NOMA‐Based Satellite‐UAV‐Terrestrial Network With Partial Relay Selection and Imperfect CSI and SIC

ABSTRACT An integrated terrestrial‐satellite network with UAV relay nodes can offer augmented connectivity, especially for users in shadowed areas like suburban and mountainous areas. With the advent of sixth‐generation (6G) wireless communication, non‐terrestrial networks (NTN) shall evolve as the Center of attention to achieve seamless global coverage with better data transmission rates and ultra‐reliable low‐latency communication. Non‐orthogonal multiple access (NOMA) also enhances spectral efficiency with large‐scale connectivity through power‐domain multiplexing. In this work, the performance of a satellite‐UAV‐terrestrial integrated network based on the amplify‐and‐forward (AF) relaying protocol at the UAV relay node is analyzed. Using Monte Carlo simulations, it is shown that the proposed system effectively alleviates outage probability compared to a no‐relay system. Moreover, deployment of a cluster of UAV relays with partial relay selection, which maximizes performance and computational complexity, enhances reliability through the selection of the best‐performing relay path based on channel conditions. Imperfect channel state information (CSI) and erroneous successive interference cancellation (SIC) are included in the analysis for practical implementation. Furthermore, integration of NTN with NOMA opens new routes to enhance spectral efficiency and coverage in 6G networks. The results confirm that the proposed system offers an efficient and effective communication system with superior performance under different parameter variations while addressing major challenges in next‐generation wireless networks.