Linear multiuser detection for R-CDMA

Several linear multiuser detectors for code-division multiple-access (CDMA) systems can be characterized as inverses of some form of correlation matrices with infinite dimension. To obtain practical detectors for CDMA systems with time-variant signature waveforms, linear finite memory-length (referred to as FIR) multiuser detectors are analyzed in this paper. They are obtained by truncating the IIR detectors or by finding the optimal FIR detectors. An iterative implementation algorithm of truncated decorrelating detector suitable to highly parallel implementation is proposed. Since correlation computation can be embedded into the algorithm, its computational requirements are moderate. The performance of the iterative algorithms is studied by computer simulations.