CoMP Transmission in Downlink NOMA-Based Cellular-Connected UAV Networks

In this paper, we explore the integration of coordinated multipoint (CoMP) transmission and non-orthogonal multiple access (NOMA) in downlink cellular-connected UAV networks, which include both aerial users (AUs) and terrestrial users (TUs). AUs are categorized into CoMP-AUs and Non-CoMP AUs based on a comparison of the desired signal strength and the dominant interference strength. CoMP-AUs receive transmissions from two cooperative Base Stations (BSs) and form two exclusive NOMA clusters with two TUs, respectively. A Non-CoMP AU forms a NOMA cluster with a TU served by the same BS. Leveraging the tools of stochastic geometry, we propose an analytical framework to assess the performance of the CoMP-NOMA-based cellular-connected UAV network in terms of coverage probability and average ergodic rate. We demonstrate the superiority of the proposed CoMP-NOMA scheme by comparing it with three benchmark schemes, and further quantify the impacts of key system parameters on network performance. By harnessing the benefits of both CoMP and NOMA, we prove that the proposed scheme can provide a reliable connection for AUs using CoMP and enhance the average ergodic rate through the application of NOMA technique.