A method in a wireless terminal transceiver includes receiving a sequence of frames from a first base station, wherein each frame in the sequence contains a first set of time-frequency resources which may be used for scheduling data and a second set of time-frequency resources not used for scheduling data. The transceiver also receives a message from the first base station identifying a third set of time-frequency resources that is a subset of the first set of time-frequency resources, and estimates the channel state based on the transmission received in the third set of time-frequency resources.