PARAFAC Receiver for Uplink Cooperative Relay-Assisted DS-CDMA Systems

In this paper, we consider the uplink of a multiuser cooperative DS-CDMA communication system, where each user communicates with the base station with the help of R relays. A cooperative DS-CDMA configuration with direct-sequence spreading at the relays is proposed and for this cooperative scenario we formulate a new trilinear model for the received signal that combines source-destination (SD) and relay-destination (RD) wireless links. Based on this trilinear model, we propose a blind receiver for the joint estimation of antenna array responses, channel gains and transmitted symbols of all the users. Numerical results are provided to illustrate the performance of the proposed blind receiver. Our results also corroborate the benefits of exploiting spreading diversity for blind multiuser detection in the considered cooperative relay-assisted DS-CDMA scenario