FCCH - Frequency Correction Channel

FCCH is propagated by the BTS to syncronize the frequencies for downlink and Uplink. It negociate the ARFCN being used between BTS and Mobile Station.

The Frequency Correction Channel (FCCH) is a special downlink channel used in GSM networks.

It serves primarily to synchronize the frequency of the mobile station with that of the base transceiver station (BTS).

When a mobile station is powered on, it initially listens for the FCCH to fine-tune its internal oscillator.

This ensures that the mobile station's transmissions are aligned correctly to the network's frequencies, allowing for accurate signal reception and reducing interference.