A sphere decoding approach to multiple symbols differential detection for UWB systems

Ultra-wideband (UWB) wireless channels are typically characterized by dense multipath scattering, which on the one hand provides very large multipath diversity, but on the other hand complicates UWB impulse radio receiver design as far as channel estimation and multipath energy capture are concerned. In this paper, we present a multi-symbols differential detector (MSDD) in which blocks of M received symbols are jointly processed based on the autocorrelation detection principle, bypassing training or costly channel estimation. As the block size M increases, the detection performance improves, but maximumlikelihood MSDD quickly becomes computationally impractical when M is over 10. To circumvent high complexity, we derive a new implementation of the MSDD decision rule based on the sphere decoding (SD) algorithm. The proposed SD approach to MSDD offers attractive detection performance based on a simple receiver structure and at affordable computational complexity polynomial in M. © 2006 IEEE