The integration of sensing and communication enables wireless communication systems to serve environment-aware applications. In this paper, we propose to leverage sensing to enhance physical layer security (PLS) in multiuser communication systems in the presence of a suspicious target. To this end, we develop a two-phase framework to first estimate the location of the potential eavesdropper by sensing and then utilize the estimated information to enhance PLS for communication. In particular, in the first phase, a dual-functional radar and communication (DFRC) base station (BS) exploits a sensing signal to mitigate the sensing information uncertainty of the potential eavesdropper. Then, in the second phase, to facilitate joint sensing and secure communication, the DFRC BS employs beamforming and artificial noise to enhance secure communication. The design objective is to maximize the system sum rate while alleviating the information leakage by jointly optimizing the time allocation and beamforming policy. Capitalizing on monotonic optimization theory, we develop a two-layer globally optimal algorithm to reveal the performance upper bound of the considered system. Simulation results show that the proposed scheme achieves a significant sum rate gain over two baseline schemes that adopt existing techniques. Moreover, our results unveil that ISAC is a promising paradigm for enhancing secure communication in wireless networks.

翻译：感知与通信的融合使无线通信系统能够支持环境感知类应用。本文针对存在可疑目标的场景，提出利用感知技术增强多用户通信系统的物理层安全（PLS）性能。为此，我们构建了一个两阶段框架：首先通过感知潜在窃听者位置，进而利用估计信息增强通信物理层安全。具体而言，在第一阶段，双功能雷达通信（DFRC）基站利用感知信号消除潜在窃听者的感知信息不确定性；在第二阶段，为实现联合感知与安全通信，DFRC基站采用波束赋形与人工噪声技术增强通信安全性。设计目标是通过联合优化时间分配与波束赋形策略，在降低信息泄露的同时最大化系统总速率。基于单调优化理论，我们提出了一种两层全局最优算法以揭示所研究系统的性能上界。仿真结果表明，相较于两种采用现有技术的基准方案，所提方案实现了显著的总速率增益。此外，研究结果揭示通感一体化（ISAC）是增强无线网络安全通信的具有前景的技术范式。