GSM原理介绍.ppt

DCS1800 Primary Band
95 MHz
1710 1735 1760 1785 1800 1825 1850 1875
Freq Uplink ( Mobile to Base ) Downlink ( Base to Mobile )
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57
1
26 1
57
-70dB
10us 8us 10us 3
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Power Time Template
Power dB 0
-70 10 8 10
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Upper Limit
Actual
Lower Limit
(操作与维护中心) NMC- Network Management Centre (网络管理中心) AUC- Authentication Centre (鉴权中心) HLR- Home Location Register (归属位置寄存器) VLR- Visitors Location Register (来访位置寄存器)
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GSM900/DCS1800/PCS1900
Uplink Downlink ARFCN range
GSM 900 890 to 915MHz 935 to 960MHz 1 to 124
TX/RX Spacing (Freq.) TX/RX Spacing (Time) Modulation Data Rate Frame Period Timeslot Period Bit Period M odulation Channel Spacing TDMA Mux MS Max Power
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DCS1800 Frequency Range • 1710 - 1785 MHz Uplink / MS Transmit • 1805 - 1880 MHz Downlink / BS Transmit • Duplex Offset 95 MHz • Channel Spacing 200kHz • Channel numbering 512 - 885 • Transmission Speed 270 Kbits
13kbit/s
GSM 900 880 to 915MHz 925 to 960MHz 0 to 124 and 975 to 1023 45MHz
DCS1800 1710 to 1785MHz 1805 to 1880MHz 512 to 885
95MHz
8W 5dBm
13kbit/s 6.5kbit/s
EIR AUC HLR
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GSM Networks
Terminology: MS- Mobile Station (移动台) BSS- Base Station System (基站系统) BTS- Base Transceiver Station (基站收发台) BSC- Base Station Controller (基站控制器) MSC- Mobile Switching Centre (移动业务交换中心) OMC- Operations and Maintenance Centre
based on prototype evalution (1986) 1989 GSM becomes an ETSI technical committe 1990 The phase 1 GSM 900 specifications are finalized 1991 First systems are running 1992 All major European GSM 900 operators begin
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GSM Primary Band
45 MHz
890 900 910 920 930 940 950 960 Freq Uplink ( Mobile to Base ) Downlink ( Base to Mobile )
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RF Aspects
• TDMA • 0.3GMSK Modulation • Burst Power Transmission • Neighbour Cells Measurement • Hopping • Uplink / Downlink DTx • BER & Receiver Testing
-67.708KHz +67.708KHz Data Type ?0
Fc + 67.708KHz
Fc
Fc + 67.708KHz
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TDMA and FDMA
Physical Channel is an ARFCN and Timeslot
Amplitude
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GMSK Modulation
1 1 0 010
PSK
11 0 0 10
Guassian Filter
Spectrum < 200kHz
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Modulation
Data Type ?1
Uplink & Downlink
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 12 3 4 56 7 0 1 2 3 456 7 ARFCN DOWNLINK
45MHz
UPLINK ARFCN
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 0 3 4 5 6 70 1 23 45
542.8 us / 147 Bits Normal Burst
10 8 10
us Time
Power Time Template
Power dB 0
-70
Upper Limit
Actual
Lower Limit 87 bits
10 8 10 321.23 us / 87 Bits 10 8 10 Access Burst
( Groupe Special Mobile ) Global System for Mobile
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GSM
GSM Development History
1982 Groupe Special Mobile?is created within CEPT 1986 A Permanent Nucleus is set up 1987 Main radio transmission techniques are chosen,
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GSM TDMA Power Burst
+4dB -6dB
Tol +1.0dB Tol -1.0dB
-6dB
-30dB
147 Useful Bits 542.8us
-30dB
-70dB
10us 8us 10us 3
148 Active Bits, 546.42us
4
1
2
3
4
5
6
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7
6
5
4 Timeslot
3
2
1 Frequency 0 ARFCN
TDMA and FDMA
Terminology:
FDMA - Frequency Division Multiple Access
TDMA - Time Division Multiple Access
MS Min Power MS Power Control Steps Voice Coder Bit Rate
45MHz
3 Timeslots
270.833kbit/s
4.615ms 576.9us 3.692us 0.3GMSK 200KHz 8 20W( 8W is max in use) 13dBm 5 to 19
8W
4dBm 0 to 15
13kbit/s
Βιβλιοθήκη Baidu
DCS1800 1710 to 1785MHz 1805 to 1880MHz 512 to 885 95MHz
1W 0dBm 0 to 15 13kbit/s 6.5kbit/s
PCS1900 1850 to 1910MHz 1930 to 1990MHz 512 to 810 80MHz
. Uplink Lags Downlink by 3 Timeslot periods . Uplink and Downlink use same Timeslot Number . Uplink and Downlink use same Channel Number (ARFCN) . Uplink and Downlink use different bands(45MHz apart for GSM900)
commercial operator
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GSM / DCS1800 Functionalities
• Speech Services • Data Services • Short Message Services (SMS) • Supplementary Services • Subscriber Identity Module (SIM) • Security Function
1710.2
1710.4
200 kHz
1710.6
1710.8
DCS1800 band
Freq
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GSM Networks
ADC
NMC
BTS
BTS BSC
BTS
BSS
MS
BTS
BTS BSC
BTS
BSS
OMC
OMC
MSC
VLR
MSC
VLR
Interface to other network
ARFCN - Absolute RF Channel Number
TS
- Timeslot
Physical - The Combination of a TS number
Channels and ARFCN.
Logical - Are Mapped on Physical Channels
Channels
1W 0dBm 30,31,0 to 15 13kbit/s
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GSM Frequency Range • 890 - 915 MHz Uplink / MS Transmit • 935 - 960 MHz Downlink / BS Transmit • Duplex Offset 45 MHz • Channel Spacing 200kHz • Channel numbering 1 - 124 • Transmission Speed 270 Kbits
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us Time
Uplink & Downlink
Downlink / MS Receive
0 12 3 4 5 670 1 234 56 7
5 670 1 234 5 6 7 0 1 23 4
Uplink / MS Transmit
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Agenda
. GSM900/DCS1800 . The GSM Network & Air Interface . Technical Basics . Speech Coding . Types of Channel . Making a Phone Call
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Carriers at the border of the GSM band
890.2
890.4
200 kHz
890.6
GSM band
890.8
Freq
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Carriers at the border of the DCS1800 band
EIR- Equipment Identity Register (设备标识寄存器)
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Air Interface
GSM Interface
Abis Interface
SS#7
BTS
BSC
SS#7
BTS MS
BTS
BSC BSC
MSC
PSTN