1. GSM Global System for Mobile communication

2. History GSM Global System for Mobile communication 1982 by ETSI
analog => digital
solve the compatibility problem
released to market in 1991
TDMA、FDMA

3. Components Mobile Station - SIM、Mobile phone Base Station System
- receiver
Mobile-service Switching Center
- the heart of the network

4. Features International Roaming Increase in capacity
- frequency hopping
Security
- frequency hopping、TDMA
- SIM (Subscriber Identity Module)
Digital Service Communication
- mobile data

5. Telecom & Datacom Circuit switch Packet switch MSC MS1 MS2 Internet PC3

6. Basic concept GSM 900/1800 - bandwidth: 890~960MHz/1710~1880MHz
- 0.2MHz per frequency carrier
- what’s different?
。distance
。power
。number of BS

7. Basic concept EM spectrum - GSM: 900/1800 MHz - Bluetooth: 2.4 GHz UV
Visible IR
Fibre communication
Satellite
Radar
UHF
Mobile communication AM
Radio FM
telephony
Wave length
Frequency
0.47m
0.76m
1cm
10cm 1m
10m
100m
1km
10km
100km
1015Hz
100GHz
1014Hz
10GHz
1GHz
100MHz
10MHz
1MHz
100KHz
10KHz
1KHz
GSM. Bluetooth
EM spectrum
- GSM:
900/1800 MHz
- Bluetooth:
2.4 GHz

8. FDMA Frequency Division Multiple Access Uplink Frequency carrier
0.2MHz
．．．．．．
124 carriers
890MHz
915MHz
935MHz
960MHz
Uplink
Downlink
Guard band
Frequency carrier

9. TDMA Only 124 people can access concurrently?!
Time Division Multiple Access
- 8 time slots per frequency carrier f
time
‧‧‧‧‧ 1 2 3 4

10. Cellular Telecommunications
124 * 8 = 992 connections are NOT enough!
Cell structure
36～53
1～17
18～35

11. Public telecom network
Communication system
BS3
BS1
BS2
MSC
LSC
CSIE CC
Mobil telecom network
Public telecom network