ain antenna h eight and al so receiver sensitivity etc So itis very important to figure out the causes of path loss and calculate how much path loss will occur for a given system To calculate the total path loss it s worthwhile to find out its individual contributors which collectively form path loss Some major constituents of path loss free s pace oss attenuation m ultipath f ading diffraction loss etc Friis transmission formula given by the Equation 5 2 P dBm P dBm G dB G dB FSL dB is a formula to predict receive power in ani deal condition where there are no other losses except F SL But in practical we do have alot of other losses also beside FSL So Equation 5 2 can be rewritten as P dBm P dBm G dB G dB Path _loss dB 000000 Equation 5 4 where path_loss dB is the total losses occurred while propagating from Tx to Rx given by the following expression Path _loss FSL dB A dB L dB L dB L GB 0 00 Equation 5 5 127 where FSL Free Space Loss A Attenuation Lmt Loss due to multipath fading Lait Loss due to diffraction Li Loss due to transmission line between Tx Rx and Tx Rx antenna Free Space Loss Free space loss FSL is the loss
198. s about 2 25 Km from GBC WS The preliminary tests indicated lack of line of sight between these two sites because of the tall trees of the Greenbelt forest The tests were conducted with aN anostation2 attachedtoa 9m pole in either site Itis estimated that a tall pole or a tower of at least 20 m height is required at both sites to have good LOS path This work may serve as reference for those who want to set up a radio link for any kind of application especially that require higher data throughput And because the technology used is unlicensed throughout the world this thesis can inspire w ork to deploy wireless internet service i nr emote andr ural areas especially in developing countries 227 APPENDIX A EDLOG PROGRAM CODE FOR GBC_WS 228 i Weather Station Program Code CR10X T This program stores the time and all weather data in final storage every fifteen minutes Rainfall is totaled for A the entire 15 minute interval The wind vector instruction is used to store average wind speed and direction Also maximum wind speed is computed and stored Weather data are transferred to the soil moisture data logger every fifteen 7 minutes one minute after it is collected The time clock of the weather logger is synchronized to that of the soil moisture logger at 2 10 a m every morning The soil moisture i logger time is updated via cell modem once a day at 2 05 a m Table 1 Program 01 10 Exec
199. s rf signal loss tutorial php WNDW Net Ed Wireless Networking in the Developing World WirelessU org 2007 p pp Pages September 12 Antennas and Large Scale Propagation Available http www ece rochester edu courses ECE245 lectures Lecture2 pdf Ubiquiti Networks September 12 AirView Available http Awww ubnt com airview VE2DBE 1998 September 12 Radio Mobile Freeware Available http www cplus org rmw english1 html 2006 September 15 Planning Link Budgets for Wireless ISP Cell Sites Available http Awww bbwexchange com turnkey planning_wisp_link_budgets asp Wikipedia September 16 Diversity scheme Available http en wikipedia org wiki Diversity_scheme Wikipedia September 16 Antenna diversity Available http en wikipedia org wiki Antenna_diversity 257 78 79 80 81 82 83 84 85 86 87 88 September 20 Radio Waves Available http www irbs com bowditch pdf chapt10 pdf Wikipedia September 20 Fresnel zone Available http en wikipedia org wiki Fresnel_ zone September 20 Fresnel Zone Calculator Available http www afar net fresnel zone calculator Netkrom September 20 Understanding Line of Sight in Wireless Networks Available http www netkrom com about_line_of_sight html Wikipedia September 20 Passive repeater Available http en wikipedia org wiki Passive_repeater Wikipedia September 20 Throughput Available http
200. s which are originally saved i n co mma se parated bi nary or pr intable American Standard f or Information Interchange ASCII format 25 e Help Help toolbar is for PC208W datalogger support software help File Types To run the CR10X datalogger for data collection from the field a program written i n E dlog edi tori s sent to dat alogger in Connect t oolbar T he only compatible program file type that can be sent to the CR10X datalogger is in DLD Download format Actually a DLD file is automatically created by compiling an Edlog program file which is in CSI format CSI files are the Edlog program files that the user edits W hen an E dlog programis saved CSI ex tension i s automatically added to the program s name Also FSL Final storage label and PTI Program trace information files are automatically created during program compilation The FSL files list the final storage labels and are used by SPLIT to help se lect ou tput v alues The PTI f iles show the execution times for each instruction block and table as well as the number of final storage locations used per day The library files having LBR extension allows us to insert a section of a program into any Edlog program 25 The collected data output file type which is downloaded from datalogger to the PC is DAT The INI Initialization files provide the PC208W program with specific information such that the devices or program defaults don t have to be reconf
201. site itis clearly seen that 1 56 ft below the direct path is free of any obstacle So the 1 Fresnel zone at that point is clear ii Calculation Near DPWS_NS2 The nearest possible obstacle that may lie within in the 1 Fresnel zone is at 300 m from the antenna There s a tree of about 5 m height So we have d1 300 m dit d2 4 74 km and d2 4 44 km f 2 422 GHz 5 9m 19 47 ff ve j 3x108 x 300x 4440 1 L Y2 422x10 x4 74x10 186 Now 60 of 5 9 m 3 54 m Conclusion From the field survey at DPWS_NS2 site it is observed that the height of LOS path from the ground at this point 300 m from DPWS_NS2 is at least 10 m and subtracting the 60 of 1 Fresnel zone radius 3 537 m from this height the result is 6 463 m which is still higher than the tallest tree obstacle of height 5 m at this point So the 60 of 1 Fresnel zone is clear iii Calculation at the Center of EESAT_NS2 and DPWS_NS2 Checking if the obstacle lies within in the 1 Fresnel zone at the center of EESAT_NS2 and DPWS_NS2 then Eq 7 3 gives the radius for 1 Fresnel zone at the center of the link We have D 4 74 km f 2 422 GHz Pees ey a ee 4f PER Tan A _ 219 12 m 39 99f1 4x 2 422 Now 60 of 39 99 ft 23 99 ft Conclusion 187 From the field survey at the halfway in between the sites EESAT_NS2 and DPWS_NS2 it is seen that 23 99 ft below the direct path is free of any obstacle So the 1 Fresnel zone at that poi
202. t date and time into input locations he N Ol OY O S Ga rrerrrrrrrroe ODIADTAKRWNHEO year day_of_yr hr min sec Time P18 3 Store Year Day Hr Min Sec in 5 consecutive locations 0 Mod By 30 Loc year End P95 d Program Input Locations T_C 5 5 RH 0 P_mmHg 0 SUN_W_m2 0 WIND_ave 0 WIND_dir 0 WIND_max 0 RAIN_tot a 0 BATT_WTHR 1 1 0 BATT_SM dss i SM1 Sa ih ol SM2 9 1 shi SM3 92S cal SM4 gb L SM5 9 1 1 SM6 17 1 1 SM7 100 SM8 ROO SM9 100 SM10 100 N Oo 242 21 22 23 24 25 26 Arl 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 11 12 CS1 CS2 REQ_ CS1 REQ_CS2 ER_CS1 ER_CS2 TAN R nT U U G year hr min sec hr_min RX_error ENSIO ENSIO_2 ENSIO_3 ENSIO_4 3 q 5 1 day_of_yr 9 1 2 9 1 17 5 5 9 5 D O O OO O OOW HBA TGT O OGOGO NO 17 NNORPRPRFPREERE OO 1 N 0 0 0 0 Program Security 0000 0000 0000 Mode 4 Final Storage Area 2 0 CR10X ID 0 CR10X Power Up 3 1 243 APPENDIX B CRBASIC PROGRAM CODE FOR DP_WS 244 Weather Station Program Code Program name Date written 5 12 2008 Transform Version 0 5 Transform file Version 1 1 C PC208W CR10X_Programs W1 C Program Files Campbel1 CRBasic angle units are in Radians by default Switch to Degrees as CR10 used Degrees Ang
203. tched with the obtained RSL if RSL d ecreases somehow t hen i t r educes t he d ata r ate au tomatically t o maintain the stability of the link e Inappropriate spectral w idth settings Spectral w idth her e in N anostation2 means rate mode Its selection c an c ause a si gnificant difference inthe 220 amount of interference that the system receives There are three options for rate mode Quarter 5 MHz half 10 MHz and full 20 MHz Increasing rate mode obviously increases the throughput but it interferes a lot more than the smaller rate mode Distance between EESAT_NS2 Tx and DPWS_NS2 Rx It is an inevitable factor due to which the maximum achievable throughput is decreased as the Tx Rx separation goes on increasing Detrimental ef fect of co mbined B and G networks Operatingin am ixed environment that includes 802 11b clients can substantially affect throughput For example throughput of 802 11g networks may drop from 25 Mbps to 7 Mbps when 802 11b clients enter the environment 90 Interference from high Tx power As throughput is directly dependent upon Tx power ev ery s ystem w ants tot ransmita tas much hi gheras possi ble knowingly or unkn owingly causing interference to each ot her and he nce degrading the throughput due to the interference from other system 8 3 2 Techniques Used to Maximize the System Throughput Interference Interference is one of the biggest contributors in degrading the throughput
204. tes The weather station datalogger and soil moisture datalogger connect by wire with each other and the program is written in such a way that once the data are collected in both of the dataloggers the data of weather station are transferred to the soil moisture station A single board computer SBC hereafter acts as an interface between the GBC weather station and CRI web server To be more specific it acts as a bridge between the datalogger and the GPRS modem Then those collected data are transmitted to GPRS net work viaa GPRS modem which operates at 900 1800 MHz The modem f orwards the data tot he CRI syst em w eb server where t heya re processed refined and finally made accessible to public via internet 2 2 Environmental Monitoring System in Discovery Park The D P_WS is located at Discovery P ark of UNT situated in Denton Texas USA The system was deployed in October 2008 by the CRI Project Team of UNT Figure 2 3 is the picture of DP_WS taken on June 2009 The main objective w as to setupat estbed fort he pr oject as wellas to monitor environmental co nditions by m easuring di fferent w eather par ameters like air temperature air pr essure r elative h umidity r ainfall w ind sp eed a nd w ind direction and solar radiation and also the so il m oisture ar ound t he w eather station The block diagram of the environmental monitoring system of DP_WS is shown below in Figure 2 4 The DP_WS installed in a tree less area counts wit
205. that customers do perform re calibration for specific soil types Since the ca libration equation v aries with t he so il t ypes appropriate calibration equation for sp ecific soil t ype should be use d Following ar et he calibration equations for three different soil types mineral soil potting soil and rockwool for the probes excited at 2500 mV 12 VWC 11 9x104 x mV O 401 eee ec ececcecececcececececeeececeas Mineral soils VWC 10 3107 x MV 0 334 icecccecceccceceeeceeeeseeeeeeenees Potting soils VWC 2 63x10 x mV 5 07 107 0 0394 cecen Rockwool where VWC volumetric water content of the soil mV output of the probe excited at 2500 mV 12 33 g Tensiometers The T4 Tensiometer is used for measuring the soil water tension and soil water pressure The sensor is factory calibrated with an offset of O kPa when in horizontal position Since the offset of the pressure transducer has a minimal drift over the years it is recommended to check the sensors once a year and re calibrate them every two years The output signal of T4 tensiometer is directly dependent on the supply voltage and hence the su pply voltage needs tobe constant and stabilized The typical supply voltage is 10 6 V DC but can intake any voltage value from 5 to 15 V A typical current consumption is about 1 3 mA at 10 6 V The measuring range of the T4 tensiometer is 85 kPa to 0 kP a of water tension The picture of at ypical T4 tensiometer is sh
206. the day time solar panel supplies power to the system and charges the battery as well Battery gives power to the system during night and also that time whenever the solar panel is not powering the system due to insufficient sunlight The color indices in above Figure 4 9 are same as in Figure 4 1 At every 15m inutes dat a ar ec ollected by dat aloggers vias ensors connected in the station All the data collected from the datalogger are stored in the d atalogger data st orage module Then t he data ar e transmitted t o C RI system server via ethernet interface and Nanostation2 4 2 2 LoggerNet 3 4 1 Datalogger Support Software for CR1000 LoggerNet 3 4 1 is a full featured datalogger support software datalogger that enables users to se tup co nfigure an dr etrieve dat af roma net work of Campbell Scientific dataloggers and share this data over ethernet communication network Loggernet so ftware su pports communication a nd d ata collection for 74 Edlog dataloggers such as CR10X and CRBasic dataloggers such as CR1000 and et c Loggernet is especially desi gned fora pplicationst hatr equire telecommunication or scheduled data retrieval used in large datalogger networks When a CR1000 datalogger is connected with a Loggernet installed PC then after clicking the software icon the main window will be opened which is shown in Figure 4 10 given below There are 12 different buttons in loggernet toolbar having their different unique functions wh
207. tive humidity within the range of 0 to 98 25 The typical supply voltage is 12 V but it can intake any voltage within the range of 7 to 28 V DC And typical current consumption is as low as 2 mA 8 Tripod tower mast a aN Solar radiation P shield i HMP50 ii 41303 6 plate Gill Solar Radiation Shield Rs Figure 3 5 Air Temperature and RH Sensor and Radiation Shield HMP50 has 5w ires black w hite b lue brown andc lear used f or temperature relative humidity signal and power reference power and s hield respectively ts connections to C R10X and C R1000 dataloggers are s hown below in Table 3 4 8 Table 3 4 HMP50 wiring with CR10X and CR1000 DESCRIPTION COLOR CR10X CR1000 Temperature Black SE3 SE1 Relative Humidity White SE4 SE2 Signal and power reference Blue G Power Brown 12 V Shield Clear G 26 c Barometric Pressure Sensor The Vaisala PTB110 barometer CS106 is used form easuring atmospheric air pressure A typical CS106 is shown below in Figure 3 6 i It can measure air pressure within the range 500 mb to 1100 mb operating under the temperature r ange of 40 t o 60 C I t can oper ate undera_ supply v oltage between 10 to 30 V but the nominal is 12 V DC A typical current consumption is about 4 mA during active period and less than 1 pA during quiescent period 9 Jumper lt lt CS106 i CS106 i CS106 jumper setting Figure 3 6 CS106 and Its Jumper
208. traveling in a m edium strike on any objects such as gas molecule water particle etc then they are absorbed by the objects in the medium T his phenomenon i s called a bsorption ofr adiow aves Duet o absorption phenomena t he energyofa _ radiow avei s absorbed wheni t propagates through the medium Low frequencies LF radio waves travel easily through brick and stone very low frequency VLF even penetrates sea water But as the frequency rises absorption effect become more important and hence need to be taken into account while working with higher frequencies Absorption i s often caused by at mosphere and he nce at mospheric absorption i s referred to as attenuation O ne ofthe m ajor ca uses of si gnal attenuation atmospheric absorption is the rain which affects significantly if the radio w ave frequency is greater than 10 GHz Other atmospheric phenomena that ca uses absorption of a radio wave are snow fog cloud etc 56 So this phenomenon is one of the major concerns in microwave co mmunication when operating in higher frequencies 116 5 2 3 Polarization of Radio Wave Property of radio waves that describes the orientation of their oscillations while m ovingt owards the direction of energy pr opagation is known as polarization 58 The plane of polarization of radio waves is the plane in which the electric field E field propagates with respect to the E arth Radio w aves polarization i s perpendiculart ot hew ave s direction o
209. ts Another simple but important task in adj usting antenna is tightening of knots and bolts in antenna clamps while mounting It is also important to check for the knots and bolts or screws used for antenna tilting If they are left not tightened after antenna alignment the strong wind can change their orientation and propagation direction m ay be ch anged which contribute in deteriorate the RSL So after final adjustments of both the antennas it s always good idea to check for all the knots and bolts and screws to ensure thatthe antennas are tightened well If itis done properly then even if there is strong wind it won t affect the antenna position that much Both the Nanostaion2 are adjusted in EESAT and DP_WS with the help of compass And after obtaining an RSL of 68 dBm that matched w ith t hat of design value 67 72 dBm the antennas are fixed and tightened properly 7 2 2 Appropriate Settings of Various Parameters Improper settings of parameters also can result in the system performance degradation in a great deal That s why it is very important to put the values of all the p arameters properly while co nfiguring t he r adio equipment Here in t his section we ll discuss about selection of Rate Mode spectral width Data Rate channel se ttingo f Tx pow er antenna pol arization se tting selection o f IEEE802 11 mode etc 172 Selection of Data Rate Data rate determines at what speed the system can transfer d ata It is
210. tseeeseeteeeeseeteeeeseeseeneeeeteeeeees 24 3 1 3 Powering and Charging DeVICES ceeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeees 35 3 1 4 Optically Isolated RS 232 Interface SC32B eee 41 3 2 Radio COM ONON S e e eeaeee t taee ches euwnsenteerchecensneses ens 43 5 3 2 1 Nanostation2 0 cece cccceccecceccecceceeceeceececaeceeceesesaecaecueaeeaeeaeeneaees 43 9 2 2 Ethernet Interface iscir aia 59 3 2 3 Network Switch esesssssesesseenesseseeeeeeeeeeeerererrerererererrrrrrrerrrereerrent 60 DATA COLLECTION PROCEDURE 2 cccccnonnnwniancekenemee 61 4 1 Greenbelt Weather Station GBC_WS s ssssssrrrrrrrrrrrrrrrrrrrrrrrrrnee 61 4 1 1 Functional Overview Greenbelt Weather Station GBC_WS 62 4 1 2 PC208W Datalogger Support Software for CR10X 64 4 1 3 EDLOG Programming Editor for CR10X 68 4 2 Discovery Park Weather and Soil Station DP_WS eee 73 4 2 1 Functional Overview of DP_WS cccccccccseeeseeeeeeeeeeeeeeeeeeeees 73 4 2 2 LoggerNet 3 4 1 Datalogger Support Software for CR1000 74 4 2 3 CRBasic Programming Editor for CR10X 82 4 2 4 nter connection of Datalogger and Nanostation2 87 WI FI TECHNOLOGY AND RADIO WAVE PROPAGATION THEORY 89 5 1 Wi Fi Technology Introduction ceeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeees 89 5 1 1 History Evolution of WI Fi eee eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeees 90 5 1 2 Advantages a
211. tted signal from the transmitter to the receiver acting as a relay Use of Repeater to Extend the Link Distance by Enhancing the Power Repeater Station Receiver Figure 7 10 Use of an Active Repeater to Retransmit the Weakened Signal Sometimes it really becomes important to establish a long distance radio link between two stations separated by se veral hundreds of miles with each 190 other In such a case a powerful radio device with high gain antenna is needed that can transmit its signal to cover such along distance But it is really a hard job to establish such a long distance radio link If anyway the link is established there will be a very poor receive signal level and a radio link having such a poor RSL is reliable at all That type of radio link may frequently breakdown even for a small change in environment So it is better to install one station in between the transmitter and the receiver depicted in above Figure 7 10 where it can intake the transmitted signal and retransmit it at a higher level power after amplification That type of station bridging bet ween the T x and R x is called active repeater That w ay a_ sufficient am ount of RSL can be r eceived atthe receiving si te enhancing the link reliability 191 CHAPTER 8 THROUGHPUT PERFORMANCE MEASUREMENT The chapter begins with first introducing the term throughput and then some of the analogies and differences be tween the two closely related terms
212. two different radio transmitters using the same frequency are located nearby or when an extraneous power is coming from a signal transmitting in an adjacent channel 101 Smartphones Bluetooth i ae aas ae 4 2 4 GHz N Wireless Technology Baby Cordless monitors Telephones J lt J l Microwave ovens Figure 5 2 A Pictorial View of 2 4 GHz Technology Applications As the 2 4 GHz ISM band is being more crowded day by day interference in this band is rapidly increasing which is one of the biggest challenges today The 2 4 GHz band is free to use and the devices and equipments operates in this band are relatively cheaper than that of 5 GHz This makes almost everyone choose this band fort heirdi fferent applications causing andr eceiving interference to and from each other The widely used 2 4 applications are Wi Fi 802 11b g n Bluetooth Microwave ovens baby monitors cordless telephones etc The above Figure 5 2 shows various types of applications that use 2 4 GHz wireless technology One of the main interferers in 2 4 GHz is cordless phones which are used in homes and offices If at least one of these cordless phones is 102 in use inthe same room where 802 11b g WLAN is deployed then y ou can notice the significant performance degradation in 802 11b g Also there s a signal degradation Despite of a very short range of Bluetooth it affects its own system performance significantly as well as oth
213. ub Beginning of Loop Delay Loop Count End P95 Measure the frequenc multiply result by Pulse P3 a e Reps fees 2 Pulse Cha Low Level S325 Loc FRE Mult ae Offset PANANANANAANANAANANANNANAANN PROGRAM ZE BeginProg Scan 5 Sec 3 0 Read soil moisture probes every fiftes If TimeInToInterval 0 15 Min Then Set port 1 high to power the probes PortSet 1 1 Wait twn execution rurlea 10 aer 1 fr Action Log M Show Only Problem Messages K rl D fatogs Srce Action Description EdLog Program E Environmental Monitoring _and Modeling SM Pra CRBasic Program E Environmental Monitoring and Modeling SM_Proai r Pulse P3 cpa t Reps sine Pulse Cha be Tare Tarren r Figure 4 12 Transformer Utility CSI to CR1 Output Files 80 The F igure 4 11 above shows a window ofa Transformer U tility The source file is the Edlog program file which is either CSI or DLD thatis to be converted and the program file is the new CR1 file that will be cr eated after conversion The F igure 4 12 above sh ows a window of a Transformer U tility showing the CRBasic file is created in the right window and Edlog source file is opened up in the left window In most of the cases such converted CR1 files canbe directly se ntt o C R1000 datalogger But sometimes t he converted program code may need some fixing such as defining some unknown variable for CRBasic though it is known
214. used for signal signal return and sh ield respectively CR10X and C R1000 bot h dataloggers have t he capability of counting switch closures on some of their control ports When a control port is used the return from the rain gage switch should be connected to 5V on the datalogger The T E525 connections to C R10X and C R1000 dataloggers are shown below in Table 3 7 11 30 Table 3 7 TE525 wiring with CR10X and CR1000 DESCRIPTION Signal Signal return Shield COLOR Black White Clear i Wiring for Pulse channel input CR10X Pulse channel G G CR1000 Pulse channel lt aS ii Wiring for Control port input COLOR CR1000 Black White 5V 5V Clear G DESCRIPTION CR10X Signal Control port Control port Signal return Shield f Soil Moisture Sensor EC 5 soil moisture se nsor m anufactured by D ecagon is used for measuring the soil moisture The sensor o btains volumetric water content by measuring t he dielectric constant o ft hem edia t hrough t he ut ilization o f capacitance frequency domain technology The operating temperature range of the sensor is 40 to 60 C The pointed prong design and higher measurement frequency allows the EC 5 to measure volumetric water content VWC from 0 to 100 and allows accurate measurement of almost all soil types and much wider range of salinities That means because E C 5 runs at hi gher m easurement frequency it is much ess sensitive to variatio
215. ution Interval seconds The following instructions ar xecuted at each execution cycle i to allow averaging over the 15 minute output period and in s the case of rainfall to detect each tip of the 01 bucket ven when the data logger has been recently restarted Read pyranometer solar radiation convert to watts m 2 and y store result at W_m2 le Volt DLE P2 1s 1 Reps 23 22 7 5 mV 60 Hz Rejection Range SAS DIFF Channel 4 23 Loc W_m2 5 200 Mult 6 0 Offset Set negative values to zero 2 If X lt gt F P89 Le 23 X Loc W_m2 2 4 lt 3 20 F 4 30 Then Do 3 Z F P30 tas 0 F 24 50 Exponent of 10 Be 23 Z Loc W_m2 4 End P95 Count switch closures of rainfall tipping bucket convert p to inches of rain during this execution cycle and store result at RAIN 229 5 Pulse P3 Ti ob Reps 25 2 Pulse Channel 2 B12 Switch Closure All Counts 4 20 Loc RAIN 52 00 1 Mult 6 0 0 Offset Read wind speed sensor convert to mph and store at WS_mph 6 Pulse P3 drea Reps 2 1 Pulse Channel 1 32 21 Low Level AC Output Hz As 2 i Loc WS_mph Se L677 Mult 6 0 4 Offset Read wind direction sensor convert to degrees from north and p store reult at WD_deg 7 Excite Delay SE P4 il Reps ZES 2500 mV Slow Range 33 3 SE Channel 4 2 Excite all r
216. vs GPRS technology FEATURE Wi Fi Technology GPRS Technology Standards IEEE 802 11a b g n GPRS Operating frequency band 2 4 5 GHz 900 1800 1900 MHz Data Rate max 600 Mbps 171 2 kbps 27 Mbps 802 11g Typical Transmission Range 5 km 25 km Throughput typical 15 40 kbps Channel Bandwidth 22 MHz 200 kHz Channel Separation 5 MHz 200 kHz Maximum power consumption 5 W 2W No of Channels 14 42 124 174 Modulation Technique FHSS DSSS OFDM GMSK License Regulation Unlicensed Licensed Interference Severe Not severe Table 5 7 29 45 47 shows some of the key differences between Wi Fi and GPRS technologies 106 5 2 Radio Wave Propagation Theory Radio signals are affected in many ways by objects in their path or and by the medium through which they travel The way in which radio signals propagate may be the prime importance to anyone associated with radio communications mobile telecommunications Wi Fi communications satellite communications etc It is even more important for the designers of above mentioned systems to know how the radio signals behave while propagating and what its impacts on system performance ar e because w ithout kn owing it one cannot designa well functioned and reliable system So it is extremely important to know radio wave propagation theory be fore designing and i mplementing any sy stem in the real world Radio waves are electromagnetic waves occurring on the radio frequency portion of
217. ween the t wo ends either in uni directional or bi directional It allows users to set various parameters that can be used to testing a net work or saying in another way it helps in optimizing a network 87 89 The n etwork performance is measured b yr unning Iperfin two P Cs connected with each other via ei ther a net work cable or a wireless medium Generally with wire means with a LAN Cat5 or Cat5e or Cat6 cable and without wire means thatthe twoP Cs areinwireless connection To start measuring throughput one should run Iperf in Client mode in one PC sender and in Server mode in another PC receiver Since the client PC sends the data and the server PC receives them they are also known as sender and receiver respectively After everything is setup a file larger file is better is transferred from client PC to the server PC using the following two different Iperf commands in two PCs Server side iperf s Client side iperf c Server PC IP Address F file name 195 After a su ccessful transfer of the file the Iperf running window outputs a display of at ime st amp showingt he amounto f data t ransferred an dt he corresponding t hroughput m easured of the link connecting the two P Cs T he lperf outputted result is as shown below in Table 8 2 Table 8 2 A typical example of an Iperf outputted result window JE SCID Interval Transfer Bandwidth L08 0 0 0 5 sec 634 MBytes 1 06 Gbits s 108
218. wn in Table 5 9 The four different colors represent the RSL lines at four different distances Blue denotes the line for 1 km brown for 5 km green for 20 km and violet for 50 km From the graph itis implied that the RSL lines are linearly increasing with the Tx power Another important thing that can be inferred from the above graph is that the RSL value will go on increasing as the Tx Rx distance becomes closer and vice versa 124 Two Ray Propagation Model In real world situation it is not always true to say that there exists only one clear LOS path between transmitter and receiver In fact this condition is very rare and most of the time there exists two radio paths which are direct LOS path and ground reflection path Unlike free sp ace propagation model th e tw o ray propagation model considers both the direct LOS path and ground reflection path while ca Iculating the receive pow erat ther eceiver This model g ives more accurate prediction for long distance propagation than free space model 52 55 64 So for this model it is not only the Tx Rx distance that influences the receive signal st rength but al sois the si gnalreflected from the g round Many r adio communication sy stems and microwave LO S r adio inks where t ransmission distance is long follow this model The Figure 5 12 shows a schematic diagram of a two ray propagation model direct path d heh hi ground d2 i reflection path 4 4 4 2 29 gt No7t t
219. x sensitivity TX power Transmission range Extended transmission range Channel bandwidth Channel spectrum width Power supply Power consumption Operating temperature Weight SPECIFICATION 2 4 GHz 2 412 2 462 GHz IEEE 802 11 b g Atheros 180 MHz MIPS 16 MB SDRAM 4MB Flash 1x10 100 BASE TX Cat 5 RJ 45 Ethernet Interface 10 dBi Adaptive Vertical Horizontal selectable 60 Azimuth 30 Elevation 54 Mbps max 25 Mbps max 97 dBm max 26 dBm max 15 km 100 km using external antenna 22 MHz 5 10 20 MHz selectable 12V 1A 4 W 20 to 70 C 0 4 kg 45 Table 3 14sh ows some technical sp ecifications of Nanostation2 Nanostation2 has 3 rate modes quarter 5 MHz half 10 MHz and full 20 MHz The Table 3 15 below shows data rate vs Rx sensitivity of 802 11b and 802 11g at given transmit power 21 Table 3 15 Data rate vs Rx sensitivity FULL MODE 20 MHz IEEE Standard Tx Power Data Rate Rx Sensitivity 1 Mbps 97 dBm 2 Mbps 96 dBm 5 5 Mbps 95 dBm 11 Mbps 92 dBm 6 Mbps 94 dBm 9 Mbps 93 dBm 12 Mbps 91 dBm 18 Mbps 90 dBm 24 Mbps 86 dBm 36 Mbps 83 dBm 48 Mbps 77 dBm 54 Mbps 74 dBm 802 11b 802 11g From the above t able itis seenthattheR x sensitivity isi nversely proportional to data rate So there should be a tradeoff between data rate and Rx sensitivity Nanostation2 is operated by a firmware called Air OS Air OS is an intuitive v ersatile and h
220. z Wi Fi Vs 5 GHz Wi Fi cceeseeeees 100 5 6 Wi Fi vs cellular technolOGies ccc ceeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee 105 5 7 Wi Fi vs GPRS technology x cncncncnencnencnnnecnennnennnenae 106 5 8 Electromagnetic SPSCINUNN a2 232 edn ed let edited ieee edie te 109 5 9 Tx power vs RSL fOr 24 GHZ oi cecccsicenck eke eee tnec eset eae date eaent cee ehen 123 5 10 Path loss vs transmission distance ceeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee 130 6 1 Field SURVey Cala catacer ieee ae Ele ae Ales 142 6 2 Overlapping and non overlapping Channels cceeeeeeeeeeeeeeeeeeeeees 148 6 3 Input parameters for modeling scsiersssxtcouissnddeverendcerdenudsensawedtertereddendcansees 155 6 4 Output parameters obtained after simulation cccecccceeeeeeeeeeeeeeeeees 156 6 5 Nanostaion2 configuration settings cee eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee 160 8 1 Bandwidth vs througn pul 2ulsct ag tawl a tel ee taeda teled taal a tela tals 194 8 2 Atypical example of an Iperf outputted result window ee 196 8 3 Iperf arguments and their purposes cceceeceeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeess 197 8 4 Throughput Expt 8 2 1 1 Parameters SettingS cccccccecsseeeeeeeeeeeees 209 8 5 Throughput Expt 8 2 1 2 Parameters SettingS ccccesseeeeeeeeeeeeees 210 8 6 Throughput Expt 8 2 1 3 Parameters SettingS

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