Optimizing the Deployment and Throughput of DBSs for Uplink Communications

Drone-mounted base stations (DBSs) are promising means to provide ubiquitous connections to users and support various emerging applications in mobile networks while full duplex communications has the potential to improve the spectrum efficiency. In this paper, we investigate the backhaul-aware uplink communications in a full-duplex DBS-aided HetNet (BUD) problem with the objective to maximize the total throughput of the network while minimizing the number of deployed DBSs. Since the BUD problem is NP-hard, it is then decomposed into three sub-problems: the joint UE association, power and bandwidth assignment (Joint-UPB) problem, the DBS placement problem (including the vertical and horizontal positions) and the problem of determining the number of DBSs to be deployed. We propose two approximation algorithms to solve the first two sub-problems and use the linear programming to solve the last sub-problem. Finally, another approximation algorithm, referred to as the AA-BUD algorithms, is proposed to solve the BUD problem with guaranteed performance based on the solutions of the three sub-problems. The performance of the AA-BUD algorithm has been demonstrated via extensive simulations, and is shown to be superior to two benchmark algorithms with up to 62% throughput improvement.