Channel Estimation and Bit-loading in Wireless Multicarrier Systems Based on Decimated Signal Feedback

We present an effective time domain method for channel identification in wireless orthogonal frequency division multiplexing (OFDM) systems. Generalizing a novel bent-pipe mechanism, the mobile receiver decimates and returns (a fraction of) its received data back to the base station. Both the downlink and uplink channel impulse response can be estimated at the base OFDM transmitter. With knowledge of the downlink channel response, the resource rich base station can employ effective adaptive modulation schemes to exploit the channel capacity. In this paper we analyze the impact of various feedback parameters on channel estimation performance. Numerical simulation results are provided to verify the effectiveness of the approach.