Decorrelate-and-forward relaying scheme for multiuser wireless code division multiple access networks

Decorrelate-and-forward relaying scheme for wireless synchronous code division multiple access (CDMA) networks where multiple sources communicate with a destination supported by multiple relays in flat Rayleigh fading channels is considered. By exploiting equicorrelated spreading sequences, a simple near–far resistant decorrelator together with a beamforming scheme at each relay and the maximal ratio combiner (MRC) at the destination are developed in order to achieve the full cooperative diversity for every source. Different from the case with a single source, the beamforming design in multiple-source networks needs to take into account the amount of transmit power each relay spends to forward the signals from the sources. As such, the authors also propose a novel power allocation scheme to improve the fairness among the sources in terms of the instantaneous signal-to-noise ratio. Simulation results demonstrate the effectiveness of the proposed solution.