Oma000001 Gsm Fundamentals Issue2.0

M900/M1800 GSM SYSTEM

BSC Training Document

OMA000001 GSM Fundamentals ISSUE2.0

[pic]

Huawei Technologies CO.,Ltd.

Training Center

Contents

1 GSM Fundamentals 1

1.1 Basic Concepts of Cellular Mobile System 2

1.2 GSM Network Components 7

1.3 Terrestrial Interface 28

1.4 Service Area and Number Planning 38

1.5 Channels on The Air Interface 52

1.6 Radio Technologies 69

1.7 The Future Development 79

GSM Fundamentals

[pic]

1 Basic Concepts of Cellular Mobile System

[pic]

[pic]

[pic]

Each cell in the Cellular Network requires a RF carrier. A RF carrier is a pair of radio frequencies. One is used in each direction (including transmitting and receiving) so that information may be passed in both directions simultaneously.

The frequency spectrum allocated for cellular system is only a narrow bandwidth. The bandwidth for the GSM system is 25MHz. The transmitting and receiving frequencies in GSM are separated by 45MHz to avoid interference. The frequency bandwidth used for the downlink (from base station to MS) is 935-960MHz. The frequency bandwidth for the uplink (from MS to base station) is 890-915MHz. The channel bandwidth is 200KHz.

Considering the interference to other systems, the very first carrier is not used. Thus, there are only 124 RF carriers in the GSM frequency band.

[pic]

The bandwidth for the DCS1800 system is 75MHz. The transmitting and receiving frequencies in DCS1800 are separated by 95MHz to avoid interference.

The frequency bandwidth used for the downlink (from base station to MS) is 1805-1880MHz. The frequency bandwidth for the uplink (from MS to base station) is 1710-1785MHz.

The channel bandwidth is 200KHz just the same as GSM. Due to interference to other systems, the very first carrier is still not used. Thus, there are 374 RF...