Throughput Maximization for UAV-enabled Integrated Periodic Sensing and Communication

Driven by unmanned aerial vehicle (UAV)'s advantages of flexible observation and enhanced communication capability, it is expected to revolutionize the existing integrated sensing and communication (ISAC) system and promise a more flexible joint design. Nevertheless, the existing works on ISAC mainly focused on exploring the performance of both functionalities simultaneously during the entire considered period, which may ignore the practical asymmetric sensing and communication requirements. To address this issue, we propose a new integrated periodic sensing and communication (IPSAC) mechanism for UAV-enabled ISAC systems to provide a more flexible trade-off between two integrated functionalities. Specifically, the system achievable rate is maximized via jointly optimizing beamforming, user association, sensing time selection, and UAV trajectory, while meeting the sensing frequency and beam pattern gain requirements for the given targets. Despite that this problem is highly non-convex, we derive the closed-form optimal beamforming vector to dramatically reduce the complexity of beamforming design and present a tight lower bound of the achievable rate to facilitate UAV trajectory design. Accordingly, we propose a two-layer penalty-based algorithm to solve the considered problem. Numerical results validate the effectiveness of our proposed designs and unveil a more flexible trade-off in ISAC systems over benchmark schemes.