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Báo cáo hóa học: " Improved Multiuser Detectors Employing Genetic Algorithms in a Space-Time Block Coded System"

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: Improved Multiuser Detectors Employing Genetic Algorithms in a Space-Time Block Coded System | EURASIP Journal on Applied Signal Processing 2004 5 640-648 2004 Hindawi Publishing Corporation Improved Multiuser Detectors Employing Genetic Algorithms in a Space-Time Block Coded System Yinggang Du Department of Electronic Engineering The Chinese University of Hong Kong Shatin New Territories Hong Kong Email ygdu@ee.cuhk.edu.hk Kam Tai Chan Department of Electronic Engineering The Chinese University of Hong Kong Shatin New Territories Hong Kong Email ktchan@ee.cuhk.edu.hk Received31 December 2002 Revised 15 November 2003 Enhanced genetic algorithms GA applied in space-time block coded STBC multiuser detection MUD systems in Rayleigh flatfading 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. Keywords and phrases genetic algorithms multiuser detection decorrelating detector minimal mean square error detector space-time block coding objective function. 1. INTRODUCTION In wireless communications space-time block coding STBC with diversity gains has been widely studied in multiuser detections MUDs 1 2 3 because STBC can utilize the information in the spatial and time domains simultaneously 4 . From the coding .