Unmanned Aerial Vehicle-Based Hybrid Backscatter and Wireless Powered Communications: 3-D Trajectory Design and Resource Scheduling

This paper proposes a hybrid backscatter and wireless powered communications system based on unmanned aerial vehicle (UAV). UAV operates both as a source of radio frequency (RF) signals and an information collector. The system integrates passive information transmission (IT) via backscatter communication (BC) and active IT via wireless powered communication (WPC) to meet the requirements of low-power multi-function communication. At the same time, the system considers the LOS/NLOS channel at variable altitude. By jointly designing the 3D flight trajectory of UAV, the system time slot resources and the active transmit power of ground equipment can maximize the fair rate of ground equipment, and the system also considers various flight restrictions of UAV. Based on the block coordinate descent algorithm, this paper divides the original problem into several sub-problems and processes them separately, and finally obtains an approximate solution through joint iteration. The simulation results show that the hybrid backscatter and wireless powered communications system based on UAV proposed in this paper can significantly improve the fair rate of ground equipment compared with other benchmark schemes.