发表机构
Xi’an Jiaotong University; Rocket Force University of Engineering; Beijing Jiaotong University; Beijing University of Posts and Telecommunications; Shanghai Jiao Tong University（西安交通大学; 中国人民解放军战略支援部队工程大学; 北京交通大学; 北京邮电大学; 上海交通大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
针对RIS赋能保密ISAC系统中移动窃听者导致信道动态变化的问题，提出联合优化波束成形、人工噪声与RIS反射系数并集成EKF跟踪的算法，提升保密速率并有效跟踪窃听者轨迹。
AI 中文摘要
本文研究了一种可重构智能表面（RIS）赋能的保密集成感知与通信（ISAC）系统，其中基站（BS）与用户之间的直连链路被阻断，且一个移动窃听者被视为潜在的窃听者和感知目标。时变的窃听者状态导致窃听信道动态变化，这可能降低基于过时窃听者信息的传统传输设计的有效性。为解决此问题，基站连续时隙跟踪窃听者，并利用预测的状态信息来调整保密传输。本文构建了一个优化问题，通过联合设计基站波束成形、人工噪声以及RIS反射系数以用于保密传输和回波感知，最大化总保密速率。同时，施加误差协方差约束以保证所需的跟踪精度。为解决该非凸且时间耦合的问题，我们提出了一种集成扩展卡尔曼滤波（EKF）和块坐标优化框架的优化算法，其中窃听者状态被递归预测和更新，而联合设计问题被分解为四个可处理的子问题。仿真结果表明，与基准方案相比，所提算法能更好地保证保密速率，并有效跟踪窃听者的移动轨迹。
英文摘要
This paper investigates a reconfigurable intelligent surface (RIS)-enabled secure integrated sensing and communication (ISAC) system, where the direct links between the base station (BS) and users are blocked and a mobile eavesdropper is treated as both a potential wiretapper and a sensing target. The time-varying eavesdropper state leads to dynamically changing wiretap channels, which may degrade the effectiveness of conventional transmission designs based on outdated eavesdropper information. To address this issue, the BS tracks the eavesdropper over consecutive time slots and exploits the predicted state information to adapt secure transmission. An optimization problem is formulated to maximize the sum secrecy rate by jointly designing the BS beamforming, artificial noise, and the RIS reflection coefficients for secure transmission and echo sensing. Meanwhile, an error-covariance constraint is imposed to guarantee the required tracking accuracy. To solve the nonconvex and temporally coupled problem, we propose an optimization algorithm integrating the extended Kalman filter (EKF) and block coordinate optimization framework, in which the eavesdropper state is recursively predicted and updated, while the joint design problem is decomposed into four tractable subproblems. Simulation results demonstrate that compared with benchmark schemes, the proposed algorithm can better guarantee the secrecy rate and effectively track the moving trajectory of the eavesdropper.
