基于NOMA系统的联合波束成形的中继选择策略

Non-orthogonal multiple access (NOMA) technology effectively solves the practical problem of spectrum resource shortage in 5G communication systems. This article constructs a multi-antenna communication system based on NOMA, introduces multiple multi-antenna relays in the system, and proposes a joint beamforming relay selection strategy to maximize user secrecy rate. This strategy aims to maximize the secrecy rate, designs a joint beamforming relay selection strategy, and constructs a joint optimization algorithm for relay selection and beamforming. Considering the coupling of optimization parameters and the difficulty in obtaining the optimal solution due to non-convex expressions, this paper uses the idea of alternating optimization to iterate the algorithm and uses the mathematical idea of successive convex approximation to convex the non-convex expression. In the simulation work, the Partial Relay Selection (PRS) - Maximum Ratio Transmission (MRT) algorithm is introduced for comparison, and it is found that the proposed algorithm has better security performance.