Path Optimization for Unmanned Aerial Base Stations with Limited Radio Resources

Abstract

We consider a mobile radio network where Unmanned Aerial Vehicles (UAVs), also known as drones, are used as a viable alternative to traditional static Terrestrial Base Stations (TBSs). UAVs can fly over the terrestrial plane, where and when TBSs cannot provide the requested coverage and capacity, that is acting as Unmanned Aerial Base Stations (UABs). To this aim, it is important to optimize both the path of the drone and the number of radio resources to be assigned to the users along the path. This paper formulates the problem as an Integer Linear Programming (ILP) model with the aim of maximizing the number of served users, weighted according to their priorities, while considering constraints on UAB battery, speed, data rate and radio resources that the UAB can provide to the users. A Rolling Horizon heuristic algorithm is proposed to heuristically solve the problem: it is based on dividing the time horizon in time windows, and iteratively solving the ILP model on the single time windows. Even though the Rolling Horizon heuristic algorithm provides sub-optimal solutions, the computing time is acceptable, thus allowing the algorithm to be used in practice.