Joint Trajectory Design and Sub-channel Allocation in the UAV Relaying OFDMA Network

In this paper, we consider an orthogonal frequency division multiple access (OFDMA)-based unmanned aerial vehicle (UAV) relaying system with multiple user equipment (UE) pairs, which has not yet been well studied despite its potential for promising use cases (e.g., a UAV relay-enabled standalone private 5G network). We study a joint optimization problem for UAV trajectory and sub-channel allocation to maximize the total average end-to-end throughput while satisfying the quality-of-serivce (QoS) requirements of UE pairs. To address this problem, we develop a block coordinate descent (BCD)-based algorithm that iteratively solves two sub-problems: 1) a sub-channel allocation optimization problem with a given UAV trajectory, and 2) a UAV trajectory optimization problem with a given sub-channel allocation. Through simulation, we demonstrate the effectiveness of the proposed algorithm.