gsm global system for mobile communication b89902008 徐士璿 b89902014 陳致穎 b89902015...

GSM Global System for Mobile communication

B89902008 徐士璿B89902014 陳致穎B89902015 江致和

Shih-hsuan Hsu. NTU CSIE, 2003 Spring

History

GSM Global System for Mobile communication

1982 by ETSIanalog => digital

solve the compatibility problem

released to market in 1991

TDMA、 FDMA


Components

Mobile Station- SIM、Mobile phone

Base Station System- receiver

Mobile-service Switching Center- the heart of the network


Features

International Roaming Increase in capacity

- frequency hopping

Security- frequency hopping、 TDMA

- SIM (Subscriber Identity Module)

Digital Service Communication- mobile data


Telecom & Datacom

Circuit switch

Packet switch

MSCMS1 MS2

Internet

PC

PC

1 2 3

1 2 3

123 123


Basic concept

GSM 900/1800- bandwidth: 890~960MHz/1710~1880MHz

- 0.2MHz per frequency carrier

- what’s different?

。 distance

。 power

。 number of BS


Basic concept

EM spectrum- GSM:

900/1800 MHz

- Bluetooth:

2.4 GHz

UV

Visible

IR

Fibre communication

SatelliteRadar

UHFMobile communication

AMRadioFM

telephony

Wave length Frequency

0.47m

0.76m

1cm

10cm

1m

10m

100m 1km

10km

100km

1015Hz

100GHz

1014Hz

10GHz

1GHz

100MHz

10MHz

1MHz

100KHz

10KHz

1KHz

GSM. Bluetooth


FDMA

Frequency Division Multiple Access

0.2MHz ．．．．．．

124 carriers

0.2MHz 0.2MHz

890MHz 915MHz

0.2MHz ．．．．．．

124 carriers

0.2MHz 0.2MHz

935MHz 960MHz

Uplink

Downlink

Guard band

Frequency carrier


TDMA

Only 124 people can access concurrently?!

Time Division Multiple Access- 8 time slots per frequency carrier

f

time

‧‧‧‧‧1 2 3 4 1 2 3 4


Cellular Telecommunications

124 * 8 = 992 connections are NOT enough! Cell structure

36～ 53

1 ～ 17

18～ 35

36～ 53

1 ～ 17

18～ 35


Communication system

BS3BS1

BS2MSC

MSC

LSC

LSC

CSIE

CCBS3

BS1BS2

Mobil telecom network Public telecom network

gsm global system for mobile communication b89902008 徐士璿 b89902014 陳致穎 b89902015...

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