Time-Reversal Diversity in Decision Feedback Equalization

This paper considers the use of a time-reversal decision fee dback equalizer (DFE) in conjunction with a conventional DFE for block processing of the received signal. A receiver structure that combines the conventional DFE output s and the time-reversal DFE outputs is proposed. An optimal combining scheme of the two s treams that minimizes the mean-squared error (MSE) at the receiver output is deriv ed. The inherent diversity between the soft outputs of the two streams is described and q uantified under a few simplifying assumptions. For the special case of a symmetric ch annel, the optimal DFE filter setting that minimizes the MSE at the output of the diversity combining block is derived. Simulation results demonstrating performance gains for th e proposed receiver structure are presented for both symmetric and asymmetric channels.