An Equivalent Channel Time Variation Mitigation Schefme for ICI Reduction in High-Mobility OFDM Systems

In time-varying channel, the Doppler effect destroys the subcarrier orthogonality of orthogonal frequency-division multiplexing (OFDM) system which leads inter-carrier interference (ICI). This paper presents a time domain ICI self-cancellation method from the view of equivalent channel time variation mitigation. By utilizing the assumption of linear time-varying channel model, a set of windowing coefficients is derived to mitigate the equivalent channel time variation of the corresponding part into flat. The ICI is therefore reduced by lessening the equivalent channel time variation. The proposed window shape is found as the Franks window. The theoretical ICI power and bit error rate (BER) performance for using the proposed window shape are investigated and validated by simulation results. Comparing to Chang´s equivalent windowing method and the 4-step window shape for low-complex windowing method, the proposed method can provide better ICI cancellation performance given with the same criterion.