Optimal training sequence design for MIMO-OFDM in spatially correlated fading

Channel estimation and training sequence design for spatially correlated fading in multiple input multiple output with orthogonal frequency division multiplexing (MIMO-OFDM) systems are still open research topics of great interest. In this paper, we investigate the linear minimum mean square error (LMMSE) channel estimation for MIMO-OFDM systems in spatially correlated fading channels. We find the lower bound of the mean square error (MSE) of channel estimation. We also propose a class of training sequences which almost achieve the performance of optimal training sequences. The effectiveness of the proposed training sequences is demonstrated empirically by simulation results.