Throughput Maximization in a UAV-Enabled Two-Way Relaying System with Multi-Pair Users

In this letter, we propose a UAV-enabled two-way relaying system where a UAV relay assists the information exchange among multiple pairs of ground users (GUs). We formulate a mixed integer non-convex programming to maximize the minimum average rate of GUs by jointly optimizing transmission scheduling parameters, transmission powers of UAV and GUs, as well as UAV trajectory. The Branch-and-Bound method and the successive convex approximation technique are adopted to solve the non-convex uplink and downlink transmission scheduling and UAV trajectory optimization, respectively. Then, an iterative algorithm is proposed to solve the joint optimization problem by adopting block coordinate descent method. Numerical results show that the proposed joint UAV trajectory communication design method could outperform other benchmark algorithms.