Patent ID: 8675586

Claim:
A wireless device which sends data to user terminals on a down stream and receives data from user terminals on an up stream, the device comprising: a controller configured to allocate up stream bursts to one or more of a plurality of user terminals, the controller allocating a particular set of subcarriers for a particular number of symbols for each of the one or more user terminals and allocating sufficient symbols per subcarrier per burst to allow each of the one or more user terminals to send two or more pilots per subcarrier per burst, calculate a channel transfer function estimate based on each pilot received for each subcarrier during a burst and compare the estimates over the burst to determine if the channel has changed over the course of the burst, and if the comparison indicates that the channel is changing within the burst, the controller adjusts the channel transfer function estimate over time for that subcarrier: and a transceiver which transmits information to the plurality of user terminals using orthogonal frequency division multiple access (OFDMA) and receives two or more pilots per subcarrier per burst from the one or more of the plurality of user terminals.