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Mobile NetworksEPFL

Prof. Jean-Pierre Hubaux

http://mobnet.epfl.ch XXX

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About this courseg The course is about the system aspects of mobile networkingg Therefore, it covers:

- networking issues (MAC, network and transport layers, principally)- estimation of network capacity and resource management- wireless security/privacy issues

g 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)

g It is focused on mechanisms, and avoids as much as possible a detailed (and boring) description of standards

g However, it does propose an insight on IEEE 802.11 and on the security of WLANs and cellular networks

g Acronyms are abundant and we have to cope with them…g The course is also an attempt to get closer to the “real world”g Heterogeneity of the audience

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Web site

http://mobnet.epfl.ch/

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

Recommended book

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D. P. Agrawal and Q.-A. Zeng

Introduction to Wireless and Mobile Systems

Third Edition, 2011Cengage

(hard copy or e-book)

Other Textbooks

http://www.inf.fu-berlin.de/inst/ag-tech/resources/mobkom/mobile_communications.htm

- J. Schiller: Mobile Communications, Second Edition Addison-Wesley, 2004

- W. Stallings: Wireless Communications & Networks, Second Edition, Prentice Hall, 2005

http://www.WilliamStallings.com/Wireless/Wireless2e.html

- L. Buttyan and JP Hubaux: Security and Cooperation in Wireless NetworksCambridge University Press, 2008

http://secowinet.epfl.ch

- M. Schwartz: Mobile Wireless Communications Cambridge University Press, 2005

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Module A – Introduction(Part A1)

Wireless communication and mobility

g Aspects of mobility:user mobility: users communicate “anytime, anywhere, with anyone”device portability: devices can be connected anytime, anywhere to the

network

g Wireless vs. mobile Examples stationary computer (desktop) Cable-Internet laptop in a hotel wireless LANs in historic buildings smart phone

g 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 802.11 or “WiFi”)Internet Mobile IP

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Examples of applications (1/2)

g Person to person communication (e.g., voice, SMS)g Person to server (e.g., location-based services, timetable

consultation, telebanking)g Vehicles

position via GPSlocal ad-hoc network with vehicles close-by to prevent accidents,

guidance system, adaptive cruise controltransmission of news, road condition, weather, music via Digital Audio

Broadcastingvehicle data (e.g., from buses, trains, aircrafts) transmitted for

maintenance g Disaster situations

replacement of a fixed infrastructure in case of earthquakes, hurricanes, fire etc.

g Military networks

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Upcoming application: road traffic

ad ho

cGSM, UMTSTETRA, ...

http://ivc.epfl.chhttp://www.sevecom.org

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Examples of applications (2/2)

g Traveling salespeopledirect access to customer files stored in a central locationconsistent databases for all agentsmobile office

g Replacement of fixed networksSensorstrade shows networksLANs in historic buildings

g Entertainment, education, ...outdoor Internet access travel guide with up-to-date

location dependent informationad-hoc networks for

multi user gamesLocation-dependent advertising

Built

150BC

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Location dependent services

g Location aware serviceswhat services, e.g., printer, fax, phone, server etc. exist in the local

environment

g Follow-on servicestransmission of the actual workspace to the current location

g Information services„push“: e.g., current special offers in the shop nearby

„pull“: e.g., where is the closest Migros?

g Support servicescaches, intermediate results, state information etc. „follow“ the

mobile device through the fixed network

g Location-Based Services (LBSs)Foursquare, Facebook Mobile,…

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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

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Wireless enabled devices

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Satellite Communications

BTCC-45 Bluetooth GPS Receiver

European attempt: Galileo

Global Positioning System (GPS)30 satellites currently

Orbit altitude: approx. 20,200 kmFrequency: 1575.42 MHz (L1)

Bit-rate: 50 bpsCDMA

Iridium 9555 Satellite Phone

Supports 1100 concurrent phone callsOrbit altitude: approx. 780 km

Frequency band: 1616-1626.5 MHzRate: 25 kBdFDMA/TDMA

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WiMAX GP3500-12 omnidirectional antenna

Frequency band: 3400-3600 MHzGain: 12 dBi

Impendence: 50 Power rating: 10 Watt

Vertical beamwidth: 10

WiMAX PA3500-18 directional antennaFrequency band: 3200-3800 MHz

Gain: 12 dBiImpendence: 50

Power rating: 10 WattVertical beamwidth: 17

Horizontal beamwidth: 20

Wireless “Last Mile”: WiMax

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IEEE 802.15.4 Chipcon Wireless TransceiverFrequency band: 2.4 to 2.4835 GHz

Data rate: 250 kbpsRF 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

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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)

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Implantable Cardioverter Defibrillator (ICD)

Medical Implants

Operating frequency: 175kHzRange: few centimeters

Medical Implant Communication Service (MICS)Frequency band: 402-405 MHz

Maximum transmit power (EIRP): 25 microwattRange: few meters

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Vehicular communications

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Dedicated short-range communications (DSRC)Frequency band (US): 5.850 to 5.925 GHz

Data rate: 6 to 27 MbpsRange: up to 1000m

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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 (0.06μV) typ.

HighIP: < -119dBm (0.25μV) typ.Frequency Stability (15min. warm-up

period):+/- 1ppm typ.

Software Defined Radio

Application: Cognitive Radios Dynamic Spectrum Access

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Mobile devices

performanceperformance

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)

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Wireless networks in comparison to fixed networks

g Higher data loss-rates due notably to interferencesemissions of e.g., engines, lightning, other wireless networks, micro-

wave ovensg Restrictive regulations of frequencies

Usage of frequencies has to be coordinated, useful frequencies are almost all occupied (or at least reserved)

g Lower transmission ratesFrom a few kbit/s (e.g., GSM) to a 100s of Mbit/s (e.g. WLAN)

g Higher jitterg Lower security (higher vulnerability)g Radio link permanently shared need of sophisticated MACg Fluctuating quality of the radio linksg Unknown and variable access points authentication

proceduresg Unknown location of the mobile station mobility management

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History of wireless communication (1/3)

g Many people in History used light for communicationheliographs, flags („semaphore“), ...150 BC smoke signals for communication

(Greece)1794, optical telegraph, Claude Chappe

g Electromagnetic waves are of special importance:1831 Faraday demonstrates electromagnetic inductionJ. Maxwell (1831-79): theory of electromagnetic Fields, wave

equations (1864)H. Hertz (1857-94): demonstrates

with an experiment the wave character of electrical transmission through space(1886)

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History of wireless communication (2/3)

g 1895 Guglielmo Marconifirst demonstration of wireless

telegraphy

long wave transmission, high transmission power necessary (> 200kw)

g 1907 Commercial transatlantic connectionshuge base stations

(30 to 100m high antennas)g 1915 Wireless voice transmission New York - San Franciscog 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)

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History of wireless communication (3/3)

g 1928 Many TV broadcast trials (across Atlantic, color TV, TV news)

g 1933 Frequency modulation (E. H. Armstrong)g 1946 First public mobile telephone service in 25 US cities (1

antenna per city…)g 1976 Bell Mobile Phone service for NY city g 1979 NMT at 450MHz (Scandinavian countries)g 1982 Start of GSM-specification

goal: pan-European digital mobile phone system with roamingg 1983 Start of the American AMPS (Advanced Mobile Phone

System, analog) g 1984 CT-1 standard (Europe) for cordless telephonesg 1992 First deployment of GSMg 2002 First deployment of UMTSg 2010 - 2013 LTE standards mature, first trials

Wireless systems: development over the last 25 years

cellular phones satellites wireless LANcordlessphones

1992:GSM

1994:DCS 1800

2001:UMTS/IMT-2000

CDMA-2000 (USA)

1987:CT1+

1982:Inmarsat-A

1992:Inmarsat-BInmarsat-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 SystemCT: Cordless Telephone PDC: Pacific Digital CellularUMTS: Universal Mobile Telecom. System PAN: Personal Area NetworkLTE: Long Term Evolution UMA: Universal Mobile Access

2005:VoIP-DECT

2012LTE

2009:IEEE 802.11n

2010UMA

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Areas of research in mobile communicationg Wireless Communication

transmission quality (bandwidth, error rate, delay)modulation, coding, interferencemedia access...

g Mobilitylocation dependent services, also called location based serviceslocation transparencyquality of service support (delay, jitter)security...

g Portabilityintegration (“system on a chip”)power consumptionlimited computing power, sizes of display, ...usability...

g Security/privacy

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Reference model

Application

Transport

Network

Data Link

Physical

Data Link

Physical

Application

Transport

Network

Data Link

Physical

Data Link

Physical

Network Network

Radiolink

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Influence of mobile communication on the layer model

location-dependent services

new applications, multimediaadaptive applicationscongestion and flow controlquality of serviceaddressing, routing, mobility managementhand-overmedia accessmultiplexing

modulationpower management, interferenceattenuationfrequency allocation

g Application layer

g Transport layer

g Network layer

g Data link layer

g Physical layer

security

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Overlay Networks - the global view

wide area

metropolitan area

campus-based

in-house

verticalhand-over

horizontalhand-over

Integration of heterogeneous fixed andmobile networks with varyingtransmission characteristics

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References (in addition to the recommended textbooks)

g B. Walke: Mobile Radio Networks, Wiley, Second Edition, 2002

g T. Rappaport: Wireless Communications, Prentice Hall, Second Edition, 2001

g A. Goldsmith: Wireless Communications,Cambridge University Press, 2005

g D. Tse and P. Viswanath: Fundamentals of Wireless Communication, Cambridge University Press, 2005