Approximate algorithms for 3-D placement of IBFD enabled drone-mounted base stations

The future 5G network is expected to provide throughput 1000 times and spectrum efficiency 10 times those of the current 4G network. In-band full-duplex (IBFD) is a promising technique for 5G that can conceivably improve spectrum efficiency. Drone-mounted base stations (DBSs) provide high mobility and high flexibility, and leveraging DBSs to provision services to UEs can facilitate the quality of service of the wireless network and enlarge the coverage area. Therefore, the throughput and the spectrum efficiency can be improved by leveraging IBFD-enabled DBSs. We formulate the drone-mounted base station placement with IBFD communications (DBSP-IBFD) problem, which consists of two sub-problems: the joint bandwidth, power allocation and UE association (joint-BPU) problem and the DBS placement problem. We first propose an approximate algorithm to solve the joint-BPU problem that provides guaranteed performance. Then, an exhaustive search method is employed to obtain the optimal locations for DBSs. After that, we propose a ₂¹ (1 − ₂¹_l )-approximation algorithm to solve the DBSP-IBFD problem, where l is the number of simulation runs. Simulation results have demonstrated that the throughput of the proposed approximate algorithm is superior to benchmark algorithms in solving the DBSP-IBFD problem.