Efficient Deployment of Multiple Unmanned Aerial Vehicles for Optimal Wireless Coverage

In this paper, the efficient deployment of multiple unmanned aerial vehicles\n(UAVs) with directional antennas acting as wireless base stations that provide\ncoverage for ground users is analyzed. First, the downlink coverage probability\nfor UAVs as a function of the altitude and the antenna gain is derived. Next,\nusing circle packing theory, the three-dimensional locations of the UAVs is\ndetermined in a way that the total coverage area is maximized while maximizing\nthe coverage lifetime of the UAVs. Our results show that, in order to mitigate\ninterference, the altitude of the UAVs must be properly adjusted based on the\nbeamwidth of the directional antenna as well as coverage requirements.\nFurthermore, the minimum number of UAVs needed to guarantee a target coverage\nprobability for a given geographical area is determined. Numerical results\nevaluate the various tradeoffs involved in various UAV deployment scenarios.\n