Outage performance of multi-relay collaborative NOMA systems supporting multiple multicast services

Abstract

A cooperative non-orthogonal multiple access (NOMA) system was proposed to support unicast primary user and multiple multicast services based on multiple relays strategy.Under the Rayleigh channel, the secondary user with the best channel condition from each multicast group was selected as full-duplex relay to decode and forward the unicast primary user’s signal, and the primary user employed the maximum ratio combining (MRC) technique to improve the signal to interference and noise ratio (SINR).The closed-form expressions for the outage probability of primary user in full-duplex and half-duplex modes with multi-relay simultaneous forwarding (MRSF) and optimal relay forwarding (ORF) were derived and verified by Monte Carlo simulations.The results verify that full-duplex relay outperforms half-duplex relay scheme.Furthermore, with same number of multicast groups, the MRSF strategy effectively improve the unicast primary user outage performance, in comparison with ORF strategy, when the number of multicast groups increases, the improvement becomes more significant.

Keywords

• non-orthogonal multiple access;multicast service;full-duplex multi-relay;outage probability