Mobile Networking Prof. JeanPierre Hubaux http:mobnet.epfl.ch

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Mobile NetworkingProf. Jean-Pierre
Hubauxhttp//mobnet.epfl.ch
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About this course

• The course is about the system aspects of mobile
  networking
• Therefore, it covers
• networking issues (MAC and routing, principally)
• wireless security issues
• estimation of network capacity and resource
  management
• 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., mobile agents)
• It is focused on mechanisms, and avoids a
  detailed (and boring) description of standards
• However, it does propose an insight on IEEE
  802.11

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Course outline/calendar and textbook
http//mobnet.epfl.ch/index.php?pagecalendar
- J. Schiller Mobile Communications, Second
Edition Addison-Wesley, 2004
http//www.inf.fu-berlin.de/inst/ag-tech/resources
/mobkom/mobile_communications.htm

• W. Stallings Wireless Communications
  Networks, Second Edition, Prentice Hall, 2005
• http//www.WilliamStallings.com/Wireless/Wireless2
  e.html

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Module A Introduction(Part A1)
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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) ? ? notebook
  in a hotel ? ? wireless LANs in historic
  buildings ? ? Personal Digital Assistant
  (PDA)
• 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)
• local area networks ? Wireless LANs (e.g., IEEE
  802.11)
• Internet ? Mobile IP

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Examples of applications (1/2)

• Person to person communication (e.g., voice, SMS)
• Person to server (e.g., 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

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Typical application road traffic
GSM, UMTS TETRA, ...
ad hoc
http//ivc.epfl.ch http//www.sevecom.org
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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-datelocation dependent
  information
• ad-hoc networks formulti user games
• Location-dependent advertising

Built 150BC
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Location dependent services

• Location aware services
• what services, e.g., printer, fax, phone, server
  etc. exist in the local environment
• Follow-on services
• automatic call-forwarding, 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

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Mobile devices

• Laptop
• functionally eq. to desktop
• standard applications

• Wireless sensors
• Limited proc. power
• Small battery

• Mobile phones
• voice, data
• simple text displays

• RFID tag
• A few thousands of logical gates
• Responds only to the RFID reader requests
  (no battery)

• Pager
• receive only
• tiny displays
• simple text messages

• PDA
• simple graphical displays
• character recognition
• simplified WWW

performance
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Wireless networks in comparison to fixed networks

• Higher data loss-rates due to 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
• Lower transmission rates
• From a few kbit/s (e.g., GSM) to a few 10s 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

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History of wireless communication (1/3)

• Many people in History used light for
  communication
• heliographs, flags (semaphore), ...
• 150 BC smoke signals for communication(Greece)
• 1794, optical telegraph, Claude Chappe
• Electromagnetic waves are of special importance
• 1831 Faraday demonstrates electromagnetic
  induction
• J. Maxwell (1831-79) theory of electromagnetic
  Fields, wave equations (1864)
• H. Hertz (1857-94) demonstrateswith an
  experiment the wave character of electrical
  transmission through space(1886)

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History of wireless communication (2/3)

• 1895 Guglielmo Marconi
• first demonstration of wireless telegraphy
• long wave transmission, high transmission power
  necessary (gt 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)

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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 Deployment of GSM
• 2002 Deployment of UMTS

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Wireless systems development over the last 25
years
wireless LAN
cordlessphones
cellular phones
satellites
1980CT0
1981 NMT 450
1982 Inmarsat-A
1983 AMPS
1984CT1
1986 NMT 900
1987CT1
1988 Inmarsat-C
1989 CT 2
1991 DECT
1991 D-AMPS
1991 CDMA
1992 GSM
1992 Inmarsat-B Inmarsat-M
199x proprietary
1993 PDC
1997 IEEE 802.11
1994DCS 1800
1998 Iridium
What is missing ?
1999 802.11b, Bluetooth
2000GPRS
2000 IEEE 802.11a,g
analogue
2001 UMTS/IMT-2000 CDMA-2000 (USA)
digital
2005 2010 (?) Fourth Generation (Internet
based)
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
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Areas of research in mobile communication

• Wireless Communication
• transmission quality (bandwidth, error rate,
  delay)
• modulation, coding, interference
• media access
• ...
• Mobility
• location dependent 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
• ...

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Reference model
Application
Application
Transport
Transport
Network
Network
Data Link
Data Link
Data Link
Data Link
Physical
Physical
Physical
Physical
Radio link
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Influence of mobile communication on the layer
model

• Application layer
• Transport layer
• Network layer
• Data link layer
• Physical layer

• 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

security
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Overlay Networks - the global view
Integration of heterogeneous fixed andmobile
networks with varyingtransmission characteristics
wide area
vertical hand-over
metropolitan area
campus-based
horizontal hand-over
in-house
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References (in addition to the 2 recommended
textbooks)

• B. Walke Mobile Radio Networks, Wiley, Second
  Edition, 2002
• T. Rappaport Wireless Communications, Prentice
  Hall, Second Edition, 2001
• M. Schwartz Mobile Wireless Communications,
  Cambridge University Press, 2004
• L. Buttyan and JP Hubaux Security and
  Cooperation in Wireless Networks, Cambridge
  University Press, 2007, http//secowinet.epfl.ch