Energy Minimization for Fixed-Wing UAV Assisted Full-Duplex Relaying With Bank Angle Constraint

In order to make turns, a fixed-wing unmanned aerial vehicle (UAV) needs to change its bank angle gradually. While banking at large angle and high velocity leads to an increased risk of stalling the aircraft. It means that there exists a bank angle constraint (BAC) for a flying UAV. However, BAC is often ignored in studies regarding a fixed-wing UAV assisted communications. This letter considers a fixed-wing UAV assisted full-duplex amplify-and-forward relaying with a BAC, where the UAV is flying along a circular path while forwarding a required amount of data-bits from a source to a destination. With the aim of minimizing the energy consumption, a joint optimization scheme for adjusting the UAV's flight velocity, radius and time is developed. The effectiveness and efficiency of the proposed joint optimization scheme as well as the impact of the BAC on the optimization scheme are verified by computer simulations.