Gsm
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GSM BY: PRASHANT CSE-2
GSM
INTRODUCTION GSM FACTS GOALS OF GSM SERVICES & FEATURES SYSTEM ARCHITECTURE CHANNEL TYPES FRAME STRUCTURE SIGNAL PROCESSING
INTRODUCTION • GSM :- ESTI standard for 2G pan- European digital cellular with international roaming. • Developed to solve the fragmentation problem of first cellular system. • First introduced in European market in 1991.
GSM F ACTS - Used in over 170 countries - Over 400 GSM network operators GSM - Over 550 million 550 People Were million subscribers to GSM
TDMA pdk CDMA 90 million
GO AL S OF G SM • • • • • •
Improved spectrum efficiency High quality speech International roaming Low cost mobile set & base station Support for new services Compatibility with ISDN & other telephone company services
SER VICE S User servi ce s : # Telephone services - emergency calling & facsimile. # Bearer services or data services – packet switched protocols data rates from 300bps to 9.6kbps. # Supplementary ISDN services – call diversion , caller identification SMS
FEATURES • SIM :- Memory device stores information( subscriber’s identification no. , networks , countries) • On air privacy :- made possible by encrypting the digital bit stream sent by GSM transmitter
SYS TEM ARCHI TECTUR E
Consist of three major parts : # base transceiver station # base station controller # the transcoder & adaptation unit
SYS TEM ARCH ITECTU RE HLR
VLR
AUC
BSC
PSTN
MSC BSC
ISDN
DATA OMC
BASE STATION SUBSYSTEM
NETWORK SWITCHING SUBSYSTEM
PUBLIC NETWORK
BASE
TRAN SRECI VER STATI ON
- Serves a single cell - Usually placed in center of a cell - Coding - Crypting - Multiplexing - Modulating - synchronizing
BASE STATI ON CO NTR OLLER BTS
BSC
• Translates the 13 kbps voice • Frequency hopping • Time and frequency • Power management • Time delay measurement
To MSC 2 mbps
Abis
UNIT
TRA NS CODE R & AD APT ATION
• (13 kbps speech or data + 3 kbps additional synchronizing data) *4 = 64 kbps (TRAU) standard rate BSD
64 kbps
TRAU MSC
in
The va rio us i nte rfa ces u sed GS M
MS BTS BTS
BSC
MSC
MS BTS
SS7 A interface (standardized)
GSM radio air interface
Abis interface
PSTN
FRA ME STRU CTU RE 6.12
SUPERFRAME
51 MULTIFRAME 120
MULTI
26 FRAME
FRAME 4.615 FRAME
T M
0
1
2
4
3
5
6
8 TIME
7
SLOTS
576.92 3
57
1
26
1
57
3
8.25
SI GN AL PROC ESSI NG • • • • •
Speech coding Channel coding for data channels Channel coding for control channels Interleaving Ciphering
SPEECH
SPEECH
Digitizing & source coding
Source decoding
Channel coding
Channel decoding
interleaving
De- interleaving
Burst formatting
Burst formatting
ciphering
modulation GSM o per ation s
De- ciphering Radio channel
fro m s peec h
demodulation inp ut to s pee ch
CONCLUSION
GSM
INTRODUCTION GSM FACTS GOALS OF GSM SERVICES & FEATURES SYSTEM ARCHITECTURE CHANNEL TYPES FRAME STRUCTURE SIGNAL PROCESSING
INTRODUCTION • GSM :- ESTI standard for 2G pan- European digital cellular with international roaming. • Developed to solve the fragmentation problem of first cellular system. • First introduced in European market in 1991.
GSM F ACTS - Used in over 170 countries - Over 400 GSM network operators GSM - Over 550 million 550 People Were million subscribers to GSM
TDMA pdk CDMA 90 million
GO AL S OF G SM • • • • • •
Improved spectrum efficiency High quality speech International roaming Low cost mobile set & base station Support for new services Compatibility with ISDN & other telephone company services
SER VICE S User servi ce s : # Telephone services - emergency calling & facsimile. # Bearer services or data services – packet switched protocols data rates from 300bps to 9.6kbps. # Supplementary ISDN services – call diversion , caller identification SMS
FEATURES • SIM :- Memory device stores information( subscriber’s identification no. , networks , countries) • On air privacy :- made possible by encrypting the digital bit stream sent by GSM transmitter
SYS TEM ARCHI TECTUR E
Consist of three major parts : # base transceiver station # base station controller # the transcoder & adaptation unit
SYS TEM ARCH ITECTU RE HLR
VLR
AUC
BSC
PSTN
MSC BSC
ISDN
DATA OMC
BASE STATION SUBSYSTEM
NETWORK SWITCHING SUBSYSTEM
PUBLIC NETWORK
BASE
TRAN SRECI VER STATI ON
- Serves a single cell - Usually placed in center of a cell - Coding - Crypting - Multiplexing - Modulating - synchronizing
BASE STATI ON CO NTR OLLER BTS
BSC
• Translates the 13 kbps voice • Frequency hopping • Time and frequency • Power management • Time delay measurement
To MSC 2 mbps
Abis
UNIT
TRA NS CODE R & AD APT ATION
• (13 kbps speech or data + 3 kbps additional synchronizing data) *4 = 64 kbps (TRAU) standard rate BSD
64 kbps
TRAU MSC
in
The va rio us i nte rfa ces u sed GS M
MS BTS BTS
BSC
MSC
MS BTS
SS7 A interface (standardized)
GSM radio air interface
Abis interface
PSTN
FRA ME STRU CTU RE 6.12
SUPERFRAME
51 MULTIFRAME 120
MULTI
26 FRAME
FRAME 4.615 FRAME
T M
0
1
2
4
3
5
6
8 TIME
7
SLOTS
576.92 3
57
1
26
1
57
3
8.25
SI GN AL PROC ESSI NG • • • • •
Speech coding Channel coding for data channels Channel coding for control channels Interleaving Ciphering
SPEECH
SPEECH
Digitizing & source coding
Source decoding
Channel coding
Channel decoding
interleaving
De- interleaving
Burst formatting
Burst formatting
ciphering
modulation GSM o per ation s
De- ciphering Radio channel
fro m s peec h
demodulation inp ut to s pee ch
CONCLUSION
