Abstract:  A clustering and power allocation algorithm is proposed for unmanned aerial vehicle assisted non-orthogonal multiple access (NOMA) downlink communication systems with non-uniformly distributed users. The optimization problems for maximizing the sum-rate and ensuring quality of service are established, and a three-step strategy is proposed to reduce the computation complexity. First, the optimal deployment position for the unmanned aerial vehicle is determined. Then, based on the unmanned aerial vehicle position, an angle-density based spatial clustering of applications with noise algorithm is proposed. Finally, a suboptimal solution to the power allocation problem is obtained using the successive convex approximation method. Simulation results show that the proposed algorithm outperforms traditional algorithms in terms of clustering effectiveness and communication performance in the same scenario.

Key words: unmanned aerial vehicle, non-orthogonal multiple access, channel gain difference, user clustering, power allocation