BER Analysis of Decision-Feedback Multiple Symbol Detection in Noncoherent MIMO Ultra-Wideband Systems

In this paper, we investigate noncoherent multiple-input multiple-output (MIMO) ultra-wideband (UWB) systems where the signal is encoded by differential space-time block code (DSTBC). DSTBC enables noncoherent MIMO UWB systems to achieve diversity gain. However, the traditional noncoherent symbol-by-symbol differential detection (DD) for DSTBC-UWB suffers from performance degradation compared with the coherent detection. We introduce a noncoherent multiple symbol detection (MSD) scheme to enhance the performance of DSTBC-UWB system. Although the MSD scheme can boost the performance more as the observation window size gets to larger, the complexity of the exhaustive search for MSD also exponentially increases in terms of the window size. To decrease the computational complexity, the concept of decision-feedback (DF) is introduced to MSD for DSTBC-UWB in this paper. The resultant DF-MSD yields reasonable complexity and also solid performance improvement. We provide the bit error rate (BER) analysis for the proposed DF-MSD. Both theoretical analysis and simulation results validate the proposed scheme.