tailieunhanh - Báo cáo hóa học: " Factor-Graph-Based Soft Self-Iterative Equalizer for Multipath Channels"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Factor-Graph-Based Soft Self-Iterative Equalizer for Multipath Channels | EURASIP Journal on Wireless Communications and Networking 2005 2 187-196 2005 Hindawi Publishing Corporation Factor-Graph-Based Soft Self-Iterative Equalizer for Multipath Channels Ben Lu Silicon Laboratories Inc. Austin TX 78735 USA Email Guosen Yue NEC Laboratories America Inc. Princeton NJ 08540 USA Email yueg@ Xiaodong Wang Department of Electrical Engineering Columbia University New York NY 10027 USA Email wangx@ Mohammad Madihian NEC Laboratories America Inc. Princeton NJ 08540 USA Email madihian@ Received 30 April 2004 Revised 23 August 2004 We consider factor-graph-based soft self-iterative equalization in wireless multipath channels. Since factor graphs are able to characterize multipath channels to per-path level the corresponding soft self-iterative equalizer possesses reduced computational complexity in sparse multipath channels. The performance of the considered self-iterative equalizer is analyzed in both single-antenna and multiple-antenna multipath channels. When factor graphs of multipath channels have no cycles or mild cycle conditions the considered self-iterative equalizer can converge to optimum performance after a few iterations but it may suffer local convergence in channels with severe cycle conditions. Keywords and phrases factor graph equalizer iterative processing multipath fading MIMO. 1. INTRODUCTION A multipath fading channel which can be mathematically described by a convolution of transmitted signals and linear channel response is one of many typical channel models occurring in digital communications. In general an equalizer that makes detection based on a number of adjacent received symbols is necessary to achieve optimal or near-optimal performance in multipath channels. In classical communication theory different representations of multipath channels have led to equalizers with different designs. By representing multipath channels as trellis structures the optimum sequence .