Performance Analysis of NOMA Beamforming Multiple Users Relay Systems

In order to improve performance of multiple users (MUs) systems, several relays are deployed to help a base station (BS) decode and forward signals to end users. We propose that the BS utilize a beamforming approach to transmit its signal to relays, and then relays forward the received signals to users by non-orthogonal multiple access (NOMA) scheme. The system performance is shown through a close-form outage probability over Rayleigh fading channel with assumption of perfect successive interference cancellation. The calculation results are compared with simulation results to verify our theoretical analysis. Furthermore, the proposed combination of NOMA and beamforming method is compared with the conventional orthogonal multiple access method and an impact of imperfect channel state information on the system performance is also discussed.