Joint Optimization Method of User Association and Spectrum Allocation for Multi-UAV-Assisted Communication

Abstract

In this paper, we mainly study the scenario where multiple UAVs act as aerial base stations (BSs) to provide communication services for ground users (GUs). We propose a method to optimize the max-min average rate of GUs in order to ensure the fairness of user communication, where spectrum reuse and co-channel interference management are considered. The mathematical model is a mixed integer non-linear programming (MINLP) problem which we solve by using the alternating optimization approach where we iteratively optimize the user association, sub-channel allocation and power allocation until convergence. We propose a heuristic algorithm to solve the user association sub-problem and use genetic algorithm (GA) to solve the sub-channel allocation sub-problem. Moreover, the geometric programming algorithm is used to convexify the non-convex power allocation sub-problem and CVX is used to solve it. Simulation results show that the proposed method can effectively improve the transmission rate and ensure the fairness of user communication.