A broadcast control channel (BCCH) is a point to multipoint, unidirectional (downlink) channel used in the Um interface of the GSM cellular standard.The BCCH carries a repeating pattern of system information messages that describe the identity, configuration and available features of the base transceiver station (BTS). These messages also provide a list of absolute radio-frequency channel numbers (ARFCNs) used by neighboring BTSs. This message pattern is synchronized to the BTS frame clock.[1] The minimum BCCH message set is system information messages 2–4, although other messages are normally present. The messages themselves are described in 3GPP Technical Specification 44.018.[2]
Any GSM ARFCN that includes a BCCH is designated as a beacon channel and is required to transmit continuously at full power.