broadcast control channel

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.{{cite web | title = GSM 3GPP Technical Specification 45.002 (Section 6.3.1.3)| publisher = 3rd Generation Partnership Project (3GPP ) | url = http://www.3gpp.org/ftp/Specs/html-info/45002.htm | accessdate = 2010-05-10}} 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.{{cite web | title = GSM 3GPP Technical Specification 44.018 (sections 9.1.31-9.1.43k)| publisher = 3rd Generation Partnership Project (3GPP ) | url = http://www.3gpp.org/ftp/Specs/html-info/44018.htm | accessdate = 2010-05-10}}

Any GSM ARFCN that includes a BCCH is designated as a beacon channel and is required to transmit continuously at full power.