gsm overview

GSM OVERVIEW

Others ….

MSC

BTS

BSC

BTS PSTN

BTSISDN

SS#7MS

MS

MS

MS

MS

MS

Mobile Station

Base Transceiver

Station

Base Station

Controller

Mobile Service

Switching Center

Visitor Location Register

Home Location Register

Authentication

Center

Equipment Identity Register

GMSCUser

HLR

MSCVLRDirectory

NumberRoutingNumber

RoutingNumber

DirectoryNumber

GMSC handling of a domestic call

GMSC

ÑÒNH NGHÓA CAÙC SOÁ VAØ NHAÄN DAÏNG TRONG HEÄ THOÁNG GSM Soá ISDN cuûa traïm di ñoäng MSISDN

MSISDN = CC+ NDC+ SN

Soá löu ñoäng cuûa maùy di ñoäng MSRN(Mobile Station Roaming Number).

MSRN = CC + NDC + SN

Nhaän daïng thueâ bao di ñoäng quoác teá IMSI (International Mobile Subscriber identity)

IMSI = MCC + MNC + MSIN.

Nhaän daïng thueâ bao di ñoäng taïm thôøi TMSI (Temporary Mobile Subscriber Identity)  

Nhaän daïng thieát bò cuûa traïm di ñoäng quoác teá IMEI (International Mobile Equipment Identity) 

IMEI = TAC + FAC + SNR + SP 

Nhaän daïng vuøng ñònh vò LAI (Location Area Identity) 

LAI = MCC + MNC + LAC 

Nhaän daïng oâ toaøn caàu (CGI) (Cell Global Identity) 

CGI = MCC + MNC + LAC + CI

Maõ nhaän daïng traïm goác (BSIC) (Base Station Identity Code)

 BSIC = NCC + BCC.

Authentication & Encryption

Authentication & Encryption

Radio S

ubsystem

RPE-LTPencoder

RPE-LTPdecoder

13 bit uniform to 8 bit A-Law

8 bit A-Law to 13 bit uniform

MS

C

PSTN/

ISDN

104 kbps13 kbps

8000 samples/s13-bit uniform

code

Analoguespeech

8000 samples/s13-bit uniform

code

8000 samples/s8-bit A-Law

ITU-T G.711, G.712,G.713, G.714

RPE-LTPencoder

RPE-LTPdecoder

13 bit uniform to Analogue

O/P

Analogue to 13 bit uniform

I/P

104 kbps 64 kbps13 kbps

System Description

Radio Access & Demod

GMSK

De-Interleaving

Forward Error

CodingInterleaving

Radio Access & ModGMSK

InterleavingForward

Error Coding

Error Correction

Radio Access & ModGMSK

Error Correction

De-Interleaving

Radio Access & Demod

GMSK

Dup Dup

Encoded speech456 bits/frame 20ms

Encoded speech456 bits/frame 20ms

22.8kbps 22.8kbps13 kbps 13 kbps

System Description

Signalling in GSM network

OAM

LAPD

BTS

MTP2

SCCP

MTP3

LAPD

OAM

RR

DTAP

BSSMAP

BSSAP

BSC

MTP1

MTP3

MTP2

SCCP

MTP2

MTP3

SCCP

BSSAPDTAP/

BSSMAP

TCAP

MM

CM MAP

NSS

RR

MM

CM

MS

UmInterface

A bisInterface

AInterface

GSM Specification

Access methodAccess method TDMA/FDMATDMA/FDMA

Frequency band (MS to BS)Frequency band (MS to BS) 890 - 915 MHz890 - 915 MHz

Frequency band (BS to MS)Frequency band (BS to MS) 935 - 960 MHz935 - 960 MHz

Channel bandwidthChannel bandwidth 200 kHz200 kHz

ModulationModulation GMSKGMSK

Bit rateBit rate 270.833 kbps270.833 kbps

FilterFilter BT = 0.3 (Gaussian)BT = 0.3 (Gaussian)

Voice channel codingVoice channel coding RPE-LPC Convolutional 13 kbpsRPE-LPC Convolutional 13 kbps

Frequency HoppingFrequency Hopping Slow hopping (217 hops/s)Slow hopping (217 hops/s)

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