Adaptive minimum bit error rate multiuser detection for asynchronous mc-cdma systems in frequency selective rayleigh fading channels

Abstract

An Adaptive minimum bit error rate (MBER) based linear multiuser detection scheme is proposed for an asynchronous multicarrier code-division multiple-access (MC-CDMA) system in frequency selective Rayleigh fading channels. In general, a MC-CDMA system employs the minimum mean square error (MMSE) receiver due to its good performance and amenability to adaptive implementation. However, the MSE cost function is nut optimal in terms of the bit error probability performance of the system. The proposed multiuser detector (MUD) that directly minimizes the BER can significantly improve the performance by employing an adaptive stochastic gradient algorithm based on the estimation of kernel density function in order to adjust the weights in the receiver. Simulation results demonstrate a clear performance improvement by using the proposed multiuser detection scheme.