Channel and TRX Mapping on GSM

Channel and TRX Mapping on GSM On GSM, each cell have TRX, typically one BTS have 3 cell. Each TRX carrying channel for TCH, signalling and packet data. One TRX divided into 8 sub timeslot. Each sub timeslot have a 16 kbps and can be configure as BCCH channel, or traffic channel (voice and data). BCCH configure only one in a cell, and configure in first TRX on first channel.

For, BTS with 3 sector and each sector have 4 trx, we can see the timeslot mapping below.

1 E1 divided in to 32 timeslot, from 0 to 31 and the capacity is 64 kbps. for timeslot 0 used for synchronization and timeslot 16 used for signaling. Each TRX take 2 time slot in E1 system. You might also like: