Path Optimization for Flying Base Stations in Multi-Cell Networks

A crucial aspect when deploying Unmanned Aerial Vehicles (UAVs) to operate as flying base stations (FBSs) assisting 5G networks is path (trajectory) optimization. Even though this topic has received significant research attention for multiple UAVs located at the same base station (BS), the area of path optimization in the case of multiple UAVs located in different BSs serving user equipment (UE) or cluster points (CPs) in a multi cell environment received less attention. This paper addresses a mixed integer linear programming (MILP) formulation for FBS path optimization in terms of travel time considering a multi-cell environment which the BSs can act as the depots for multiple UAVs. Numerical investigations reveal that the proposed UAV path optimization approach can decrease the overall travel time for the deployment of the FBSs compared to other solutions that do explicitly optimize the case of multiple BSs and the UEs and/or CPs that belong within the coverage area of different BSs.