A channel estimation technique for OFDM systems in dispersive time-varying channels

Coherent modulation is more appropriate than differential modulation for orthogonal frequency division multiplexing (OFDM) systems requiring high data rate and spectral efficiency. Channel estimation is therefore required as an integral part of the receiver design. An iterative maximum likelihood-based channel estimation algorithm for an OFDM system in dispersive time-varying channels is proposed. The multipath fading channel is modeled such that the channel state can be determined by estimating the unknown channel parameters. A second-order Taylor series expansion is adopted to simplify the channel estimation problem. The performance of the proposed algorithm is analyzed and numerical experiments are performed to confirm the theoretical analysis.