NOMA-Aided Multi-UAV Communications in Full-Duplex Heterogeneous Networks

To address spectrum scarcity in unmanned aerial vehicle (UAV) communications, nonorthogonal multiple access (NOMA) aided multi-UAV communications in full-duplex (FD) heterogeneous networks (HetNets) are investigated in this article. Specifically, an ergodic capacity analysis of NOMA-aided multi-UAV communications in FD-HetNets is conducted through a moment generating function (MGF) approach within a stochastic geometry framework. By employing the MGF approach to evaluate ergodic capacity, exact expressions that are simpler to evaluate are obtained. When compared against half-duplex HetNets, i.e., HD-HetNets, FD-HetNets with effective interference management enable higher ergodic capacity to be obtained by the macro base station and UAVs. Furthermore, we show that it is possible for NOMA-aided multi-UAV communications in FD-HetNets to achieve higher ergodic sum capacity and ergodic capacity gains than HD-HetNets while supporting more UAVs at low altitude due to a stronger desired signal. Even with lower levels of self-interference suppression and strong phase noise, NOMA-aided multi-UAV communications in FD-HetNets is still able to achieve higher ergodic sum capacity over HD-HetNets. Therefore, the attractiveness of NOMA-aided multi-UAV communications in FD-HetNets is highlighted as a promising solution toward improving spectrum utilization in UAV communications.