Complexity reduction of RBF multiuser detector for DS-CDMA using a genetic algorithm

Authors : Mustafa Uğur TORUN, Damla Gürkan KUNTALP

Pages : 1134-1150

Doi:10.3906/elk-1110-61

View : 19 | Download : 6

Publication Date : 0000-00-00

Article Type : Research Paper

Abstract :The optimal receiver for detecting direct sequence code division multiple access insert ignore into journalissuearticles values(DS-CDMA); signals suffers from computational complexity that increases exponentially with the number of users. Several suboptimal multiuser detectors insert ignore into journalissuearticles values(MUDs); have been proposed to overcome this problem. Due to the nonlinear nature of the decision boundary of the optimal receiver, it is known that nonlinear receivers outperform linear receivers. Radial basis function insert ignore into journalissuearticles values(RBF); MUD is a nonlinear suboptimal receiver that can perfectly approximate this decision boundary and it needs no training since it is fully determined when the spreading codes of all users and the channel impulse response insert ignore into journalissuearticles values(CIR); are known. However, the RBF MUD suffers from structural complexity since the number of hidden nodes insert ignore into journalissuearticles values(center functions); in its structure increases exponentially with the number of users. In this study, we propose a new method to minimize the number of center functions of the RBF MUD using a genetic algorithm insert ignore into journalissuearticles values(GA); and the least mean squares insert ignore into journalissuearticles values(LMS); algorithm. With simulations performed in AWGN and multipath channels it is shown that the proposed method immensely reduces the complexity of the RBF MUD with a negligible performance degradation.
Keywords : DS CDMA, radial basis function multiuser detector RBF MUD, genetic algorithm GA,