Decision-feedback multiple symbol detection for differential space-time block coded UWB systems
The symbol-by-symbol differential detection scheme, originally employed to detect differential space-time block coded (DSTBC) ultra-wideband (UWB) signal in previous work, suffers from a performance degradation compared with coherent detection. In this paper, a noncoherent multiple symbol detection (MSD) scheme is proposed to enhance the performance of DSTBC-UWB system. After the signal model of DSTBC-UWB is analyzed, the optimal maximum likelihood (ML) MSD is derived and then a suboptimal ML-MSD is obtained by channel approximating. However, exhaustive search based MSD is impractical in DSTBC-UWB systems since its complexity increases exponentially with observation window size. To decrease the computational complexity, the decision-feedback (DF) scheme is introduced to MSD. The resultant DF-MSD yields reasonable complexity and solid performance improvement.
differential detection ultra-wideband (uwb) multiple symbol detection (msd) space-time block code (stbc)