NSATC: An Interference Aware Framework for Multi-cell NOMA TUAV Airborne Provisioning

Recently, wireless service provisioning via Unmanned Aerial Vehicles (UAVs) has emerged in 5G and beyond mobile networks. Due to the limited capacity of UAV batteries, tethered UAVs (TUAVs), which are powered from ground, are increasingly deployed in worldwide projects. However, the deployment of TUAVs in mobile networks requires high spectral efficiency, particularly in dense areas. Non-orthogonal Multiple Access (NOMA), serving users with strong channels and weak channels in the same Resource Blocks (RBs), helps overcome this issue. Due to the dynamic and massive deployment of TUAVs, inter-cell interference becomes critical. To alleviate the submerging of signals between TUAVs, we introduce a new parameter named Channel Gain Plus Interference (CGPI), reputing the interference as channel characteristics. Then, we formulate the joint optimization of power, altitude and user association. To solve this high-complexity problem, we design an algorithm, called NOMA SIC-Aware TUAV Base Station Control (NSATC) based on Multi-Agent Deep Deterministic Policy Gradient (MADDPG). The experiment shows our proposed algorithm presents a performance enhancement between 18.8% and 121.77% of throughput and 23.76% and 51.62% of serving users than the greedy algorithm.