1 Mobile Networks EPFL Prof. Jean-Pierre Hubaux XXX

2 About this course  The course is about the system aspects of mobile networking  Therefore, it covers: - networking issues (MAC, network and transport layers, principally) - estimation of network capacity and resource management - wireless security/privacy issues  It does not cover: - radio propagation models - modulation and equalization techniques - source or channel coding - speech coding or other signal processing aspects - software-centric aspects (e.g., operating systems, mobile agents, smart phone programming)  It is focused on mechanisms, and avoids as much as possible a detailed (and boring) description of standards  However, it does propose an insight on IEEE and on the security of WLANs and cellular networks  Acronyms are abundant and we have to cope with them…  The course is also an attempt to get closer to the “real world”  Heterogeneity of the audience

3 Web site Of particular relevance: - Calendar - Material (all slides used at the lectures, homeworks,…) - Previous exams

Recommended book 4 D. P. Agrawal and Q.-A. Zeng Introduction to Wireless and Mobile Systems Third Edition, 2011 Cengage (hard copy or e-book)

5 Other Textbooks - J. Schiller: Mobile Communications, Second Edition Addison-Wesley, W. Stallings: Wireless Communications & Networks, Second Edition, Prentice Hall, L. Buttyan and JP Hubaux: Security and Cooperation in Wireless Networks Cambridge University Press, M. Schwartz: Mobile Wireless Communications Cambridge University Press, 2005

6 Module A – Introduction (Part A1)

Wireless communication and mobility  Aspects of mobility: user mobility: users communicate “anytime, anywhere, with anyone” device portability: devices can be connected anytime, anywhere to the network  Wireless vs. mobile Examples  stationary computer (desktop)  Cable-Internet laptop in a hotel wireless LANs in historic buildings smart phone  The demand for mobile communication creates the need for integration of wireless networks or mobility mechanisms into existing fixed networks: telephone network  cellular telephony (e.g., GSM, UMTS, LTE) local area networks  Wireless LANs (e.g., IEEE or “WiFi”) Internet  Mobile IP

8 Examples of applications (1/2)  Person to person communication (e.g., voice, SMS)  Person to server (e.g., location-based services, timetable consultation, telebanking)  Vehicles position via GPS local ad-hoc network with vehicles close-by to prevent accidents, guidance system, adaptive cruise control transmission of news, road condition, weather, music via Digital Audio Broadcasting vehicle data (e.g., from buses, trains, aircrafts) transmitted for maintenance  Disaster situations replacement of a fixed infrastructure in case of earthquakes, hurricanes, fire etc.  Military networks

9 Upcoming application: road traffic ad hoc GSM, UMTS TETRA,

10 Examples of applications (2/2)  Traveling salespeople direct access to customer files stored in a central location consistent databases for all agents mobile office  Replacement of fixed networks Sensors trade shows networks LANs in historic buildings  Entertainment, education,... outdoor Internet access travel guide with up-to-date location dependent information ad-hoc networks for multi user games Location-dependent advertising Built 150BC

11 Location dependent services  Location aware services what services, e.g., printer, fax, phone, server etc. exist in the local environment  Follow-on services transmission of the actual workspace to the current location  Information services „push“: e.g., current special offers in the shop nearby „pull“: e.g., where is the closest Migros?  Support services caches, intermediate results, state information etc. „follow“ the mobile device through the fixed network  Location-Based Services (LBSs) Foursquare, Facebook Mobile,…

12 Quad band GSM (850, 900, 1800, 1900 MHz) GPRS/EDGE Tri band UMTS/HSDPA (850, 1900, 2100 MHz) LTE GPS + accelerometers WiFi (802.11b/g/a/n) Bluetooth Modern mobile phones

13 Wireless enabled devices

14 Satellite Communications BTCC-45 Bluetooth GPS Receiver European attempt: Galileo Global Positioning System (GPS) 30 satellites currently Orbit altitude: approx. 20,200 km Frequency: MHz (L1) Bit-rate: 50 bps CDMA Iridium 9555 Satellite Phone Supports 1100 concurrent phone calls Orbit altitude: approx. 780 km Frequency band: MHz Rate: 25 kBd FDMA/TDMA

15 WiMAX GP omnidirectional antenna Frequency band: MHz Gain: 12 dBi Impendence: 50  Power rating: 10 Watt Vertical beamwidth: 10  WiMAX PA directional antenna Frequency band: MHz Gain: 12 dBi Impendence: 50  Power rating: 10 Watt Vertical beamwidth: 17  Horizontal beamwidth: 20  Wireless “Last Mile”: WiMax

16 IEEE Chipcon Wireless Transceiver Frequency band: 2.4 to 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 outdoors TelosB Sensor Mote MicaZ Imote2 Wireless sensors Iris Mote Cricket Mote

17 RFID tag SDI 010 RFID Reader ISO14443-A and B (13.56 MHz) Operating distance: 1cm Communication speed: up to 848 Kbit/s Radio-frequency Identification (RFID)

18 Implantable Cardioverter Defibrillator (ICD) Medical Implants Operating frequency: 175kHz Range: few centimeters Medical Implant Communication Service (MICS) Frequency band: MHz Maximum transmit power (EIRP): 25 microwatt Range: few meters

19 Vehicular communications 19 Dedicated short-range communications (DSRC) Frequency band (US): to GHz Data rate: 6 to 27 Mbps Range: up to 1000m

20 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 ( MHz BW 2.3KHz): Standard: < -131dBm (0.06μV) typ. HighIP: < -119dBm (0.25μV) typ. Frequency Stability (15min. warm-up period): +/- 1ppm typ. Software Defined Radio Application: Cognitive Radios  Dynamic Spectrum Access

21 Mobile devices performance Pager receive only tiny displays simple text messages Mobile phones voice, data web access location based services PDA simple graphical displays character recognition simplified WWW Laptop functionally eq. to desktop standard applications Wireless sensors Limited proc. power Small battery RFID tag A few thousands of logical gates Responds only to the RFID reader requests (no battery)

22 Wireless networks in comparison to fixed networks  Higher data loss-rates due notably to interferences emissions of e.g., engines, lightning, other wireless networks, micro- wave ovens  Restrictive regulations of frequencies Usage of frequencies has to be coordinated, useful frequencies are almost all occupied (or at least reserved)  Lower transmission rates From a few kbit/s (e.g., GSM) to a 100s of Mbit/s (e.g. WLAN)  Higher jitter  Lower security (higher vulnerability)  Radio link permanently shared  need of sophisticated MAC  Fluctuating quality of the radio links  Unknown and variable access points  authentication procedures  Unknown location of the mobile station  mobility management

23 History of wireless communication (1/3)  Many people in History used light for communication heliographs, flags („semaphore“), BC smoke signals for communication (Greece) 1794, optical telegraph, Claude Chappe  Electromagnetic waves are of special importance: 1831 Faraday demonstrates electromagnetic induction J. Maxwell ( ): theory of electromagnetic Fields, wave equations (1864) H. Hertz ( ): demonstrates with an experiment the wave character of electrical transmission through space (1886)

24 History of wireless communication (2/3)  1895 Guglielmo Marconi first demonstration of wireless telegraphy long wave transmission, high transmission power necessary (> 200kw)  1907 Commercial transatlantic connections huge base stations (30 to 100m high antennas)  1915 Wireless voice transmission New York - San Francisco  1920 Discovery of short waves by Marconi reflection at the ionosphere smaller sender and receiver, possible due to the invention of the vacuum tube (1906, Lee DeForest and Robert von Lieben)

25 History of wireless communication (3/3)  1928 Many TV broadcast trials (across Atlantic, color TV, TV news)  1933 Frequency modulation (E. H. Armstrong)  1946 First public mobile telephone service in 25 US cities (1 antenna per city…)  1976 Bell Mobile Phone service for NY city  1979 NMT at 450MHz (Scandinavian countries)  1982 Start of GSM-specification goal: pan-European digital mobile phone system with roaming  1983 Start of the American AMPS (Advanced Mobile Phone System, analog)  1984 CT-1 standard (Europe) for cordless telephones  1992 First deployment of GSM  2002 First deployment of UMTS  LTE standards mature, first trials

Wireless systems: development over the last 25 years cellular phonessatellites wireless LANcordless phones 1992: GSM 1994: DCS : UMTS/IMT-2000 CDMA-2000 (USA) 1987: CT : Inmarsat-A 1992: Inmarsat-B Inmarsat-M 1998: Iridium 1989: CT : DECT 199x: proprietary 1997: IEEE : b, Bluetooth 1988: Inmarsat-C analog digital 1991: D-AMPS 1991: CDMA 1981: NMT : NMT : CT0 1984: CT1 1983: AMPS 1993: PDC 2000: GPRS 2000: IEEE a,g NMT: Nordic Mobile TelephoneDECT: Digital Enhanced Cordless Telecom. AMPS: Advanced Mobile Phone System (USA)DCS: Digital Cellular System CT: Cordless TelephonePDC: Pacific Digital Cellular UMTS: Universal Mobile Telecom. SystemPAN: Personal Area Network LTE: Long Term EvolutionUMA: Universal Mobile Access 2005: VoIP-DECT 2012 LTE 2009: IEEE n 2010 UMA

27 Areas of research in mobile communication  Wireless Communication transmission quality (bandwidth, error rate, delay) modulation, coding, interference media access...  Mobility location dependent services, also called location based services location transparency quality of service support (delay, jitter) security...  Portability integration (“system on a chip”) power consumption limited computing power, sizes of display,... usability...  Security/privacy

28 Reference model Application Transport Network Data Link Physical Data Link Physical Application Transport Network Data Link Physical Data Link Physical Network Radio link

29 Influence of mobile communication on the layer model location-dependent services new applications, multimedia adaptive applications congestion and flow control quality of service addressing, routing, mobility management hand-over media access multiplexing modulation power management, interference attenuation frequency allocation  Application layer  Transport layer  Network layer  Data link layer  Physical layer security

30 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

31 References (in addition to the recommended textbooks)  B. Walke: Mobile Radio Networks, Wiley, Second Edition, 2002  T. Rappaport: Wireless Communications, Prentice Hall, Second Edition, 2001  A. Goldsmith: Wireless Communications, Cambridge University Press, 2005  D. Tse and P. Viswanath: Fundamentals of Wireless Communication, Cambridge University Press, 2005