Achievable NOMA Gain for Downlink Ultra-Dense Small Cell Networks

In this paper, we analyze the downlink performance of non-orthogonal multiple access (NOMA) in ultra-dense networks (UDNs) incorporated into line-of-sight (LOS)/non-line-of- sight (NLOS) propagation.000 Nakagami fading is also considered for the small-scale fading. The expressions for coverage probability (CP) and network throughput are obtained. The numerical results show that the performance of NOMA first increases with the growth of base station (BS) density, and then decreases as the UDNs becomes denser. Moreover, the NOMA still show the superiority with network densification.