Abstract: Doppler frequency offsets in rapid mobile environments result in both the fast fading of radio channels and intercarrier interference (ICI) in Orthogonal Frequency Division Multiplexing (OFDM) systems. In order to combat the impact of ICI on OFDM systems in fast fading channels, an ICI mitigation technique is proposed in this paper. The symbol shift cancellation method is used to cancel the impact of ICI on the far sub-carriers, then the adjacent sub-channel filter method is used to cancel the impact of ICI on the adjacent sub-carriers, and the fast fading channel is tracked and estimated by comb-type pilot-symbol scheme. By utilizing the distribution of the adjacent intercarrier interference after shift cancellation, the channel response matrix and adjacent interference filter method are simplified, and a special training pilot scheme is proposed to improve the accuracy of channel estimation. The proposed algorithm can achieve trade-off between the bandwidth efficiency and the complexity of ICI cancellation method. Simulation results show that the proposed technique can effectively improve BER performance of the OFDM system.

Key words: OFDM, itercarrier interference, channel estimation, symbol shift cancellation, adjacent sub-channel filter