A GSM network is made up of three subsystems:
• The Mobile Station (MS)
• The Base Station Sub-system (BSS) – comprising a BSC and several BTSs
• The Network and Switching Sub-system (NSS) – comprising an MSC and associated
registers
The interfaces defined between each of these sub systems include:
• 'A' interface between NSS and BSS
• 'Abis' interface between BSC and BTS (within the BSS)
• 'Um' air interface between the BSS and the MS
Abbreviations:
MSC – Mobile Switching Centre BSS – Base Station Sub-system
BSC – Base Station Controller HLR – Home Location Register
BTS – Base Transceiver Station VLR – Visitor Location Register
TRX – Transceiver AuC – Authentication Centre
MS – Mobile Station EIR – Equipment Identity Register
OMC – Operations and Maintenance Centre
PSTN – Public Switched Telephone Network
• The Mobile Station (MS)
• The Base Station Sub-system (BSS) – comprising a BSC and several BTSs
• The Network and Switching Sub-system (NSS) – comprising an MSC and associated
registers
The interfaces defined between each of these sub systems include:
• 'A' interface between NSS and BSS
• 'Abis' interface between BSC and BTS (within the BSS)
• 'Um' air interface between the BSS and the MS
Abbreviations:
MSC – Mobile Switching Centre BSS – Base Station Sub-system
BSC – Base Station Controller HLR – Home Location Register
BTS – Base Transceiver Station VLR – Visitor Location Register
TRX – Transceiver AuC – Authentication Centre
MS – Mobile Station EIR – Equipment Identity Register
OMC – Operations and Maintenance Centre
PSTN – Public Switched Telephone Network