A method is provided for maintaining synchronization between an AT and a base station during an idle period. During the idle period, a reduced number of uplink reference signals for uplink channel quality estimation are sent to the base station by the AT. The uplink reference signals are sent to assist coherent demodulation and uplink channel quality estimation for scheduling. During the uplink idle period, the numbers of uplink reference signals are designed to be reduced in selective coherent bandwidths. The selection of the coherent bandwidth alternates in time and covers the entire spectrum to allow the channel quality estimation through the entire spectrum.