부산대학교 도서관

Unmanned aerial vehicle (UAV)-assisted wireless networks have gained much attention in mission-critical applications due to their low cost, immediate deployment, and high mobility. The deployment of UAVs and user association are vital in the success of UAV-assisted mission-critical networks while considering key parameters. In this paper, we propose a priority-based mathematical framework to minimize the number of UAVs, user-UAV distance, and deployment cost while maximizing user-UAV connectivity. We jointly optimize the deployment of UAVs and users on the ground. We consider constraints on the minimum number of connected users, users' connectivity with deployed UAVs, UAV-user assignment, connectivity, budget, coverage, and UAV deployment. We propose a heuristic algorithm based on interior point method and iterative rounding algorithm to solve the formulated problem with less computational complexity. A branch and bound algorithm is adopted as a benchmark for the performance of the heuristic algorithm. Simulation results are given for prioritized and non-prioritized environments in which the number of UAVs is minimized along with the distance and cost, whereas the number of users is maximized. Simulation results show that the number of users is increased when the practical scenario is prioritized to establish immediate connections to the users in need.