A Low Complexity Pilot-Aided Channel Estimation Resisting Residual Timing Errors for OFDM Systems

This paper, patent pending, put forwards a novel low complexity channel estimator for a special case of comb-type pilot pattern with pilot interval I = 2, which can combat the effect of residual timing offset on interpolation-based channel estimation. The channel estimation algorithm based on comb-type pilots is divided into pilot signal estimation and channel interpolation. The pilot subcarriers estimation can be based on least square (LS) or minimum mean square error (MMSE) algorithms which can achieve better performance than LS at the cost of high complexity. Furthermore MMSE need to know in advance the priori knowledge of noise variance and channel covariance. So considering engineering implementation, LS algorithm for pilot subcarriers estimation and linear interpolation for non-pilot subcarriers estimation are adopted in this paper. Then the effect of residual timing offset on such channel estimator is analyzed. Based on the unique characteristics of the special pilot pattern focused by this paper, a quite simple correction method is put forward. And simulation results show that the proposed method can effectively improve the system performance when existing residual timing offset.