Performance evaluation and UAV placement optimization in full-duplex hybrid satellite-UAV NOMA networks with CCI

This research investigates a hybrid satellite-UAV (HS-UAV) terrestrial network based on non-orthogonal multiple access (NOMA). In this architecture, a satellite transmits data to ground users via a full-duplex (FD) unmanned aerial vehicle (UAV) relay operating in decode-and-forward (DF) mode. The UAV is configured to operate under two distinct antenna schemes: dynamic antenna mode (DAM) and static antenna mode (SAM). Additionally, an optimized power allocation scheme is employed to efficiently manage transmission between near and far users. To model the random distribution of users, we utilize a homogeneous Poisson point process (PPP) and analyze system behavior through stochastic geometry methods. Users encounter varying levels of co-channel interference (CCI). A more realistic assumption is adopted, where perfect channel state information (CSI) at the receiver is unattainable, and signal degradation follows distance-based path loss. We derive analytical expressions for outage probability (OP) and throughput for both near and far users. Furthermore, system throughput is evaluated under a delay-limited transmission model. To further improve performance, we optimize the UAV’s location to maximize the total transmission rate. Simulation results yield several key findings: (i) outage floors arise due to factors such as channel estimation errors, UAV self-interference, and CCI; (ii) DAM design outperforms SAM; (iii) strategic UAV placement plays a crucial role in improving the system performance; and (iv) our proposed work performs better than similar existing works.