wireless communication session 1...
TRANSCRIPT
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About this course The course is about the system aspects of Wireless communication.
Therfore, it covers:- Radio propagation models
- Fading and other effects channel in wireless channel.
- modulation and equalization techniques
- Cellular concept
- Frequency reuse and channel allocation algorithms
- Networking issues (MAC, network and transport layer, principale)
It does not cover:- Antenna Design
- Propagation waves differential equations (Maxwell Equation)
- 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 802.11 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”
Text books
http://www.inf.fu-berlin.de/inst/ag-tech/resources/mobkom/mobile_communications.htm
- J. Schiller: Mobile Communications, Second EditionAddison-Wesley, 2004
- W. Stallings: Wireless Communications & Networks, Second Edition, Prentice Hall, 2005
http://www.WilliamStallings.com/Wireless/Wireless2e.html
- Andrea Goldsmith : Wireless CommunicationsStanford University Press, 2004
- M. Schwartz: Mobile Wireless CommunicationsCambridge University Press, 2005
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 802.11 or “WiFi”)
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., location-based services, timetable consultation, telebanking)
Vehiclesposition 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 situationsreplacement of a fixed infrastructure in case of earthquakes,
hurricanes, fire etc.
Military networks
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Upcoming application: road traffic
GSM, UMTSTETRA, ...
http://ivc.epfl.chhttp://www.sevecom.org
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Examples of applications (2/2)
Traveling salespeopledirect access to customer files stored in a central location
consistent databases for all agents
mobile office
Replacement of fixed networksSensors
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
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Location dependent services
Location aware serviceswhat services, e.g., printer, fax, phone, server etc. exist in the
local environment
Follow-on servicestransmission 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 servicescaches, intermediate results, state information etc. „follow“ the
mobile device through the fixed network
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 2.1
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 9505A Satellite Phone
Iridium Satellite
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 ourdoors
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
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 readerrequests (no battery)
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Wireless networks in comparison to fixed networks
Higher data loss-rates due notably to interferencesemissions of e.g., engines, lightning, other wireless networks, micro-
wave ovens
Restrictive regulations of frequenciesUsage of frequencies has to be coordinated, useful frequencies are
almost all occupied (or at least reserved)
Lower transmission ratesFrom 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
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History of wireless communication (1/3)
Many people in History used light for communicationheliographs, 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 (> 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-specificationgoal: 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
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
2010LTE
2009:IEEE 802.11n
2010UMA
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Areas of research in mobile communication
Wireless Communicationtransmission quality (bandwidth, error rate, delay)
modulation, coding, interference
media access
...
Mobilitylocation dependent services, also called location based services
location transparency
quality of service support (delay, jitter)
security
...
Portabilityintegration (“system on a chip”)
power consumption
limited computing power, sizes of display, ...
usability
...
Security/privacy
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Typical 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, 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
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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)
B. Walke: Mobile Radio Networks, Wiley, Second Edition, 2002
T. Rappaport: Wireless Communications, PrenticeHall, Second Edition, 2001
D. Tse and P. Viswanath: Fundamentals of Wireless Communication, Cambridge University Press, 2005