Fixed-Wing UAV Aided Full-Duplex Amplify-and-Forward Relaying With Constant Ambient Wind

This paper studies a fixed-wing unmanned aerial vehicle (UAV) aided full-duplex amplify-and-forward relaying in the presence of a constant ambient wind, where the UAV flies along a predetermined ground track and provides relaying service to two ground users so as to meet their demand of data transmission. According to aerodynamics and the wind triangle, engine power of the UAV under wind disturbance is evaluated. It is shown that the UAV’s engine power is related only to the vertical component of the wind-speed while not to the horizontal component when the UAV performs a level flight at a constant air-speed. On this basis, an optimization problem corresponding to the adjustment of the UAV’s air-speed, flight time and attitude (namely, crab and pitch angles) is studied. According to the wind triangle, three sub-problems are derived from the initial problem and solved by three propositions proposed, which leads to a novel optimization method. Computer simulation results confirmed that the developed optimization method can allow the UAV to fly according to the predetermined ground track and provide satisfactory relaying service for the two ground users through the adjustment of the UAV’s air-speed and flight time as well as its crab and pitch angles.