GSM原理介绍英文).PPT

1、Agenda,. GSM900/DCS1800 . The GSM Network & Air Interface . Technical Basics . Speech Coding . Types of Channel . Making a Phone Call,Global System for Mobile,( Groupe Special Mobile ),G S M,1982Groupe Special Mobile?is created within CEPT 1986A Permanent Nucleus is set up 1987 Main radio transmissi

2、on techniques are chosen, based on prototype evalution (1986) 1989GSM becomes an ETSI technical committe 1990The phase 1 GSM 900 specifications are finalized 1991First systems are running 1992 All major European GSM 900 operators begin commercial operator,GSM Development History,Speech Services Data

3、 Services Short Message Services (SMS) Supplementary Services Subscriber Identity Module (SIM) Security Function,GSM / DCS1800 Functionalities,RF Aspects,TDMA 0.3GMSK Modulation Burst Power Transmission Neighbour Cells Measurement Hopping Uplink / Downlink DTx BER & Receiver Testing,GSM900/DCS1800/P

4、CS1900,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,DCS1800 Frequency Range,1710 - 1785 MHz Uplink / MS Transmit 1805 - 1880 MHz Downlink / BS Transmit Du

5、plex Offset 95 MHz Channel Spacing 200kHz Channel numbering 512 - 885 Transmission Speed 270 Kbits,GSM Primary Band,890,900,910,920,930,940,950,960,Freq,45 MHz,Uplink ( Mobile to Base ),Downlink ( Base to Mobile ),DCS1800 Primary Band,1710,1735,1760,1785,1800,1825,1850,1875,Freq,95 MHz,Uplink ( Mobi

6、le to Base ),Downlink ( Base to Mobile ),Carriers at the border of the GSM band,890.2,890.4,890.6,890.8,Freq,GSM band,200 kHz,Carriers at the border of the DCS1800 band,1710.2,1710.4,1710.6,1710.8,Freq,DCS1800 band,200 kHz,GSM Networks,BSC,BTS,BTS,BTS,BSS,BSC,BTS,BTS,BTS,BSS,MSC,MSC,OMC,OMC,ADC,NMC,

7、VLR,VLR,HLR,AUC,EIR,Interface to other network,MS,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 (操作与维护中心) NMC

8、- 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) EIR- Equipment Identity Register (设备标识寄存器),MSC,BSC,BSC,BSC,PSTN,BTS,BTS,BTS,Air Interface,Abis Interface,SS#7,SS#7,GSM Interface,MS,GMSK Modulation,1

9、,1,0,0,1,0,1,1,0,0,1,0,PSK,Guassian Filter,Spectrum 200kHz,Modulation,4,0,1,2,3,4,5,6,7,1,2,3,4,5,6,Frequency,Amplitude,ARFCN,Timeslot,Physical Channel is an ARFCN and Timeslot,TDMA and FDMA,TDMA and FDMA,Terminology: FDMA - Frequency Division Multiple Access TDMA - Time Division Multiple Access ARF

10、CN - Absolute RF Channel Number TS - Timeslot Physical - The Combination of a TS number Channels and ARFCN. Logical - Are Mapped on Physical Channels Channels,10us,10us,10us,10us,8us,8us,3,3,1,1,57,57,26,148 Active Bits, 546.42us,147 Useful Bits,542.8us,-70dB,-30dB,-6dB,+4dB,-6dB,-30dB,-70dB,Tol -1.

11、0dB,Tol +1.0dB,GSM TDMA Power Burst,Power Time Template,542.8 us / 147 Bits,10,8,10,10,8,10,Time,Power,-70,0,dB,Upper Limit,Lower Limit,Actual,us,Normal Burst,Power Time Template,321.23 us / 87 Bits,10,8,10,10,8,10,Time,Power,-70,0,dB,Upper Limit,Lower Limit,Actual,us,Access Burst,87 bits,Uplink & D

12、ownlink,Downlink / MS Receive,5,6,7,0,1,2,3,4,5,6,7,0,1,3,4,2,0,6,7,0,1,2,3,4,5,6,7,1,3,4,2,Uplink / MS Transmit,5,Uplink & Downlink,ARFCN,0,2,4,7,3,6,0,1,3,5,0,6,1,4,7,2,5,3,1,2,6,4,5,7,2,4,6,0,3,5,7,1,3,2,1,0,4,5,6,7,0,1,2,3,4,5,6,7,0,0,3,4,5,6,7,0,1,2,3,4,5,1,ARFCN,UPLINK,DOWNLINK,45MHz,. Uplink

13、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),Frequency Hopping,20ms Blocks,Speech Coder,Bits Ordered,260 Bits,260 Bits,50,132,78,. RELP and LT

14、P Coder RELP- Residual-Excited Linear Prediction Coder LTP- Long Term Prediction . Converts Speech to Low Data Rate . 20ms Speech makes 260Bits . Output 13kbit/s,Very Important Bits,Important Bits,Other Bits,Speech Coder,Error Correction,Type Ia 50,Type Ib 132,Type II 78,50,132,78,3,Type Ia,CRC,Type

15、 Ib,Type II,Block Code,25,66,25,66,3,4,78,Re-ordering,378,78,Half rate convolutional code,456 Bits from 20ms of Speech,Type Ia,Type Ib,Type Ib,Type Ia,Tail,Type II,CRC,262 Bits,In,456 Bits,Out,Diagonal Interleaving,456 Bits from 20ms of Speech,456 Bits from 20ms of Speech,57,57,57,57,57,57,57,57,57,

16、57,57,57,57,57,57,57,57,57,57,57,57,57,57,57,57,57,57,57,57,57,TCH,Traffic Channel (TCH) Bursts Carry Two 57 Bits Blocks (114) Each 120ms of Speech = 456x6 = 2736 bits 2736/114 = 24 bursts I.e. 24frames(mobile transmits once per frame) Multiframe has 26 frames in 120ms There are 2 spare frames厖 One

17、SACCH, one Idle,Speech to Radio / Radio to Speech,Channel coding,Speech,Digitizing and Source coding,Interleaving,Burst formatting,Ciphering,Modulation,Channel decoding,Speech,Source decoding,De-interleaving,Burst formatting,Deciphering,Demodulation,MS Camp on Flow Chart,MS Turn On,MS searches chann

18、els and orders by signal strength,FCCH on BCCH and adjusts timebase,SCH on BCCH and fine tunes timebase & timing,Decode BCCH & store info,MS Next Stongest BCCH,YES,NO,YES,NO,NO,Location = Previous Location?,YES,YES,MS camped on - listens for page, can request service,Using SACCH - adjust power, TA &

19、 report RX Qual etc,MS sends RACH,BS assigns SDCCH to MS using the CCCH,Orignated Call,MS sends RACH,BS ORIGINATED CALL,MS ORIGINATED CALL,MS transmits and receives speech on TCH,TCH,Using the SDCCH, authentication, call setup, and TCH assignment,Using the SACCH, BS commands MS to adust power + timi

20、ng, MS reports power + Rx quality of BCCH + adjacent BCCH,MS transmits + receives speech on TCH,Using the SACCH on TCH, MS reports power + Rx quality , BS commands MS to adjust power ,TA,Call disconnected by MS or BS,Subscriber Identity Module ( SIM ),SIM contains ( at least ) following information : IMSI (International M