Frequency Correction Channel

A Broadcast Channel (BCH) is a downlink channel in a GSM system that is used by the base stations to provide signalling information to the mobile stations . The mobile station needs this information to find a network, synchronize with it and to connect to it.

A broadcast control channel (BCCH) is a point to multipoint, unidirectional (downlink) channel used in the Um interface of the GSM cellular standard .

SACCH stands for Slow Associated Control Channel and SDCCH stands for Stand Alone Dedicated Control Channel . SDCCH is the channel used for exchange of signaling messages between GSM mobile and network(base station). This is used for pure signaling purpose or establishing traffic connection.