Research on UAV-NOMA communication system based on improved grey wolf optimization algorithm

Considering that UAV, serving as base stations, can enhance the flexibility of communication system transmission, reduce transmission delays, and provide temporary communication, this paper proposes a NOMA-assisted UAV downlink communication network model in a Rician fading channel, which is more suitable for air-to-ground transmission. The joint optimization of UAV three-dimensional trajectory, pitch angle is studied to improve the sum rate of the communication system. To address the issue of nonlinear programming, this paper proposes an improved algorithm that combines the Grey Wolf Optimization (GWO) algorithm and the Particle Swarm Optimization (PSO) algorithm to overcome the insufficient global search ability of the grey wolf optimization algorithm. Simulation results indicate that the GWOPSO algorithm can better improve the system's sum rate compared to the Cuckoo Search (CS) algorithm and the PSO algorithms.