UAV-to-Everything (U2X) Networks Relying on NOMA: A Stochastic Geometry Model

This article mainly focus on addressing the non-orthogonal multiple access (NOMA) enhanced unmanned aerial vehicle (UAV)-to-Everything (U2X) networks. A novel three dimension (3D) network for providing wireless services to randomly roaming NOMA receivers (Rxs) in the sphere space is proposed by utilizing stochastic geometry tools. In an effort to evaluate the performance of the proposed network, we first derive the closed-form expressions for the outage probability and the ergodic rate of the paired NOMA Rxs. Both the diversity orders and the high-signal-to-noise (SNR) slopes of the paired NOMA Rxs are derived. The spectrum efficiency (SE) in both the NOMA and orthogonal multiple access (OMA) enhanced U2X networks are derived. Our analytical results demonstrate that the diversity order and the high-SNR slope of the proposed network are fading parameter $m$ and one, respectively. Numerical results are provided to confirm that: i) the proposed NOMA enhanced U2X networks have superior outage performance and SE compared with the OMA enhanced U2X networks; and ii) for the case of fixed LoS probability, the outage performance of the paired NOMA Rxs mainly depends on the poorer channel conditions.