Priority-Focused Trajectory Planning for UAV-Assisted Full-Duplex OWC Systems

More recently, unmanned aerial vehicle (UAV)-assisted full-duplex (FD) communication has been considered to enhance system capacity and reliability. Nevertheless, traditional UAV-assisted systems based on radio frequency (RF) face certain challenges, including limited bandwidth and inability to operate in RF-denied areas. In fact, the optical wireless communication (OWC) approach can effectively resolve the aforementioned issues, which is rarely employed in UAV-assisted systems. In this paper, we develop a UAV-assisted FD OWC system utilizing light-emitting diodes (LEDs) and vertical-cavity surface-emitting laser (VCSEL) arrays for downlink (DL) and uplink (UL) light sources to facilitate communications of ground users (GUs). To effectively allocate resources for GUs with different priorities, we introduce a priority-focused UAV trajectory planning approach for this system and apply deep reinforcement learning (DRL) techniques to determine UAV flight trajectories, thereby enhancing the DL communication capacity for each GU. Numerical results demonstrate that the proposed system improves the DL communication capacity of each GU, and successfully achieves the intended tilting of communication resources with the introduced priority sets.