BCCH is allocated on first timeslot of the first ARFCN in a cell. Opposed to the BCCH, the PBCCH can be configured on each timeslot of each ARFCN (there may be only 1 PBCCH per cell). PBCCH is NOT mandatory even if GPRS is provided in a cell, while BCCH is mandatory in a cell. If PBCCH exists, the GPRS mobile is only required to camp on the PBCCH to obtain cell info about GSM services. The information whether a PBCCH is allocated in a cell is broadcast in the System Information 13 message.