EURASIP Journal on Wireless Communications and Networking 
Volume 2005 (2005), Issue 2, Pages 187-196
doi:10.1155/WCN.2005.187

Factor-Graph-Based Soft Self-Iterative Equalizer for Multipath Channels

Ben Lu,1 Guosen Yue,2 Xiaodong Wang,3 and Mohammad Madihian2

 1Silicon Laboratories, Inc., Austin 78735, TX, USA
2NEC Laboratories America, Inc., Princeton 08540, NJ, USA
3Department of Electrical Engineering, Columbia University, New York 10027, NY, USA
Received 30 April 2004; Revised 23 August 2004

Abstract

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.