Coarse symbol timing for OFDM systems by ranking preamble cross-correlations

In this paper, we develop a novel coarse symbol timing estimator for wireless orthogonal frequency division multiplexing (OFDM) systems. The proposed preamble-based estimator generates a new sequence from a repeated preamble and its cycling shift. The new sequence obtained by ranking the correlation coefficients is used for cross-correlation. Moreover, the proposed scheme can refine the estimation performance and is robust to the degree of channel distortions by using several sorted candidate sequences. Compared with the conventional schemes, our scheme improves the mean square error (MSE) performance in highly Doppler spread multipath fading channels, and it is attractive for realistic applications, such as multicast-broadcast single frequency network (MBSFN) and satellite communications networks.