Base Station SubSystem (BSS)

Base Station Subsystem is composed of two parts that communicate across the standardized Abis interface allowing operation between components made by different suppliers:
1. Base Transceiver Station (BTS)
2. Base Station Controller (BSC)
Base Transceiver Station (BTS):
Encodes, Encrypts, Multiplexes, Modulates and Feeds the RF signals to the antenna.
Frequency hopping.
Communicates with Mobile station and BSC.
Consists of Transceivers (TRX) units.
Base Station Controller (BSC):
Manages Radio resources for BTS.
Assigns Frequency and time slots for all MS’s in its area.
Handles call set up.
Transcoding and rate adaptation functionality.
Radio Power control.
It communicates with MSC and BTS.