BSC:

The Base Station Controller is part of the BSS and interconnects a number of BTS's to the Network Switching Subsystem (NSS). The BTS's are connected to the BSC via the Abis-interface while a variable number of A-trunks connects a BSC to the MSC. Note that between BSC and MSC there is usually the TRAU.

The general architecture of a BSC is illustrated in the figure below.

Bsc.gif (24522 Byte)

Important Functions of the BSC:

The main function of the BSC is to relieve the MSC from most radio-related control functions that are required to operate a GSM network. Therefore, the functions of the BSC are as follows:

  • Allocation of circuit-switched radio resources to subscribers.
  • Processing of the circuit-switched measurement reports from mobile station and BTS in case of an ongoing transaction.
  • Processing of channel quality reports for idle channels.
  • Power Control for the BTS and the mobile station in uplink and downlink direction in case of an ongoing transaction.
  • Handover Decision (also in case of Inter-MSC Handovers !)
  • Permanent Storage of BTS operation software.
  • Permanent Storage of BTS site specific software.