EURASIP Journal on Applied Signal Processing 
Volume 2004 (2004), Issue 5, Pages 640-648
doi:10.1155/S1110865704312163

Improved Multiuser Detectors Employing Genetic Algorithms in a Space-Time Block Coded System

Yinggang Du and Kam Tai Chan

 Department of Electronic Engineering, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong
Received 31 December 2002; Revised 15 November 2003

Abstract

Enhanced genetic algorithms (GA) applied in space-time block coded (STBC) multiuser detection (MUD) systems in Rayleigh flat-fading channels are reported in this paper. Firstly, an improved objective function, which is designed to help speed up the search for the optimal solution, is introduced. Secondly, a decorrelating detector (DD) and a minimum mean square error (MMSE) detector have been added to the GA STBC MUD receiver to create the seed chromosome in the initial population. This operation has improved the receiver performance further because some signal information has been intentionally embedded in the initial population. Simulation results show that the receiver employing the improved objective function and the DD or MMSE detector can converge faster with the same bit error rate (BER) performance than the receiver with the initial population chosen randomly. The total signal-to-noise ratio (SNR) improvement contributed by these two modifications can reach 4 dB. Hence the proposed GA receiver is a promising solution of the STBC MUD problem.