  Using drone base stations (drone-BSs) in wireless networks has started
attracting attention. Drone-BSs can assist the ground BSs in both capacity and
coverage enhancement. One of the important problems about integrating drone-BSs
to cellular networks is the management of their placement to satisfy the
dynamic system requirements. In this paper, we propose a method to find the
positions of drone-BSs in an area with different user densities using a
heuristic algorithm. The goal is to find the minimum number of drone-BSs and
their 3D placement so that all the users are served. Our simulation results
show that the proposed approach can satisfy the quality-of-service requirements
of the network.
