Joint Trajectory and Scheduling Design for UAV Aided Secure Backscatter Communications

In a secure backscatter communication system, an unmanned-aerial-vehicle (UAV) operates both as a source of radio frequency (RF) signals and an information collector. Batteryless backscatter devices (BDs) exploit RF signals emitted by the UAV to upload their own information to the UAV with the existence of multiple eavesdroppers (EDs). Uplink fair-secrecy-rate of BDs is maximised by jointly designing the UAV's trajectory, the BDs' scheduling indicators and their backscattering coefficients, while achieving the energy harvesting requirements of batteryless BDs and various flight constraints of the UAV. A block coordinate descent (BCD) algorithm is developed for solving the non-convex optimisation problem. Simulation results demonstrate the substantial performance gain of our design for UAV aided secure backscatter communications.