Joint Deployment and Resource Allocation for Service Provision in Multi-UAV-Assisted Wireless Networks

There has been a growing interest in using unmanned-aerial-vehicles (UAVs) for high-rate wireless communications due to their flexibility in deployment and relatively low costs. In this article, we consider an UAV-assisted wireless network, where a multiantenna ground base station provides communication services to a group of users through a set of UAVs using the in-band wireless backhaul. We propose a novel framework for optimizing the multi-UAV-assisted wireless network and consider the following two problems: one minimizes the total system cost and the other maximizes the system utility. In contrast to the previous studies, we consider the deployment cost of UAVs and the impact of the UAV locations on the backhaul capacity for both the problems. The two problems are complicated mixed-integer nonlinear programming (MINLP) problems, which involve the joint optimization of the UAV selection and their locations, the UAV-user association, and the wireless resource allocations subject to the Quality of Service requirements of users and the wireless backhaul capacity constraints. Therefore, we propose the block coordinate descent-based algorithms combined with successive convex approximation to solve the two problems. Simulation results show that the proposed methods are adaptable to the wireless backhaul constraints and outperform the other benchmark methods.