Energy-Efficient UAV Backscatter Communication With Joint Trajectory Design and Resource Optimization

Backscatter communication which enables wireless-powered backscatter devices (BDs) to transmit information by reflecting incident signals, is an energy- and cost-efficient technology for Internet-of-Things. This paper considers unmanned aerial vehicle (UAV)-assisted network (UBCN) consisting of multiple BDs carrier emitters (CEs) on the ground as well a UAV. A communicate-while-fly scheme first designed, in illuminated their associated CEs flying UAV time-division-multiple-access manner. Considering critical issue UAV's limited on-board energy CEs' transmission energy, we maximize efficiency (EE) UBCN jointly optimizing trajectory, BDs' scheduling, power, subject throughput constraints harvested constraints, other practical constraints. Furthermore, propose iterative algorithm based block coordinated decent method solve formulated mixed-integer non-convex problem, each iteration variables are alternatively optimized leveraging cutting-plane technique, Dinkelbach's successive convex approximation technique. Also, convergence complexity proposed analyzed. Finally, simulation results show that achieves significant EE gains compared with hover-and-fly scheme, state-of-the-art CE-relay scheme. Useful insights optimal trajectory design resource allocation also obtained.