1. GSM OVERVIEW Others …. MSC BTS BSC BTS PSTN BTS ISDN SS#7 M S M S M S M S M S M S
2. Mobile Station Base Transceiver Station Base Station Controller Mobile Service Switching Center Visitor Location Register Home Location Register Authentication Center Equipment Identity Register
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15. GMSC GMSC User HLR MSC VLR Directory Number Routing Number Routing Number Directory Number GMSC handling of a domestic call
19. System Description Radio Subsystem RPE-LTP encoder RPE-LTP decoder 13 bit uniform to 8 bit A-Law 8 bit A-Law to 13 bit uniform MSC PSTN / ISDN 104 kbps 13 kbps 8000 samples/s 13-bit uniform code Analogue speech 8000 samples/s 13-bit uniform code 8000 samples/s 8-bit A-Law ITU-T G.711, G.712, G.713, G.714 RPE-LTP encoder RPE-LTP decoder 13 bit uniform to Analogue O/P Analogue to 13 bit uniform I/P 104 kbps 64 kbps 13 kbps
20. System Description Radio Access & Demod GMSK De- Interleaving Forward Error Coding Interleaving Radio Access & Mod GMSK Interleaving Forward Error Coding Error Correction Radio Access & Mod GMSK Error Correction De- Interleaving Radio Access & Demod GMSK Dup Dup Encoded speech 456 bits/frame 20ms Encoded speech 456 bits/frame 20ms 22.8kbps 22.8kbps 13 kbps 13 kbps
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22. Signalling in GSM network O A M L A P D BTS MTP2 SCCP MTP3 L A P D O A M R R D T A P B S S M A P BSSAP BSC MTP1 MTP3 MTP2 SCCP MTP2 MTP3 SCCP BSSAP DTAP/ BSSMAP T C A P MM CM M A P NSS R R MM CM MS LAPDm LAPDm RADIO RADIO PCM PCM PCM E1 T1 ISUP/TUP Um Interface A bis Interface A Interface
23. GSM Specification Access method TDMA/FDMA Frequency band (MS to BS) 890 - 915 MHz Frequency band (BS to MS) 935 - 960 MHz Channel bandwidth 200 kHz Modulation GMSK Bit rate 270.833 kbps Filter BT = 0.3 (Gaussian) Voice channel coding RPE-LPC Convolutional 13 kbps Frequency Hopping Slow hopping (217 hops/s)
