Energy-Efficient UAV Backscatter Communication with Joint Trajectory and Resource Optimization

This paper considers a UAV-enabled backscatter communication network (UBCN) in which multiple backscatter devices (BDs) on the ground are illuminated by their associated ground carrier emitters (CEs) and transmit information to a flying UAV in a dynamic time-division-multiple-access manner. To tackle the critical issue of limited UAV on-board energy and CE transmission energy, we maximize the energy efficiency (EE) by jointly optimizing the BD scheduling, the BDs' power reflection coefficients, the CEs' transmission powers, and the UAV trajectory, subject to the BDs' throughput constraints and other practical constraints. Furthermore, we propose an iterative algorithm to solve the formulated non-convex problem, by leveraging the block coordinated decent and the successive convex approximation techniques. Finally, extensive simulation results show that the proposed communicate-while-fly scheme achieves significant EE gains compared to the benchmark hover-and-fly scheme.