Performance of DAF Cooperative CDMA Networks in Frequency-Selective Fading Channels

In this paper, the performance of cooperative networks introduced in the literature is analyzed for asynchronous direct sequence code-division-multiple-access (DS-CDMA) systems in frequency-selective slow fading environment. We show that the full benefits of cooperative diversity cannot be achieved if no multiuser interference suppression is employed at the cooperative end. We consider two scenarios; perfect and imperfect inter-user channel. The bit-error-rate performance of the cooperative system is investigated for an uplink transmission where a decorrelator detector is used at both the relay and base station receivers. The proposed receiver has the advantage of mitigating the effects of multipath fading and multiple-access interference. Both simulation and analytical results are presented to demonstrate the diversity gains of cooperative networks.