Spatio-Temporal Trajectory Design for UAVs: Enhancing URLLC and LoS Transmission in Communications

This letter explores the potential of unmanned aerial vehicles (UAVs) to support Ultra-Reliable Low-Latency Communication (URLLC). The primary objective is to enhance link quality by leveraging the high-probability Line-of-Sight (LoS) links inherent in UAV communication systems. This letter presents a novel trajectory planning framework that addresses energy consumption in the high-dynamic flight states of UAVs while maintaining communication quality by managing communication constraints. To achieve this, the framework introduces a LoS persistence-based motion prediction method and a path exploration technique that considers Device-to-Device (D2D) communication quality. These methods establish optimal topology structures and evaluate the costs associated with signal quality loss. Additionally, the study proposes an efficient trajectory optimization method for generating spatio-temporally optimal trajectories within predefined flight corridors, aimed at achieving optimal LoS link quality. To ensure flight safety and LoS persistence, specific optimization expressions are designed to concurrently address all these requirements. Simulation results indicate that this approach not only maintains high communication signal link quality but also minimizes flight time.