Polynomial estimation of time-varying multipath gains with ICI mitigation in OFDM systems

In this paper, we present a mean square error (MSE) theoretical analysis for a multipath channel complex gains estimation algorithm with inter-sub-carrier-interference (ICI) mitigation in orthogonal frequency division multiplexing (OFDM) high speed mobile receiver. Each complex gain time- variation is approximated in a polynomial fashion within several OFDM symbols, where the polynomial coefficients are obtained from the estimated time-averaged gain values. After that, the channel matrix is easily computed and the ICI is reduced by using successive interference suppression (SIS) during data symbol detection. The algorithm performance is further enhanced by an iterative procedure. Theoretical analysis for Rayleigh channel with Jakes´spectrum and simulation results show that the low computational complexity proposed algorithm has good performance in the presence of high normalised Doppler spread.