BTS–Base Transceiver Station

BTS provides physical connection of an MS to the network in the form of Air Interface.
On the other side BTS connected to BSC thru Abis-interface.
Cabinet size is reduced substantially from 1991 to current.
Functionality and basic structure largely unchanged.
A BTS cabinet can have up to 16 TRX (GSM recommendation)

TRX – Most important module of BTS from signal processing point of view

Consists of a low frequency part for signal processing and a high frequency part for modulation/demodulation.

Both parts are connected by a separate or integrated Frequency hopping unit.
All other parts of BTS are associated with TRX and perform auxiliary or admin tasks.