BSC

• Base station controller[edit]

  The base station controller (BSC) provides, classically, the intelligence behind the BTSs. Typically a BSC has tens or even hundreds of BTSs under its control. The BSC handles allocation of radio channels, receives measurements from the mobile phones, and controls handovers from BTS to BTS (except in the case of an inter-BSC handover in which case control is in part the responsibility of the anchor MSC). A key function of the BSC is to act as a concentrator where many different low capacity connections to BTSs (with relatively low utilisation) become reduced to a smaller number of connections towards the mobile switching center (MSC) (with a high level of utilisation). Overall, this means that networks are often structured to have many BSCs distributed into regions near their BTSs which are then connected to large centralised MSC sites.
  The BSC is undoubtedly the most robust element in the BSS as it is not only a BTS controller but, for some vendors, a full switching center, as well as an SS7 node with connections to the MSC and serving GPRS support node (SGSN) (when using GPRS). It also provides all the required data to the operation support subsystem (OSS) as well as to the performance measuring centers.
  A BSC is often based on a distributed computing architecture, with redundancy applied to critical functional units to ensure availability in the event of fault conditions. Redundancy often extends beyond the BSC equipment itself and is commonly used in the power supplies and in the transmission equipment providing the A-ter interface to PCU.
  The databases for all the sites, including information such as carrier frequencies, frequency hopping lists, power reduction levels, receiving levels for cell border calculation, are stored in the BSC. This data is obtained directly from radio planning engineering which involves modelling of the signal propagation as well as traffic projections.
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• Paging, specifically call handling
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• Location updation
• Handover management
• Billing for all subscribers based in its area
• Reallocation of frequencies to BTSs in its area to meet heavy demands
• Echo canceller operation control
• Signaling interface to databases like HLR, VLR.
• Gateway to SMS between SMS centers and subscribers
• Handle interworking function while working as GMSC

FUNCTIONS OF BSC

• It is connected to BTS and offloads MSC
• Radio resource management
• Inter-cell handover
• Reallocation of frequencies
• Power control
• Time delay measurement of the received signals from MS with respect to BTS clock.
• Performs traffic concentration to reduce the number of lines from BSC to MSC.
• BSC performs call processing
• TRAU are generally located at the site of MSC.
• BSC- BTS configurations as per requirement.
• Data from OMC and can be down loaded to BSC