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The Wireless Communication System. Xihan Lu. Wireless Communication. Cellular phone system Cordless telephone system Bluetooth Infrared communication Microwave communication IEEE Wireless LANs (Wi-Fi) Satellite communication. Why “ Cellular ” ?. Three Generations. AMPS NMT TACS

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Wireless communication
Wireless Communication

  • Cellular phone system

  • Cordless telephone system

  • Bluetooth

  • Infrared communication

  • Microwave communication

  • IEEE Wireless LANs (Wi-Fi)

  • Satellite communication


Why cellular
Why “Cellular”?


Three generations
Three Generations

AMPS

NMT

TACS

HCMTS

GSM

GPRS

WCDMA

CDMA2000

TD SCDMA

1G

2G

3G


1G

  • Start early 80’s

  • Analogue technique

  • AMPT (Advanced Mobile Phone System): North America

  • NMT (Nordic Mobile Telephony):North Europe

  • TACS (Total Access Communication Service):Europe, China

  • HCMTS (High Capacity Mobile Telephone System):Japan


FDMA

  • Frequency Division Multiple Access

  • Different carrier frequencies are assigned to different traffic channels(speech)

  • One carrier frequency can only carry one single speech channel at one time



Shortage
Shortage

  • Voice information only

  • Unsafe (eavesdropping)

  • Waste of frequency resource


2G

  • Start early 90’s

  • Digital technique

  • GSM : Global System of Mobilephone

  • GPRS : General Packet Radio Service

  • D-AMPS : Digital AMPS


GSM

  • TD/FDMA: A mix of FDMA and TDMA

  • The whole useable spectrum was divided to many 200k Hz carrier frequencies —FD

  • Each carrier was divided into 8 timeslots (burst) —TD

  • Each burst is assigned to a user(a logical traffic channel)

  • One carrier frequency can carry up to 8 logical traffic channels (voice or data) at the same time

  • The maximum data communication rate is 14.4 kbps




Bts bsc and msc
BTS,BSC and MSC

  • BTS & BSC: Base Transceiver System and Base Station Controller. Radio signal transceiver, a connection between handset and MSC

  • MSC: Mobile services Switching Center, switching center of the GSM network, and connect to other networks


Databases
Databases

  • HLR : Home Location Register, contains static information of subscribers and location update data

  • VLR : Visitor Location Register, embedded in MSC to avoid delay, contains current location information of handsets

  • AUC : Authentication Center, stores secret keys for authentication and encryption of the radio channel

  • EIR : Equipment Identity Register, contains a list of all valid mobile equipment in the network, by its International Mobile Equipment Identity (IMEI)


GPRS

  • Upgrade of existed GSM network

  • Improves the data communication ability



Network nodes
Network nodes

  • GGSN: Gateway GSM Support Node,

  • Protocol transferring, data encapsulation, a connection to external networks

  • SGSN: Service GSM Support Node,

  • Communicate with HLR and mobile handsets, authorization and admission control, charging, mobility management


Data communications
Data communications

  • In GSM, one user occupies one traffic channel to exchange voice/data information

  • In GPRS, up to 8 traffic channels(a whole carrier) can be dynamically combined together for one data communication application

  • The theoretically maximum data transmission rate: 14.4k bps * 8 = 115.2k bps


Advantages of gprs
Advantages of GPRS

  • Higher data rate

  • Seamless connection to internet

  • Packet switching rather than circuit switch, bandwidth is only used when the data is actually used, even though it is always connected

  • A primary step to 3G


Shortage1
shortage

  • Not fast enough for the multimedia service

  • The data rate falls when the network is busy

  • Upgrade of handset



3g standards
3G-Standards

  • Three CDMA standards approved by ITU:

  • Direct Spread CDMA(WCDMA) : Europe, Japan

  • Multi-Carrier CDMA(CDMA 2000) : North America

  • TD-Synchronous CDMA(CDMA TDD) : Europe, China


3g cdma
3G-CDMA

  • Code Division Multi Address

  • Spread spectrum technology

  • Each single traffic channel occupies the whole spectrum, but distinguished by a unique digital code

  • Walsh code: an orthogonal 64 bit pattern, unique in the network



Features
Features

  • Better voice quality

  • Up to 2 Mbps data communication rate

  • Increase battery life

  • Soft hand-off

  • Excellent data safety

  • More effective spectrum usage than 2G




References
References

  • www.gsmworld.com/technology/gprs/index.html

  • www.3gsmamericas.com/pdfs/EOF_Cannes_2003/Nortel_David_Smith.pdf

  • http://www.fcc.gov/Bureaus/Wireless/Reports/fcc98091.pdf

  • www.rogers.com

  • http://www.itu.int/ITU-D/ict/publications/wtdr_99/material/glossary.html

  • www.itu.int/home/imt.html

  • http://www.boeschatt.at/Mobil/mobilfunk_html.php?gsm_netzarchitektur.php

  • http://www.pt.com/products/gsmintro.html


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