  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.
