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  1. 1. Mobile Networking Prof. Jean-Pierre Hubaux
  2. 2. About this course <ul><li>The course is about the system aspects of mobile networking </li></ul><ul><li>Therefore, it covers: </li></ul><ul><ul><li>- networking issues (MAC, network and transport layers, principally) </li></ul></ul><ul><ul><li>- wireless security/privacy issues </li></ul></ul><ul><ul><li>- estimation of network capacity and resource management </li></ul></ul><ul><li>It does not cover: </li></ul><ul><ul><li>radio propagation models </li></ul></ul><ul><ul><li>modulation and equalization techniques </li></ul></ul><ul><ul><li>source or channel coding </li></ul></ul><ul><ul><li>speech coding or other signal processing aspects </li></ul></ul><ul><ul><li>software-centric aspects (e.g., operating systems, mobile agents) </li></ul></ul><ul><li>It is focused on mechanisms , and avoids a detailed (and boring) description of standards </li></ul><ul><li>However, it does propose an insight on IEEE 802.11 </li></ul><ul><li>Acronyms... </li></ul>
  3. 3. Web site <ul><li> </li></ul><ul><li>Of particular relevance: </li></ul><ul><li>- Calendar </li></ul><ul><li>Material (all slides used at the lectures, homeworks,…) </li></ul><ul><li>Previous exams </li></ul><ul><li>Contact person: Mr Julien Freudiger </li></ul>
  4. 4. Textbooks Recommended: - J. Schiller: Mobile Communications , Second Edition Addison-Wesley, 2004 - W. Stallings: Wireless Communications & Networks , Second Edition, Prentice Hall, 2005 Mandatory: N. Vaidya: Wireless Networks. Book draft , available at the « Vente des cours », EPFL
  5. 5. Module A – Introduction (Part A1)
  6. 6. Wireless communication and mobility <ul><li>Aspects of mobility: </li></ul><ul><ul><li>user mobility : users communicate “anytime, anywhere, with anyone” </li></ul></ul><ul><ul><li>device portability : devices can be connected anytime, anywhere to the network </li></ul></ul><ul><li>Wireless vs. mobile Examples   stationary computer (desktop)   notebook in a hotel   wireless LANs in historic buildings   Personal Digital Assistant (PDA) </li></ul><ul><li>The demand for mobile communication creates the need for integration of wireless networks or mobility mechanisms into existing fixed networks: </li></ul><ul><ul><li>telephone network  cellular telephony (e.g., GSM) </li></ul></ul><ul><ul><li>local area networks  Wireless LANs (e.g., IEEE 802.11) </li></ul></ul><ul><ul><li>Internet  Mobile IP </li></ul></ul>
  7. 7. Examples of applications (1/2) <ul><li>Person to person communication (e.g., voice, SMS) </li></ul><ul><li>Person to server (e.g., timetable consultation, telebanking) </li></ul><ul><li>Vehicles </li></ul><ul><ul><li>position via GPS </li></ul></ul><ul><ul><li>local ad-hoc network with vehicles close-by to prevent accidents, guidance system, adaptive cruise control </li></ul></ul><ul><ul><li>transmission of news, road condition, weather, music via Digital Audio Broadcasting </li></ul></ul><ul><ul><li>vehicle data (e.g., from buses, trains, aircrafts) transmitted for maintenance </li></ul></ul><ul><li>Disaster situations </li></ul><ul><ul><li>replacement of a fixed infrastructure in case of earthquakes, hurricanes, fire etc. </li></ul></ul><ul><li>Military networks </li></ul>
  8. 8. Typical application: road traffic ad hoc GSM, UMTS TETRA, ...
  9. 9. Examples of applications (2/2) <ul><li>Traveling salespeople </li></ul><ul><ul><li>direct access to customer files stored in a central location </li></ul></ul><ul><ul><li>consistent databases for all agents </li></ul></ul><ul><ul><li>mobile office </li></ul></ul><ul><li>Replacement of fixed networks </li></ul><ul><ul><li>Sensors </li></ul></ul><ul><ul><li>trade shows networks </li></ul></ul><ul><ul><li>LANs in historic buildings </li></ul></ul><ul><li>Entertainment, education, ... </li></ul><ul><ul><li>outdoor Internet access </li></ul></ul><ul><ul><li>travel guide with up-to-date location dependent information </li></ul></ul><ul><ul><li>ad-hoc networks for multi user games </li></ul></ul><ul><ul><li>Location-dependent advertising </li></ul></ul>Built 150BC
  10. 10. Location dependent services <ul><li>Location aware services </li></ul><ul><ul><li>what services, e.g., printer, fax, phone, server etc. exist in the local environment </li></ul></ul><ul><li>Follow-on services </li></ul><ul><ul><li>automatic call-forwarding, transmission of the actual workspace to the current location </li></ul></ul><ul><li>Information services </li></ul><ul><ul><li>„ push“: e.g., current special offers in the shop nearby </li></ul></ul><ul><ul><li>„ pull“: e.g., where is the closest Migros? </li></ul></ul><ul><li>Support services </li></ul><ul><ul><li>caches, intermediate results, state information etc. „follow“ the mobile device through the fixed network </li></ul></ul>
  11. 11. Modern mobile phones iPhone Quad band GSM (850, 900, 1800, 1900 MHz) GPRS/EDGE Tri band UMTS/HSDPA (850, 1900, 2100 MHz) GPS + accelerometers WiFi (802.11b/g) Bluetooth 2.0+EDR
  12. 12. Wireless enabled devices
  13. 13. Satellite Communications BTCC-45 Bluetooth GPS Receiver Global Positioning System (GPS) Orbit altitude: approx. 20,200 km Frequency: 1575.42 MHz (L1) Bit-rate: 50 bps CDMA Iridium 9505A Satellite Phone Supports 1100 concurrent phone calls Orbit altitude: approx. 780 km Frequency band: 1616-1626.5 MHz Rate: 25 kBd FDMA/TDMA Iridium Satellite
  14. 14. Wireless “Last Mile”: WiMax WiMAX GP3500-12 omnidirectional antenna Frequency band: 3400-3600 MHz Gain: 12 dBi Impendence: 50  Power rating: 10 Watt Vertical beamwidth: 10  WiMAX PA3500-18 directional antenna Frequency band: 3200-3800 MHz Gain: 12 dBi Impendence: 50  Power rating: 10 Watt Vertical beamwidth: 17  Horizontal beamwidth: 20 
  15. 15. Wireless sensors IEEE 802.15.4 Chipcon Wireless Transceiver Frequency band: 2.4 to 2.4835 GHz Data rate: 250 kbps RF power: -24 dBm to 0 dBm Receive Sensitivity: -90 dBm (min), -94 dBm (typ) Range (onboard antenna): 50m indoors / 125m ourdoors TelosB Sensor Mote MicaZ Imote2 Iris Mote Cricket Mote
  16. 16. Radio-frequency Identification (RFID) RFID tag SDI 010 RFID Reader ISO14443-A and B (13.56 MHz) Operating distance: 1cm Communication speed: up to 848 Kbit/s
  17. 17. Medical Implants Implantable Cardioverter Defibrillator (ICD) Operating frequency: 175kHz Range: few centimeters Medical Implant Communication Service (MICS) Frequency band: 402-405 MHz Maximum transmit power (EIRP): 25 microwatt Range: few meters
  18. 18. Vehicular communications Dedicated short-range communications (DSRC) Frequency band (US): 5.850 to 5.925 GHz Data rate: 6 to 27 Mbps Range: up to 1000m
  19. 19. Software Defined Radio Tuning Frequency: 30KHz - 30MHz (continuous) Tuning Steps: 1/5/10/50/100/500Hz & 1/5/9/10KHz Antenna Jacket / Impedance: BNC-socket / 50Ohms Max. Allowed Antenna Level : +10dBm typ. / saturation at -15dBm typ. Noise Floor (0.15-30MHz BW 2.3KHz): Standard: < -131dBm (0.06 μ V) typ. HighIP: < -119dBm (0.25 μ V) typ. Frequency Stability (15min. warm-up period): +/- 1ppm typ. Application: Cognitive Radios  Dynamic Spectrum Access
  20. 20. Mobile devices performance <ul><li>Pager </li></ul><ul><li>receive only </li></ul><ul><li>tiny displays </li></ul><ul><li>simple text messages </li></ul><ul><li>Mobile phones </li></ul><ul><li>voice, data </li></ul><ul><li>web access </li></ul><ul><li>location based services </li></ul><ul><li>PDA </li></ul><ul><li>simple graphical displays </li></ul><ul><li>character recognition </li></ul><ul><li>simplified WWW </li></ul><ul><li>Laptop </li></ul><ul><li>functionally eq. to desktop </li></ul><ul><li>standard applications </li></ul><ul><li>Wireless sensors </li></ul><ul><li>Limited proc. power </li></ul><ul><li>Small battery </li></ul><ul><li>RFID tag </li></ul><ul><li>A few thousands of logical gates </li></ul><ul><li>Responds only to the RFID reader requests (no battery) </li></ul>
  21. 21. Wireless networks in comparison to fixed networks <ul><li>Higher data loss-rates due notably to interferences </li></ul><ul><ul><li>emissions of e.g., engines, lightning, other wireless networks, micro-wave ovens </li></ul></ul><ul><li>Restrictive regulations of frequencies </li></ul><ul><ul><li>Usage of frequencies has to be coordinated, useful frequencies are almost all occupied </li></ul></ul><ul><li>Lower transmission rates </li></ul><ul><ul><li>From a few kbit/s (e.g., GSM) to a few 10s of Mbit/s (e.g. WLAN) </li></ul></ul><ul><li>Higher jitter </li></ul><ul><li>Lower security (higher vulnerability) </li></ul><ul><li>Radio link permanently shared  need of sophisticated MAC </li></ul><ul><li>Fluctuating quality of the radio links </li></ul><ul><li>Unknown and variable access points  authentication procedures </li></ul><ul><li>Unknown location of the mobile station  mobility management </li></ul>
  22. 22. History of wireless communication (1/3) <ul><li>Many people in History used light for communication </li></ul><ul><ul><li>heliographs, flags („semaphore“), ... </li></ul></ul><ul><ul><li>150 BC smoke signals for communication (Greece) </li></ul></ul><ul><ul><li>1794, optical telegraph, Claude Chappe </li></ul></ul><ul><li>Electromagnetic waves are of special importance: </li></ul><ul><ul><li>1831 Faraday demonstrates electromagnetic induction </li></ul></ul><ul><ul><li>J. Maxwell (1831-79): theory of electromagnetic Fields, wave equations (1864) </li></ul></ul><ul><ul><li>H. Hertz (1857-94): demonstrates with an experiment the wave character of electrical transmission through space (1886) </li></ul></ul>
  23. 23. History of wireless communication (2/3) <ul><li>1895 Guglielmo Marconi </li></ul><ul><ul><li>first demonstration of wireless telegraphy </li></ul></ul><ul><ul><li>long wave transmission, high transmission power necessary (> 200kw) </li></ul></ul><ul><li>1907 Commercial transatlantic connections </li></ul><ul><ul><li>huge base stations (30 to 100m high antennas) </li></ul></ul><ul><li>1915 Wireless voice transmission New York - San Francisco </li></ul><ul><li>1920 Discovery of short waves by Marconi </li></ul><ul><ul><li>reflection at the ionosphere </li></ul></ul><ul><ul><li>smaller sender and receiver, possible due to the invention of the vacuum tube (1906, Lee DeForest and Robert von Lieben) </li></ul></ul>
  24. 24. History of wireless communication (3/3) <ul><li>1928 Many TV broadcast trials (across Atlantic, color TV, TV news) </li></ul><ul><li>1933 Frequency modulation (E. H. Armstrong) </li></ul><ul><li>1946 First public mobile telephone service in 25 US cities (1 antenna per city…) </li></ul><ul><li>1976 Bell Mobile Phone service for NY city </li></ul><ul><li>1979 NMT at 450MHz (Scandinavian countries) </li></ul><ul><li>1982 Start of GSM-specification </li></ul><ul><ul><li>goal: pan-European digital mobile phone system with roaming </li></ul></ul><ul><li>1983 Start of the American AMPS (Advanced Mobile Phone System, analog) </li></ul><ul><li>1984 CT-1 standard (Europe) for cordless telephones </li></ul><ul><li>1992 Deployment of GSM </li></ul><ul><li>2002 Deployment of UMTS </li></ul><ul><li>2010 LTE standards mature, first trials </li></ul>
  25. 25. Wireless systems: development over the last 25 years cellular phones satellites wireless LAN cordless phones 1992: GSM 1994: DCS 1800 2001: UMTS/IMT-2000 CDMA-2000 (USA) 1987: CT1+ 1982: Inmarsat-A 1992: Inmarsat-B Inmarsat-M 1998: Iridium 1989: CT 2 1991: DECT 199x: proprietary 1997: IEEE 802.11 1999: 802.11b, Bluetooth 1988: Inmarsat-C analog digital 1991: D-AMPS 1991: CDMA 1981: NMT 450 1986: NMT 900 1980: CT0 1984: CT1 1983: AMPS 1993: PDC 2000: GPRS 2000: IEEE 802.11a,g NMT: Nordic Mobile Telephone DECT: Digital Enhanced Cordless Telecom. AMPS: Advanced Mobile Phone System (USA) DCS: Digital Cellular System CT: Cordless Telephone PDC: Pacific Digital Cellular UMTS: Universal Mobile Telecom. System PAN: Personal Area Network LTE: Long Term Evolution UMA: Universal Mobile Access 2005: VoIP-DECT 2010 LTE 2009: IEEE 802.11n 2010 UMA
  26. 26. Areas of research in mobile communication <ul><li>Wireless Communication </li></ul><ul><ul><li>transmission quality (bandwidth, error rate, delay) </li></ul></ul><ul><ul><li>modulation, coding, interference </li></ul></ul><ul><ul><li>media access </li></ul></ul><ul><ul><li>... </li></ul></ul><ul><li>Mobility </li></ul><ul><ul><li>location dependent services, also called location based services </li></ul></ul><ul><ul><li>location transparency </li></ul></ul><ul><ul><li>quality of service support (delay, jitter) </li></ul></ul><ul><ul><li>security </li></ul></ul><ul><ul><li>... </li></ul></ul><ul><li>Portability </li></ul><ul><ul><li>integration (“system on a chip”) </li></ul></ul><ul><ul><li>power consumption </li></ul></ul><ul><ul><li>limited computing power, sizes of display, ... </li></ul></ul><ul><ul><li>usability </li></ul></ul><ul><ul><li>... </li></ul></ul><ul><li>Security/privacy </li></ul>
  27. 27. Typical reference model Application Transport Network Data Link Physical Data Link Physical Application Transport Network Data Link Physical Data Link Physical Radio link Network Network
  28. 28. Influence of mobile communication on the layer model <ul><ul><li>location-dependent services </li></ul></ul><ul><ul><li>new applications, multimedia </li></ul></ul><ul><ul><li>adaptive applications </li></ul></ul><ul><ul><li>congestion and flow control </li></ul></ul><ul><ul><li>quality of service </li></ul></ul><ul><ul><li>addressing, routing, mobility management </li></ul></ul><ul><ul><li>hand-over </li></ul></ul><ul><ul><li>media access </li></ul></ul><ul><ul><li>multiplexing </li></ul></ul><ul><ul><li>modulation </li></ul></ul><ul><ul><li>power management, interference </li></ul></ul><ul><ul><li>attenuation </li></ul></ul><ul><ul><li>frequency allocation </li></ul></ul><ul><li>Application layer </li></ul><ul><li>Transport layer </li></ul><ul><li>Network layer </li></ul><ul><li>Data link layer </li></ul><ul><li>Physical layer </li></ul>security
  29. 29. Overlay Networks - the global view wide area metropolitan area campus-based in-house vertical hand-over horizontal hand-over Integration of heterogeneous fixed and mobile networks with varying transmission characteristics
  30. 30. Campus Application Contest <ul><li>NRC Lausanne is launching once again a contest for the best application! </li></ul><ul><li>Develop any application related to campus life on Nokia devices; e.g.: </li></ul><ul><ul><li>Menus of the day </li></ul></ul><ul><ul><li>Local public transport timetables </li></ul></ul><ul><ul><li>Map of the campus, guidance (also indoors) </li></ul></ul><ul><ul><li>Schedule of the different classes </li></ul></ul><ul><ul><li>Homeworks </li></ul></ul><ul><ul><li>Library services </li></ul></ul><ul><li>Win the latest Nokia devices (e.g. N900) and have your application pre-installed on all Nokia phones sold to the student’s community next Fall! </li></ul><ul><li>More information: </li></ul><ul><li>Register by email to [email_address] until March 19 th 2010 </li></ul>
  31. 31. References (in addition to the 2 recommended textbooks) <ul><li>B. Walke: Mobile Radio Networks , Wiley, Second Edition, 2002 </li></ul><ul><li>T. Rappaport: Wireless Communications , Prentice Hall, Second Edition, 2001 </li></ul><ul><li>M. Schwartz: Mobile Wireless Communications, Cambridge University Press, 2004 </li></ul><ul><li>L. Buttyan and JP Hubaux: Security and Cooperation in Wireless Networks, Cambridge University Press, 2008, </li></ul>