Base Transceiver StationEach BTS coverage to a specific area. Here is a geographical BTS:

Cell
An area served by one BTS. MS will differentiate each cell that is by using the BSIC (Base Station Identification Code).

Local Area (LA)
The combination of several cell. One local area is also a region where pagging message emanating Subscriber to find it's correct. In one LA, there are more than one BTS, depending on one or more of the BSC and one still in the MSC / VLR.

PLMN service area (Public Line Mobile Network)
The combination of some of LA, which provides telecommunications service.

GSM service area
Regional network interconnection services, the GSM network.

MSC service area:
A geographic area from the GSM network coverage area is served by one MSC. Each MS can enter this area when it is registered in the VLR (Visitor Location Register) BTS is a radio device that is required to serve one cell. BTS system contain antenna, RF Power Amplifiers and Digital Equipment Signalling.