无小区集成感知与通信（ISAC）网络中针对移动窃听者的跟踪辅助鲁棒安全传输
Tracking-Assisted Robust Secure Transmission Against a Mobile Eavesdropper in Cell-Free ISAC Networks
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中文总结 AI 辅助
本文针对无小区ISAC网络，提出跟踪辅助鲁棒安全传输框架，通过EKF与雅可比各向异性椭球模型处理移动窃听者的信道不确定性，联合优化波束成形与感知信号，实现保密性能提升。
中文摘要 AI 辅助
本文针对无小区集成感知与通信（ISAC）网络，提出一种跟踪辅助鲁棒安全传输框架，该框架利用分布式多静态感知递归跟踪移动窃听者并量化相关位置不确定性。由于鲁棒波束成形需要的是通信信道不确定性而非位置不确定性，直接将跟踪信息融入安全传输并非易事，这一挑战在无小区ISAC场景下更为突出：共同的位置不确定性会以不同方式传播到地理分布式接入点（AP）的信道，进而产生与各AP耦合的信道不确定性。为应对该挑战，我们利用扩展卡尔曼滤波器（EKF）融合来自分布式AP和感知接收机的多静态感知测量值，并提出一种基于雅可比矩阵的各向异性椭球不确定性模型，将EKF的位置误差协方差映射为与各AP耦合的信道不确定性。基于所提模型，我们在每个AP的发射功率和感知均方误差约束下，构建了鲁棒和保密速率最大化问题，并开发了一种高效的交替优化算法，用于联合设计通信波束成形和感知信号。仿真结果表明，跟踪精度与保密性能之间存在基本权衡，验证了无小区ISAC中分布式多静态感知与协作传输的优势，以及所提鲁棒设计在应对移动性引发的信道不确定性时提升保密可靠性的有效性。
英文摘要
In this paper, we propose a tracking-assisted robust secure transmission framework for cell-free integrated sensing and communication (ISAC) networks that exploits distributed multistatic sensing to recursively track a mobile eavesdropper and quantify the associated position uncertainty. Since robust beamforming requires communication channel uncertainty rather than position uncertainty, directly incorporating tracking information into secure transmission is nontrivial. This challenge becomes more pronounced in cell-free ISAC, where the common position uncertainty propagates differently to the channels of geographically distributed access points (APs), resulting in coupled AP-specific channel uncertainties. To address this challenge, we fuse multistatic sensing measurements from distributed APs and sensing receivers using an extended Kalman filter (EKF) and propose a Jacobian-based anisotropic ellipsoidal uncertainty model that maps the EKF position-error covariance to coupled AP-specific channel uncertainties. Based on the proposed model, we formulate a robust sum secrecy-rate maximization problem under per-AP transmit-power and sensing mean-square error constraints and develop an efficient alternating optimization algorithm for the joint design of communication beamforming and sensing signals. Simulation results demonstrate a fundamental trade-off between tracking accuracy and secrecy performance, the benefits of distributed multistatic sensing and cooperative transmission in cell-free ISAC, and the effectiveness of the proposed robust design in improving secrecy reliability under mobility-induced channel uncertainty.
