Transmission Performance Analysis of Cognitive NOMA with SWIPT over Nakagami-m Fading Channels

Both cognitive radio and non-orthogonal multiple access (NOMA) are spectral efficient techniques in the future wireless communication networks. In this paper, a novel cooperative NOMA transmission scheme with the aid of Simultaneous Wireless Information and Power Transfer (SWIPT) is proposed in a cognitive radio network (CRN). In the new scheme, a secondary transmitter (ST) acts as a decode-and-forward relay to help forward primary information and collects energy from it by using SWIPT. In return, the ST is allowed to transmit its own signals on the same resource as the secondary system by using NOMA technique. According to the statistic characteristics of Nakagami-m fading channels, the outage probability and throughput for the primary and secondary networks are respectively derived in closed forms for the proposed transmission scheme. Simulation results show that by using NOMA transmission scheme with overlay CRNs and SWIPT, the outage probability is reduced and the throughput performance is increased. It indicates that the proposed energy cooperative cognitive NOMA system is capable of improving both the outage and throughput performance.