Outage Performance Analysis of Cooperative PDMA with the Full-Duplex Relay

Pattern division multiple access (PDMA), which can exploit time, frequency, spatial resources or any combination of these resources, has been a promising candidate multiple access technology for the fifth generation (5G) wireless systems. Addressing the high-reliability, low-latency and massive-connectivity requirements of 5G systems is becoming one of the most promising research trends. In this paper, we combine the PDMA with the full-duplex relay and propose a cooperative PDMA (Co-PDMA) system to improve the reliability of cell-edge users with a short delay. We analyze the outage performance of the Co-PDMA system when the instantaneous channel state information could or could not be available at the transmitter. In addition, we also compare the outage performance in the cooperative and the non-cooperative PDMA system when the selection combining (SC) or the maximum ratio combining (MRC) scheme is utilized at the receiver. The numerical results show that the proposed Co-PDMA system can obviously improve the outage performance, and the MRC scheme can further improve the system reliability. Moreover, when the instantaneous channel state information is known at the transmitter, the PDMA with successive interference cancellation (SIC) decoding has a great advantage on improving reliability compared with the conventional orthogonal multiple access (OMA).