Techniques for efficiently deriving uplink channel estimates without consuming much additional uplink resources are described. A user equipment (UE) may send a request for uplink resources on a request channel (REQCH) whenever the UE desires to transmit data on the uplink. The UE may send the REQCH on a set of subcarriers and from multiple antennas, e.g., send REQCH data on data subcarriers and pilot on pilot subcarriers. A Node B may receive the request, estimate the complex channel gains for the pilot subcarriers based on received pilot symbols, and coherently demodulate received data symbols based on the channel gain estimates. The Node B may estimate the complex channel gains for the data subcarriers based on demodulated data symbols and derive a channel estimate for each UE antenna based on the channel gain estimates for the pilot and data subcarriers. The Node B may use the channel estimates for MIMO scheduling, subband scheduling, and rate selection.
