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USB dongles for mobile broadband

1. Devices Tomorrow never waits Online Available http www ztedevice com product Mobile Hotspot 554228b5 689c 4fc5 b40d e868863e42ec html Accessed 14 un 2015 X Fang Reply MM Non OMI Huawei modems without PPP support 2012 Online Available https mail gnome org archives networkmanager list 2012 November msg00 127 html Accessed 15 un 2015 Huawei Huawei e5770 Online Available http consumer huawei com minisite worldwide e5770 index htm Acoessed 15 Jun 2015 B Molina and M della Cava Apple beats Samsung in Q4 smartphone sales USA TODAY Online Available http www usatoday com story tech 20 15 03 03 apple samsung smartphones 24320385 Accessed 15 un 2015 S Anthony In 2015 tablet sales will finally surpass PCs fulfilling Steve J obs post PC prophecy ExtremeTech Online Available http www extremetech com computing 185937 in 2015 tablet sales will finally surpass pcs fulfilling steve jobs post pc prophecy Accessed 15 un 2015 M Dynamics YouGov s DongleTrack study USB Dongle Market is shrinking MVNO Dynamics Online Available http www mvnodynamics com 2011 02 12 yougov e2 80 99s dongletrack study usb dongle market is shrinking Accessed 15 un 2015 Strategy Analytics Third Consecutive Annual Decline in Mobile Broadband Modem Market in 2014 says Strategy Analytics Online Available http
2. IMS IoT IP IRP IRQ ISP LTE MDL MDS MIMO NAT First Generation Second Generation Third Generation 3rd Generation Partnership Project Fourth Generation Authentication Authorization and Accounting Acknowledgement Abstract Control Model Access Point Communications Device Class Code Division Multiple Access 2000 Correspondent Host Central Processing Unit Cyclic Redundancy Check Call Session Control Function Digital Enhanced Cordless Telecommunications Dynamic Host Configuration Protocol Domain Name System Digital Subscriber Line Extensible Authentication Protocol European Telecommunications Standards Institute Frame Check Sequence Gateway GPRS Support Node Global Positioning System General Packet Radio Service Global System for Mobile Communications High Level Data Link Control Home Subscriber Server High Speed Packet Access Interrogating CSCF Information and Communication Technologies Institute of Electrical and Electronics Engineers Input Output IP Multimedia Subsystem Internet of Things Internet Protocol I O Request Packet Interrupt Request Internet Service Provider Local Area Network Long Term Evolution Memory Descriptor List Multi access Data Server Multiple Input Multiple Output Negative Acknowledgement Network Address Translation List Acronyms and Abbreviations NCM OFDMA OS P CSCF PDA PID PPP Network Control Model
3. Today mobile phones are so common that a mobile phone is probably the first device you think of when hearing of wireless services Mobile telephony also known as cellular telephony operators generally use licensed spectrum to provide telephone services over a contiguous area normally a large area covered by numerous cells Cellular technology is the underlying technology for these wide area mobile wireless communication systems Each cell provides wireless connectivity for a given area while the mobile network s core infrastructure provides the required functions to enable a user to be authenticated to be reachable despite the terminal move from one cell to another and to provide connectivity to devices within a cell The original cellular networks now referred to as the first generation 1G used analog traffic channels The second generation 2G networks were based on digital technologies These 2G devices were introduced into the telecommunication market in the 1990s The 2G vendors and operators had great success and 2G technologies are still used today although in a number of countries these devices are being phased out and many operators are planning to terminate 2G service Voice telephony was the main focus of 1G and 2G mobile phone services however data services have become increasingly important in recent years especially after the introduction of third generation 3G technologies The high data rates 7 Mbps in the downlink dire
4. www prnewswire com news releases third consecutive annual decline in mobile broadband modem market in 20 14 says strategy analytics 300000499 html Accessed 15 J un 2015 ABI Research Global Wi Fi Hotspots Will Grow to 7 1 Million in 2015 as a Method to Offload Traffic 2014 Online Available https www abiresearch comy press global wi fi hotspots will grow to 71 million in 2 Accessed 15 un 2015 J Terve WiFi calling a powerful customer retention tool 2015 Online Available http wireless kth se wp content uploads 2015 04 Wi Fi Calling E2 80 93 Slides pdf Accessed 15 un 2015 51 USB dongle data rate in uploading Comviq Surt Connect Transfer 4 Transfer Time 00 03 50 3 4 Upload 4 Speed 336 95 Kb s 4 Data 4 20 MB Download 4 Speed 6 95 Kb s 4 Data 346 35 KB 19 Statistics 4 Time Last Reset 09 04 2010 08 25 is Daily 4 Uploaded Data 18 17 MB 4 Downloaded Data 21 45 MB Monthly 4 Uploaded Data 23 46 Danmlaadad Mates 221 LA MD 4 m v SMS Phonebook n Tull Turbo 36 Comvig Eb 6 95 4 6 95kb s 52 Appendix A 2 USB dongle data rate downloading Comviq Surf Connect EJE Tn Connection xs Sis SMS Phonebook 2 Transfer A 4 Transfer Time 00 14 43 3 4 Upload 4 Speed 7 25 Kb s 4 Data 7
5. In our case the TE will be the laptop MT is the USB dongle and the TA is integrated within the dongle as the module that processes AT commands The network setup process is displayed in Figure 3 19 first a user uses the laptop to send AT commands through the serial link to the dongle The adaptor receives and analyzes these commands and then transfer control the dongle The dongle processes the command by interacting with the network and sends the resulting status information back to the laptop through the adapter response MT status TE laptop TA MT dongle AT cmds MT control Networkmessage User amp applications network Figure 3 19 AT commands between laptop and dongle PPP and AT commands are used in a traditional USB dongle to make the dongle work as a serial dial up modem For this project our purpose a dongle design in which the dongle can provide multiple heterogeneous network service for example the dongle could have interfaces for WLAN 3G and 4G The first step is to recognize that using PPP as the interface between the dongle and laptop is no longer a good idea as we are not simply trying to look like a dial up modem but rather should look like a packet interface Furthermore the interface may need to expose multiple ports as it may want signal quality and status information while remaining connected with the Internet 38 Therefore we can see that having a single serial port for PPP communication is not sufficient
6. These tests utilized a Huawei E1550 3G USB dongle An interesting question is how this power consumption compares to the power consumption when accessing the Internet by WLAN One might assume that using a WLAN interface should require less power than using a 3G interface because the cellular base stations are likely to be further away and it requires more energy to move a given amount of data over a longer distance within the same time period Based upon mobile users feedback available on the Internet most users feel 3G communication requires more power than comparable communication over a WLAN However Andrew Baxter reports that the actual WLAN power consumption is very similar to the 3G power consumption 28 By using the formula below we can calculate the battery lifetime in hours of a laptop with without a USB dongle Laptop Battery lifetime in Hours Battery Capacity Power Consumption More specifically a IEEE 802 11g interface was used 22 Method The battery capacity and power consumption can be measured by a program called BatteryMon 29 When the author s laptop with a battery capacity of 40759 mWh is playing online video by WLAN and the screen brightness is high the power consumption is 20304 mW This power consumption is shown in Figure 3 3 File Edit Run Info Help Status Stopped r Battery details Power source Bat Battery Status Ful o Z Life left 85 ipo cic Time Remai
7. We make this simplification since this project started originally during 2009 during that time the most wide spread type of 3G network was WCDMA and WCDMA offered the highest peak data rates of the various 3G networks thus with respect to our analysis it presented the strongest alternative to WLAN To be specific we will focus on the cellular standards introduced by the 3rd Generation Partnership Project 3GPP By 2015 the new mobile network Long Term Evolution LTE has been widely deployed in many countries LTE uses a different wireless communication standard than WCDMA however this thesis focuses on the communication interface with a laptop computer rather than external radio links so our research did not shift to LTE The conclusions should be valid for both WCDMA and LTE radio interfaces Therefore throughout this thesis the term mobile broadband simply refers to high speed wide area wireless access to the Internet 1 1 Problem statement Wireless Internet access has become very common in recent years and there are many different access solutions People can connect their laptop to the Internet via a WLAN hotspot through a mobile phone portable modem or other similar device implemented for example as a 3G Universal Serial Bus USB dongle There are various USB dondles are available in the market and the market is huge Huawei a Chinese telecommunications manufacturer announced that the company shipped more than 50 million
8. Communications vol 18 no 3 pp 10 21 Jun 2011 V A Dubendorf Wireless Data Technologies 1 edition Chichester West Sussex England Hoboken NJ Wiley 2003 J D Carlson PPP Design Implementation and Debugging 2 edition Boston Addison Wesley Professional 2000 BCE Glossary Online Available http www bce ca glossary d Accessed 23 May 2015 S Sendra M Garc a Pineda Turr Ribalta and J Lloret WLAN IEEE 802 11 a b g n Indoor Coverage and Interference Performance Study in International Journal On Advances in Networks and Services 2011 vol 4 pp 209 222 LitePoint IEEE 802 11ac What Does it Mean for Test 2013 Online Available http litepoint com whitepaper 80211ac Whitepaper pdf Accessed 24 May 2015 Kurose and W Ross Computer Networking A Top Down Approach Featuring the Internet Third edition Boston Addison Wesley 2004 W Stallings Data and Computer Communications 8 edition Upper Saddle River Prentice Hall 2006 K Roebuck 4G Standard High impact Emerging Technology What You Need to Know Definitions Adoptions Impact Benefits Maturity Vendors Tebbo 2011 ETSI ETSI TR 122 934 V9 0 0 Digital cellular telecommunications system Phase 2 Universal Mobile Telecommu nications System UMTS LTE Feasibility study on 3GPP system to Wireles Local Area Network WLAN interworking 3GPP TR 22 934 version 9 0 0 Release 9 2
9. ICN 2005 P Lorenz and P Dini Eds Springer Berlin Heidelberg 2005 pp 1047 1054 G Mola Interactions of Vertical Handoffs with 802 11b wireless LANs Handoff Policy Master thesis KTH Royal Institute of Technology 2004 Lampropoulos N Passas L Merakos and A Kaloxylos Handover management architectures in integrated WLAN cellular networks IEEE Communications Surveys Tutorials vol 7 no 4 pp 30 44 Fourth 2005 S Balasubramaniam and J Indulska Vertical handover supporting pervasive computing in future wireless networks Computer Communications vol 27 no 8 pp 708 719 2004 G Bertrand The IP Multimedia Subsystem in Next Generation Networks Rapport technique ENST Bretagne vol 7 2007 B Vucetic K S Munasinghe and A J amalipour Interworking between WLAN and 3G Cellular Networks An IMS Based Architecture 2007 S Olivier and P Poiraud Public WLAN for mobile operators Alcatel telecommunications review no 4 1 pp 114 120 2003 A Baxter Laptop Battery Life How Wireless Affects Power Consumption NotebookReview com Online Available http www notebookreview com news laptop battery life how wireless affects power consumption Accessed 25 May 2015 PassMark BatteryMon UPS amp laptop computer battery monitoring software Online Available http www passmark com products batmon htm Accessed 25 May 2015 Usb Sniffer for Windows Online A
10. Most GSM UMTS modems have a second AT port however most CDMA modems do not 39 Moreover in RAS mode IP packets must be encapsulated with headers and trailers to form PPP frames to be sent over a dedicated link Obviously RAS mode is not efficient Instead of using a dedicated point to point communication link if the communication interface between the dongle and laptop were a IEEE 802 network adapter for Method 35 example an Ethernet adapter then data is simply encapsulated as an Ethernet frame for transport This new network adapter interface is even more appropriate for today s all networks Before continuing with the next subsection we need to clarify the two interfaces of a mobile terminal i e USB dongle and we borrow the names Um and Rm introduce by Sang Woo Park US Patent 20100074155 40 to describe these two interfaces In our case Um is the air interface between a USB dongle and a base station or WLAN access point Rm is the physical data communication interface between a dongle and a laptop computer The two interfaces are illustrated in Figure 3 20 The scope of this thesis focuses on the Rm interface Despite heterogeneous wireless networks and the need for multiple Um interfaces such as GSM 3G 4G WLAN we only need one Rm interface for these various Um interfaces Base station USB Laptop Figure 3 20 Two interfaces of USB dongle 3 4 2 Remote Network Driver Interface Specification
11. OUT 85 OxD684E030 OxD68ASDEO STATUS SUCCESS 0 311 URB 178023 BULK OR INTERRUPT TRA OUT 85 OxD6FI4B60 OxD68ASDEO STATUS SUCCESS 0 3x URB 178023 BULK OR INTERRUPT TRA IN 85 OxD6F14B60 OxD68ASDEO STATUS PENDING 0 m URB 17 8033 BULK OR INTERRUPT TRA IN 85 OxD6F14860 OxD6BABDEO STATUS SUCCESS 058002 003 314 URB 178033 BULK OR INTERRUPT OUT 85 OxD684E030 OxD68ABDEO STATUS SUCCESS 315 URB 17 8034 BULK OR INTERRUPT TRA OUT 85 OxD6F14860 OxDEBABDEO STATUS SUCCESS ou Figure 3 15 Polling transaction The next step is to connect to the Internet After watching the communication using USBTrace we found there are thousands of BULK OR INTERRUPT TRANSFER requests during the communication process and there is too much irrelevant detail For this reason we used the filter function in USBTrace to filter out this type of URB thus this URB will not be displayed Comparing the traces with without BULK INTERRUPT TRANSFER we learn that the connection process begins with a continuous series of SYNC RESET PIPE AND CLEAR STALL These URBs do preparation work They clear and reset all the serial pipes except for isochronous pipes on the host and device in order to perform new transfers without queued URBs The next several bulk transfers are followed by a series of CLASS INTERFACE and CONTROL TRANSFER URBs see Figure 3 16 these URBs send specific commands to an interface of the device and transfer data from or
12. Orthogonal Frequency Division Multiple Access Operating System Proxy CSCF Personal Computer Memory Card International Association Peripheral Component Interconnect Personal Digital Assistant Packet ID Plug and Play Point to Point Protocol Qualcomm MSM Interface Quality of Service Remote Authentication Dial in User Service Radio Access Network Remote Access Service Radio Network Controller Remote Network Driver Interface Specification Serving CSCF Serving GPRS Support Node Subscriber Identification Module Session Initiation Protocol Short Message Service Signal to Noise Ratio Stream Transmission Control Protocol Time Division Synchronous Code Division Multiple Access User Equipment Universal Mobile Telecommunications System USB Request Block Universal Serial Bus USB Implementers Forum UMTS Terrestrial Radio Access Network Wideband Code Division Multiple Access Wireless Fidelity Wireless Local Area Network Introduction 1 1 Introduction Information and communication technologies ICT have completely changed the world in a relatively short period of time Only two to three decades ago the telegraph was still widely used for long distance message transmission in many countries and most people had never heard the word Internet Today the Internet has become an indispensable part of people s lives throughout the world Instead of going to the post office to send a telegram you can generally reach nearl
13. 2 5 3 Industrial proposals iris 15 2 6 Chapter SUMMa rss da 16 A A u 19 3 1 Research method roses inani decana ceca c c nn nn nn nn 19 3 2 Power consumption 20 3 3 Watching USB communication using USBTrace 23 3 3 1 USB communication overview 23 3 3 2 Watching USB communication 26 3 4 Communication between the laptop and dongle 33 3 4 1 Remote Access 33 3 4 2 Remote Network Driver Interface Specification 35 3 5 General architecture of the dongle 37 LEE CUL c ee ee 39 4 1 Technical 5 39 4 2 Market anall SIS PRBRBRERPRERFEFRERERRBERFEERERERFRFEERERFDERFEEREREEFRFRFRERERERFEERFRFRER 41 5 Conclusions and Future 45 5 1 GONCIUSIONS m 45 5 2 WOrke cada daa aid 46 viii Table of Contents 5 3 Reflections xiii 46 REfereN CCS etr da 47 Appendix me A 51 USB dongle data rate in uploading 51 A 2 USB dongle data rate in downloading 52 Dll gr 53 List of Figures
14. 8 55658 STATUS SUCCESS 24296 INTERNAL DE 312 873565 SUBMIT IDLE NOTIFICATION IN 0 OxC89CF208 0xC898AB48 STATUS CANCELLED 24297 POWER 312 873605 SET POWER OUT 0 OxC89CF208 0x855ECEO0 STATUS SUCCESS 20 POWER 312873609 POWER IN 0 OxC89CF208 0x855ECE00 STATUS SUCCESS 24299 PNP 312 873681 QUERY DEVICE RELATIONS OUT 0 89 208 0x86D00608 STATUS SUPPO 230 PNP 312 873684 QUERY DEVICE RELATIONS IN 0 OxC89CF208 0x86D00608 STATUS SUPPO 24301 312873734 QUERY DEVICE RELATIONS OUT 0 OxC89CF208 0x86D00608 STATUS SUCCESS 24302 PNP 312873737 QUERY DEVICE RELATIONS N 0 OxC89CF208 0x86D00608 STATUS SUCCESS 24303 URB 312 873965 CLASS INTERFACE OUT 0 0xC89CF208 0 855 00 STATUS SUCCESS 24304 URB 312 873969 CLASS INTERFACE N 0 OxC89CF208 Ox855ECEO0 STATUS NO SUCH D 24305 URB 314 873346 BULK OR INTERRUPT TRANSFER OUT 68 0xC89CF208 0 8591 570 STATUS SUCCESS 24306 URB 314 873353 BULK OR INTERRUPT TRANSFER IN 68 OxC89CF208 0x8591E570 STATUS NO SUCH D 24307 URB 314 873360 SYNC RESET PIPE OUT 68 OxC89CF208 0 807 700 STATUS SUCCESS 24308 URB 314 873363 SYNC RESET PIPE IN 68 0xC89CF208 0 07 700 STATUS NO SUCH D 24309 PNP 316 900560 SURPRISE REMOVAL OUT 0 OxC89CF208 0x871A18A0 STATUS SUPPO 24310 PNP 316 900808 SURPRISE REMOVAL N 0 OxC89CF208 0x871A18A0 STATUS SUCCESS 24311 PNP 317 012519 REMOVE DEVICE OUT 0 OxC89CF208 0x871A18A0 STATUS SUCCESS 24312 PNP 317 012544 RE
15. However there is no standard solution which is good for all research therefore researchers should deliberately choose suitable research methods for each research project Researchers must be explicitly aware of the questions they are going to figure out and know what type of information is required to answer the questions and then select the methods that can produce the required information and data So we need to carefully consider the research questions before we can choose suitable methods for this thesis project The aim of the thesis is to explore how heterogeneous networks could be exploited to provide a laptop user with locally optimal service while hiding the complexity of this heterogeneous service The goal is to understand the implications of integrating multiple network interfaces into a single USB dongle Section 1 2 on page 2 listed some of the questions that this thesis should answer To answer these questions we need to know related background information the features of a traditional USB dongle what interface is used by the dongle and how the dongle works Then based on this information we propose an improved solution for a USB dongle and analyze the advantages and market prospects of this new dongle The first method we applied was a literature study a special kind of observational study where related documents and information are checked By using this method we found both academia and industry have fully understood th
16. average and maximum data rates and potentially reduce the costs for the user both economic cost and battery power consumption 14 Background 2 5 Related work Coupling 3G and WLAN networks has attracted a lot of interest from researchers leading to many different proposals This section presents some of this related work both proposals in academic literature as well as industrial examples 2 5 1 Policy based loose coupling framework There already exists extensive literature concerning proposed 3G and WLAN coupling architectures especially those proposing loosely coupling The common feature for all the proposed architectures using loose coupling is the use of Mobile IP as the basic instrument of inter system mobility and the high level perspective of the integration process 23 Another important focus is policy based handoff Since in practice a handoff decision is not only based on signal strength but might depend on many parameters thus policy based handoff is a common solution An example of a loose coupling policy based handoff framework proposal by S Balasubramaniam and J Indulska 24 is presented below This proposed framework categorizes policy parameters as static context or dynamic context Static contexts refer to parameters that do not change very often such as the devices networks and their QoS requirements while dynamic contexts include current information about users and networks that change dynami
17. by using our proposed small low cost device and users might even cancel their expensive data subscriptions for smartphones and tablets if they can always bring this small device with them Therefore this thesis project might offer attractive economic values for both operators and users References 47 References 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 GSMA The Mobile Economy 2013 2013 Online Available http www gsmamobileeconomy com GSMA 20Mobile 20Economy 202013 pdf Accessed 08 May 2015 C Coonan Change of tack for third biggest global smartphone vendor 2013 Online Available http www thenational ae business technology change of tack for third biggest global smartphone vendor Accessed 22 May 2015 D Cavalcanti D Agrawal C Cordeiro B Xie and A Kumar Issues in integrating cellular networks WLANs AND MANETs a futuristic heterogeneous wireless network IEEE Wireless Communications vol 12 no pp 30 41 J un 2005 Song and A J amalipour Network selection in an integrated wireless LAN and UMTS environment using mathematical modeling and computing techniques IEEE Wireless Communications vol 12 no 3 pp 42 48 Jun 2005 A Damnjanovic J Montojo Y Wei T Ji T Luo M Vajapeyam T Yoo O Song and D Malladi A survey on 3GPP heterogeneous networks IEEE Wireless
18. connections and decide which network is better they would simply plug such a dongle into their laptop and then the dongle would try to connect with the user s preferred network usually a WLAN offering the best communication quality If there are no accessible WLANs then the dongle would connect via a wide area cellular operator s mobile broadband service for example via a 3G network Not only users but mobile network operators would benefit from this combined dongle since they can use the WLAN network for mobile data offloading to ease the traffic burdens due to the explosion growth of Internet data traffic via their cellular networks Because the communication modules are inside the USB dongles rather than integrated with laptops or smartphones it is much easier to modify and upgrade to new dongles to get access to new types of wireless networks which is good news for dongle producers The aim of the thesis is to explore how heterogeneous networks could be exploited to provide a laptop user with locally optimal service while hiding the complexity of this heterogeneous service The goal is to understand the implications of integrating multiple network interfaces into a single USB dongle Questions that this thesis should answer include 1 Istherea market for a dongle that contains some specific set of wireless interfaces 2 What should be the communication interface between this dongle and the host operating system 3 What parameters
19. data is actually ready to be provided to the computer If the request type of the USB device is isochronous or interrupt for example a mouse then there are no repeated attempts to make a data transfer However if the request type is a control or bulk transfer then the polling loop will be repeated again and again As the 3G USB dongle uses bulk transfer the device continuously polls until the Internet connection is set up 32 Method Seq Type Time Request VO EndPoint Device Object IRP Status Buffer Snippet Buffer Size xU URB 178004 BULK OR INTERRUPT TRA IN 85 0 0685 008 STATUS SUCCESS 058002003 36 302 URB 17 8004 OR INTERRUPT TRA OUT 85 0 0684 030 0 06854008 STATUS SUCCESS 0 303 URB 17 8004 BULK OR INTERRUPT TRA OUT 85 0 06 14860 0 0685 008 STATUS SUCCESS 0 URB 17 8004 BULK OR INTERRUPT TRA IN 85 OxD6F14B60 0 0685 008 STATUS PENDING 0 35 URB 17 8015 BULK OR INTERRUPT TRA IN 85 0 06 14860 0 0685 008 STATUS SUCCESS 555342530 13 306 URB 17 8015 BULK OR INTERRUPT TRA OUT 4 0xD684E030 OxD68ASDEO STATUS SUCCESS 55534243E 31 307 URB 178015 BULK OR INTERRUPT TRA OUT 4 4 60 OxD68ASDEO STATUS SUCCESS 55534243E 31 308 URB 17 8015 BULK OR INTERRUPT TRA IN 4 OxD6FI4B60 OxD68ABDEO STATUS PENDING 0 309 URB 17 8023 BULK OR INTERRUPT TRA IN 4 4 60 OxD68ASDEO STATUS SUCCESS 0 310 URB 17 8023 BULK OR INTERRUPT TRA
20. might the user want to be able to configure using this interface to the dongle 4 What should be the future direction for development 3G 4G dongles There are various research strategies and methods for ICT research topics To apply the appropriate research methods we need explicitly aware of our research aim and questions clearly understand what type of information is helpful to answer the questions and then select the methods which can generate the requisite data This thesis focuses on design research literature studies and experimental tests as the main methods Common methods for social research such as interviews and questionnaires were not utilized as when the work started there were no dongles available that provided heterogeneous wireless Internet connectivity and much of the technical community was either focused on high speed cellular networks or LANS thus there seemed to be little that could be gained by asking people about a device that would exploit heterogeneous networks In the years that have passed since this project started there has been a growing interest in heterogonous networks especially for off loading macro cellular networks One of the main reasons to complete this thesis project was the chance to revisit some of the design decisions and questions that this thesis raised long ago and to see if the questions and answers have changed 1 3 General background about wireless networks Wireless communications techn
21. mobile broadband units in 2012 including data cards dongles embedded modules etc 2 An example of such a USB dongle is shown in Figure 1 1 2 Introduction COMVIQ Figure 1 1 Huawei E1550 a 3G USB dongle Today mobile broadband offers both high speed access and mobility Technically mobile broadband allows Internet access as long as your mobile transceiver can access your cellular network operator s network However in practice the data rates experience by a user via mobile broadband are not comparable to the data rates that users experience via WLAN especially as the data rate that the user experiences is both unstable and often lower than the data rate that users are used to when using their home or office WLAN Moreover 3G based mobile broadband was developed based upon an infrastructure that was optimized for telephony i e the focus was on voice service Such an infrastructure is not an optimal solution for high speed data service For this reason 3GPP has introduced new standards and 3G operators have been modifying their core networks to better support packet data Additionally there are several different standards for 3G mobile broadband hence to provide a user with locally optimal service requires that the user make use of heterogeneous networks Furthermore the variety of networks has increased due to the emergence of 4G networks The research about heterogeneous networks has attracted many researchers there are a lot o
22. seen as three devices by the Windows device manager Method 31 After the storage device is removed the PnP manager sends a series of IRP MJ requests to gather information about the new composite device 1 the modem This process is very similar to the PnP process that configured and then removed the mass storage device In the same process as described for the first 45 packets the PnP IRPs QUERY INTERFACE QUERY ID and QUERY DEVICE TEXT shown in Figure 3 14 occur for the new device starting with packet 133 Also as before to learn detailed information about the new device we can click on URB FUNCTION CONTROL TRANSFER see Appendix B Examining this URB we learn that the device has one configuration five interfaces and eleven endpoints After the URB process starts PnP requests continue For example the URB FUNCTION GET DESCRIPTOR FROM DEVICE IRP MN QUERY ID and URB FUNCTION CONTROL TRANSFER transactions compose a group of requests to retrieve the string descriptor for the device This group of requests occurs five times since the device has five interfaces Seq Type Time Request VO EndPoint Device Object IRP Status Buffer Snippet Buffer Size 127 PNP 17 5722 QUERY LEGACY BUS INF OUT 0 OxD684E030 0 068650 0 STATUS SUPPORTED 0 PNP 17 5722 QUERY LEGACY BUS INF IN 0 0 0684 030 0xD6865DE0 STATUS NOT SUPPORTED 0 129 PNP 17 5724 QUERY RESOURCE REQUI OUT 0 0 0684 030 0 068650 0 STATUS NO
23. session can be initiated if the authentication was successful In this architecture all WLAN accounting information is stored in the AAA server of the cellular network There are two methods to perform authentication One reuses the SIM card mechanisms and Extensible Authentication Protocol EAP while the other uses a one time password which could be sent as a Short Message Service SMS message Billingin WLAN is normally hard to handle hence Alcatel s architecture reuses the existing billing mechanisms of the cellular network In particular e WLAN access network APs generate the relevant accounting information and send it to the MDS of UMTS which makes it available for postpaid bill processing e Data traffic associated with the user s WLAN session activity can be securely tunneled to the UMTS I GGSN so that value added real time content can be charged for using enhanced on line or off line billing This is the responsibility of the real time content charging manager 2 6 Chapter summary This chapter first introduced some background knowledge about WLAN coupling and policy based routing and then described some relevant academic and industrial work concerning 3G WLAN coupling Loose coupling was given more attention than tight coupling since loose coupling is easy to deploy and can couple networks belonging to different operators However it seems very difficult to implement the upper service levels of 3GPP s six integration scena
24. started the USB Implementers Forum USB IF defined a number of USB Communications Device Class CDC protocols to provide this virtual Ethernet functionality such as CDC ACM Abstract Control Model In addition Microsoft defined their own Remote Network Driver Interface Specification RNDIS to provide similar functionality fortheir Windows OS machines The start of this thesis also predates the standardization and introduction of USB CDC Network Control Model NCM NCM in fact eliminates the need for the PPP encapsulation of IP packets thus showing that in fact the idea that was initially proposed in 2009 for this thesis project was a good idea 1 6 Structure of thesis This first chapter has introduced the general background and stated the problem that is the focus of this thesis project Chapter 2 will give more background about the different types of networks that will be considered and how the user can make use of these heterogeneous networks Chapter 3 describes the research methods and details of applying this method to solve the problem Chapter 4 describes some technical parameters of the new designed dongle and business analysis for the market Finally Chapter 5 summarizes the conclusions suggests future work and sets this thesis in the context of economic social environmental and ethical considerations relevant to this thesis project Background 7 2 Background There are several different wireless internet access technologi
25. to a control pipe The driver initiates the Internet connection during this process with the main information transferred being control information not bulk data Seq Type Time Request VO EndPoint Device Object IRP Status Buffer Snippet Buffer Size 65 URB 50 137778 OR INTERRUPT TRANSFER IN 86 Qx868C0440 086905080 STATUS SUCCESS 55 534253 13 6346 URB 50 276780 CLASS INTERFACE OUT 0 OxC89CF208 0868233388 STATUS SUCCESS 0 6347 URB 50 276787 CLASS INTERFACE OUT 0 087658400 086823338 STATUS SUCCESS 0 6348 URB 50 276871 CONTROL TRANSFER IN 0 0x87658A00 096823338 STATUS PENDING 0 EN URB 50 278184 CONTROL_TRANSFER N 0 0x87658A00 096823338 STATUS SUCCESS 00 2010000 7 6350 URB 50 278303 CLASS INTERFACE OUT 0 OxC89CF208 0868233348 STATUS SUCCESS 0 6351 URB 50 278308 CLASS INTERFACE OUT 0 087658400 0x86823338 STATUS SUCCESS 0 6352 URB 50 278361 CONTROL TRANSFER IN 0 087658400 086823338 STATUS PENDING 0 33 URB 50 280206 CONTROL_TRANSFER N 0 0x87658A00 0x86823338 STATUS SUCCESS 00 2010000 7 6354 URB 50 280354 CLASS INTERFACE OUT 0 0xC89CF208 0x86823338 STATUS SUCCESS 0 6355 URB 50 280360 CLASS INTERFACE OUT 0 0x87658A00 0x86823338 STATUS SUCCESS 0 6356 URB 502804117 CONTROL_TRANSFER N 0 0x87658A00 096823338 STATUS PENDING 0 657 URB 50 282178 CONTROL TRANSFER N 0 0x87658A00 0x86823338 STATUS SUCCESS 00 2010000 7 Figure 3 16 Connecting to the Internet After the host computer is connected with the Int
26. two flag fields to indicate the start and end of a PPP frame The flag field always has value 34 Method 01111110 or Ox7E in hexadecimal Since PPP is used for a point to point link there is actually no need for an address field so the address field is typically set to the broadcast address 11111111 Similarly the control field has a fixed value 00000011 The reason to keep these unnecessary fields is that PPP frame is based on and follows High Level Data Link Control HDLC framing The most important fields in PPP are the protocol and information fields The protocol field identifies the type of encapsulated protocol in the information field The maximum length of the information field including possible padding is 1500 bytes and this field contains an encapsulated datagram from the network layer The Frame Check Sequence FCS field is used to check whether the frame has errors following its transmission and reception lbyte 1byte 1byte 2bytes 1500 bytes 2bytes lbyte Flag Address Control Protocol Information Flag Figure 3 18 General PPP frame format For a USB dongle in RAS mode the Hayes command set also know as commands means attention is very important These commands provide the command language used between the laptop computer and USB dongle From 3GPP specification 37 we learned that these AT commands involve three parties Terminal Equipment TE Mobile Termination MT and Terminal Adaptor TA
27. van Halteren and H Hermens Context aware middleware architecture for vertical handover support to multi homed nomadic mobile services in Proceedings of the 2008 ACM symposium on Applied computing 2008 pp 481 488 Maguire r Speed Online Available http people kth se maguire Talks Nordic IT 971006 Nordic IT 971006 4 html Accessed 14 un 2015 Kelly 802 1lac vs 802 11n WiFi What s The Difference Forbes Online Available http www forbes com sites gordonkelly 2014 12 30 802 5 802 11n wifi whats the difference Accessed 14 un 2015 50 References 55 56 57 58 59 60 61 62 63 64 65 66 67 Ricknas TeliaSonera Launches First Commercial LTE Services PCWorld 14 Dec 2009 Online Available http www pcworld com article 184549 article html Accessed 14 Jun 2015 5 Perry Vodafone 3G On Apple MacBook Via USB Digital Lifestyles Online Available http digital lifestyles info 2006 08 01 vodafone 3g on apple macbook via usb Accessed 14 un 2015 Huawei FCC ID QISE220 Huawei Technologies Co Ltd Users Manual for HSDPA USB Modem 2006 Online Available https fccid net document php id 672546 Accessed 14 un 2015 D Pogue Wi Fi to Go No Cafe Needed The New York Times 07 May 2009 Corporation MF70 Mobile Hotspot
28. 010 Online Available http www etsi org deliver etsi tr 122900 122999 122934 09 00 00 60 tr 1229 34v090000p pdf Accessed 24 May 2015 J M Rodr guez Castillo Energy Efficient Vertical Handovers Master thesis KTH Royal Institute of Technology 2013 N Adigozalov The Intelligent Use of Multiple Interfaces Using multiplexing to reduce the overhead for small packets Master thesis KTH Royal Institute of Technology 2013 Ruggeri A Iera and S Polito 802 11 Based Wireless LAN and UMTS Interworking Requirements Proposed Solutions and Open Issues Comput Netw vol 47 no 2 pp 151 166 2005 7 Guo A New Authenticator An Alternative to Binary Authentication Using Traffic Shaping Master thesis KTH Royal Institute of Technology 2010 Raul Garcia Corporate Wireless IP Telephony Master s thesis KTH Royal Institute of Technology School of Information and Communication Technology Kista Stockholm Sweden 2005 48 References 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 S L Tsao and C C Lin Design and evaluation of UMTS WLAN interworking strategies in Vehicular Technology Conference 2002 Proceedings VTC 2002 Fall 2002 IEEE 56th 2002 vol 2 pp 777 781 vol 2 F Siddiqui S Zeadally and E Yaprak Design Architectures for 3G and IEEE 802 11 WLAN Integration in Networking
29. 11 MB 3 3 Download 4 Speed 518 12 Kb s 4 Data 31 79 MB 1 Statistics 4 Time Last Reset 09 04 2010 08 25 Big Daily 4 Uploaded Data 21 08 MB 4 Downloaded Data 52 90 MB m Monthly 4 Uploaded Data 26 37 MB DPA Matas 222 40 AAD 4 m p Turbo 3G Comviq E 725 4 518 12Kb s Information about device descriptors of the USB dongle URB_FUNCTION_CONTROL_TRANSFER Urb Field USBD Status USBD_STATUS_SUCCESS 0x0 EndpointAddress 0x0 PipeHandle 0x86ADDA5C Ox86AD563B TransferFlags USBD_TRANSFER_DIRECTION_IN USBD SHORT TRANSFER OK A TransferBufferLength 0x83 TransferBuffer 0x86AAB888 li TransferBufferMDL 0x88664E50 UrbLink 0x0 SetupPacket 0x80 0x6 0x0 0x2 0x0 0x0 0x83 0x0 0x80 Direction Device to host Type Standard Recipient Device Request 0x6 GET_DESCRIPTOR Value Pecan USB_CONFIGURATION_DESCRIPTOR_TYPE Index 0x0 Length 0x83 Configuration Descriptor bLength 0x9 bDescriptorType USB_CONFIGURATION_DESCRIPTOR_TYPE wTotalLength 0x83 bNuminterfaces 0 5 iConfiguration 0x3 OxEO E MaxPower OxFA Interface Descriptor bLength 0 9 binterfaceNumber 0x0 bAlternateSetting 0 0 54 Urb Field bNumEndpoints 0x3 binterfaceClass OxFF Vendor Specific binterfaceSubClass OxFF binterfaceProtocol OxFF ilnterface 0x0 Endpoint D
30. 5 0 6412 0 6855 1 4 50 4 51 High upload throughput 4 22 4 23 0 25 0 26 1 0575 1 0972 High download throughput 4 20 4 23 0 25 0 27 1 0575 1 194 measure the power consumed during the period when there is high upload throughput we use TCP spray as a packet generator to send packets to a server When using TCP spray we can set the packet size and rate to generate the desired upload traffic Figure 3 2 shows the command used for this test With these parameters TCP spray generates 1000 packets with a size of 2048 bytes to the server at IP address 130 237 209 214 A total of 2 050 048 bytes are sent in 53 961 seconds and the average transmission speed is about 37 kbytes s It should be noted that this command sends the traffic to a TCP service called discard on the target computer thus before running this command we need to turn this service on since usually it is turned off for security reasons For testing during high download throughput we viewed an online video since this load is representative of the highest download throughput application used by most users We can see from the test results that the power consumption for this service could be more than 1 1W Related graphs are provided in Error Reference source not found Users ve gt tcpspray b 2048 n 1000 130 237 209 214 Transmitted 2650648 bytes 53 961 seconds lt 37 101 007 kbytes s gt Figure 3 2 Generating packets using TCP spray
31. 7767 SURPRISE REMOVAL OUT 0 OxD6ELAO30 0 0 660618 STATUS SUCCESS 0 PNP 107772 SURPRISE REMOVAL 00614030 004660618 STATUS SUCCESS 0 PNP 111439 REMOVE DEVICE OUT 0 0 06 14030 0x06896590 STATUS SUPPORTED 0 11 1439 REMOVE DEVICE IN 0 OxD6ELA030 0xD6896590 STATUS SUCCESS 0 PNP 174240 QUERY CAPABILITIES OUT 0 0xD684E030 0xD685A008 STATUS SUPPORTED 0 PNP 174240 QUERY CAPABILITIES N 0 0xD684E030 0xD685A008 STATUS SUCCESS 0 PNP 17 4502 QUERY CAPABILITIES OUT 0 0xD684E030 0 0685 008 STATUS NOT SUPPORTED 0 PNP 174 2 QUERY CAPABILITIES IN 0 006848030 0 0085 008 STATUS SUCCESS 0 Figure 3 12 Mass storage device is removed during the enumeration E Device Manager lale File Action View Help es mE HT ml 18 15 H a Sound video and game controllers DEC Storage controllers System devices B Universal Serial Bus controllers 8 Intel R ICH8 Family USB Universal Host Controller 2830 Intel R ICH8 Family USB Universal Host Controller 2831 Intel R ICH8 Family USB Universal Host Controller 2832 Intel R ICH8 Family USB Universal Host Controller 2834 Intel R ICH8 Family USB2 Enhanced Host Controller 2836 Intel R ICH8 Family USB2 Enhanced Host Controller 283A USB Composite Device USB Composite Device USB Mass Storage Device USB Mass Storage Device USB Root Hub USB Root Hub USB Root Hub USB Root Hub USB Root Hub USB Root Hub Figure 3 13 The dongle is
32. A as the target 3G network since it was the most wide spread type of 3G network when this project started thus offering the most popular alternative to WLAN Hereafter we will refer to this technology simply as UMTS since in the discussion of the different types of couplings it does not matter which of the 3G link technologies is used Figure 2 2 shows the architectures of loose and tight coupling Details of the figure are explained in the following subsections Background 11 network K GGSN SGSN RNC Node B A Figure 2 2 UMTS WLAN loose coupling and tight coupling UE User equipment Radio network controller UTRAN UMTS terrestrial radio access network SGSN Serving GPRS Support Node GGSN Gateway GPRS Support Node 2 3 1 Loose coupling In a loose coupling interworking architecture the WLAN gateway connects with the core IP network without a direct connection to the UMTS network elements The data paths of WLAN and UMTS traffic are separate and the interconnected networks are loosely coupled independent networks The data traffic from a mobile node in a WLAN to user equipment a 3G terminal does not go directly to the UMTS network rather the traffic passes first through an IP network such as the Internet then through a gateway to the UMTS network The disadvantage of this architecture is that roaming agreements with multiple different WLANs need to be established However the advantage i
33. AN scenarios and their capabilities 14 Scenarios e n gt 5 8 ES 5 ig gt da 3 E 9 a En gt 0 A 5 ud IET A e oo D X vel r 7O 3 2 o Sas gt uu m 5 e 2a Nn 3 d C m S 0 S n gt a D s6 9 5 8 O E os N AS em z 5 E E N 2 0 oO B o e m E 2a e o E T o i i 5 E E 5 Service and operational 5 3 zu 5 5 poe g Gy E S un capabilities 2 2 Common billing X X X X X X Common customer care X X X X X X 3GPP system based X X X X X access control 3GPP system based X X X X X access charging Access to 3GPP system X X X X packet switched based services from WLAN Service continuity X X X Seamless service X X continuity Access to 3GPP system X circuit switched based services with seamless mobility Generally speaking there are two different main approaches to design a heterogeneous 3G WLAN network loose coupling and tight coupling These two approaches were initially proposed by the European Telecommunications Standards Institute ETSI We will discuss these methods in detail in the following subsections As mentioned in the beginning of the thesis we choose UMTS WCDM
34. B FUNCIION CONTROL TRANSFER Figure 3 11 shows the device descriptor information captured using USBTrace In this descriptor bcdUSB is 0x200 indicating that it is a USB 2 0 device The fields bDeviceClass bDeviceSubClass and bDeviceProtocol are used by the operating system to identify a class driver However most class specification is determined at the interface level so these three fields are normally set to 0 The field bMaxPacketSize0 shows the maximum packet size for endpoint 0 The fields idVendor idProduct and bcdDevice are assigned respectively by the USB Implementers Forum Inc see USB org the manufacturer in this case Ox12D1 indicates Huawei Technology and the device developer in this case 0x1446 indicates the product is a E1550 or E1750 device 0 The field bNumConfigurations specifies how many configurations the device has and for this device the value is Ox1 so there is only one configuration descriptor Following packet 48 some URB FUNCIION CONTROL TRANSFER packets continue to show up these URBs contain Method 29 information about the configuration descriptor interface descriptors and endpoint descriptors After receiving these URBs we know this device has one configuration two interfaces and four endpoints Device Descriptor bLength 0x12 bcdUSB 0x200 bDeviceClass 0x0 bDeviceSubClass 0x0 bDeviceProtocol 0x0 bMaxPacketSize0 0x40 idVendor 0x12D1 idProduct 0x1446 bcdDevice 0 0 iManufacturer 0x2 iProduct 0
35. Both academia and industry have realized the deficiency of USB dongle working as a dial up modem and several protocols to provide Ethernet style networking over USB have been designed in recent years The USB Implementers Forum USB IF defined a number of USB Communications Device Class CDC protoools to provide this virtual Ethernet functionality such as CDC ACM Abstract Control Model and CDC Network Control Model NCM Microsoft defined its proprietary protocol Remote Network Driver Interface Specification RNDIS to provide a virtual Ethernet link over USB to most versions of the Windows operating systems Although RNDIS is not recommend by certain companies such as 41 given Microsoft Windows 91 07 market share in desktop and laptop computers operating systems 42 Microsoft Windows still has a dominant position in the market so we select RNDIS as the protocol to examine in our research RNDIS is naturally compatible with recent Windows systems which are used by the overwhelming majority of customers This large number of potential customers leads to greater opportunities for all participants in the value chain For Apple Mac users it is also possible to use RNDIS by installing drivers for example HoRNDIS 43 RNDIS is based on NDIS which was developed by Microsoft and 3Com to provide an application programming interface for network adapters in Windows systems The NDIS interface is located between the physical network adapter a
36. DEGREE PROJECT COMMUNICATION SYSTEMS SECOND LEVEL STOCKHOLM SWEDEN 2015 De KTH VETENSKAP 98 OCH KONST Xp undo USB dongles for mobile broadband Data communications for laptop computers LIU KTH ROYAL INSTITUTE OF TECHNOLOGY INFORMATION AND COMMUNICATION TECHNOLOGY USB dongles for mobile broadband Data communications for laptop computers Liu Enfei 2015 06 24 Master s Thesis Examiner and Academic adviser Gerald Q Maguire Jr KTH Royal Institute of Technology School of Information and Communication Technology Department of Communication Systems SE 100 44 Stockholm Sweden Abstract Abstract Today a growing number of people need to work on laptops with wireless Internet connection There are two common wireless Internet access solutions wireless local area network WLAN via hotspot and high speed wide area cellular network via mobile broadband device such as 3G 4G Universal Serial Bus USB dongle USB dongle was the pioneer product in 3G 4G market and it is still a popular device in many countries Mobile broadband can offer both high speed access and mobility Technically mobile broadband allows Internet connection as long as your mobile transceiver can access your cellular network operator s network However in practice the data rates experienced by a user via mobile broadband are not comparable to the data rates that are available via WLAN Moreover
37. Device 2010 Online Available http download c huawei com download downloadCenter downloadId 12143 Accessed 05 J un 2015 Qualcomm Qualcomm Collaborates with Leading OEMs to Announce the Availability of Multi mode LTE TDD Devices in India Qualcomm 2011 Online Available https www qualcomm com news releases 2011 08 30 qualcomm collaborates leading oems announce availability multi mode lte tdd Accessed 05 Jun 2015 Microsoft Overview of Remote NDIS RNDIS Online Available https msdn microsoft com en us library windows hardware ff569967 v ws 85 aspx Accessed 05 un 2015 Microsoft RNDIS Windows Embedded CE 6 0 Online Available https msdn microsoft com en us library ee484414 v winembedded 60 aspx Accessed 05 Jun 2015 A George A Kumar D Cavalcanti and D P Agrawal Protocols for mobility management in heterogeneous multi hop wireless networks Pervasive and Mobile Computing vol 4 no 1 pp 92 116 2008 F Siddiqui and 5 Zeadally Mobility management across hybrid wireless networks Trends and challenges Computer Communications vol 29 no 9 pp 1363 1385 2006 J Zhang H C Chan and V Leung A location based vertical handoff decision algorithm for heterogeneous mobile networks in Global Telecommunications Conference 2006 GLOBECOM 06 IEEE 2006 pp 1 5 Pawar Wac Van Beijnum Maret A
38. ELAD3O 0x04567440 STATUS SUPPORTED 0 OUT 0 OxDA3F6490 STATUS SUCCESS 0 N 0 OxDA3F 490 STATUS SUCCESS 0 OUT 0 OxD6ELA030 0x04567440 STATUS SUCCESS 0 OUT 0 087788830 004567440 STATUS SUCCESS 0 IN 0 87788830 004567440 STATUS PENDING 0 IN 0 081788330 00456740 STATUS SUCCESS 120100020 18 OUT 0 OxD6ELAO30 0x04567440 STATUS SUCCESS 0 OUT 0 87788830 00456740 STATUS SUCCESS 0 IN 0 87788830 004567440 STATUS PENDING 0 N 0 681788330 004567440 STATUS SUCCESS 090237000 9 The beginning of URB 28 Method A USB Request Block URB is a data structure designed for USB communications Instead of direct communication the USB device driver transfers URBs to the bus driver The USB controller uses these URBs to execute the requests If we compare the USB bus to a highway then URBs are comparable to vehicles travelling on the highway Some fields in the URB are common although there are many URB functions with their own specific fields By using USBTrace we can see the detailed URB information by clicking on a specific packet For example Figure 3 10 shows the detailed information about packet 48 a URB FUNCTION CONTROL TRANSFER URB_FUNCTION_CONTROL_TRANSFER Length 0x50 USBD Status USBD_STATUS_SUCCESS 0x0 EndpointAddress 0x0 PipeHandle 0xD68B998C 0x72004F USBD_TRANSFER_DIRECTION_IN TransferFlags USBD SHORT TRANSFER TransferBufferLength 0x12 Tr
39. List of Figures Figure 1 1 Figure 2 1 Figure 2 2 Figure 2 3 Figure 3 1 Figure 3 2 Figure 3 3 Figure 3 4 Figure 3 5 Figure 3 6 Figure 3 7 Figure 3 8 Figure 3 9 Figure 3 10 Figure 3 11 Figure 3 12 Figure 3 13 Figure 3 14 Figure 3 15 Figure 3 16 Figure 3 17 Figure 3 18 Figure 3 19 Figure 3 20 Figure 3 21 Figure 3 22 Figure 3 23 Figure 4 1 Figure 4 2 Huawei E1550 a USB 2 Architecture of an infrastructure mode WLAN 8 UMTS WLAN loose coupling and tight coupling 11 Horizontal handoff and vertical handoff 13 Test voltage in parallel circuit sess 20 Generating packets using 21 Laptop power information from BatteryMon when using the WLAN interia E er hr hera EC Ou 22 Laptop power information from BatteryMon when using 3G o NR 23 USB packet types ade Sn ki ov n usa 24 Three USB communication 25 USB desaiptors das qua een 26 The beginning of USB enumeration 27 The beginning of 27 Detailed URB information eese 28 Device descriptor information 29 Mass stor
40. MOVE DEVICE IN 0 OxC89CF208 0x871A18A0 STATUS SUCCESS Figure 3 17 The last 21 packets watched by USBTrace 3 4 Communication between the laptop and dongle In this section we descript how the laptop uses the dongle to access a remote access service and then review Microsoft s Remote Network Driver Interface Specification 3 4 1 Remote Access Service A traditional USB dongle looks and acts like a serial modem thus it has to connect to a terminal server via PPP negotiate which protocol family it is going to use get assigned an IP address then it can start to encapsulate IP packets and transmit them to the destination If the connection is lost then it has to start all over again This kind of dial up service is supported by Remote Access Service RAS a technique which was originally created by Microsoft 36 RAS connects remote dial up clients to a host computer known as a remote access server Via this server client computers can access to a LAN or the Internet RAS uses PPP as the client program to establish the connection between the remote dient and server The result is as if the client were connected directly by a serial cable to the server PPP is alink layer protocol which can encapsulate and transport multiple network layer protocols over dedicated point to point links between two nodes It can also provide authentication configuration encryption etc The general frame format for PPP is shown in Figure 3 18 Each PPP frame has
41. REQUIREMENTS and then it sends IRP MN START DEVICE to enable the driver s to start the device Starting with packet 45 USB Request Block URB functions are used to control the device However the PnP manager occasionally sends some IRPs QUERY CAPABILITIES QUERY DEVICE RELATIONS and QUERY PNP DEVICE STATE to collect capability information finding child devices and changing configuration respectively Type PNP PNP PNP PNP PNP PNP PNP PNP 5 URB 5 ur URB URB URB ure E URB A Time 77844 7785524 Request 7785216 QUERY LEGACY BUS INFORMATION 7 785219 QUERY LEGACY BUS INFORMATION QUERY RESOURCE REQUIREMENTS 7285427 QUERY RESOURCE REQUIREMENTS FILTER RESOURCE REQUIREMENTS 7 785527 FILTER RESOURCE REQUIREMENTS 7811380 START DEVICE 7812228 DEVICE 7812242 DESCRIPTOR FROM DEVICE 7812247 GET DESCRIPTOR FROM DEVICE 7812329 CONTROL TRANSFER 7813584 CONTROL TRANSFER 7813623 DESCRIPTOR FROM DEVICE 7813628 GET DESCRIPTOR FROM DEVICE 7813683 CONTROL TRANSFER 7815585 CONTROL TRANSFER Figure 3 9 VO EndPoint Device Object IRP Status Buffer Snippet Buffer Size OUT 0 004567440 STATUS SUPPORTED 0 N 0 OxD6ELAO30 0xD4567440 STATUS SUPPORTED 0 OUT 0 OxD6ELAO30 0x04567440 STATUS SUPPORTED 0 0 xD6ELAO30 00456740 STATUS NOT SUPPORTED 0 OUT 0 OxD6ELA030 0x04567440 STATUS NOT SUPPORTED 0 N 0 OXDG
42. SB protocols is a consensus view in manufacturers for example Huawei 3G modems supports more ECM NCM MBIM rather than PPP 60 Despite the application of new USB protocols mobile WiFi is even more popular than USB dongle in current mobile broadband market because mobile WiFi does not need the physical connection to other host computer or power source It can support itself with own battery so it greatly release the power burden of laptop and laptop users do not need to think about the power share between USB dongles and laptops which is a very important issue for users Actually current mobile WiFi can even work as a power bank to provide power to other mobile devices 61 a further improvement to traditional USB dongles Today mobile devices are very popular many people bring more than one mobile device during travelling That is why it is important for USB dongles be able to create own WiFi hotspot to share cellular networks with other mobile devices Ten years ago the most common wireless connection scenario is laptop with WLAN but now smartphone with cellular network is the most popular way This is a great change The main two factors to promote the change is the extensive deployment of 3G 4G and the rapid development of mobile devices especially devices from Apple Since Apple released its first generation iPhone in 2007 smartphones with a touchscreen user interface soon became the mainstream mobile phones The sales of smartphones wor
43. STATUS NOT SUPPORTED 0 EN 1 182301 uev 0 OxD6E1A030 OxDA3F6490 STATUS SUCCESS 0 PNP 7 782412 QUERY CAPABILITIES OUT 0 050614030 OxDA3F6490 STATUS SUPPORTED 0 m 7 782415 QUERY CAPABILITIES IN 0 OxD6ELAO30 OxDA3F6490 STATUS SUCCESS 0 7 782435 QUERY CAPABILITIES OUT 0 OxDA3F6490 STATUS NOT SUPPORTED 0 7282438 5 IN 0 OxD6ELAO30 0 0 6490 STATUS SUCCESS 0 PNP 778457 QUERY INTERFACE OUT 0 OXDA3FG490 STATUS NOT SUPPORTED 0 QUERY INTERFACE IN 0 OxD6ELAO30 OxDA3F6490 STATUS NOT SUPPORTED 0 15 PNP 7282488 QUERY ID OUT 0 OxD6ELAQ30 0xD4567440 STATUS NOT SUPPORTED 0 7 782492 QUERY_ID OXDGELAO3O 0504567440 STATUS SUCCESS 0 PNP 7 782505 QUERY_CAPABILITIES OUT 0 OxD6ELA030 00457440 STATUS NOT SUPPORTED 0 mu 7 782508 QUERY CAPABILITIES IN 0 4567440 STATUS SUCCESS 0 PNP 7 782548 QUERY DEVICE TEXT OUT 0 0xD4567440 STATUS SUPPORTED 0 i 782552 QUERY_DEVICE TEXT IN 0 OxD6ELAO30 OXDAS67440 STATUS SUCCESS 0 PNP 7 782556 QUERY_DEVICE TEXT OUT 0 0xD4567440 STATUS NOT SUPPORTED 0 Figure 3 8 The beginning of USB enumeration As we can see in Figure 3 9 the PnP process continues until packet 44 The PnP manager learns the resource requirements and filters for these resources QUERY RESOURCE REQUIREMENTS and FILTER RESOURCE
44. T SUPPORTED 0 m PNP 17 5724 QUERY RESOURCE REQUI IN 0 0 0684 030 0xD6865DE0 STATUS NOT SUPPORTED 0 131 PNP 17 5725 FILTER RESOURCE REQUIR OUT 0 0 0684 030 0xD6865DE0 STATUS NOT SUPPORTED 0 ml PNP 17 5725 FILTER RESOURCE REQUIR IN 0 0 0684 030 0xD6865DE0 STATUS NOT SUPPORTED 0 133 PNP 17 5729 START DEVICE OUT 0 0 0684 030 0xD6865DE0 STATUS SUCCESS 0 m PNP 17 5736 START DEVICE IN 0 0 0684 030 0xD6865DE0 STATUS SUCCESS 0 135 PNP 17 5737 QUERY INTERFACE OUT 0 0 0684 030 0 06854008 STATUS NOT SUPPORTED 0 16 17 5737 QUERY INTERFACE IN 0 0 0684 030 0xD685A008 STATUS NOT SUPPORTED 0 137 URB 17 5738 GET DESCRIPTOR FROM OUT 0 0 0684 030 0 0685 008 STATUS SUCCESS 0 138 URB 17 5738 GET DESCRIPTOR FROM OUT 0 OxD68AD020 0 0685 008 STATUS SUCCESS 0 19 URB 17 5739 CONTROL TRANSFER IN 0 0 068 0020 0 0685 008 STATUS PENDING 0 URB 17 5753 CONTROL TRANSFER IN 0 OxD68AD020 0xD685A008 STATUS SUCCESS 120100020 18 Figure 3 14 New device starts Continuing to watch the USB communication two requests appear many times SYNC RESET PIPE AND CLEAR STALL and BULK OR INTERRUPT TRANSFER The second request is especially frequent see Figure 3 15 This seemingly endless process is called a polling transaction The reason that the BULK OR INTERRUPT TRANSFER repeats steadily is that the IN token from the USB dongle is always pending However because the dongle is yet not connected to the Internet no
45. ackets token data and handshake comprise a USB transaction A complete USB communication procedure consists of numerous such transactions The procedure can be divided into three stages setup stage data transfer stage and status stage Figure 3 6 illustrates these three stages Note that during the data transfer stage the data is separated into the fixed sized payloads except for the last one Method 25 Setup stage Data transfer stage Status stage Token packet Token packet Token packet Data packet Data packet Data packet Token packet Data packet Token packet USB host D ata packet Figure 3 6 Three USB communication stages Under Microsoft s Windows operating system Plug and Play PnP a type of hot swapping enables adding or removing peripheral components without shutting down the host system PnP is an important characteristic of USB The PnP manager a subsystem of Microsofts Windows I O manager provides the PnP functionality As PnP technology is implemented for USB the host OS automatically configures each device after it is added Note that the USB host controls all the communications so there is no need for each external device to be allocated an Interrupt Request IRQ vector slot or I O addresses However the USB bus controller inside the computer does have an assigned IRQ and an address on the PCI bus which is used for communication between the CPU and all devices on the USB As a
46. age device is removed during the enumeration 30 The dongle is seen as three devices by the Windows device Manager es 30 New device starts nes 31 Polling transaction year 32 Connecting to the 32 The last 21 packets watched by 33 General PPP frame format sees 34 AT commands between laptop dongle 34 Two interfaces of USB dongle eese 35 NDIS driver architecture 36 RNDISarchitectite u a 37 USB dongle 37 A simple workflow of USB dongle 40 Main functions of configuration 41 List of Tables List of Tables Table 2 1 Examples of IEEE 802 11 standards 9 10 7 Table 2 2 3G WLAN scenarios and their capabilities 14 10 Table 2 3 Comparison between loose coupling and tight coupling 16 Table 3 1 Huawei E1550 USB dongle power consumption 21 Table4 1 Handoff policy parameters eser 40 List Acronyms Abbreviations xiii List of Acronyms and Abbreviations 1G 2G 3G 3GPP 4G AAA ACK DECT DHCP DNS DSL ETSI FCS GGSN GPS GPRS GSM HDLC HSS HSPA I CSCF ICT IEEE
47. an be a source of data or the sink for data output the USB host All data is transferred through a virtual serial pipe between the host and this endpoint There are four transfer types for endpoints control interrupt isochronous and bulk For a USB dongle the data is transferred using a bulk transfer 26 Method Device descriptor Configuration Configuration descriptor descriptor Interface Interface descriptor descriptor Endpoint Endpoint Endpoint Endpoint descriptor descriptor descriptor descriptor Figure 3 7 USB descriptors 3 3 2 Watching USB communication We used USBTrace to monitor the communication in order to understand the entire device enumeration process Other software analyzers such as SnoopyPro use a filter driver to capture USB bus activity however a serious limitation when using such a driver is that we cannot log any activity until the driver for the device is loaded so this driver would miss the USB enumeration process between the host and the device USBTrace avoids this limitation thus we can monitor the communication starting immediately after a USB dondle is plugged into a host computer Figure 3 8 shows the first 21 requests in the enumeration process after a 3G USB dongle is plugged into the author s laptop The packets supporting the PnP process are 1 request packets IRPs T
48. ansferBuffer 0x84FC8578 TransferBufferMDL 0xDA667078 UrbLink 0x0 Figure 3 10 Detailed URB information From the figure we can see that the EndpointAddress is 0 Note that the EndpointAddress is not only 0 in packet 48 but also all packets shown in Figure 3 9 Endpoint 0 is the default address and it receives all of the device control and status requests during enumeration PipeHandle contains the control pipe handle used for I O transactions on the virtual pipe created by the endpoint TransferFlags specifies the direction of the transfer in or out Data may be read from or written to a resident buffer or Memory Descriptor List MDL In either case the size of the buffer is shown in TransferBufferLength The resident buffer address is in field TransferBuffer and the address of the MDL is in the field TransferBufferMDL Normally either TransferBuffer or TransferBufferMDL should be null For example if the driver initializes the TransferBufferMDL to be null then the USB stack will use TransferBuffer to exchange data However internally the USB stack might create an MDL store a pointer to the MDL in TransferBufferMDL and use this MDL to pass data down the stack Although the USB stack frees the MDL memory there is no guarantee that TransferBufferMDL will still be null when the driver is processing the URB in the completion routine 35 In addition to the URB field information shown in the figure above a device descriptor is also sent by UR
49. ation If the connection is lost then the process has to start all over again This is the approach used by many current dongles but in this thesis a new approach is proposed This thesis proposes that a dongle should look like a WLAN or Ethernet interface rather than a modem The device would simply send and receive link frames which encapsulate IP packets This network interface could make better use of the underlying network s packet capabilities by sending individual packets without the overhead of initiating a PPP session Such a network interface would remove the need for the Internet service provider ISP to provide a PPP server If the ISP has an IPvG network then the device simply needs to know the IPv6 prefix of the network and it could proceed to send IPv6 packets this leaves aside the question of how the device authenticates itself and how it would be authorized to use the network these questions are left as future work see section 5 2 6 Introduction 1 5 Limitations It is important to note that this project started in 2009 long before the introduction of 3GPP s Long Term Evolution LTE networks This thesis will not consider the case of LTE networks however the use of such networks rather than or in addition to UMTS WCDMA networks is largely a matter the difference in the radio links and does not change the communication between the laptop computer and an external radio communication module After this project was
50. b rbara datorer med anslutning till tr dl st Internet Det finns tv vanliga tr dl sa Internet anslutningar tr dl st lokalt n tverk WLAN engelska via en hotspot eller h ghastighets mobiln t via mobilt bredband som 3G 4G Universal Serial Bus USB dongel USB dongeln var pionj r produkten inom 3G 4G marknaden och den r fortfarande en popul r enhet m nga l nder Mobilt bredband kan erbjuda b de tillg ng till h ga hastighet och bra mobilitet Mobilt bredband till ter rent tekniskt anv ndaren h lla en Internet anslutning s l nge mobilen har tillg ng till mobiln tets operat rsn t Men praktiken r datahastigheterna som anv ndaren upplever ha via det mobila bredbandet inte j mf rbar med de datahastigheter som ar tillgangliga via WLAN Dessutom har mobilt bredband implementerats enligt flera olika standarder S ledes f r att f rutse en anv ndare med en optimal lokal tj nst kr vs det att anv ndaren m ste anv nda heterogena n tverk Dessutom blir olika n tverk allt st rre grund av uppkomsten av olika 4G nat Syftet med denna avhandling r att unders ka hur heterogena n tverk skulle kunna utnyttjas f r att f rutse en laptop anv ndare med optimal lokal n tverksservice samtidigt d lja komplexiteten f r anv ndaren om den heterogena tj nsten Forskningen fokuserar p konsekvenserna av att integrera flera n tverksgr nssnitt till en enda USB dongel V r forskning visar att det fortfaran
51. ber of laptops and mobile devices such as smartphones and tablets continues to increase Today many people have more than one mobile node when they are travelling For this reason it would be great if the USB dongle can work as a wireless access point thus the user can share their Internet connection with the user s other mobile nodes or with other users Though some network operators and users may not want to have tethering or virtual Wi Fi functions due to the substantial increase in network traffic and mobile data it is still a good idea to provide this service as an optional function of the dongle For this reason we suggest that tethering as disabled by default but if they would like to have this function then users could simply turn it on via a configuration interface This suggests the dongle should have a built in web server to provide this configuration interface thus it would be similar to many Wi Fi APs and Internet routers Since several mobile nodes may use the USB dongle at the same time we need Network Address Translation NAT so one public address in the dongle can correspond to different private IP addresses in mobile nodes Additional common network modules which are required for our dongle include a Dynamic Host Configuration Protocol DHCP server a Domain Name System DNS server and firewall With a DHCP server the dongle could provide local addresses to other tethered devices By providing a DNS server actually a DNS pr
52. bile node based on the registered information then a connection ora call can be delivered successfully As we described in section 2 4 there are two types of handoff horizontal and vertical The handoff in heterogeneous networks is vertical handoff The vertical handoff process may be divided into three phases network discovery handoff decision and handoff implementation 50 In network discovery the mobile node or USB dongle in our case searches for reachable wireless networks and receives the networks information by activating the dongle s multiple wireless interfaces WLAN and cellular networks If the USB dongle always keeps these interfaces on then the node could find available networks timely However it would cost much more battery power by turning the network interfaces always on and it could seriously reduce the working time of the USB dongle and its connected laptop To eliminate this problem one method is to periodically activate the network discovery phase and find a balance between the system discovery time and power efficiency but how to set appropriate discovery period in heterogeneous networks is a topic that needs future research Another method could be Location Service Server LSS 51 LSS oollects the wireless network information in its nearby area so the dongle can get the information from LSS This method can find nearby available network quickly with relatively less power consumption but it is quite a challenge to ma
53. cally when user location or network conditions change These contexts are gathered in a Context Repository which is one of two crucial functional modules in their framework The other module is an Adaptability Manager which decides how to adapt to context changes and when to execute a handoff This manager is divided into two different processes vertical handoff decision and QoS mapping Heterogeneous networks within a domain are formed as a domain network cluster with each cluster supported by its own adaptability manager and context repository Thereis also a proxy in each network which receives notifications about requested handoff operations from the adaptability manager and redirects communication streams between different domains such as a correspondent host CH domain and a network domain A characteristic of this proxy is that it bi casts the communication stream during handoffs i e the proxy delivers two streams A mobile host s traffic follows a route from network 1 to network 2 and then on to a UMTS network Initially a communication stream is transmitted through the proxies in and network 1 to the mobile host When a handoff is triggered the stream is not only forwarded to the mobile host but a copy is also forwarded to the new proxy in the network that the mobile host 15 moving into The bi casting operation is terminated as soon as the redirected packets begin to arrive Bi casting minimizes QoS violations during handoff in te
54. comes to the question howto identify the user is subscribed to China Mobile We can borrow the idea from WiFi calling 67 WiFi calling enables cellular network users to make and receive calls and texts over a WiFi connection SO user can access a local WiFi hotspot while there is no or very bad cellular coverage User uses the same phone number during communication and the SIM card is checked by an AAA server to authenticate and authorize the user so the user can use WiFi network as long as the WiFi operator allows the AAA agreement with the cellular operator Similar to a mobile phone USB dongle also has a SIM card We can use the SIM card for WLAN authentication If the local WiFi hotspot can identify the dongle by its SIM card then it would allow the user to join the hotspot so the WiFi client module in a dongle greatly improve the possibility to access the Internet Since the prevalence of smartphones and tablet computers the market for USB dongle is decreasing Customers can browse the Internet in smaller devices than laptop computers The good news is that nowadays more and more people need to work on laptops with Internet access so there is still a steady market for mobile broadband devices However USB dongle probably can only share a smaller part in that market because mobile WiFi has many advantages over USB dongle and actually vendors have already produced more mobile WiFis than USB dongles Mobile WiFi is usually expensive than USB do
55. ction and nearly 1Mbps in the uplink direction in the first 3G devices and networks made mobile web browsing smooth and convenient The wide deployment of fourth generation 4G cellular networks further promotes this trend In addition to web browsing an ever increasing variety of Internet based services are becoming available via mobile broadband These services range from simple services such as uploading and downloading documents images etc to augmented reality such as Layar http www layar com and Wikitude http www wikitude org 14 Modems and USB dongles The term modem is derived from a contraction of the words modulation and demodulation The original modems worked exactly and only as the name implies i e at the transmitter the device modulated a signal based upon an input and at the receiver the device demodulated the signal to reproduce the input Current modems are more sophisticated products and offer many extra functions such as integrated routers and firewalls The point to point protocol PPP is widely used together with modems and simple links in order to transport data between two peers PPP is a full duplex bit oriented protocol that can run over synchronous or asynchronous links 7 PPP was not specifically designed for any particular type of higher layer protocols PPP supports data transfers over many types of physical media including but not limited to serial amp parallel twisted pair li
56. d guidance for the product development 4 1 Technical analysis Thanks to the rapid development of ICT today s mobile users can choose a variety of wireless networks such as WLAN UMTS and WiMAX However the widespread deployment of heterogeneous networks also brings many problems to network users and operators Users need different devices to connect different networks operators must think over the integration of heterogeneous networks to provide the best available network depending on users requirements There are three important issues we need to consider for heterogeneous networks security location management and handoff Radio communications networks do not provide physically secure connection paths but both cellular networks and WLAN have respective security mechanisms about authentication authorization privacy confidentiality integrity trust etc In heterogeneous networks however a communication process may involve networks belonged to several different operators How to guarantee security issues under different technologies and QoS is a challenge Location management is a two stage process which enables the network to discover the locations of mobile users 49 The first stage is location registration the mobile node periodically notifies the network by sending specific signals to inform the network of its current location The second stage is paging or call delivery the network is queried about the location of the mo
57. de beh vs en multi mode USB dongel p marknaden dock existerar det konkurrens fr n smartphones och mobila WiFi enheter p pekar ven avhandlingen att PPP Point to Point Protocol baserade USB dongeln b r uppdateras till Ethernet USB protokoll sasom RNDIS Remote Network Driver Interface Specification eller USB CDC Communications Device Class protokoll Vidare f resl r vi att en USB dongel b r kunna fungera som en kopplingspunkt f r att dela Internet med andra mobila enheter och att den ocks b r fungera som en WLAN klient som kan ansluta sig till andra hotspots Om hotspot operat rer kan autentisera USB donglar genom SIM kort s kan anv ndarna enkelt f tillg ng till ett stort antal hotspots som tillh r dessa operat rer Nyckelord Datakommunication USB WLAN 3G 4G Acknowledgements Acknowledgements I would like to express my sincere gratitude to my examiner and academic adviser Professor Gerald Q Maguire Jr who is the most intelligent knowledgeable efficient and vigorous person I have ever seen Probably that is the reason why we call him Chip Professor Maguire is not only an outstanding scientist but also a very popular teacher who has supervised hundreds of bachelor and master students 1 would never have been able to finish my thesis without his brilliant guidance and continuous support thought the thesis It has been a long journey to complete this thesis fortunately with the help of Profess
58. design decisions and conclusions Therefore we reviewed the market in recent years in order to extract information from customers 20 Method feedback regarding this product and then use this to indicate some potential future trends This analysis is presented in Chapter 4 3 2 Power consumption One of the important features of USB is that it is able to provide a limited amount of power to a device Users do not need search for an external electrical outlet to supply power to the device they simply plug the USB dongle into their laptop This makes a USB dongle an easily portable device Moreover the user does not have to worry about charging a battery in the device Customers however often are concern about the power consumption of the laptop s power when they are in mobile environment without a connection to an external power supply It would be a serious drawback if the dongle consumes too much power from the laptop via the USB So it is necessary to understand the USB dongles power consumption This section describes an experiment to measure this power consumption We measured the voltage and current flowing to a Huawei E1550 3G USB dongle by cutting a USB extension cable and connecting it to a multimeter to form either a series circuit to measure the current 1 or parallel circuit to measure the voltage V Based upon these measurements we can calculate the power consumption using the formula VI Figure 3 1 shows the equipmen
59. e a WLAN client which can connect via other hotspots If hotspot operators can authenticate USB dongles by SIM cards then users can easily access a great number of 46 Conclusions Future work hotspots Also as we explained before the PPP modem solution is too outdated for today s USB dongle hence manufacturers should update their USB interface to RNDIS or another USB CDC protocols 5 2 Future work Section 1 4 indicated that in the case of IPv6 the process of a dongle getting an IP address and sending IPv6 packets was very straight forward but did not answer the questions of 1 how the device authenticates itself and 2 how it would be authorized to use the network These are questions that should be answered in future work Although these questions might be changed to focus on authentication of the packets and authorization of the packets to be forwarded by the access network rather than focusing the questions of authentication and access control on the device sending them This change would be very interesting in the context of Internet of Things IoT devices that often only infrequently send data Meanwhile existing authentication and authorization protocols such as TEEE 802 1 could be used Alternatively non binary authentication and authorization protocols might be used 18 The concept of a shared and distributed firewall service suggested in Section 3 5 should be explored in future work The ability to have the filtering
60. e coverage area of a WLAN is often called a Wi Fi hotspot as Wi Fi has become a de facto synonym for WLAN and because the coverage area is often a location where there are likely to be users The use of the term hotspot is often used to emphasize the difference in expectation of coverage ie a WLAN is expected to provide only localized coverage while a wide area cellular network is expected to provide nearly ubiquitous coverage Viewed another way lack of WLAN coverage is expected to be the norm while lack of wide area cellular network coverage is expected to be an exception Interestingly in 2015 the lack of WLAN is increasingly exceptional and unexpected while the lack of wide area cellular coverage indoors is becoming more common in Stockholm due to the high loss to the radio frequencies being used caused by the energy efficient windows that are increasingly installed in buildings There are two operational modes defined in the 802 11 WLAN standards infrastructure mode and ad hoc mode An access point AP is a vital component in an infrastructure mode network An AP acts as a bridge to allow WLAN interface equipped devices to connect to a backbone network see Figure 2 1 Note that this backbone network could be a wired or wireless network In contrast in an ad hoc network an AP is not necessary as the devices communicate directly 8 Background Figure 2 1 Architecture of an infrastructure mode WLAN TEEE working grou
61. e keyboards in smartphones are too small and that this results in low input speeds Additionally as we have seen the screens of smartphones are becoming bigger but they are stil much smaller than the screens in laptops Moreover smaller size constrains the computing processing and battery storage abilities of smartphones Due to these inherent deficiencies smartphones or tablets are mainly used for browsing information on the Internet or doing simple office work for example checking emails Today a growing number of office workers and university students need to work on laptops with Internet connection This group of people are the main customers of mobile broadband devices especially when they need to work outside of their offices and universities The USB dongle was the mainstream mobile broadband device but now many manufacturers and Operators prefer to launch mobile WiFi rather than market USB dongles However these two devices can provide the same service and mobile WiFi does not need to physically connect to a USB host The main advantage a USB dongle is probably its low price so it still remains attractive for customers who are sensitive to price for example young students Since many laptop users also have smartphones or tablets a current USB dongle should have the ability to be a WLAN access point so that several mobile devices can share the Internet connectivity provided by one dongle We suggest that the dongle should also b
62. e market requirement for coupling cellular networks and WLAN and realized the traditional USB dongle s deficiency is working as a dial up modem These publications and products are also evidence to show that our research is not simply exploring a scientific question for our own personal interests but rather a development driven by many researchers and by market needs To comprehend the operation of a USB dongle an experimental method has been adopted as the research method Since power is a significant issue for mobile device we compared the power consumption of a USB dongle for WLAN and for a 3G network to demonstrate if whether using the cellular network consumes more power than when using a WLAN see Section 3 2 To thoroughly understand the communications between USB dongle and laptop computer we monitored the whole Internet connection process when using a USB dongle see Sections 3 3 and 3 4 Based on our literature study and experimental tests after careful analysis and extensive search on the Internet we select RNDIS as the interface between USB dongle and laptop To evaluate the market acceptance for a product typically questionnaire or interviews are applied as the research method Due to various containts these methods were not employed However since the time that this project began in 2009 several vendors have produced products similar to what was proposed in 2009 we can use information about these products to evaluate our earlier
63. e represent only a narrow band interferer and are well shielded thus the major interferer is Bluetooth which hops all over the 2 4 GHz band thus generating the maximum interference all be it in a narrow band at any given time hence for a given IEEE 802 11 b g n channel this appears as short term interference 2 2 Cellular networks The term cellular refers to the fact that a geographical area is partitioned into a number of geographic coverage areas known as cells Each cell contains a base station which transmits signals to and receives signals from the mobile stations in its cell 11 This approach is the basis of the cellular network technology used by mobile phones today Before the introduction of cellular networks radio telephone service was provided by powerful transmitters connected to a large antenna in order to provide a long transmission radius typically around 70 80 km 12 Unfortunately although the area was large the system s bandwidth was only sufficient to support about 25 channels at a time with one user per analog channel This meant that only a few people could enjoy mobile phone service Background 9 within that huge area at any given time In contrast modern cellular networks use numerous lower power base stations and divide the area into smaller cells each cell is assigned a band of frequencies time slots or codes depending upon the particular system technology so that thousands of users or more can u
64. ecoming prevalent soon in the whole world The initial USB dongles for instance Huawei E220 57 actually do not look like a USB flash drive and it needs an extra USB cable to connect to a laptop User must install driver manually before using the dongle but it is already a technical advancement since the driver is saved in the flash memory inside the dongle so the USB dongle vendor does not need ship an extra CD with each device as other device vendors did ten years ago Novatel Wireless introduced a wireless router called MiFi in 2009 58 This device can be connected to a cellular network and provide Internet to other mobile nodes as a WLAN access point Although it is not a USB device it greatly affected USB dongle manufacturers Many manufacturers borrowed the idea of mobile WiFi hotspot and even the name MiFi A USB dongle can not only be a 3G modem with SIM card but also be a WLAN access point it receives wireless connections from cellular networks and transmits the signals to other mobile nodes in the hotspot One example of such USB dongle is ZTE MF70 59 This device is a 3G dongle with WiFi router and it can support up to 10 devices in its hotspot A special feature is that this device can start to work without setup in a laptop Tt just need to be connected to a USB power source and then it begins to work Though we are not sure we suppose MF70 should support RNDIS or other USB protocols because supporting these new U
65. ed handoff In heterogeneous UMTS WLAN networks a handoff also occurs when a mobile user roams between different networks A laptop in a UMTS network may want to change from UMTS to WLAN when WLAN connectivity is available because normally the data rate in a WLAN is higher than UMTS and generally traffic charges are flat rate or lower than the cellular data traffic charges A handoff occurring between two dissimilar networks is called a vertical handoff while a horizontal handoff occurs when roaming between different cells subnets that use the same technology for instance handoff from one cellular network cell to another cell Furthermore vertical handoff could be classified as upward or downward Upward vertical handoff is a handoff from a small sized cell to a larger sized cell e g from WLAN to UMTS whereas downward refers to movement form larger cell to small cell Figure 2 3 illustrates the difference between horizontal and vertical handoff Background 13 UMTS Vertical handoff Figure 2 3 Horizontal handoff and vertical handoff Horizontal handoff can be triggered based upon parameters such as signal to noise ratio SNR bit error rates frame error rates etc 22 For example we can simply define that a handoff should take place when the SNR of a new WLAN hotspot is greater than the SNR of the current hotspot however this simplified method is not appropriate for dissimilar networks since it is not meaningful to com
66. en a 3G network and aWLAN If there is anew high speed WLAN available then the user must manually switch to this network As regards wireless routers such as the MiFi they simply utilize a 3G network while providing the functionality of a local WLAN AP In addition many wireless routers need external power which substantially decreases their portability Customers need products that exploit both 3G 4G and WLAN interfaces while automatically performing handoffs between these two technologies For vendors this is fortunate because it means there is a great potential market therefore many companies are working in this area and each hopes to design such a coupling device although some of these designs may require modifications to the infrastructure networks Alcatel a proposed aWLAN 3G interworking architecture 27 This architecture provides extensive integration of UMTS and WLAN by using Mobile IP It offers seamless connectivity without requiring any user interaction i e the coupling is transparent to the user Some important components of this architecture are an Intelligent GGSN I GGSN multi access data server MDS and real time content charging manager 16 Background The MDS is responsible for UMTS WLAN roaming and implements AAA mechanisms When a mobile user needs to access a WLAN while connected to a cellular network the AAA server in the MDS of the WLAN forwards an authentication request to the subscriber s home network A
67. ernet all of the packets that are transferred are BULK OR INTERRUPT TRANSFER and this persists until we terminate the connection During termination CLASS INTERFACE and CONTROL TRANSFER URBs are used for transferring control information The last step occurs when the user ejects and unplugs the USB dongle by clicking the USB icon in the bottom right of the Windows interface Note that the USBTrace reveals that there Method 33 are bulk transfers even after we virtually unplug the dongle from host and these transfers continue for about 90 seconds until packet 24266 IOCTL INTERNAL USB SUBMIT IDLE NOTIFICATION The client driver sends this request to the bus driver when a device goes idle After this the bus driver determines if it is safe to put the device in a low power state by sending a IRP MN SET POWER packet and finally USBTrace stops detecting communication at packet 24295 At this point we physically unplugged the dongle from the laptop resulting in a SURPRISE REMOVAL and a REMOVE DEVICE URB see the last 21 packets shown by USBTrace see Figure 3 17 Seq Type Time Request EndPoint Device Object IRP Status 24292 URB 187 092694 CONTROL_TRANSFER N 0 0x87658A00 0 8 55658 STATUS UNSUCCESS 22203 URB 187109093 BULK OR INTERRUPT TRANSFER IN 81 0x87658A00 0x8591E570 STATUS CANCELLED 24294 POWER 187 205966 SET POWER OUT 0 0 89 208 0 8 55658 STATUS SUPPO 24295 POWER 187 206279 SET POWER IN 0 OxC89CF208 0
68. es available for mobile users Of these the most common are WLAN and cellular networks This chapter provides some background information about these two types of access technologies and then presents some of the methods that can be used to couple them 21 WLAN The Institute of Electrical and Electronics Engineers IEEE has approved a set of standards for WLANs the IEEE 802 11 family Table 2 1 shows some of the most frequently used IEEE 802 11 standards Wireless Fidelity Wi Fi is a trademark of the Wi Fi Alliance and the label Wi Fi Certified on a product means that the product has been tested to comply with the indicated standard However the term Wi Fi is often misused by many writers as a synonym for IEEE 802 11 or another type of WLAN Table 2 1 Examples of IEEE 802 11 standards 9 10 Standard Frequency Data rates max Max range indoor 802 11b 2 4 GHz 11 Mbps 38 meters 802 11 5 GHz 54 Mbps 35 meters 802 115 2 4 GHz 54 Mbps 38 meters 802 11n 2 4 5 GHz 600 Mbps 70 meters 802 11 5 GHz 1 7 3 5 Gbps 35 meters WLANS have occupied an important place in the local area network LAN market during the past twenty years Today deploying a WLAN is a compulsory complement to traditional LANs in many organizations In some cases businesses only deploy WLANs and only deploy wired LANs within their data centers WLANs offer an efficient solution for places that are not easily served by wired LANs Th
69. escriptor bLength 0x7 bEndpointAddress 0x81 IN bmAttributes 0x3 USB_ENDPOINT_TYPE_INTERRUPT wMaxPacketSize 0x40 binterval 0x5 Endpoint Descriptor bLength 0x7 bEndpointAddress 0x82 IN bmAttributes 0x2 USB_ENDPOINT_TYPE_BULK wMaxPacketSize 0x200 binterval 0x20 Endpoint Descriptor bLength 0x7 bEndpointAddress 0x1 OUT bmAttributes 0x2 USB_ENDPOINT_TYPE_BULK wMaxPacketSize 0x200 binterval 0x20 Interface Descriptor bLength 0x9 binterfaceNumber 0x1 bAlternateSetting 0x0 bNumEndpoints 0x2 binterfaceClass OxFF Vendor Specific binterfaceSubClass OxFF binterfaceProtocol OxFF ilnterface 0x0 Endpoint Descriptor bLength 0x7 bEndpointAddress 0x83 IN Value 55 Urb Field Value bmAttributes 0x2 USB_ENDPOINT_TYPE_BULK wMaxPacketSize 0x200 binterval 0x20 Endpoint Descriptor bLength 0x7 bEndpointAddress 0x2 OUT bmaAttributes 0x2 USB_ENDPOINT_TYPE_BULK wMaxPacketSize 0x200 binterval 0x20 Interface Descriptor bLength 0x9 binterfaceNumber 0x2 bAlternateSetting 0x0 bNumEndpoints 0x2 binterfaceClass OxFF Vendor Specific binterfaceSubClass OxFF binterfaceProtocol OxFF ilnterface 0x0 Endpoint Descriptor bLength 0x7 bEndpointAddress 0x84 IN bmaAttributes 0x2 USB_ENDPOINT_TYPE_BULK wMaxPacketSize 0x200 binterval 0x20 Endpoint Descriptor bLength 0x7 bEndpointAddress 0x3 OUT bmAttributes 0x2 USB_ENDPOINT_TYPE_BULK wMaxPac
70. f explorations about this area 3 4 5 With the increasing prevalence of smartphones and tablet computers current mobile broadband networks can provide users with acceptable data rates together with mobility The popularity of smartphones and tablets however does not mean these devices have yet replace laptop computers people still need wireless access to the Internet via their laptops Laptops have many prominent advantages such as physical keyboards bigger screens more disk storage greater computing performance and file amp software compatibility with desktop computers The research question that we have addressed is How to smoothly make use of heterogeneous networks to provide laptop users with better Internet service 1 2 Research purpose Today WLAN modules are integrated in laptops so laptop users are used to accessing the Internet wirelessly by WLAN Common mainstream laptops do not have modules to connect to cellular networks therefore many users utilize a USB dongle for wide area mobile broadband connectivity While smartphones can share Internet connection with laptops by wireless tethering USB dongles are much smaller and cheaper than smartphones Additionally USB dongles are specifically designed for Introduction 3 providing network connectivity A USB dongle which combines WLAN and cellular modules together would give laptop users a lot of convenience Users would not need to manually search for available wireless
71. f these strategies 52 In this thesis our aim is to make the USB dongle take charge of the handoff between WLAN and cellular networks A simple workflow of the dongle is shown in Figure 4 1 We presume that user sets WLAN interface as the priority so the dondle first tries to search WLAN networks in the vicinity and the dongle only tries to connect with 3G network if there is no available WLAN in the neighborhood This is just a very simple example the real workflow could be much more complex in practice There may be many WLANSs available the dongle may have the ability to connect to heterogeneous cellular networks such as 3G hence the dongle should also decide whether to connect to a WLAN or cellular networks after the signal strength decreases or the connectivity is lost WLAN available Yes y search WLAN Connect WLAN start WLAN first u Search 3G Figure 4 1 A simple workflow of USB dongle Terminate Connect 36 36 available This USB dongle should be able to connect to the Internet automatically without the operation of a user However the dongle may need some configurations depending on the user s requirements Similar to many wireless routers the dongle should have a built in web server to provide this configuration interface Figure 4 2 demonstrates the main functions in the configuration page There are three groups network connection network management and other functions Each group has
72. he first request is an IRP MN QUERY CAPABILTITES This request is sent by the PnP manager to learn the capabilities of a device such as whether the device can be locked or ejected The first time stamp is 7 782311 second but this is not when the enumeration began rather the timer started when the user clicks the Start Monitor icon in the graphical interface of USBTrace Thus this time stamp indicates how quickly the user plugged in the USB device after starting the monitoring program The net three PnP IRPs are QUERY INTERFACE QUERY ID QUERY DEVICE TEXT All of these are minor functions to the major function PNP The PnP manager sends these IRPs to gather device information such as Capabilities UINumber HardwareID LogConf BootConfig etc Method 27 Seg Type Time Request VO EndPoint Device Object IRP Status Buffer Snippet Buffer Size O START 0000000 START OF LOG 1 PNP 7 782311 QUERY CAPABILITIES OUT 0 OxD6ELAO30 OxDA3F6490 STATUS SUPPORTED 0 PNP 7 782316 QUERY CAPABIUTES IN 0 OxD6ELAO30 0 0 6490 STATUS SUCCESS 0 PNP 7 782340 QUERY CAPABILITIES OUT 0 OxD6ELAO30 OxDA3F6490 STATUS SUPPORTED 0 7 782342 QUERY CAPABIITES IN 0 OxD6ELAO30 OXDA3FG490 STATUS SUCCESS 0 PNP 7 782365 QUERY CAPABILITIES OUT 0 OxD6ELAO30 OxDA3F6490 STATUS SUPPORTED 0 7 782367 QUERY CAPABILITIES IN 0 OxD6ELAO30 0 0 6490 STATUS SUCCESS 0 727 PNP 717039 QUERY CAPABIITIES OUT 0 OxD6ELAO30 OxDA3F6490
73. inating sessions consisting of one or more media streams SIP is an application layer protocol designed to be independent of the underlying transport layer such as TCP UDP or STCP The Call Session Control Function is a key element in IMS as it processes control messages and all signaling via SIP The CSCF can be categorized into 3 parts Proxy CSCF P CSCP Interrogating CSCF I CSCF and Serving CSCF S CSCF The P CSCF is a proxy for all SIP messages from end points to the rest of the IMS network Normally it resides in the subscriber s home network but could also be in a visited network The I CSCF acts as an entrance from a P CSCF to an S CSCF and it acts a Home Subscriber Server HSS to determine the relevant S CSCF once it receives SIP message Finally an S CSCF is the node that eventually performs the actual user registration and session control An IMS SIP based framework proposed by Munasinghe et al 26 Although this is not strictly a tight coupling architecture it is a closely coupled framework In this framework there are two initial steps before establishing a SIP session In the beginning a MH does not know the IP address of the P CSCF After learning the IP address of the P CSCF the MH acts as a SIP client and sends a SIP registration message through the P CSCF to the S CSCF and HSS After registration the MH can establish or be invited to a SIP session In an MH originated session the session data flow is ini
74. intain all LSSs in a big heterogeneous network Handoff decision is about the ability to decide when to perform the handoff In homogeneous networks the timing to handoff can be just depending on the signal quality for handoff in heterogeneous networks however many issues should be considered for example network bandwidth cost security QoS or user preferences so a decision algorithm based on various policies should be designed Table 4 1 displays the common handoff policy parameters We use four dimensions to divide these parameters in four groups The dimensions are static context dynamic context network related and user related 40 Analysis Table 4 1 Handoff policy parameters Policy parameter Network related User related Static context Operator network type User preference cost security bandwidth network configuration application QoS mobile node coverage latency feature Dynamic context Signal strength current data rate Movement velocity location packet loss rate network traffic history priority mobile node battery To smoothly perform the handoff implementation protocols which support the data transfer from old link to new link should be designed A series of actions such as registration cancelation connection and reconnection should be performed Traditionally the handoff can be controlled entirely by the network or entirely by the mobile node is also possible to combine both o
75. ketSize 0x200 binterval 0x20 Interface Descriptor bLength 0x9 bInterfaceNumber 0x3 bAlternateSetting 0x0 bNumEndpoints 0x2 56 Urb Field Value binterfaceClass 0x8 Mass Storage binterfaceSubClass 0x6 SCSI Transparent Command Set binterfaceProtocol 0x50 Bulk Only Transport Endpoint Descriptor ilnterface 0x0 bLength 0x7 bEndpointAddress 0x85 IN bmAttributes 0x2 USB_ENDPOINT_TYPE_BULK wMaxPacketSize 0x200 binterval 0 0 Endpoint Descriptor bLength 0x7 bEndpointAddress 0x4 OUT bmAttributes 0x2 USB_ENDPOINT_TYPE_BULK wMaxPacketSize 0x200 Interface Descriptor bLength 0x9 Be binterfaceNumber 0x4 bAlternateSetting 0x0 bNumEndpoints 0x2 binterfaceClass 0x8 Mass Storage binterfaceSubClass 0x6 SCSI Transparent Command Set binterfaceProtocol 0x50 Bulk Only Transport A ilnterface 0x0 Endpoint Descriptor bLength 0x7 bEndpointAddress 0x5 OUT bm Attributes 0x2 USB ENDPOINT TYPE BULK wMaxPacketSize 0x200 Endpoint Descriptor bLength 0x7 bEndpointAddress 0x86 IN bmAttributes 0x2 USB_ENDPOINT_TYPE_BULK binterval 0x0 binterval 0x0 Appendix 57 Urb Field wMaxPacketSize 0x200 binterval 0x0 2015 144
76. l 20protocols pdf Accessed 03 Jun 2015 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 References 49 D William Mobile Broadband and Qualcomm Proprietary Protocols Dan Williams blog 2010 Online Available https blogs gnome org dcbw 20 10 04 15 mobile broadband and qualcomm proprietary protocols Accessed 04 Jun 2015 S W Park Park Y Kim S H J ang and U J Kim Mobile terminal and communication mode switching method thereof U S Patent US20100074155 Al 2010 Online Available http patentimages storage googleapis com pdfs US20100074155 pdf Accessed 02 un 2015 T Moore Advances in USB Technology for Wireless Products 2009 Online Available http www mcci cn pdf L2 5b pdf Accessed 03 un 2015 Net Applications Operating system market share 2015 Online Available http www netmarketshare com operating system market share aspx qprid 88qpcustomd 0 Accessed 04 un 2015 J Wise HoRNDIS USB tethering driver for Mac OS X Joshua Wise s domain Online Available http joshuawise com horndis Accessed 05 un 2015 Corporation USB Modem User Manual 2011 Online Available https netcom no documents 10156 12072 mf820d helpEN pdf Accessed 05 J un 2015 Huawei E367 HSPA 3G Wireless Broadband USB Data Modem
77. ldwide topped 1 2 billion in 2014 62 Another Apple product iPad immediately became the hot cake in market since its first launch in 2010 Gartner predicts that tablet computers sales will finally surpass traditional PCs in 2015 63 With the crazy growth of new mobile devices more and more customers get used to browse the Internet by smartphones and tablet computers rather than laptop computers Actually a survey performed in 2011 had shown the declining likelihood for customers to buy a mobile broadband Analysis 43 device 64 and the market proved that the global shipments of mobile broadband devices was indeed continuing decreasing in 2013 and 2014 65 Strategy Analytics lists a number of factors are impacting market growth such as a declining PC market carriers bundling tablets with smartphones and offering subsidies or service extras providing lower cost SIM only data plans lengthening modem lifecycles a healthy second hand modem market and shared data plan tariffs across multiple devices but it also points that mobile hotspot routers continue to be the bright point in an otherwise gloomy market 65 We agree mobile WiFi devices still has a quite steady market especially for multi mode devices which can support heterogeneous networks such as WLAN WiMAx 3G and even 2 Although mobile WiFi and many current USB dongles combine WLAN and cellular networks their working methods are still different with our require
78. ments proposed in 2009 Current mobile broadband devices provide users WLAN service by connecting to cellular networks but our idea is that the dongle should be able to work as a wireless client which can receive signals from other access points for example wireless routers Readers may ask why we connect to a WLAN access point by an extra USB dongle instead of the laptop itself considering almost all laptops have already integrated WLAN modules Our initial reason is to make the Internet connection as simple as possible All Internet related operations are moved to the dongle so users do not need search available WiFi hotspots manually by laptop they just need simply plug the dongle into laptop and then all connection works are automatically done by the dongle Users even do not need to consider what types of networks they are using Another reason is that most WLAN networks need user authentication even for public WLANS in airports libraries hospitals etc Users must get some kinds of passwords and usernames before they can access the WLANs For most laptop users this means they are excluded from these WLANs Fortunately cellular network operators usually deploy a lot of hotspots or have using agreements with other hotspot operators for example China Mobile has been built 420 000 WiFi hotspots in China 66 So if a user subscribes to China Mobile s cellular networks the user may have the possibility to access that huge amount of hotspots Then
79. mobile broadband has been implemented according to multiple different standards Hence in order to provide a user with locally optimal service requires that user must make use of heterogeneous networks Furthermore the variety of networks gets increasing due to the emergence of various 4G networks The aim of this thesis is to explore how heterogeneous networks could be exploited to provide a user of a laptop computer with locally optimal service while hiding the complexity of this heterogeneous service The research focuses on the implications of integrating multiple network interfaces into a single USB dongle Our research shows that multi mode USB dondle is still needed in market though there are competitions from smartphones and mobile WiFi devices We point out that the PPP Point to Point Protocol based USB dongle should update to Ethernet USB protocols such as RNDIS Remote Network Driver Interface Specification or USB CDC Communications Device Class protocols Furthermore we suggest a USB dongle should be able to work as a WLAN access point to share Internet with other mobile devices and it should also work as a WLAN client which can join other hotspots If hotspot operators can authenticate USB dongles by SIM cards then users can easily access a great number of hotspots belong to these operators Keywords Data communications USB WLAN 3G 4G Sammanfattning iii Sammanfattning Mer n n gonsin beh ver m nniskan arbeta med
80. mproving the end user s experiences The RNDIS architecture is illustrated in Figure 3 22 With RNDIS user does not need to consider driver installation the user simply plugs the USB dongle into the laptop and then the user can start to explore the Internet Method 37 NDIS RNDIS Miniport Driver RNDISUSB Transport Driver USB Bus Driver USB Controller Driver USB Controller USB Network Device Device Firmware Figure 3 22 RNDIS architecture 3 5 General architecture of the dongle A comprehensively design of all of the functions of a USB dongle exceeds the scope of a single master s thesis In this section we briefly describe our design The general architecture for the proposed USB dongle is illustrated in Figure 3 23 As explained in the previous section the RNDIS architecture was selected for the Rm interface of the USB dongle For the Um interface s the dongle should be able to support both mobile broadband and WLAN and the dongle should automatically utilize the best interface to provide the user with the best quality or personally preferred network For this reason we need interface for both cellular network and WLAN A policy manager which can manage handoff policy parameters and decide when and how to switch between heterogeneous networks is also required Cellular module Firewall Policy manager RNDIS DNS Figure 3 23 USB dongle architecture 38 Method The num
81. munications before and after the software installation we found that the device that is removed during enumeration process is a mass storage device which stores the software to be installed Because the host found that the required software was already installed the driver it performs a SURPRISE REMOVAL This means that the first 92 packets were used to detect if the connection control software is installed Although the check for the mass storage device is performed every time the USB dongle is inserted it only takes 3 36 seconds based upon subtracting time stamp 11 1439s in the 92nd packet from the 7 7823s timestamp of the first packet The delay is short enough that most users will hardly notice this delay 30 Method Seg Type Time Request VO EndPoint Device Object IRP Status Buffer Snippet Buffer Size PNP 7824856 QUERY DEVICE RELATIONS IN 0 OxDA3F 490 STATUS SUCCESS 0 SYSTE 7 825131 REGINFO EX OUT 0 0xD68A8008 STATUS NOT SUPPORTED 0 SYSTE 7 825219 EX IN 0 OxD6E1A030 0 06848008 STATUS SUCCESS 0 PNP 105737 QUERY DEVICE RELATIONS OUT 0 0 06 14030 0xDA66D618 STATUS NOT SUPPORTED 0 PNP 10577 QUERY DEVICE RELATIONS IN 0 xD6E1A030 0 0 660618 STATUS SUPPORTED 0 PNP 105737 QUERY DEVICE RELATIONS OUT 0 0 0 660618 STATUS SUCCESS 0 PNP 10 5738 QUERY DEVICE RELATIONS IN 0 OxD6ELAO30 0504660618 STATUS SUCCESS 0 89 PNP 10
82. n is the next logical step toward the implementation of seamless handoff in an integrated WLAN UMTS environment 25 From a user s perspective however it does not matter how the underlying UMTS and WLAN are utilized because the user simply wants a device that utilizes some mechanism to choose the right wireless network automatically and transparently This suggests that the solution is policy based and need not be coupled to the specific types of underlying networks that might be utilized Method 19 3 Method The purpose of this chapter is to describe the research methods used in this thesis and what we have done based on the methods First we provide an overview of the research methods and research process in section 3 1 Section 3 2 focuses the power consumption test for USB dongle Section 3 3 describes the USB communication between the dongle and laptop and demonstrates the whole Internet connection process by using USB dongle Section 3 4 introduces two communication interfaces between dongle and laptop and compares the differences Finally based on results from research methods section 3 5 shows the general architecture for our designed dongle 3 1 Research method How to select the appropriate scientific method is an issue that we must take into account in the beginning of each research project There are a number of well established research strategies and methods such as survey experiment case study observation study etc
83. nce this thesis will not consider USB 3 0 24 Method Token packet Sync 8 32 bits Data packet Sync PID Data 8 32 bits 8 bits 0 1024 bytes Handshake packet Sync 8 32 bits 3 5 USB packet types n a in this figure means not applicable All USB packets start with a synchronization sync field This field is used for synchronization of the clock in the receiver with the clock in the transmitter and it is 8 bits long in both low amp full speed and 32 bits long in high speed mode The next field is a Packet ID PID This ID indicates the type of the packet The cyclic redundancy check CRC field is 5 bits long in a token packet and 16 bits in a data packet The last field of every packet is End of Packet EOP This field terminates the packet The token packet specifies which device and endpoint the packet is to be sent to Thus there is an address ADDR and an endpoint ENDP field in the token packet A USB host can support at most 127 devices since the ADDR field has 7 bits and address 0 is not valid There are three different handshake packets ACK which acknowledges to the sender that a packet has been successfully received NAK which indicates that the packet could temporarily not be sent or received and STALL which indicates that the endpoint halted or a control request is not supported All of these handshake types are distinguished based upon their PID values These three different p
84. nd upper layers such as TCP IP As shown in Figure 3 21 NDIS contains three types of drivers from top to bottom these are a protocol driver intermediate driver and miniport driver The NDIS miniport driver interacts with network adapter normally this driver varies with the hardware and it is developed by network adapter manufacturers The NDIS protocol driver is independent of the underlying hardware and it is responsible to handle various upper layer protocols such as TCP IP and to transport packets to the next lower level The NDIS intermediate driver is in the middle and it has two different interfaces to communicate with its upper and lower drivers respectively The protocol driver looks like an intermediate driver to a miniport driver whereas the intermediate driver looks like a protocol driver from the miniport driver s view NDIS can deal with a USB dongle as a network adapter Modern personal computer operating systems have quite good support for Ethernet and WLAN network adapters so NDIS mode can have a better performance than RAS mode when carrying TCP IP traffic Some vendors have produced USB 36 Method dongles with both RAS NDIS modes 44 45 Rather than command based communication with modems NDIS can use non AT protocols such as Qualcomm MSM Interface QMD an interface for communicating with Qualcomm Mobile Station Modems provides a better service for high data rate mobile broadband and in practice vario
85. network RAN just like other RANs that are attached to that UMTS network The WLAN gateway must support all the protocols required in a UTRAN In this scenario a mobile node in a WLAN must connect to a UMTS network before it can access the Internet The communications between UMTS and WLAN occur just as between any other cells The coupling could occur at the Gateway GPRS Support Node GGSN or a Serving GPRS Support Node SGSN Mobile IP or other UMTS mobility protocols could be used for interworking Normally tight coupling solutions have shorter handoff latencies than loose coupling solutions because the interworking occurs at a closer point to the mobile terminal Simulation results of real time services and applications 20 show that loose coupling based on Mobile IP suffers longer handoff latency than a tight coupling approach Siddiqui Zeadally and Yaprak 21 indicate that the overall delays not only handoff latencies are much lower when the data exchange is done through the GGSN node as compared to when the networks are connected through the SGSN node Another clear strength of a tight coupling architecture is that the Authentication Authorization and Accounting AAA billing mobility and QoS support in UMTS networks can potentially be reused over the WLAN cells however this is only feasible if WLAN and UMTS networks belong to the same operator Unfortunately in practice it is unlikely that a mobile user can always connect via network
86. ngle so USB dongle can focus on customers who are sensitive to prices Another alternative is to embed mobile WiFi or USB dongle functions into laptop and then customers do not need bring extra network devices just one laptop is enough Conclusions and Future work 45 5 Conclusions and Future work In the last chapter of this thesis we conclude our research Some related researches which are out of the scope of this thesis are suggested as future work The chapter ends with some reflections on what economic values operators and users can get from our work 5 1 Conclusions Ten years ago it was uncommon to see many laptop users surfing on the Internet in public places outside of universities and offices Today WiFi hotspots are almost a standard as they are deployed in many airports restaurants libraries etc However they remain hotspots with limited coverage areas although the number of hotspots continues to grow rapidly Fortunately we have an alternative solution mobile broadband Despite the relatively lower data rates and higher traffic charges mobile broadband greatly extends the geographical range of wireless Internet Users can access the Internet from almost anywhere as long as their device s can transmit amp receive a sufficiently strong cellular signal This unique feature made USB dongles quite successful in the initial deployment of 3G 4G networks As a pioneer in 3G 4G market the USB dongle had many advantages First n
87. ning 01 42 49 Total Time 01 59 33 Time on Battery 00 13 08 Num samples fis aren poe 25 Run time 5 00 11 33 H W Discharge Rate ES Comparison Rate None gt so q NH Figure 3 3 Laptop power information from BatteryMon when using the WLAN interface e e n 4 Based upon the formula given above the battery lifetime in hours is 40759mWh 20304mW 2 hours and 0 5 minute repeated the test in the same environment but used 3G USB dondle instead of the Wi Fi interface According to the results shown in Figure 3 4 the battery operating with 3G is 3G Battery Hours 40759mWh 20347mW 2 hours and 0 2 minute So there is only 0 3 minute difference between the two scenarios thus most customers will experience negligible difference in battery operating times This test demonstrates that USB dongle is no more power consuming than using WLAN when streaming a video from an internet server Method 23 ation version 73 Charge File Edit Run Info Help Status Stopped r Battery details Power source Bat Battery Status Full Life left 73 ke Us A al Time Remaining 01 27 51 Total Time 02 00 20 Time on Battery 00 30 21 S Num samples 150 Run time 5 00 11 16 E Discharge Rate 2016 8 Comparison Rate None y Figure 3 4 La
88. nks and cellular networks In practice PPP is widely used as a data link layer protocol to encapsulate IP packets for transmission over modem links A mobile phone could be used as a wireless modem to connect a laptop computer to the Internet Using a USB cable was once the mainstream way to connect a mobile phone and a laptop but a Bluetooth or infrared link could also be used depending upon the phone Nowadays connecting via WLAN to a smartphone is very popular and this allows the computer connected via the WLAN interface to utilize the wide area cellular connectivity of the smartphone This sharing of wide area or local area connectivity through one device is often referred to as tethering or Internet Sharing If the tethering is not done over WLAN then generally the software of the laptop uses the mobile phone as if it were a dialup modem Hence the protocol used for this data communication is PPP Introduction 5 Instead of connecting the laptop with a mobile phone several types of wireless modem cards can be directly inserted into the computer Traditionally many of these devices used the Personal Computer Memory Card International Association PCMCIA card format or the later ExpressCard format The early designs of these devices were made to look like a dialup modem to the computer hence the data communications protocol used was PPP While this may have been convenient from the point of view of being able to utilize the modem
89. ology is not new Guglielmo Marconi developed the first wireless telegraph system in 1896 6 Today consumer adoption of wireless technology is a major telecommunications trend Wireless communication technology is evolving rapidly and there are an increasing number of wireless communication applications in use every day Examples of this technology include broadcast radio and television various satellite navigation systems such as GPS WLANS cordless amp mobile telephones and the explosion in the use of tablets and smartphones In this thesis we will focus on two of these technologies WLANs and the wide area cellular networks that have evolved to support mobile phones WLANSs offer an efficient complement to wired LANs Most WLANs use unlicensed radio frequencies to transmit and receive data over the air Some of the major reasons for the success of WLAN have been that WLANS can easily be deployed WLAN equipment is available at low cost and 4 Introduction WLAN interfaces offer data rates comparable to wired local area networks Typically WLAN is implemented as part of home or corporate network Some WLANSs are open to public users for example in libraries airports and restaurants The popularity of WLAN has led to more and more users using it Additionally the popularity of WLANs has led to the incorporation of WLAN interfaces in all current laptop computers and an increasing fraction of handheld devices including mobile phones
90. or Maguire the journey is finally turning to be a gift to my life a master degree with invaluable experience Table of Contents Table of Contents A A i C i sammanfallning 2 24 2 22 een iii een iii Acknowledgements 11 11 1111 11111 nnana V Table ot Contents eoo illes ee vii ria lg cH Ix LisLof AA E xi List of Acronyms and Abbreviations xiii 1 1 1 1 Problem state mE en 1 1 2 044 ri 2 1 3 General background about wireless networks 3 1 4 Modems and USB dongles sess 4 1 5 LIMITAONS A ne 6 1 6 Structure of thesis oec ai 6 2 Background noci tie 7 2 1 WLAN m age 7 2 2 Cellular networks oinnia 8 2 3 Coupling WLAN and 9 2 3 1 Loose COPIA 11 2 3 2 UP ne 12 2 4 Policy based airis ve Edu Rd ado 12 2 5 Related WIM qe 14 2 5 1 Policy based loose coupling framework 14 2 5 2 IMS SIP based coupling framework 14
91. orld first public LTE networks in Oslo and Stockholm in the late of 2009 55 With LTE users can have much better Internet experiences for watching videos attending webinars playing online games etc However even though current LTE networks have quite high data rates 42 Analysis the new WLAN standard such as 802 11ac still has many advantages over LTE just as 802 11b to WCDMA Today USB is the standard connection between personal computers and computer peripherals The newest USB standard is USB 3 1 and USB Type C which is a small reversible plug connector for USB devices Unlike the half duplex communication mechanism in USB 2 0 USB 3 0 and USB 3 1 use two unidirectional data paths to make the interface as full duplex to be able to receive and send data simultaneously From USB 3 0 USB ports can provide up to 900 mA so USB devices are able to consume more power and the good news is that it does not mean USB devices must consume more power Because USB 3 0 has better power management it can conserve power when the USB device is connected to a computer but in idle status The new USB standards have much faster speed than USB 2 0 so a USB dongle with USB 3 0 interface can better match current fast mobile broadband data rates USB dongle has entered the market for around ten years after 3G networks were widely deployed Customers were quite surprised when they first found a 3G modem with USB connection 56 and this fancy device was b
92. ormally there is a time lag between mobile devices and network deployment as the old mobile devices cannot support the new networks very well For example 3G networks were widely deployed several years before smartphones became prevalent As a result a USB dongle was the best solution to provide mobile Internet access during that time interval as customers did not need wait for new mobile devices a dongle can help them connect to the Internet via their laptop Second the price a USB dondle is much less than many smartphones When one considers spending several thousand Swedish kronor to buy a smartphone many customers would choose a USB dongle costing only several hundred Swedish kronor Third a USB dongle is specifically designed for providing Internet connectivity hence its performance is largely determined by the available network quality In contrast other mobile devices such as smartphones and tablet computers have many functions hence their user s Internet experience will be greatly affected by the quality of devices themselves Being a market pioneer however also means that its market share decreases after the market becomes mature and stable Nowadays more and more customers have smartphones and they can browse the Internet using these small devices which can put in their pockets Smaller size is a good feature for a mobile device but it also brings some deficiencies if it is too small For example many customers complain that th
93. owever according to BCE Inc the word dongle is now widely used to refer to a broadband wireless adapter 8 There are 3G 4G USB dongles in various sizes and shapes Most look similar to USB flash drives with various types of antennas attached to them These dongles can indeed be used as flash drives or memory stick since there are flash memories present in these dongles This flash memory contains a file system with software which the host computers can load and run This software frequently includes a driver for one or more operating systems OSs and a management application so that the user can control the dongle However this flash memory could be used to provide other software for example the software could provide routing software to route packets to WLAN or 3G interfaces AII the necessary drivers and software are stored in the dongle by the manufacturer so that the user can conveniently use the dongle immediately or soon after they plug the dongle into their laptop Each USB dongle contains a small modem and transceiver inside the dongle enabling the device to connect to a 3G 4G network To access the Internet via a cellular network the OS frequently makes use of the dongle as a modem to connect to a terminal server via PPP The OS begins by negotiating the protocol family it is going to use gets assigned an IP address and then the OS encapsulates IP packets into PPP frames and transmits these frames over the PPP link to their destin
94. oxy server all of the local Internet devices would be able to take advantage of the caching gains which this proxy could offer thus speeding up web browsing and other services Proving a firewall to all of the local internet devices could reduce the impact of unwanted remote traffic on each of the local devices and their local communication network Note that this firewall should probably work in conjunction with a firewall service in the different network operators to push filtering to these operators rather than having this unwanted traffic flow across the Um link s to the dongle However the details of such a shared and distributed firewall service remain for future work Another requirement for the dondle is to support both IPv4 and IPv6 Although IPv6 was designed to replace IPv4 IPv4 is still extensively used in many systems To enable most customers to use our product the USB dongle should support both IPv4 and IPv6 This can be implemented by a dual stack approach Additionally the dongle could allow local devices to use IPv4 and it could provide a IPv4 proxy service while actually using IPv6 over each of the Um links Analysis 39 4 Analysis In this chapter we present the detailed analysis for our designed USB dongle Technical issues such as policy based handoff and configuration interface are discussed We also review the market changes since USB dongle launched into the market show the market trend and give some suggestions an
95. pare the SNR from different technologies For upward vertical handoff from WLAN to UMTS the trigger can be when no WLAN hotspots are detected whereas downward vertical handoff from UMTS to WLAN needs more considerations especially as there may not be an appropriate WLAN AP to make the handoff to Certainly a downward vertical handoff could be triggered by the user but since our aim is reduce the burden on users a more sophisticated handoff policy involving parameters such as potential data rate power consumption cost reliability etc should be used Additional important parameters that can be taken into account for all kind of handoffs are the velocity of the mobile node and what are the current amp near term expected requirements upon the link A dwell timer can be utilized to avoid the so called ping pong effect that is caused by mobile nodes frequently performing handoffs back and forth between a pair of networks This thesis concerns the use of heterogeneous networks by applications running on a laptop computer rather than a smartphone or tablet computer Due to the nature of a laptop large size moderate to heavy weight and large screen size we can assume that the laptop is stationary when it is used hence we do not need to be concerned about rapid handoff due to node mobility and hence we focus on vertical handoff especially on downward vertical handoff as this can reduce the load on the operator s macro cell increase the user s
96. performed before the traffic flows over the Um link would be a very good added value that network operators could provide However there are many open questions that need to be addressed before such a service could be deployed As we discussed in Section 4 2 the SIM card authentication for mobile broadband device as a WiFi client need more research Since some operators have already introduced WiFi calling a possible research direction could be how to utilize AAA server in WiFi calling for mobile broadband devices If an operator can launch this service it might greatly increase its market share 5 3 Reflections Building one WLAN hotspot is an easy task whereas the task will become a huge expense as the number of hotspots grows Deploying ubiquitous cellular networks is theoretically quite possible however in practice certain places in buildings may be blind spots for cellular signals for example basements Both WLAN and cellular network have their own advantages and disadvantages but operators will not wildly deploy more hotspots and cells without limit just to give us better user experiences because they need to consider their costs and profit Using the solution proposed in this thesis with users providing more of the broadband access facilities operators can provide users better service without building more networks and ease the burden of cellular networks by offloading data to WLAN networks Users can enjoy always on Internet acoess
97. ps have developed a number of WLAN standards The maximum theoretical data rates of the commonly available 802 11 standards were shown in Table 2 1 Due to the high data rates of WLAN there is little difference for a typical user when surfing the Internet via WLAN or LAN Because of the very large numbers of devices made and the fact that the majority of the devices are customer installed WLAN is relatively cheap and easy to deploy hence it has become very popular However WLAN does have an obvious flaw As the name suggests WLAN is a technology for local access which means that the wireless coverage area is not a very large area hence as noted earlier these coverage areas are often called hotspots Because of this limited coverage users can not count on hotspots being everywhere nor are all hotspots open to the public Another problem of WLAN is caused by the frequency band s used by these devices The popular IEEE 802 11 b g n standards devices share the unlicensed 2 4 GHz radio frequency with many other devices e g Bluetooth microwave ovens cordless phones etc so there is a potential for conflict when attempting to transmit as well as interference when multiple devices are operating in close proximity However in Europe in practice most cordless phones are Digital Enhanced Cordless Telecommunications DECT phones and hence use the 1 88 19 GHz band assigned to DECT and most consumer microwave ovens are single frequency henc
98. ptop power information from BatteryMon when using 3G interface 3 3 Watching USB communication using USBTrace To understand how the USB interface works we analyze the data communication across the USB interface There are several USB analysis tools available on the Internet for downloading such as SnoopyPro 30 SniffUSB 31 and USBTrace 32 Since USBTrace has good support for Windows system the operating system running on the author s laptop 1 choose to use USBTrace as the analysis software Before using this powerful USB analyzer we first give an overview of USB communication 3 3 1 USB communication overview USB provides an easy to use solution to connect various devices to computers by a standard interface USB is host controlled thus there has to be a host acting as a bus master The communication utilizes token data and handshaking frames here after referred to as packets The USB protocol stack has several layers The maximum data rate of USB 2 0 in high speed mode is 480 Mbps 1 5 Mbps in low speed and 12 Mbps in full speed mode Unlike other similar serial interfaces in which the data format is not clearly defined USB communication utilizes transactions similar to Ethernet frames but with each USB transaction consisting of 3 packets a token packet a data packet and a handshake packet The formats of these three types of packets are shown in Figure 3 5 USB 3 0 was not defined at the time that this project started he
99. radio technology used in 3G systems was abandoned in 4G and replaced by Orthogonal Frequency Division Multiple Access OFDMA and other frequency domain equalization schemes Combined with Multiple Input Multiple Output MIMO technique 4G networks can transfer much higher data rates than its predecessor networks 13 However as we mentioned in the first chapter the research in thesis is based on 3G technology and the market penetration of 3G is still much bigger than 4G The biggest advantage of a wide area cellular network is the large coverage area Users can access the Internet anywhere as long as their device can transmit amp receive a sufficiently strong signal However the main disadvantages of these wide area cellular networks are their higher traffic charges and comparatively lower data rates in comparison with WLAN although data rates increased a lot with the introduction of 3G 4G technologies In some areas that are not yet covered by 3G 4G service the user might only have access to a 2G service such as General Packet Radio Service GPRS or even Global System for Mobile Communications GSM which offers much lower maximum data rates 2 3 Coupling WLAN and 3G 3G networks provide what appears to the user to be always on wide area internet connectivity While these networks allow high mobility their disadvantage is relatively low user data rates and high traffic charges While WLANs offer users much higher and more stable data rates
100. result all of the devices attached to a single USB host interface share a single interrupt and a single I O address 33 To recognize different USB devices sharing the same interface USB uses a technique called enumeration to find all of the devices and then the operating system associates each device with a device descriptor When a USB device is plugged into a USB host the host will perform an enumeration to determine all of the devices attached to this USB controller The host will recognize the presence of the device and assign it a unique 7 bit device address After assigning each of the devices an address the host queries each device for its descriptors These descriptors contain information about each specific device USB devices have a hierarchy of descriptors These descriptors are shown in Figure 3 7 Each USB device can only have one device descriptor but can have more than one configuration descriptor Most devices however only have one configuration descriptor since changing the configuration requires all activity on each endpoint to stop 34 thus it is inconvenient to do so in practice A single configuration can have many interfaces and each interface looks like a group of endpoints that accomplish a single function of a composite USB device All communication between the USB host and a USB device is addressed to a specific endpoint of the device keeping in mind that a given device can implement multiple endpoints The endpoint c
101. rios 17 shown in Table 2 2 on page 10 Tight coupling can implement the upper level 3GPP scenarios and these approaches are expected to offer low handoff latency than loose coupling but must face the serious disadvantage of a bottleneck arising due to the amount of data from to WLAN APs as the UMTS backbone was not designed to support these high data rates nor the high aggregated data rates Another drawback is that the coupled networks need to belong to the same operator or have agreements with operators which could not be a easy work in practice Table 2 3 summarizes some of differences between loose and tight coupling Table 2 3 Comparison between loose coupling and tight coupling Loose coupling Tight coupling Data bottleneck No Yes Deployment Common AAA solution Modifications on UMTS WLAN problems Mobile IP in UMTS and WLAN components and terminals Deployment WLAN providers Cellular network operators preference Deployment Bar Low Medium Medium High complexity Handoff Low Medium Medium High performance Background 17 Loose coupling normally utilizes Mobile IP for handoff management This approach is most suitable for the 3G USB modems which using PPP connections Many tight coupling solutions employ IMS and SIP These solutions are well adapted to services which are not based on PPP Although tight coupling is currently more difficult to implement many researchers believe that tight integratio
102. rms of exceeding bounds on delay jitter or packet loss This proposal also includes a detailed handoff decision algorithm Their experiments with a prototype showed that smart decision mechanisms are necessary for smooth adaptation of the communication streams under different conditions 2 5 2 An IMS SIP based coupling framework In tight coupling architectures a WLAN is directly attached to a UMTS component such as the GGSN or SGSN A clear advantage is the possibility to reuse the UMTS mobility management techniques However tight coupling is difficult to implement in networks belonging to different operators and less literature exists about this approach than for loose coupling Rather than using Mobile IP some frameworks based on the IP Multimedia Subsystem IMS and Session Initiation Protocol SIP have been proposed for tight coupling Before presenting this type of framework we give a brief overview of IMS and SIP IMS is based upon internet protocols IMS is a network architecture aiming to merge Internet and cellular worlds by providing a horizontal control layer that isolates the access network from the service layer It is seen as a promising solution for facilitating multimedia service creation and deployment as Background 15 well as supporting interoperability and network convergence IMS was specified by 3GPP was introduced in UMTS releases 5 and 6 25 SIP is widely used in IMS for creating modifying and term
103. s operated by the same operator Moreover both UMTS and WLAN devices and configurations needed to be modified to realize this tight coupling and the UMTS backbone network must be modified to handle the increased data traffic from WLAN APs Due to these drawbacks this architecture is more difficult to deploy and fewer researchers have focused on this approach as compared to loose coupling 2 4 Policy based handoff In cellular telecommunications the term handoff or handover refers to the process of transferring an ongoing call or data session from one channel link connected to a base station to another channel link or another base station As a fundamental operation for any cellular networks handoff management ensures mobile users maintain network connectivity despite users moving to different cells Details of this process have a great impact on how the old links are released and new links are established Traditionally handoff depends on measurements of the signals between the mobile device and the base station s and the reverse For example if the original link signal continues to decrease in signal strength and the signal strength of a potential new link is increasing then a handoff would be initiated However in many cases there may be a need to decide upon when to make the handoff based on other rules or policies such as a terminal s capabilities application types costs or user preferences This kind of handoff is called a policy bas
104. s that WLAN and UMTS networks can be deployed independently by different providers and the user can freely choose which network they wish to use when both are available Considering the large number of WLAN providers establishing roaming agreements between UMTS and WLAN operators is an expensive and complex problem as generally these agreements are bi lateral agreements so each pair of operators have to reach an agreement however in some places there are exchanges where all the operators can connect and there is a standard settlement agreement via the exchange Another advantage of loose coupling is that it avoids potential traffic bottlenecks in the UMTS network since data traffic can be routed directly via networks In literature about roaming in a heterogeneous infrastructure the loosely coupled architecture is a frequent researched architecture For example Ruggeri Iera and Polito 17 cited several similar works and indicated that IEEE 802 1X EAP extensible authentication protocol and RADIUS Remote Authentication Dial In User Service can be used for AAA An alternative offering non binary authentication using traffic shaping has been explored in 18 In Raul Garcia s Master s thesis 19 he shows mobility can be supported via Mobile IP and the Session Initiation Protocol SIP 12 Background 2 3 2 Tight coupling In a tight coupling approach WLAN network is an integral part of a UMTS network acting as a radio access
105. se their mobile phones at the same time With the widespread deployment of 3G and 4G more and more people are using cellular networks to access the Internet There were three main types of 3G networks available when 3G were launched into the market in the beginning of 21st century Wideband Code Division Multiple Access WCDMA Code Division Multiple Access 2000 CDMA2000 and Time Division Synchronous Code Division Multiple Access TD SCDMA WCDMA had been deployed worldwide while CDMA2000 is primarily used in North America and South Korea and TD SCDMA is commercially available only in China Nowadays most WCDMA networks have been upgraded into High Speed Packet Access HSPA and Evolved HSPA also called HSPA which offer much higher data rates and significant improvement in battery life Since the second decade of this century 4G networks are becoming globally deployed Several 4G candidate systems were developed but now only two 4G standards are commercially in the market Mobile Worldwide Interoperability for Microwave Access Mobile WiMAX and Long Term Evolution LTE Of these two LTE is the current dominant 4G network worldwide A distinct feature of 4G is that it is not designed for the traditional circuit switched telephony network but rather it was designed to support IP packet switched services 4G networks even use IP within their core networks hence these cellular core networks are often called all IP networks The spread spectrum
106. software built into many operating systems unfortunately this approach lead to the software treating this link as it would a dial up modem hence the behavior is to connect and then remain continuously connected until the connection is explicitly terminated This has a number of undesirable effects including unnecessary power consumption when there is not continuous user traffic and vendors network operators thought in terms of connected services hence delaying the transition to packet based services Current laptop computers have one or more universal serial bus USB interfaces USB version 2 0 offers a maximum data rate of 480 Mbps and compatibility with many products The latest USB 3 1 also known as SuperSpeed USB increases the maximum data rate to 10 Gbps Today the USB interface has even replaced the traditional RS 232 serial interface PS2 keyboard port and PS2 mouse port on most desktop computers Because of the USB Forum s efforts to foster the standardization and interoperability of USB devices a very wide range of devices exist with USB interfaces Among these devices are flash drives modems and Ethernet interfaces A USB wireless adapter is often called dongle although this term was originally used for devices that were used by applications to check that an application should be able to run on this computer In this earlier usage the dongle acted like a hardware key that was required in order to run the application H
107. sub groups In network connection the user can select to connect the Internet automatically or manually and the user can set handoff policies In network management the user can see statistics about the network traffic change tethering default and manually switch to a different network if the user is not satisfied with current network The USB dongle can also be used as a normal flash drive so users do not need bring extra flash drives if they have this USB dongle The dongle is driver free for the current Analysis 41 mainstream Windows operating systems but the dongle should also provide drivers if the user is using a legacy system for instance Windows XP so the dongle can cover more users by providing drivers Connect automatically Network Connect manually Traffic statistics Configuration Network Tethering managment configuration Network switch functions Figure 4 2 Main functions of configuration page 4 2 Market analysis The ICT industry evolves much faster than other industries It is argued that the Internet time is seven times more than our real time 53 When this thesis project was proposed in 2009 the multi mode USB dongle which provides heterogeneous networks with a Ethernet interface was just an idea Today however there are many similar products in the market The ICT world has experienced a great deal of changes in the past a few years Time is probably the best e
108. t used for this test Figure 3 1 Test voltage in parallel circuit The USB voltage output by the author s laptop is 5 08V when no device is plugged in After a USB dongle is plugged and connected to the Internet the current varies from 0 05 A to 0 27 A The current is higher when data throughput increases whereas the voltage decreases somewhat at lower data rates We identified 5 different usage phases and present the details of these phases in Table 3 1 From this table we can see that the 3G USB dongle starts to consume power after it is plugged into the laptop no matter whether the dongle has established a connection to the Internet or not After connecting to the Internet the power consumption of the dongle is about 0 65 W when there is no active communication and around 0 75 W at very low data throughput Once the throughput exceeds roughly 10 Kbps the power consumption quickly rises the more data transferred per unit time the more work that has to be done by the USB dongle Note that in this state the voltage and current vary over a relatively small range and the power consumption when uploading or downloading is very similar Method 21 Table 3 1 Huawei E1550 USB dongle power consumption Usage Phase Voltage V Current A Power W USB dongle connected to laptop but not connected to the Internet 4 86 4 87 0 05 0 06 0 2435 0 2916 Connected to the Internet but no active data communication 4 57 4 58 0 14 0 1
109. this is at the cost of low mobility and limited geographic service areas The advantages and disadvantages of 3G and WLAN with respect to peak data rate make these two technologies complementary Hence integration of 3G and WLAN is a natural demand from the market In response to this demand more and more service providers have started to offer such a service Many proposals have been presented in the literature for how to solve the many technical problems concerning the design and implementation of such a heterogeneous network such as how to do authentication authorization and accounting AAA billing support mobility and provide quality of service QoS guarantees The 3rd Generation Partnership Project 3GPP proposed in a preliminary feasibility study 14 six possible 3G WLAN integration scenarios based on the service experienced by the user Each scenario extends the preceding one towards tighter integration These six scenarios are showin Table 2 2 In addition to combining WLAN and 3G service to achieve the best possible user throughput in a given location there are also many reasons for performing so called vertical handovers between these two technologies An analysis of such vertical handovers to minimize battery power consumption is 10 Background described in 15 Additionally devices that are equipped with several interfaces might want to use multiple interfaces at the same time as described in 16 Table 2 2 3G WL
110. tiated by a SIP INVITE message sent from the MH and is followed by several SIP messages such as Provisional ACK UPDATE and ACK Although the transmission mechanism in this framework is very different from the Mobile IP based approach used in previous section the handoff solution is logically very similar Their framework also utilizes policy based decision making and introduces a network entity called a Mobility Manager to manage vertical handoff 2 5 8 Industrial proposals Devioes combining 3G and WLAN interfaces are available in the market for instance as incorporated into wireless routers and some netbooks Plugging a 3G USB dongle into a pocket size wireless router such as the Huawei D100 or Option Globesurfer X 1 customers can access the Internet by wirelessly connecting to the router A similar product originally from Novatel Wireless Inc called the MiFi does not even need a USB dongle this credit card size device can be turned into a hotspot by simply insert a Subscriber Identity Module SIM card Netbooks can also access the Internet via built in 3G and WLAN modules but they lost the market after the great success of Apple s iPad and since 2011 many personal computer manufacturers produce Chromebooks for the same segment of the market that netbooks serviced However all of above products have obvious drawbacks For example a netbook can access both 3G and WLAN networks but it is not able to automatically perform a handoff betwe
111. us Qualcomm chipsets are widely used by USB dongle vendors for instance the MDM9x00 46 which can support 2G 3G LTE multi mode service Upper Layer NDISProtocol Driver Miniport Interface Miniport Interface NDIS Intermediate Driver Protocol Interface Protocol Interface NDIS Miniport Driver Network Adpter Figure 3 21 NDIS driver architecture NDIS is a driver architecture which can work with several different types of links for example Ethernet WLAN and Bluetooth RNDIS is a USB protocol tightly coupled with NDIS drivers that provides virtual Ethernet over USB For the NDIS architecture network device vendors must develop miniport driver by themselves and users must install the driver otherwise the host computer would not recognize the device RNDIS defines a bus independent message set and a description of how this message set operates over the USB bus by creating a miniport driver and a USB transport driver in host computer 47 RNDIS standardized the set of host drivers so RNDIS can support any number of networking devices attached to the USB bus The RNDIS solution has two significant advantages 48 First the device manufacturers do not need to develop a NDIS miniport driver they simple need to implement their firmware conforming to the RNDIS protocol which simplifies the development of the network device Second RNDIS eliminates the requirement to install the device driver on the host computer thus i
112. vailable http sourceforge net projects usbsnoop Accessed 25 May 2015 SniffUSB 2 0 A USB Sniffer for Windows Release Notes 2007 Online Available http www pcausa com Utilities UsbSnoop RELEASE TXT Accessed 25 May 2015 SysNucleus USBTrace Online Available http www sysnucleus com Accessed 25 May 2015 D S Lawyer Plug and Play HOWTO PnP for External and Plug in Devices 2007 Online Available http tldp org HOWTO Plug and Play HOWTO 8 html Accessed 25 May 2015 C Peacock USB in a Nutshell Making Sense of the USB Standard 2002 Online Available http www ru lv peter macibas datoru arhitektura usb pdf Accessed 18 May 2015 Microsoft Best Practices Using URBs Online Available https msdn microsoft com en us library windows hardware hh406258 28v vs 85 29 aspx Accessed 23 May 2015 Microsoft About Remote Access Service Online Available https msdn microsoft com en us library windows desktop aa373643 28v vs 85 29 aspx Accessed 03 un 2015 ETSI ETSI TS 127 007 V10 3 0 2011 04 2011 Online Available http www etsi org deliver etsi TS 127000 127099 127007 10 03 00 60 ts 127 007v100300p pdf Accessed 02 un 2015 A Morgado So your mobile broadband modem speaks what 2013 Online Available https aleksander es data FOSDEM20 13 20 20Mobile 20broadband 20modem 20contro
113. valuation for a product Reviewing the changes in market and technology can show us a better overview and assessment of USB dongle and it can also indicate us the future trend for this product The mainstream WLAN standards have moved from IEEE 802 11a b g to IEEE 802 11n ac WLAN is becoming popular from the beginning of this century and the old standard for instance IEEE 802 11b can provide single user the data rate which is enough for most Internet applications but the data rate may decrease a lot if too many users share one access point Due to new techniques such as MIMO and Multi user MIMO IEEE 802 11n ac greatly increase the data rate and transmission range so one hotspot can provide more users with fast Internet connections 802 11ac can support up to eight antennas to reach the highest data rate However we must note the USB dongle cannot reach the highest theoretical speed because normally a USB device just support 1 or 2 antennas due to cost and space reasons 54 When USB dongle started to become popular in the market WCDMA was the most common 3G network worldwide Then it updated to HSPA and HSPA Nowadays 4G networks especially has been widely deployed in many countries LTE has the highest data rates in commercial cellular networks and it was designed based on packet networks so it is quite appropriate for data applications in all IP networks Actually USB dongle was the first LTE device when TeliaSonera launched the w
114. x1 iSerialNumber 0x0 bNumConfigurations 0x1 Figure 3 11 Device descriptor information Continuing to watch the enumeration process until packet 92 an unexpected status result appears As shown in Figure 3 12 the device is removed and the enumeration process restarts again from IRP_MN QUERY CAPABILITIES The reason for this is due to the need for software installation To surf on the Internet using this dongle first we need to install the bundled connection control software which is storage in flash memory in the dongle Although the USB 3G dondle is a modem from the user s perspective it not only functions as a modem but in fact it consists of several devices from the point of view of the host OS In Figure 3 13 we can see there are six USB host controllers in the author s laptop including two enhanced host controllers specialized for high speed USB functions Every USB host controller has an embedded root hub so in total there are six root hubs The Huawei USB dongle is controlled by an enhanced host controller 2836 and is recognized as a composite device with two mass storage devices The connection software is storage in one USB mass storage device thus avoiding the need to supply the user with a compact disk or digital video disks containing the software that the vendor provides This vendor software for managing the modem is automatically installed when the dondle is inserted in the host computer for the first time After tracing the USB com
115. y anyone by simply sending an email from any location that has Internet connectivity Another remarkable change brought about by ICT is the widespread popularity of mobile phones Today the number of mobile phone subscribers is much greater than the number of landline subscribers Many countries have a mobile phone penetration rate above 10096 For instance Europe has the highest mobile penetration rate in the world with the total number of connections being 13296 of the population of Europe in 2012 1 With the increasing use of the Internet and mobile phones there has been a spontaneous market demand for convergence of these two technologies Customers are not content to access the Internet via a fixed desktop computer but expect to surf and access the Internet wirelessly from any location that has network connectivity This demand has stimulated the deployment of many types of wireless networks of the most prevalent types of wireless networks are the wireless local area network WLAN and high speed wide area cellular networks often called mobile broadband Today the most popular instance of the later type of network is the various types of third generation 3G and more recently fourth generation 4G cellular networks In this thesis unless otherwise stated we will simply equate mobile broadband with one specific type of 3G network Universal Mobile Telecommunications System UMTS Wideband Code Division Multiple Access WCDMA

USB dongles for mobile broadband

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