Noncoherent Multiple Symbol Detection for 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). Considering the specific signal format of DSTBC-UWB system and employing the property of DSTBC, a noncoherent multiple symbol detection (MSD) scheme is developed by generalized likelihood ratio testing (GLRT) approach. Although the proposed MSD scheme can enhance the performance of DSTBC-UWB system, the complexity of the exhaustive search based MSD exponentially increases with observation window size. To decrease the computational complexity, the original MSD metric is transformed into another equivalent form which can be implemented by sphere decoding (SD) for DSTBC-UWB system. Moreover, a suboptimal Decision-Feedback (DF) based MSD with lower complexity than SD based MSD is proposed to further reduce the computational complexity.