An enhanced MMSE based pre-processing scheme for time reversal MIMO-UWB systems in an imperfect CSI

Time Reversal (TR) solution is an attractive and appropriate candidate for high data rate Multiple-Input Multiple-Output Ultra-Wideband (MIMO-UWB) systems. This method leads to low complexity receivers in extremely multipath channels. In spite of TR´s good performance in MIMO-UWB systems in perfect Channel State Information (CSI), it suffers from performance degradation in an imperfect CSI case. In this paper, an enhanced TR pre-filter is designed together with a MMSE equalizer in TR-MIMO-UWB system where is robust against channel imperfection conditions. We show that the robust pre-filter optimization technique, considerably improves the BER performance of TR-MIMO-UWB system in imperfect CSI, where temporal focusing of the TR technique is kept, especially for high SNR values. Numerical and simulation results are presented to confirm the performance advantage attained by the proposed robust optimization in an imperfect CSI scenario.