ML Time-Frequency Synchronization for MIMO-OFDM Systems in Unknown Frequency Selective Fading Channels

This paper addresses maximum-likelihood (ME) time-frequency synchronization algorithm joint with channel estimation for MIMO-OFDM systems in frequency selective fading channels. In proposed algorithm, we use two steps to maximize a proposed metric to obtain first frequency offset and then timing. Using these two estimates, the channel is identified. An iterative algorithm is proposed to improve frequency offset estimation. The performance of the proposed synchronization approach, in terms of timing failure probability and mean square error of the estimated frequency offset, was compared with literature. Based on simulation results, the Cramer-Rao lower bound is obtained with a few iterations