Iterative Block Decision Feedback Equalizer for Time-Frequency Interleave Diversity Scheme

The time-frequency interleave (TFI) diversity scheme for single carrier block transmission with frequency domain equalization (SC-FDE) has been proposed. For single antenna wireless communication systems, it can provide frequency diversity in frequency selective channels by interleaving and retransmitting. In this article, the iterative block decision feedback equalization (IBDFE) structure for TFI diversity scheme is proposed. Both the feed-forward filter (FFF) and feed-backward filter (FBF) work in the frequency domain, which makes the implementation complexity low. The FFF and FBF coefficients based on minimum mean square error (MMSE) criterion are derived. The correlation between the transmitted symbols and the detected symbols are estimated in a simple iterative manner. Simulation results show that for TFI diversity scheme with IBDFE, a much better bit error rate (BER) performance can be obtained than TFI with frequency domain linear equalizer (FD-LE) only for one more iteration. Compared to IBDFE without TFI diversity, the performance gain is impressive.