Throughput Maximization for Laser-Powered UAV Wireless Communication Systems

Laser power has become a viable solution to provide convenient and sustainable energy supply to unmanned aerial vehicles (UAVs). In this paper, we study a laser-powered UAV wireless communication system, where a laser transmitter sends laser beams to charge a fixed-wing UAV in flight, and the UAV uses the harvested laser energy to communicate with a ground station. To maintain the UAV's sustainable operation, its total energy consumption cannot exceed that harvested from the laser transmitter. Under such a laser energy harvesting constraint, we maximize the downlink communication throughput from the UAV to the ground station over a finite time duration, by jointly optimizing the UAV's trajectory and its transmit power allocation. However, due to the complicated UAV energy consumption model, this problem is non-convex and difficult to be solved. To tackle the problem, we first consider a special case with a double-circular UAV trajectory which balances the tradeoff between maximizing the performance of laser energy harvesting versus wireless communication at the UAV. Next, based on the obtained double-circular trajectory, we propose an efficient solution to the general problem, by applying the techniques of alternating optimization and sequential convex programming (SCP). Finally, numerical results are provided to validate the communication throughput performance of the proposed design.