Non-orthogonal multiple access for a full-duplex cooperative network with virtually paired users

Abstract

Non-orthogonal multiple access (NOMA) is recognized as a promising radio access technology for next generation wireless networks. In this paper, a novel full-duplex (PD) cooperative relaying scheme for a NOMA based system (termed FD-NOMA-VP) is proposed, where K similar gain near users and relay-aided N similar gain far users are distributed into different NOMA cluster. In each cluster, one near user is virtually paired (VP) with multiple far users over non-overlapping frequency bands. In FD-NOMA-VP, the near user directly communicates with the base station, whereas far users communicate via a dedicated FD relay, in each cluster. The performance of FD-NOMA-VP is studied comprehensively in terms of the ergodic sum capacity, outage probability, and outage sum capacity along with analytical derivations under both perfect and imperfect interference cancellation (IC) scenarios. The results demonstrate that FD-NOMA-VP shows significant performance gains compared to the conventional multiple access scheme under perfect IC, while the residual interference has a substantial impact on the performance gain under imperfect IC. In addition, a strong agreement between analytical and simulation results affirms the correctness of our analysis.