Tensor-Based Multiuser Detection for Uplink DS-CDMA Systems with Cooperative Diversity

In the present paper, a semi-blind receiver for a multiuser uplink DS-CDMA (Direct-Sequence Code-Division Multiple-Access) system based on relay aided cooperative communications is proposed. For the received signal, a quadrilinear Parallel Factor (PARAFAC) tensor decomposition is adopted, such that the proposed receiver can semi-blindly estimate the transmitted symbols, channel gains and spatial signatures of all users. The estimation is done by fitting the tensor model using the Alternating Least Squares (ALS) algorithm. With computational simulations, we provide the performance evaluation of the proposed receiver for various scenarios. Keywords— Semi-blind receiver, DS-CDMA, Cooperative communications, PARAFAC, Tensor model, Alternating least squares.