Optimal design of DS-CDMA systems under multipath fading channel: array signal processing approach

In this study, based on multirate technique, the detection problem of DS-CDMA systems is transformed to an equivalent signal of beamforming systems. In this situation, the channel plus spreading code in DS-CDMA systems is equivalent to a steering matrix in the signal processing of beamforming systems. Based on an optimum beamforming technique, an optimum detection design is proposed for DS-CDMA systems. Furthermore, stochastic processes model the time-varying tap coefficients of multipath fading channels. The channel parameter or steering matrix estimation algorithm is developed based on the Kalman state estimation method. Finally, an adaptive design for DS-CDMA systems is also discussed in this paper. Consistency of the proposed method is shown, and some illustrative simulations are presented.