Trajectory Design for Integrated Sensing and Communication Enabled by Cellular-Connected UAV

Integrated sensing and communication (ISAC) is one of the key technologies enabling the sixth-generation (6G) communication systems. Assisted by unmanned aerial vehicles (UAVs), terrestrial ISAC systems can take advantage of the UAVs' flexibility and line-of-sight. In this letter, we propose a new ISAC system enabled by a cellular-connected UAV, where the UAV and a base station (BS) form a bistatic synthetic aperture radar. The UAV records the reflections of wireless downlink signals, and sends the signals to the BS for object sensing and imaging. The UAV's flight path and transmit power are optimized to minimize its flight and communication energy meanwhile satisfying ISAC requirements. The considered problem is non-convex. We convexify the task and acquire a KKT solution using successive convex approximation and variable substitution. Extensive simulations display effectiveness of our approach in target imaging and verify that it can save as much as 46% energy compared to the benchmarks.