03.643GPPGeneral Packet Radio Service (GPRS)Overall description of the GPRS radio interfaceStage 2TS
The MS shall use the PTCCH and idle frames of the PDCH multiframe for the following tasks:
– BSIC identification for cell re-selection (22.214.171.124)
– Continuous timing advance procedures (126.96.36.199)
– Interference measurements for power control (188.8.131.52.2)
It is not necessary to exactly specify the scheduling of these tasks.
The PTCCH frames used for timing advance signalling is stated in 184.108.40.206.1. During the frames when the MS receives TA-messages it can also make interference measurements. During the frames when the MS transmits access bursts it may also be possible to make measurements on some channels.
The MS shall schedule the BSIC identification as efficiently as possible, using the remaining PTCCH frames and the idle frames and also considering the requirements for interference measurements. When the MS is synchronised to a BTS, it knows the timing of the SCH. Therefore, only a few certain frames are required for BSIC identification. In those frames it may also be possible to make measurements on some channels. When the MS shall synchronise to a new BTS, it has to prioritise that task. It may then use half of the PTCCH and idle frames, i.e. the same amount as available for circuit switched connections.
The remaining PTCCH and idle frames shall be used for interference measurements.