IQ-Mower: PN-sequence-transmission using Bluetooth.
Contents
1. Country Frequency Range Available Chan GHz nels J apan 2 471 2 497 23 France 2 4465 2 4835 23 Spain 2 445 2 475 23 Elsewhere Europe and U S 2 400 2 483 79 There are functions to set different country codes 4 5 Frequency Hopping The operating band of 83 5 MHz is divided into 1 MHz spaced channels each signalling data at 1M Symbols per second so as to obtain the maximum available channel bandwidth This split up gives 79 available channels J apan France and Spain 23 chan nels A data channel hops randomly 1 600 times per second be tween the 79 or 23 channels 11 I Q Mower PN sequence transmission 2002 06 24 using Bluetooth 4 6 Slots Each channel is divided into 625 us time slots A TDD Time Division Duplex scheme is used which means that the time slots are used alternately for transmitting and receiving One packet can be transmitted per time slot The master transmits a packet on its time slot k on frequency f k toa slave In the next time slot k l on frequency f k 1 it receives a packet from the slave before it transmits again Note the packet does not occupy the full time Slot 625 us as time is reserved to allow the device to switch be tween transmission and receiving modes Figure 4 1 describes this f k 1 f k 2 oh m m Figure 4 1 Slot timing for single slot packets 4 7 Piconet and Scatternet The frequency hopping scheme also enables Bluetooth to work in not only p2. If SCO links are used not more then three beacons can be connected at a time The I Q M over then have to stop when it is time to change from one beacon to another This is because it will take some second up to 20s 5 to find and connect to a new one This stop will probably be shorter if AU X1 packets can be used If FPGAs are going to be used the embedded architecture will be the best think This can be something for a student who knows more about FPGAs than I do to study in a coming project HTU then have to by a Bluetooth module for embedded solutions Blue tooth Development Kit from Teleca is a module for embedded so lutions the price is today 6500 USD Another thing that would be interesting to look at are the differ ent profiles Can the Generic Access Profile be something for the I Q M over and of course it would be important to test the use of a multipoint device in order to connect more then one beacon to the I Q M over The connection to the second beacon will be done in the same way as the first they answered me when mailed the sup port regarding this You only have to change the BD Address To understand Bluetooth have been forced to learn more about C especially classes and pointers have not used Visual C before and that was a big step to understand the program before could study the Bluetooth Test Sample application in order to modify it 11 Conclusions It will be possibly to use Bluetooth in the I Q M
3. L2CAP to send data Bluetooth s higher layers such as RFCOMM and SDP also use it so L2CAP is a com pulsory part of any Bluetooth system The idea behind L2CAP is to provide an interface similar to TCP IP function calls 6 1 3 RFCOMM RFCOMM is a transport protocol with additional provisions for emulating RS 232 serial ports The RFCOMM protocol support up to 60 simultaneous connections between two BT devices For the purposes of RFCOMM a complete communication path involves two applications running on different devices with a communica tion segment between them RF COMM is able to transmit receive data packets of up to 32 KB over such a link In this context the term application may mean other things than end user applica tion eg higher layer protocols or other services acting on behalf of end user applications 6 1 4 SDP Service Discovery Protocol Discovery of services is a crucial part of the Bluetooth framework Service discovery is fundamental for all the usage models Blue tooth is designed to allow you to walk into an area and finda printer without having to preconfigure settings When you used the printer you can walk away and forget its details SDP is the part of Bluetooth that allows this to happen The SDP provides a means for applications to discover which services are available and to determine the characteristics of those available services using an existing L2CAP connection After that an appropriate separa
4. Reference Stack by Ericsson Toinsure interoperability of Bluetooth modules from various manufacturers the Bluetooth Specification defines a standard in terface and Communications protocol that can be used by all Bluetooth modules and by all host devices that incorporate the Bluetooth technology The Bluetooth standard for the HCI defines the following e Command packets used by the host to control the module e Event packets used by the module to inform the host of changes in the lower layers e Data packets to pass voice and data between host and module e Transport layers which can carry HCI packet flow This Host Controller Interface HCI while not a mandatory com ponent of the Bluetooth Specification it is not completely neces sary if the Bluetooth module is fully integrated into the design of the host device is useful for those Bluetooth devices that are meant to be used in an add on or accessory fashion 6 1 2 L2CAP Logical Link control and Adaptation Proto col L2CAP provides connection oriented and connectionless data ser vices to upper layer protocols with protocol multiplexing capabil ity segmentation and reassemble operation and group abstrac tions L2CAP permits higher level protocols and applications to 29 I Q Mower PN sequence transmission 2002 06 24 using Bluetooth transmit and receive L2CAP packets up to 64 Kilobytes in length L2CAP only supports ACL links All applications must use
5. Unlike all the other ACL packets AUX1 packets are not retransmitted The AUX1 is for the moment the only ACL packet that is not re transmitted 4 9 2 SCO Link SCO links support symmetrical circuit switched point to point connections and are typically used for voice transmission An ex ample of a SCO link is the voice link between a cellular phone and headset SCO links reserve two consecutive slots one for trans mission and one for reception at fixed intervals A master can support up to three SCO links to the same slave or to different slaves A slave can support up to three SCO links from the same master in a piconet or two SCO links if the links origi nate from different masters SCO packets are never retransmitted IN a piconet there can be up to three SCO links of 64 kbits per second each To avoid timing and collision problems the SCO links use reserved slots set up by the Master Notice the SCO link in figure 4 4 it sends every 6 th slot A slave is allowed to send a SCO packet even if no packet was received in the previous mas ter slot 152 I Q Mower PN sequence transmission 2002 06 24 using Bluetooth SCO ACL SCO ACL ACL SCO SCO ACL MASTER H H We PUTT H SLAVE 1 E SLAVE 2 H SLAVE 3 0 ETEA pa ni 1 n Pe Qarcirig I ESU DIE Change who notice Figure 4 4 An example of different links to different Slaves Figure 4 4 shows how a Master is able to communicate with sev
6. defined to enable a wide range of electronic de vices to have Bluetooth functionality and to ensure interoperabil ity between devices from different manufacturers The radio specification defines the frequency bands channel ar rangement and transceiver characteristics for a Bluetooth system The Bluetooth base band specification defines packet formats physical and logical channels and the different modes of operation that support the transfer of voice and data between devices Audio is needed to transfer voice The specification for the Blue tooth voice interface follows both ITU T and GSM recommenda tions 5 1 The Bluetooth Device In general terms a Bluetooth device is any complete electronic product that incorporates a Bluetooth radio The radio itself is not the device it is only a component of the device In practical terms a Bluetooth device could be a mobile phone or a personal digital assistant PDA or a portable computer or even an Q Mover As long as the complete product incorporates Blue tooth technology the item can be called a Bluetooth device Natu rally any Bluetooth device incorporates more technology than just the Bluetooth radio Every device has its own distinct purpose a printer is Supposed to print an I Q M over is supposed to move around and soon 20 I Q Mower PN sequence transmission 2002 06 24 using Bluetooth 5 1 1 The Host and the Bluetooth Module In Bluetooth terminology the non Bluetoot
7. dures and uniform ways of using the lower layers of Bluetooth By doing this the Bluetooth profiles provide a way for Bluetooth ae I Q Mower PN sequence transmission 2002 06 24 using Bluetooth technology to slot into different devices and applications yet still work in standardised ways For example a Bluetooth headset pur chased form Manufacturer A will interwork with a Bluetooth en abled cellular phone purchased from Manufacturer B File Transfer networking intercom F Headset i Intercom Headset Networking Object Push Frofiles Generic Object Exchange Profiles Generic Transport Serial Port Part Profiles Service discover Generic access application Generic Bluetooth Access Profiles Figure 5 5 Bluetooth profiles implemented by Bluetooth version 1 0 Figure 5 5 shows how Bluetooth profiles are organised into groups with each profile building upon the one beneath For de velopers this means that key features of one Bluetooth solution can be recycled in other solutions bringing down development costs and speeding up the development cycle The Generic Access Profile GAP is the most basic Bluetooth pro file all other profiles are built upon it and use its facilities 5 3 1 New Profiles A series of SIG working groups continue the process of producing and refining the Bluetooth specification They will come with new profiles ahead 271 I Q Mower PN sequence transmission 2002 06 24 using Bluet
8. over system 47 I Q Mower PN sequence transmission 2002 06 24 using Bluetooth 12 References 1 Miller Michael Discovering Bluetooth USA 0 7821 2972 2 2 Bray J Sturman C Bluetooth connect Without Cables USA 2001 3 Bluetooth Special Interest Group Specification of the Blue tooth System version 1 1 Bluetooth Special Interest Group 22 February 2001 Available from www bluetooth com 4 Users Manual Ericsson Bluetooth PC Reference Stack R1C Ericsson Mobile Communication AB 19 J anuary 2001 5 Bray J Bluetooth Application Developer s Guide The Short Range Interconnect Solution USA 2002 6 Users Manual Ericsson Bluetooth PC Reference Stack R2B Ericsson Mobile Communication AB 14 May 2001 13 Appendix I 2 3 4 5 MSC I Q M ower BT_TestSampleClientDlg cpp implementation file dient c BT TestSampleServerDlg cpp implementation file server c 48
9. the water in flesh and it heats up as it shakes But as the radiated output power of Bluetooth devices is incredibly low and spread in spectrum in time experts concur that Bluetooth radiation does not pose a risk to health A 1mW Bluetooth radio emits 1 1 000 000 the amount of power in a 1KW microwave oven Also in a microwave oven all the power is directed inward at the food while in a Bluetooth device the power iS radiated outward so the user only ever intercepts the smallest fraction of the radio waves that are heading in their direction 19 I Q Mower PN sequence transmission 2002 06 24 using Bluetooth IN comparing with other popular communications devices Blue tooth operates at 2 4GHz and uses 1mW OdBm for most applica tions with a maximum of LOOmW 20dB M for extended range This means that Bluetooth signals have a penetration depth of 1 5cm into flesh 2 Cellular handsets have a power of 10mW to 2W peak using 450M Hz to 2200M hz and exhibit a penetration depth of 2 5cm in the middle of their range at 900M Hz So mobile cellular handsets give rise to a measurable heating effect of 0 1 C compared with no measurable increase for Bluetooth devices 2 5 The Bluetooth Architecture The Bluetooth Specification 3 defines all aspects of the Bluetooth technology including hardware and software components and shared processes and procedures Standard radio base band interface and software protocol specifi cations have been
10. 6 4 9 1 1 Inquiry Result Filter An Inquiring device may not be interested in every device in the area To provide the host with some control over the result it sees theHCI Set Event Filter command can be used to set an inquiry result filter which means that some devices will not be reported in HCI Inquiry Result Events Inquiry results can be filtered out using three criteria e Report only new devices not seen before e Report only devices with a specific device type e Report only the device with a specified Bluetooth device address Of course this filtering could be done at the Application Level in stead of the HCI Level 42 I Q Mower PN sequence transmission 2002 06 24 using Bluetooth 6 4 9 2 The Page Procedure It is possible to carry out the paging procedure with no prior in quiry if the device address is already known as may be the case with the I Q M over The paging device is able to address the in tended Slave but because no CLKE estimate of the Slave s clock iS available the procedure will take much longer In theory the maximum length of time is 10s After that the connection can be established by then using the Page command When paging is completed a connection between the two Blue tooth devices can be established This includes e link establishment The physical link is a sequence of transmission slots on a physical channel alternating be tween master and slave time slots e channel esta
11. EEE LE EEE EL ELL LEE LEE LEE EEE ELLE ELLE LL EEE E LEE EEE EEC L LLL LEE A SARA ASAASRARSABRARBLA SCM RFCOMM SDP Host Stack HCI Driver Figure 7 1 How the different parts of the sample application interacts with each other the stack and VOS The Test Sample Application consists of three parts the first ap plication acting like a server slave the second application acting like a client master and the third one handling the BT security Table 7 1 File description of the Test Sample Application 44 I Q Mower PN sequence transmission 2002 06 24 using Bluetooth Client side application client c client h This module contains an example of a client type of application running on top of RFCOMM This client expects a headset server in a fixed destination device Server side server c server h This server acts as a headset server application Security module security c security h This component takes care of accepting a new ACL connection and provides the stack with a PIN code when necessary The stack supports several client and server sessions at a time but only one can be the security manager The security manager in this sample is a stand alone application You can read more about the original Test Sample Application in the User Manuals 4 and 6 7 2 My Modified Test Sample have used the inquiry page and connection functions as they were have also used the headset profile an
12. SIlOtS ssseesssersssersersererrrrrrrrrrra 18 Figure 5 1 Bluetooth Application Tool Kit s ssssssesssrssersssrrsserrserrserorrrrrserrserrrerrrrrrrrrrrrrrrr rea 21 Figure 5 2 The three stack implementation models sssmosssrssssrrssrerrrrrerrrrerrrrerrrrrrrrrrrrrrrrrrr ra 22 Figure 5 3 The different layers of the Bluetooth Module sssesssersssersssererrrrrrrrrrrrrrerrrrerrr gt 23 Picure 5 4B LU ia Wind Ow sits a isons Sandezcwbnanntdostdeadsattgensdeshawadsasiosadayantedeasderteet 26 Figure 5 5 Bluetooth profiles implemented by Bluetooth version 1 0 sssmmssssresssrrrssrrrrrernrs 27 Figure 6 1 An overview of the PC Reference Stack and its components sessssser00 gt 28 Figure 6 2 The Com server and Com client on top of the Module ssssessserssrsrrsrsererrerrrs 31 Figure 6 3 HCI command packets s cssssssiessdsexedensluinssabevendlvscbxansecens sasdcusasannseisecuedaltess 33 Picure 64 MCE Vent PaK Ennio iioa a a e on an 33 Picure 6 5 HCV ACL Data Packe laipsniu a a a a s A 33 Picure 66O HCLSCO Data Packet s ssestensssvisdes eonia e a e i a EENET 34 Figure 6 7 Inter process communication within the Bluetooth Host Stack 35 Figure 6 8 Communication principles between different layers s sssssssssersssrerrsrsrrrrrerrrrerrr gt 35 Fiure 6 9 Command Evenboer r eerren EnEn NEEE Eaa Aa ae a a Ai 36 Fiure 61O The start PE OCCOUILE serseri e e aea a ae ba Rn renade a i 38 Figure 6 11 Registration and DeRe
13. Thesis IQ Mower PN sequence transmission using Bluetooth Ann Britt Carlsson Supervisor Peder Carlsson 2002 06 24 H gskolan Trollh ttan Uddevalla Institutionen f r Teknik Box 957 461 29 Trollh ttan Tel 0520 47 50 00 Fax 0520 47 50 99 I Q Mower PN sequence transmission 2002 06 24 using Bluetooth Foreword It has been interesting to study the Bluetooth technology I would like to Thank my supervisor Peder Carlsson for letting me have this study as my examination I would also like to thank Mattias Ottosson for helping me come into the Visual C programming and for his wonderfully smile when managed to transmit the first A and thanks to Gunne Andersson for making a cable connection specially for my Blue tooth experiments Thanks also to Lisbeth for answering my strange questions and wonders in the beginning of this work You were right do laugh towards them today And special Thanks to Pelle and the rest of my family for letting me study all those evenings and weekends I Q Mower PN sequence transmission 2002 06 24 using Bluetooth Abstract The lQ mower is a new type of lawn mower It will cut the grass all by itself in an intelligent way Three beacons are going to send noise sequences to it If the Q mower knows how long time the noise sequences took from the beacons to the I Q mower it will calculate were on the lawn it is The beacons need to send the se quence once every second but not al
14. at all Ericssons released Modules do not fit whit all versions of their Stack had some trouble before I no ticed the Tool Bluetooth Traffic Light Utility a Ss I Q Mower PN sequence transmission 2002 06 24 using Bluetooth 1 Bluetooth Traffic Light Utility Check Aigsh stack a Hiel nogaenle Poort Compatibility btttLe rtts tE rtt Figure 5 4 BTU main window This program is used to determine the compatibility between the used PC Reference Stack and the connected Module The version number for PC Reference Stack in the application called Host Stack is picked up from the stack From the Module the follow ing information is retrieved e Bluetooth address e Manufacturer number e HCl version number e LMP version number e HCl revision number e LMP subversion number You can read more about this in User Manual 6 5 3 The Bluetooth Profiles The purpose of a profile is to provide a clear description of how a full specification of a standard system should be used to imple ment a given end user function If everyone deploys a particular communications standard in the same way then each product so created should be able to interoperate This notion of profiles originated from the International Organisation for Standardisa tion ISO IEC TR10000 Bluetooth profiles work in just the same way They ensure inter operability by providing a well defined set of higher layer proce
15. ave 4 9 Physical Links 4 9 1 ACL Link 4 9 1 1 AUXI 4 9 2 SCO Link 4 10 Packet Definition 4 10 1 Access Code 4 10 2 Header Code 4 10 3 Payload 4 10 4 Error correction 4 10 5 Miulti slot packets 4 11 Bluetooth Clocks 4 12 Unique Bluetooth Address 4 13 Security 4 14 Health 5 THE BLUETOOTH ARCHITECTURE 5 1 The Bluetooth Device 5 1 1 The Host and the Bluetooth Module 2002 06 24 10 10 11 12 12 13 14 14 15 15 16 16 16 17 17 18 18 19 19 19 20 20 21 I Q Mower PN sequence transmission 2002 06 24 using Bluetooth 52 The Module used at HTU 21 5 1 3 Three Different Bluetooth Implementation Models 21 5 2 The Lower Layers of the Stack 23 Id The Bluetooth Radio 24 5 2 2 Bluetooth Baseband 24 3225 The Link Manager LM 25 5 2 4 The Host Controller HC 25 5 2 4 1 Bluetooth Traffic Light Utility BTU 25 5 3 The Bluetooth Profiles 26 Fl New Profiles 27 6 THE ERICSSON SYSTEM LEVEL DESCRIPTION 28 6 1 The Upper Stack 28 6 1 1 HCI The Host Controller Interface 29 6 1 2 L2CAP Logical Link control and Adaptation Protocol 29 6 1 3 RFCOMM 30 6 1 4 SDP Service Discovery Protocol 30 6 1 5 OBEX 30 6 1 6 TCS Telephony Control protocol Specification 31 6 2 COM server 31 6 3 HCI packets 32 6 3 1 HCI Command packet 32 6 3 2 HCI Event packets 33 6 3 3 HCI Data packet 33 6 4 API Application Programmers Interface 34 6 4 1 API supported profiles 34 6 4 2 The stack API 34 6 4 3 Global API Descript
16. bes an al gorithm that can calculate a frequency hop sequence from a Blue tooth device address and a Bluetooth clock When Slaves connect to a Master they are told the Bluetooth device address and clock of the Master They then use this to calculate the frequency hop sequence Because all Slaves use the Master s clock and address all are synchronised to the Master s frequency hop sequence 4 13 Security The high speed pseudo random frequency hopping algorithm em ployed in Bluetooth makes it very difficult to listen in on a Blue tooth connection In fact the U S military considers a communica tions link using frequency hopping over 79 channels to be secure in it self 2 Authentication prevents spoofing and unwanted access to critical data For example connecting a laptop to a cellular phone may require a PIN to be entered Encryption prevents eavesdropping and maintains link privacy 4 14 Health Bluetooth uses frequency spectrum in the range of 2400M Hz to 2483 5MHz This range encompasses the natural frequency of H2O molecular oscillation at 2450M Hz which is also used by mi crowave ovens specifically to excite water molecules inside food in order to cook it Sharing the same frequency range as microwave ovens has led to some concerns that Bluetooth devices might cook their users Some microwave radiation will be absorbed in flesh It will be ab sorbed to heat through molecular friction Basically the micro waves shake
17. blishment A logical link is established to setup a Bluetooth channel between the two devices e connection establishment Finally a connection between the applications on the two Bluetooth devices is estab lished In the connection state a connection has been established and packets can be sent back and forth between the master and slave devices 6 4 9 3 Avoiding collisions In order to avoid collisions between devices that wake up in the same inquiry hop channel a protocol is used which ensures that each time a slave responds to the same Inquiry message it does so on different frequencies and at different times 7 TEST SAMPLE APPLICATION SUITE In Ericssons Bluetooth Tool Kit two applications are included e The TestSample Application Suite 43 I Q Mower PN sequence transmission 2002 06 24 using Bluetooth e The Chat Application Suite The Test Sample Application is intended as guidance when de signing own applications for non windows environment making use of Ericssons PC reference stack as a development tool When writing windows specific programs it is better to take the Chat application as guidance have modified the TestSample Application in order to get appli cations Master and Server applications for our I Q M over See appendix The Security Application did I use right as it was 7 1 Test Sample application GED Cain Application Application Application Q 0 9 PO PPL P PPP PLE P PLO LL LLL
18. command have fixed size Each command will specify each parameter and size of each parameter contains the command OpCode Parameter Total OCF Length Parameter 1 Parameter Parameter 0 Parameter N 1 Parameter N Me ye I Q Mower PN sequence transmission 2002 06 24 using Bluetooth Figure 6 3 HCI command packets 6 3 2 HCI E vent packets Used by the host controller to notify the host when events occur The format of the HCI Event packet is shown in figure 6 4 The Event occupies 1 byte of the packet and the parameter length 1 byte Event Parameter N 1 Event Parameter N Figure 6 4 HCI Event packet 6 3 3 HCI Data packet Used for exchange data between the host and host controller There are two types defined depending on the connection The format for the ACL is shown in Figure 6 5 below It consist of 14 bits for the connection handler 2 bits for the flag the total length of the data that is in the packet and the data it self Data Total Length Figure 6 5 HCI ACL Data packet HCI Data Packets are used to exchange data between the Host and Host Controller The data packets are defined for both ACL and SCO data types The Flag Bits consist of the Packet Boundary Flag PB and Broadcast Flag BC The Packet Boundary Flag is telling which number the packet is for example if it is the first the last or someone in the middle The Broadcast Flag says if the packet is going to be broadcas
19. d SCO link as they were The echo function did I take away because we don not want handshakes have placed a timer just after the SendData func tion and investigate a new event TIMEOUT 2 EVT This makes a loop of data transmissions An A is transmitted every 1 10 sec ond This ends when anyone turns the disconnect button The time between the transmissions is easy to change Bluetooth 1Q Mover Chent DEVICE 0x00803 14544D seral Interface Who are you 7 IQ Mover f START Sessions OE 0 Inquiry Failed 1 Disconnect SCO CLOSE Connections Faled O Destination Address foxoog0371 45438 12 hes values start with Ox MSB first Figure 7 2 My modified Test Sample Client oy e I Q Mower PN sequence transmission 2002 06 24 using Bluetooth Bluetooth 1Q Mover Server DEVICE Ox008037145438 Serial Interface SARA te Connections Message A Figure 7 3 My modified Test Sample Server The module has to be connected to the PC with the serial port af ter the modification 8 Bluetooth and FPGAs For a technology such as Bluetooth which is not terrible demand ing of current ASIC technology a good FPGA implementation is very feasible 2 Most Bluetooth IP suppliers at present have demonstration sys tems that utilise high performance F PGAs and these are able to promote confidence in the IP prove the technology and provide better coverage of bugs and system testing Of course there are some po
20. e a license fee per device if they are using an other vendor s upper layers The fully embedded model requires a Silicon solution that allows the application code to be written and downloaded to it without compromising the integrity of the Blue tooth stack that should have already undergone the stringent qualification procedure Any change to the stack requires it to be requalified The upper stack layers above HCI can be licensed from numer ous vendors Due to the inherent interoperability requirement of any qualified Bluetooth component the choice is open All of the available stack offerings will be conpatible with the chosen sili con s lower layers You can write your own upper layers but it will be a vast software undertaking illustrated by the cost of licens ing one Protocol stack can be expensive but an expensive stack might just offer you extra features that help to sell your product 5 5 2 The Lower Layers of the Stack The lower stack controls all of the physical functionality the ra dio the base band and the Link Manager and Link Controller layers Figure 5 2 shows the lower layers of one Bluetooth module Link Manager Baseband Figure 5 3 The different layers of the Bluetooth Module Bluetooth Training Tool Kit does not include the audio part 2233 I Q Mower PN sequence transmission 2002 06 24 using Bluetooth 5 2 1 The Bluetooth Radio The Bluetooth radio is just like any broadcas
21. e applica tion programmer is given full access to the features provided by the Bluetooth technology In the description that follows when 34 I Q Mower PN sequence transmission 2002 06 24 using Bluetooth discussing different layer such as layer A and layer B etc the lay ers can be any of the components of the stack Request A 7 Function Call Se Request Message Add Get Functions Optional ia Confirm Message Confirm Message Figure 6 7 Inter process communication within the Bluetooth Host Stack Layer A communicates with layer B by calling the correct request message function which is the same for every layer The request function allocates memory to send data and parameters which in the next step is sent to layer B Layer B waits for messages from the queue when a new message arrives to layer B it s handled in a state machine Depending on if the message results in a confir mation a message is send directly to layer A In case it results in another message to another layer then layer B calls the correct request function All the message handling is done by the operat ing system routines 6 4 3 Global API Description Request Req Confirm Cnf CnfNeg Indication Ind Response Rsp RspNeg 6 3 Function gt Message Figure 6 8 Communication principles between different layers 2852 I Q Mower PN sequence transmission 2002 06 24 using Bluetooth Control message is t
22. er in a reasonable error free environment FEC gives unnecessary overhead that reduces the throughput Therefore different packet types have been de fined FEC in the payload or not resulting in the DM Data Medium rate and DH Data High rate packets for the ACL link and the HV High quality Voice packets for the SCO link this packet can send data as well as voice The packet header is always protected by a 1 3 rate FEC it con tains valuable link information and should be able to sustain more bit errors A simple 3 times repetition FEC code is used for the header The repetition code is implemented by repeating the bit three times see the illustration in figure 4 6 Figure 4 6 Bit repetition encoding scheme The 3 bit repetition code is used for the entire header and also for the voice field in the HV1 packet To determine whether the payload is correct or not a cyclic re dundancy check CRC code is added to the packet The ARQ scheme only works on the payload in the packet only that pay 17 I Q Mower PN sequence transmission 2002 06 24 using Bluetooth load which has a CRC The packet header and the voice payload are not protected by the ARQ scheme 4 10 5 Multi slot packets To support high data rates multi slot packets have been defined with a packet occupying one time slot three time slots or five time slots However the hop frequency used in the first slot will be used throughout the transmi
23. eral Slaves in sequence The Master always transmits on even slots and the Slave replies on odd numbered slots In the slots not reserved for SCO links the master can exchange packets with any slave on a per slot basis 4 10 Packet Definition The data on a channel is transmitted in packets Data in a packet can be up to 2 745 bits in length The standard packet format is shown in figure 4 5 LSB 72 54 0 2745 MSB ACCESS CODE HEADER PAYLOAD Figure 4 5 Standard packet format 4 10 1 Access Code Every packet exchanged on the physical channel has a 68 72 bit access code derived from the BD ADDR of the master and is unique for that channel The access code identifies the piconet to whom the packet is going to be sent 4 10 2 Header Code The header code identifies the slave to who the packet is going to be sent lt 16 I Q Mower PN sequence transmission 2002 06 24 using Bluetooth 4 10 3 Payload The data you want to transmit is called the payload You can read more about packet format in Specification of the Bluetooth System 3 or in User Manual Bluetooth Pc Reference Stack by Ericsson version Ric 4 4 10 4 Error correction There are three error correction schemes defined for Bluetooth packets e 1 3 rate FEC Forward Error Correction e 2 3 rates FEC e ARQ Automatic Repeat request scheme for the data The purpose of the FEC scheme on the data payload is to reduce the number of retransmissions Howev
24. es these requirements is at 2 4 GHz the Indus trial Scientific M edical ISM band The ISM band is also license free and open to any radio system Since the ISM band is open to anyone radio systems operating in this band must cope with several unpredictable sources of inter ference such as e baby monitors e cordless phones e garage door openers e microwave ovens 10 I Q Mower PN sequence transmission 2002 06 24 using Bluetooth Microwave ovens are the strongest sources of interference but in most cases you only need to move the Bluetooth device a little bit one or two meters away from the oven to get less interference 2 Three countries Spain France and J apan had previously reserved portions of the 2 4GHz range for local primarily military use This could have potentially defeated the global nature of the Blue tooth standard if devices built for these three countries had to in corporate slightly different radio technology The Bluetooth SIG has worked with officials from each country to try to lift restric tions on 2 4GHz transmissions As of J anuary 2001 all three coun tries have agreed at least in principle to free up at least some of the reserved portions of the band in their respective regions Table 4 1 compares the frequency ranges available for Bluetooth use in the problematic regions with the standard 2 4GHz band available elsewhere in the world Table 4 1 Regional Bluetooth frequency limitations
25. g Bluetooth B RspData Data function for successfully sending data to peer B_DataAlloc Allocates a buffer containing a MSG_TDataMsg and a Length in bytes B_DataFree Frees buffer created with B_DataAlloc Pointer is a byte array to the data buffer B_DataExtract Extract the header information and data from ptDataInd Function returns length and pointer to the start of the data Table 6 2 Communication from layer B to layer A Message Description B_START_CNF Start message confirm for start component B REGISTER CNF Control message for confirm set up control connection B REGISTER CNF NEG Control message for negative confirm set up control con nection B DEREGISTER CNF Control message for confirm control disconnection B DEREGISTER CNF NEG Control message for negative confirm control disconnec tion B CONNECT CNF Control message for confirm set up connection with task B B CONNECT CNF NEG Control message for negative confirm set up connection with task B B CONNECT IND Control message for set up connection at peer side B DATA CNF NEG Data message for negative confirm sending data to the other peer Name Message Description B DATA IND Data message for sending data at peer side 37 I Q Mower PN sequence transmission 2002 06 24 using Bluetooth 6 4 5 Start B ReqStart C ReqStart D ReqStart C START CNF D START CNF START CNF Mm Function FO Messages Figure 6 10 The start procedure Before makin
26. g any use a component one has to start the interface to the lower layer layer A starts the interface with layer B etc This is done by function B_ReqgStart Figure 6 10 shows the start procedure 6 4 6 Registration amp DeRegistration Client Server B ReqRegister Registration unsuccessful 38 I Q Mower PN sequence transmission 2002 06 24 using Bluetooth B ReqDeRegister B DEREGISTER CNF V Function FO Messages Figure 6 11 Registration and DeRegistration The registration is next step a server must register to lower level with B_ReqRegister As the lower level must know were to send the received messages A Client layer does not need to register itself because it receives messages from higher layer and thereby knows were to send back the response If the registration is suc cessful the two layers can set up a connection and send data One important note sever registration has no effect on the client side A de registration is done by sever sending B_ReqDeRegister See Figure 6 11 6 4 7 Connection amp DisConnection Set up Client Server Connection Successful B CONNECT CNF Connection Unsutcessful B ReaDisconnect B DISCONNECT EVT B DISCONNECT CNF FP Function FO Messages 39 I Q Mower PN sequence transmission 2002 06 24 using Bluetooth Figure 6 12 Connection and disconnection sequence A client initiates the set up connection by calling the B ReqConnec
27. gistration s sssssssrsesserrsssrrrrrerrrrererrererrrrrrrrrerrrrrrrrrrrrrrr rna 39 Figure 6 12 Connection and disconnection sequence s sssmererssrrsrrersrrrrrrrrrrrrrrrrrrrrrrrrerrrrrrr na 40 Figure 6 13 Data transmission 4ssvsssss uses iore neers aE EEEE EENE pra beer a Ah 41 Faure Oa MANN 253 ie eerste a Brodin kr RR Re een RE E FORSS EES 42 Figure 7 1 How the different parts of the sample application interacts with each other the STACK ATV VAC eaa ken seg NE rent ren BN saree seein Care ae ate 44 Figure 7 2 My modified Test Sample Client ssmmsssersssersserrserrserrrerrrrerrrrrrrrrrrrrrrrrrrrrrrrrrr rna 45 Figure 7 3 My modified Test Sample Servet c ccccsesssconssseceneseecetenssccssevescccenescenens 46 Table index Table 4 1 Regional Bluetooth frequency limitations ssmssssesssrrssrrssrrsrsrrrsrrrsrrrrrrrrrerrrrrrrrra 11 Table 5 1 Output Power for Each Bluetooth Power ClaSS s ssseessersserorserssrrsserrsrrrrsrrrrrra 24 Table 6 1 Communication from layer A to layer B smsssmmssssesssrrsserrsrrrserrssrrrrrrrrerrrrrrrrrrrrrra 36 Table 6 2 Communication from layer B to layer A smmssssssssesssrrssrrrserrserrsserrrrrrrrrrrrrrrrrrrrrra 37 Table 7 1 File description of the Test Sample Application ssssssersserssersssrrrserrrsrrrrerrrrra 44 I Q Mower PN sequence transmission 2002 06 24 using Bluetooth 1 Introduction At HTU thereis a project going on with an intelligent lawn mower This lawn mower is going to cu
28. h part of a device is called the host 5 1 2 The Module used at HTU At HTU we have used the Bluetooth Application and Training Tool Kit from Ericsson This is a hosted model see chapter 5 1 3 the module only has the lower stack on its chip see figure 5 3 and it only support point to point operation aii s Bluetooth Application ERICSSON 5 amp Training Tool Kit Bluetooth Figure 5 1 Bluetooth Application Tool Kit 5 1 3 Three Different Bluetooth Implementation Models There are three implementation models 5 for the stack the stack is described later in the thesis dependent upon the func tionality or resources the respective product has hosted embed ded and fully embedded see Figure 5 2 21 I Q Mower PN sequence transmission 2002 06 24 using Bluetooth Application Application SDP RFCOMM L2CAP Application Connection Manager SDP RFCOMM SDP RFCOMM Link Manager Link Controller Chip chip set Chip chip set Chip chip set Hosted Embedded Fully Embedded Lower stack on chip Full stack on chip Stack and applica Upper stack on chip Application on host tion on chip Figure 5 2 The three stack implementation models In the hosted model the lower stack layers reside on the Blue tooth device while the upper stack resides on a host this may be a PC or a micro controller if the product is mobile or standalone They communicate via the Host Controller I nterface which sits between the lowe
29. he communication between different layers which exchanges information with each other A data message passes through the stack where each layer adds its header to the data packet In the same way on the other side each layer re moves the headers one by one The difference between command messages and event messages can be seen below A command message is messages sent from a higher layer to a lower layer which is a request An event message is the opposite a lower layer sent a message to a higher corresponds to an indication Command Cmd Event Evt Figure 6 9 Command amp Event 6 4 4 Layer to layer Communication between two protocol layers is described here Because all the protocol components have the same kind of mes sages one could use the standard message to communicate with all the other different protocols in another word replacing the B with SCM_ COM_ SD_ L2CAP or HCI Table 6 1 shows the messages which can be sent from layer A to B Table 6 1 Communication from layer A to layer B Function Description B ReqStart Start message to start component B_ReqRegister Control function for set up control connection between two layers B_ReqDeRegister Control function for control disconnection between two layers B_ReqConnect Control function for set up connection with task B peer to peer Data function for sending data to the other peer 36 I Q Mower PN sequence transmission 2002 06 24 usin
30. iconet Each link has a supervision timeout such ensures that such links are closed down 4 7 1 Point to point and point to multi point With a point to point Bluetooth module you can only establish one link to one other Bluetooth device With a point to multi point module you can establish several links between one master device and up to seven slaves ACL connections only three with SCO connections Point to Point Point to multipoint Figure 4 3 Point to point and point to multipoint piconets The type of Ericssons Bluetooth modules you can identify from the sticker on the hardware P N 51 1106 xx is the point to point ver sion and P N 51 1208 xx is the point to multipoint version 13 I Q Mower PN sequence transmission 2002 06 24 using Bluetooth Datasheets of the Ericsson Bluetooth Modules with the number rok101007 is point to multipoint and rok101008 is point to singlepoint functionality 4 8 Master and Slave Since the radios in all Bluetooth devices are essentially identical in function any device can be a Master and any can bea Slave It is really a function of which device broadcasts first e Master The device that initiates an exchange of data e Slave The device that responds to the Master A piconet has one Master and up to seven Slaves The Master transmits in even time slots Slaves in odd time slots 4 9 Physical Links A link is established between a device acting as Master and a de vice ac
31. implify this is to make calls directly tothe HOST Stack APIs To do that a couple of files have to be included in the main file in your application These files are 31 I Q Mower PN sequence transmission 2002 06 24 using Bluetooth e bt_interface lib e serverevents cop e serverevents h and e header files located in the exp folder in the delivery struc ture The file serverevents cpp creates a COM client shell to enable communication with the HOST Stack For example see the two application suites TestSample and Chat containing the deliv ery of the Bluetooth Pc Reference Stack by Ericsson They are im plemented this way You can read more about this in User Man ual 6 6 3 HCI packets There are three different types of HCI packets HCI commands packets are sent from the host to Bluetooth module and HCI event packets which are sent from the Bluetooth module to the HCI host Finally there are HCI data packets 6 3 1 HCI Command packet This is used for sending commands to host controller from the host The format is shown in Figure 6 3 Each command consists of 2 bytes Opcode used to identify different types of commands The Opcode parameters are divided into two fields Opcode Com mands Field OCF and Opcode Group Field OGF The OGF occupies the upper 6 bits of the Opcode and the OCF occupies the other 10 bits of the Opcode Further more all of the command parameters for each
32. ion 35 6 4 4 Layer to layer 36 6 4 5 Start 38 6 4 6 Registration amp DeRegistration 38 6 4 7 Connection amp DisConnection Set up 39 6 4 8 Data transmission 40 6 4 9 The Page and Inquiry Procedures 41 6 4 9 1 The Inquiry Procedure 41 6 4 9 1 1 Inquiry Result Filter 42 6 4 9 2 The Page Procedure 43 6 4 9 3 Avoiding collisions 43 7 TEST SAMPLE APPLICATION SUITE 43 7 1 Test Sample application 44 7 2 My Modified Test Sample 45 8 BLUETOOTH AND FPGAS 46 9 RESULTS 46 10 11 12 13 I Q Mower PN sequence transmission using Bluetooth DISCUSION CONCLUSIONS REFERENCES APPENDIX 2002 06 24 46 47 48 48 I Q Mower PN sequence transmission 2002 06 24 using Bluetooth Figure index Figure 1 1 The IQ Mover radio systemie oss sv berber Nej Rs en a 8 Figure 4 1 Slot timing for single slot PACKetS sssssserrsssersrsererrerrrrrerrrrrerrrrerrrrrrrrrrrrrrrrrra 12 Figure 4 2 Schematic figure over piconet and SCatterNet seesssersssersrrrrrsrrrrrrrrerrrrerrr gt 12 Figure 4 3 Point to point and point to multipoint piconets ssressrrsserrserrssrrsrrrrrrrrrrra 13 Figure 4 4 An example of different links to different Slaves ssssmmeressserssrerrrrrerrrrerrrrrrrrrrr rna 16 Figure 4 5 Standard packet format ionene EE E a 16 Figure 4 6 Bit repetition encoding scheme ssmesssserssrerssrrrrrrrerrrrrrrrrrrrrrrrrrrr rer rr rrrr rr rr rr rr rr na 17 Figure 4 7 One time slot three time slots and five time
33. l in the same time The IQ mower has to tell which beacon to transmit to and when to transmit It will only get the noise sequence in return any re transmission of the turn on sequence is not allowed If any transmission fails the Q mower has to wait for the next one Bluetooth is a new communication technology It can work ina piconet with one master and up to seven slaves This project has researched if Bluetooth can be used in the Q mower system to send the turn on sequences from the Q mower to the beacons The Ericsson Bluetooth Application amp Training Tool Kit has been used in this project The Test Sample Application in the Kit has been modified to test if it will fit the Q Mower Due to the fact that the two Bluetooth modules in the kit were only point to point it has not been possible to try the application with three beacons If hardware for an embedded solution with full stack on chip and application on host is used and SCO or AUX1 Bluetooth packets transmit the turn on sequences it will be possible to use Blue tooth in the Q mower system I Q Mower PN sequence transmission using Bluetooth Index INTRODUCTION AIM OF STUDY METHOD MATERIAL WHAT IS BLUETOOTH 4 1 How it started 4 2 Bluetooth Special Interest Group SIG 4 3 Royalty free license 4 4 Worldwide operation 4 5 Frequency Hopping 4 6 Slots 4 7 Piconet and Scatternet 4 7 1 Point to point and point to multipoint 4 8 Master and Sl
34. n 1998 five key companies Erics son IBM Intel Nokia and Toshiba formed the Bluetooth Special Interest Group SIG to coordinate the development of and pro mote the Bluetooth technology Bluetooth was formally an nounced in May of 1998 and the Bluetooth SIG released version 1 0 of the Bluetooth specification in J uly of 1999 1 Since then membership in the Bluetooth SIG has grown to include more than 2400 different companies Four other large companies 3Com Lucent Technologies Microsoft and Motorola have joined the five founding companies as so called promoter members These nine companies provide direction and promotion for the en tire 2000 company Bluetooth effort You can read more about SIG on www bluetooth com Bluetooth has been adopted by all the major players in the tele com and computer worlds as well as an interesting cross section of companies in other industries including the home entertain ment automotive health care industrial automation and toy in dustries 4 3 Royalty free license The Bluetooth technology itself is available to all member compa nies via a royalty free license J ust about any company can use Bluetooth technology at no charge All new Bluetooth radios and profiles have to be tested by SIG to manage the standard 4 4 Worldwide operation One of the key requirements in the design of the air interface was that it should be able to operate worldwide The only frequency band that satisfi
35. n of data and voice in both stationary and mobile environments Bluetooth is a technology that promises to eliminate most of the cables that connect various personal computing devices and to create new types of smart wireless communications Bluetooth technology will enable all different electronic devices to connect to each other without wires Bluetooth is more than just a cable replacement technology It is also a technology that enables any electronic device to communi cate with any other electronic device automatically This means over short distances up to 100 meter your cell phone or personal digital assistant PDA can connect to synchronise with and even control the other electronic devices in your home or office such as your personal computer printer television set home alarm system or home office telephone system All of this communica tion can take place without your being aware totally automati cally 4 1 How it started The idea that eventually became Bluetooth was born in 1994 when engineers at Ericsson Mobile Communications investigated the feasibility of a low power low cost radio interface between mobile phones and their accessories 4 2 Bluetooth Special Interest Group SIG In 1997 Ericsson approached several manufacturers of portable electronic devices to discuss the development of this new short I Q Mower PN sequence transmission 2002 06 24 using Bluetooth range wireless technology And i
36. oint to point connections but also in point to multipoint connections This means that two or more units sharing the same channel form a piconet consisting of one master and up to seven slaves When more than one master is involved in the piconet then they form a scatternet Figure 4 2 shows the two concepts Piconet Scatternet AEFOSS posi Mobile Phone Master Q 9 CY siave a cal O ad Pa Sf far Mouse Laptop Figure 4 2 Schematic figure over piconet and scatternet 12 I Q Mower PN sequence transmission 2002 06 24 using Bluetooth The Bluetooth devices have to be in range of each other to estab lish connections they also have to be of type point to multipoint see chapter 4 7 1 to be able to establish piconet or scatternet con nections Once multiple links are in place the device must handle QOS Quality of Service balancing between the links That is to say it must decide how much bandwidth to allocate to each link The devices in a piconet share a common communication data channel The channel has a total capacity of 1 megabit per second Mbps Headers and handshaking information consume about 20 percent of this capacity If two piconets are close by each set of Slaves will only receive packets on their own piconet which have that piconets sync word Similarly a Master will only receive from its own Slaves As mobile devices move around they can easily move out of range and lose contact with the p
37. ooth 6 The Ericsson System Level Description Windows COM client framework COM Ser Wer APREN i Interface Application Programmers Interface A Pi Hos Stack by Ericsson HCl Driver fese HCl Firmware gt Windows COM server RFCO M M Link Manager 7 Bluetooth PC Refernce Stack Bluetooth Module Bluetooth Host Stack by Ericsson JU Figure 6 1 An overview of the PC Reference Stack and its components 6 1 The Upper Stack The upper stack that is delivered together with the Ericsson Blue tooth Module is the Bluetooth PC Reference Stack by Ericsson The Stack gives the costumer a ready to use module containing selected higher level Bluetooth protocols to be integrated ina Windows environment The Bluetooth PC Reference Stack will run in a Windows NT 98 or 2000 environment The Bluetooth PC Reference Stack by Ericsson the host stack in figure 6 1 containing the following higher layers I nterfaces of the Bluetooth protocol stack compliant to the Bluetooth foundation specification 28 I Q Mower PN sequence transmission 2002 06 24 using Bluetooth e RFCOMM is a transport protocol e SDP Service Discovery Protocol e L2CAP Logical Link Control and Adaptation Protocol e HCI Driver Host Controller Interface e OBEX OBject E Xchange protocol e TCS Telephony Control protocol Specification 6 1 1 HCI The Host Controller Interface Named HCI Driver in Bluetooth PC
38. r layers and upper layers of the protocol stack forming a bridge between them The two most common physical transports are UART H4 and USB H2 The hosted model is optimum for applications where powerful host processors are already available and there is plenty of mem ory Examples of hosted devices include USB dongles PCMCIA cards compact flash cards V90 modems I nternet gateways and PC motherboards In the embedded model the complete stack resides on a Bluetooth device but a separate user application is running on a host This model is ideal for 2 and 3G mobile phones ticket or vending ma chines or PC peripherals that have limited processing power and available memory In the fully embedded model the complete stack and the user ap plication are all on the Bluetooth device There is limited memory resource on the Bluetooth device so any application will need to be relatively simple The best example of a fully embedded device is 22 I Q Mower PN sequence transmission 2002 06 24 using Bluetooth a headset It has no need for complex processing so the whole Bluetooth stack can run on the single microprocessor within the Bluetooth chip chip set The lower stack up tothe HCI is always provided with the Blue tooth chip chip set as it is unique to that silicon implementation With the embedded model the upper layers are also provided by the chip chip set vendor either free of charge if it is their own stack or there may b
39. rting issues to be addressed when moving to an ASIC implementation such as embedded ASIC RAM block It is particu larly important to ensure that enough validation is carried out on the ASIC design itself and not just to rely on the lab bench verifi cation of the FPGA based system 9 Results have managed to modify the Test Sample Application in order to send one sequence every second to one beacon An SCO link was used in order to get rid of retransmissions The Bluetooth M od ules used were only point to point so for that reason have not been able to try to connect to more then one beacon The Ericsson Module has only the lower layers the upper layer has been placed ina PC 10 Discusion Bluetooth is still a new technology It will take some time before this will be as easy to use as the SIG would like it to be There will be new functions added for a long time think 46 I Q Mower PN sequence transmission 2002 06 24 using Bluetooth The optimal solution for the I Q M over would be an ACL link witch does not retransmit all packets The AU X11 is that kind of packet but it does not have any type of bit error control in the transmitted data sequences have not been able to try the AUX1 packet type There is an inconsistency in the Ericsson stack im plementation have emailed them about this and they say they are going to correct it in the future If the AUX1 packet is not Ok you can try to use SCL links in stead
40. sequence transmission 2002 06 24 using Bluetooth Figure 6 13 Data transmission 6 4 9 The Page and Inquiry Procedures To establish new connections between Bluetooth devices in order to form a piconet the page and inquiry procedures are used Page is used to contact a Bluetooth unit you already know the BD ADDR and inquiry is to request the BD_ADDR of units in the area 6 4 9 1 The Inquiry Procedure The units in range can respond to an inquiry The figure 6 14 shows the Inquiry procedure and answer from two different de vices The units respond with their BD ADDR and the CLK sothe inquiry unit can have knowledge on the address and the clock of those units that responds to the inquiry The uclnquiryLength specifies the total duration of the Inquiry UCN rofResponses specifies the number of responses that must be received before the inquiry is halted An ucNrofResponses of zero indicates unlimited responses 41 I Q Mower PN sequence transmission 2002 06 24 using Bluetooth HCI Reqlnquiry uiSeqNr 34 tlap O0x9E8B33 ucInquiryLength 5 ucNrofResponses 0 HCI_INQUIRY_EVT tBtAddress 0x11 22 33 4455 66 ucPageScanRepMode ucPageScanPeriodMode ucPageScanMode tcod uiClockOffset HCI_INQUIRY_EVT iBtAddress AA BB CC DD EE FF ucPageScanRepMode ucPageScanPeriodMode ucPageScanMode tod uiClockOffset HCILINQUIRY_CNF uiseqNr 34 Mm Function IFO Messages Figure 6 14 Inquiry
41. ssion 525 ua fik 1 F K 1 fF K 2 0 f k 3 IT K 4 if k 5 i fik 6 Tik f k 3 f K 4 F k f k 5 f k 6 rrr Figure 4 7 One time slot three time slots and five time slots Figure 4 7 shows the three different sizes of packets Notice the empty slots they are reserved for Slave to Master packets 4 11 Bluetooth Clocks Every Bluetooth device has an internal system clock Known as a native clock CLKN which determines the transceiver timing for that device CLKN is never adjusted or turned off Piconet synchronisation is determined by the master s clock of the piconet CLK CLK is identical to the master s native clock CLKN Slaves in the piconet add a timing offset to their own na tive clock to synchronise with the master clock To maintain pi conet synchronisation the timing offsets of the slave clocks are updated regularly each time a packet is received from the mas ter The master can request this clock offset anytime during a connec tion By saving this clock offset the master knows on what RF channel the slave wakes up to PAGE SCAN see chapter 6 4 9 after it has left the piconet This can be used to speed up the pag ing time the next time the same device is paged 18 I Q Mower PN sequence transmission 2002 06 24 using Bluetooth 4 12 Unique Bluetooth Address Every Bluetooth device has a unique Bluetooth device address The baseband part of the Bluetooth specification descri
42. t function of the protocol layer it wants to use If the sever is registered to the lower layer aB CONNECT IND isre ceived As seen above the server can decide whether to accept or to decline depending what the server send as B_RspConnect pa rameters Either client or the server can send a B_ReqgDisconnect the other side receivesaB DISCONNECT EVT 6 4 8 Data transmission When the connection is established both the server and the client can start sending data to the other side The highest layer must call the B_DataAlloc function which allocates memory in the stack and the highest layer can put its data in there After this a B DataSend is send toa lower layer This function call has a pointer to the allocated memory as parameter This means that the data is not copied on every level as the data travels though the layers On the opposite side a B DATA IND is received which indicates that data is delivered to layer A This layer then sends a B_DataExtract to retrieve a pointer to the data block and the length of it If this is successful then a B_RspData is sent De pending on the correctness of the data a positive or negative re Sponse is indicated the return parameter Figure 6 13 shows a data sending scheme Client Server Client Server B DataAlloc B DataSend Data Send Sudcessful B DATA IND B DataExtract B DATA CNF B RspData negative result B DataAlloc IP Function IFO Messages 40 I Q Mower PN
43. t sent or point to point sent The SCO Data Packet is shown in Figure 6 6 33 I Q Mower PN sequence transmission 2002 06 24 using Bluetooth Connection Handle eserved Data Total Length Figure 6 6 HCI SCO Data Packet The Reserved Bits consist of four bits they are reserved for future use Length of SCO data measured in bytes 6 4 API Application Programmers Interface With the Tool Kit comes a special interface to the stack it is named the BTAPI The interface is an Ericsson propriety API designed as environment independent and flexible as possible 6 It allows the establishment and tear down of data and voice con nections sending and receiving of data as well as other Bluetooth functions such as performing inquiries and page function Dy namically loading profile and adding own API complements suit able for the selected environment One other important feature is the ability to access the L2CAP layer directly in order to imple ment new protocols on top of L2CAP by the user 6 4 1 API supported profiles e Dail up networking e LAN Access e Fax e Serial Port e Headset Missing profiles can be added by copying an existing profile rou tine and adapt it to your wishes You can read more about this in the Users Manual 6 6 4 2 The stack API The stack API gives application programmers access to the APIs provided by the different layers of the stack RFCOMM SDP L2CAP SCM and HCI interfaces By using the API th
44. t the grass all by itself It is named the Q Mower In Figure 1 1 you can se the radio system that is going to help the Q M over to know were it is The micro processor FPGA A D AGC and RS will be placed in the IQ Mower the RM CPLD and power amplifier will be placed ina beacon There will be at least three beacons in one system Micro processor RS Radio transmitter RM Radio receiver 7 Figure 1 1 The IQ Mover radio system The IQ M over needs to send a sequence to every beacon one by one once every second to start the CPLD We do not want any retransmission of the sequence If any transmission fails the bea con have to wait for the next transmission 2 Aim of study The aim of this study is to investigate whether it is possible to use Bluetooth in the radio transmitter and receiver above 3 Method Material In this degree thesis the following products have been used _ eee ae ee ee sc ae eo I Q Mower PN sequence transmission 2002 06 24 using Bluetooth e Ericssons Bluetooth Application amp Training Tool Kit e Ericssons Bluetooth PC Reference Stack Ria and R2B e Bluetooth Specification version 1 0 and 1 1 e Visual CH e Word 2000 e Windows 98 4 What is Bluetooth It is a new type of smart wireless communication The Bluetooth system is a universal radio interface on the globally available 2 4 GHz frequency band facilitating wireless communicatio
45. te connection between two or more Bluetooth devices can be established using information obtained via SDP The service discovery application does not make use of SDP as a means of ac cessing a service but rather as a means of informing the user of a Local Device the services that are available to his her device by and possibly via Remote Device s 6 1 5 OBEX OBEX is based on the rOBEX protocol which is a compact effi cient binary protocol that enables a wide range of devices to ex change data in a simple and spontaneous manner Spontaneity is 30 I Q Mower PN sequence transmission 2002 06 24 using Bluetooth important for Bluetooth where short duration ad hoc connections can be set up OBEX runs on top of RFCOMM 6 1 6 TCS Telephony Control protocol Specification TCS is using point to point or point to multipoint signalling to establish speech and data calls between Bluetooth devices The calls are mapped towards the L2CAP layer point to point via a connection oriented channel point to multi point via a connec tionless channel sent as a piconet broadcast 6 2 COM server The Ericsson Bluetooth Pc Reference Stack is a COM server con taining the Bluetooth HOST Stack Because of that your applica tion has to be a COM dient to be able to communicate with the HOST Stack Hl driver US BYUART US BYUART HEI Link Manager Figure 6 2 The Com server and Com client on top of the Module A way tos
46. ting as Slave Once a link has been set up there are two basic types of data packets that may be exchanged with one very important distinction between the two each is characterised by the two following link types e Asynchronous Connection Less ACL e Synchronous Connection Oriented SCO 4 9 1 ACL Link An ACL link exists between a Master and a Slave as soon as a connection has been established A Master may have a number of ACL links to a number of different Slaves at any onetime but only one link can exist between any two devices ACL links support symmetrical or asymmetrical packet switched point to multi point connections and are typically used for data transmission ACL is either point to point master to one slave or broadcast to all the slaves Broadcast packets are ACL packets that are not addressed to a specific Slave and so are received by every Slave ACL slaves can only transmit when requested by the master A Slave is allowed to return an ACL packet in the slave to master Slot if and only if it has been addressed in the preceding master to slave slot 14 I Q Mower PN sequence transmission 2002 06 24 using Bluetooth Most ACL packets facilitate error checking and retransmission to assure data integrity 4 9 1 1 AUXI All of the ACL packets contain a 2 byte CRC Cyclic Redundancy Checksum code except for the AU X1 packet AUX1 packets are DH 1 Data High rate packets with the CRC replaced by data
47. ting radio except a whole lot smaller and less powerful A Bluetooth radio is small enough to fit between the gap in your two front teeth and broad casts a minuscule 1 milliwatt The Bluetooth radio transmits over the 2 4GHz RF band utilizing spread spectrum frequency hop ping and Time Division Duplexing TDD technologies A Class 2 Bluetooth radio the most common type of device can function over a 10 meter range There are actually three different classes of Bluetooth radios de fined in the Bluetooth Specification see table 5 1 Power output and thus send receive range is the differentiator between the classes Table 5 1 Output Power for Each Bluetooth Power Class dBm decibel relative to one milliwatt is an alternate measure ment of output power Unlike the radioin your audio system the Bluetooth radio func tions both as a transmitter and a receiver 5 2 2 Bluetooth Baseband The Baseband is the physical layer of the Bluetooth It manages physical channels and links apart from other services like error correction data whitening hop selection and Bluetooth security The Baseband layer lies on top of the Bluetooth radio layer in the Bluetooth stack It is implemented as a Link Controller which works with the link manager for carrying out link level routines like link connection and power control The Baseband also man ages asynchronous and synchronous links handles packets and does paging and inquiry to access and inq
48. uire Bluetooth devices in the area The Baseband transceiver applies a time division du plex TDD scheme alternate transmit and receive Therefore apart from different hopping frequency frequency division the time is also slotted See chapter 4 6 24 I Q Mower PN sequence transmission 2002 06 24 using Bluetooth 5 2 3 The Link Manager LM It isthe LM that translates HCI see 6 1 1 commands into opera tions at the baseband level managing the following operations e Attaching Slaves to a piconet e Breaking connections to detach Slaves from a piconet e Configuring the link including controlling Master Slave Switches where both devices must simultaneously change roles e Establishing ACL and SCO link e Putting connections into low power modes Hold Sniff and Park I don t write about these modes because the Blue tooth Module used does not support them e Controlling test modes 5 2 4 The Host Controller HC The host Controller HC in figure 5 3 named HCI is the part of the Bluetooth that manages all communication and interaction between the Bluetooth module and the host device The connec tion between the two parts can be hardwired that is the Blue tooth module can be built into the host device s main circuit board or modular with the Bluetooth module attached to the host device as an add on accessory or plug in card 5 2 4 1 Bluetooth Traffic Light Utility BTU It is important to know th
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