UAV Positioning and Power Control for Wireless Two-Way Relaying

This paper investigates an unmanned-aerial-vehicle-enabled (UAV-enabled) wireless two-way relaying system. The UAV positioning and the transmission powers of all nodes are jointly designed to maximize the sum rate of both uplink and downlink subject to signal-to-noise ratio constraint on the UAV control channel. The formulated joint design problem has an intricate expression of the sum rate due to two-way transmissions and is difficult to solve in general. We propose a novel concave surrogate function for the sum rate and employ the successive convex approximation (SCA) technique for obtaining a high-quality approximate solution. We show that the proposed surrogate function has a smaller curvature and can enable a faster convergence of SCA. Simulation results show that the optimized UAV position is non-trivial and the proposed algorithm greatly outperforms heuristic methods.