Analysis of iterative demapping and decoding for MBOK DS-UWB systems via EXIT chart

This paper presents an analysis of iterative demapping and decoding for coded M-ary bi-orthogonal keying direct sequence UWB (MBOK DS-UWB) systems via an extrinsic information transfer chart (EXIT chart). In MBOK DS-UWB systems, which have been considered a type of PHYs suitable for high-speed wireless personal area networks (WPANs) in IEEE802.15.3a, one of useful error correction techniques is iterative demapping and decoding between soft-input/soft-output (SISO) MBOK demapper and SISO channel decoder. The EXIT chart has been invented by ten Brink (1999) to allow the prediction of turbo cliff position and bit error rate after arbitrary number of iterations. Through analyses, the bit error rate performance of the iterative demapping and decoding highly depends on the UWB channel conditions in multipath fading UWB channels. We show that the use of RAKE reception is effective approach in multipath fading UWB channels for the iterative demapping and decoding via the EXIT chart.