Modeling and Analysis of UAV-Assisted Cellular Networks with Non-Orthogonal Multiple Access

Unmanned aerial vehicles (UAVs) provide a fast and feasible solution for emergency communications in areas where traditional ground base stations (BSs) cannot provide reliable wireless communication links, relying on their fast and flexible deployment. In this paper, the isolated region of target coverage is modeled as a circle, and the interference BSs outside the area is modeled as a homogeneous Poisson point process (HPPP) in the infinite 2D plane. User equipments (UEs) are evenly distributed in a circular area, served by drones suspended in the center of the area. At the same time, considering the shortage of UAV communication resources, the non-orthogonal multiple access (NOMA) technology enables multiple users to share the same resources to improve the coverage performance of the UAV. At this time, this paper analyzes and solves the UAV downlink transmission performance based on distance and signal-to-noise ratio (SNR) by using stochastic geometry and order statistics theory. In order to better characterize channel fading, we use probabilistic multi-slope path loss large-scale model and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{Nakagami}-m$</tex> small-scale model.On this basis, the influence of various parameters on the coverage performance is studied.