Jointly Optimizing Drone-Mounted Base Station Placement and User Association in Heterogeneous Networks

Applying Drone-mounted Base Station (DBS) to assist Macro Base Station (MBS) can potentially increase the throughput of the mobile access network. In this paper, we first derive the spectral efficiency of delivering traffic from the MBS to a Ground User (GU) via the DBS, which is operated in the half-duplex in-band mode, upon which we formulate the problem by jointly optimizing the DBS placement (i.e., the altitude of the DBS) and user association in order to maximize the spectral efficiency of the hotspot area. We design the Spectral efficienT Aware DBS pLacement and usEr association (STABLE) algorithm to solve the proposed problem and demonstrate the performance of STABLE via simulations.