标题： 面向安全ISAC波束赋形：需要多少专用感知波束？ 显示英文标题

标题： Towards Secure ISAC Beamforming: How Many Dedicated Sensing Beams Are Required?

摘要： 在本文中，研究了多用户多窃听者集成感知与通信（ISAC）系统中的感知辅助安全通信。 保密通信信号和专用感知信号由基站（BS）联合传输，以同时服务用户并感知空中窃听者（AEs）。 在AEs的信噪比加干扰比（SINR）和感知信杂比加噪声比（SCNR）约束下，制定了一个总速率最大化问题。 开发了一种基于分数规划的交替优化算法来解决这个问题，适用于完全数字阵列，其中依次凸近似（SCA）和半定松弛（SDR）被用来处理非凸约束。 此外，通过最坏情况下的秩界分析了专用感知波束的最小数量，在此基础上，所提出的波束成形设计进一步扩展到混合模拟-数字（HAD）阵列架构，其中通过流形优化解决了单位模约束。 仿真结果表明，仅需少量感知波束即可同时实现感知和干扰AEs，所提出的方案始终优于强基线方案，同时也揭示了通信与感知之间的权衡。 显示英文摘要

摘要： In this paper, sensing-assisted secure communication in a multi-user multi-eavesdropper integrated sensing and communication (ISAC) system is investigated. Confidential communication signals and dedicated sensing signals are jointly transmitted by a base station (BS) to simultaneously serve users and sense aerial eavesdroppers (AEs). A sum rate maximization problem is formulated under AEs' Signal-to-Interference-plus-Noise Ratio (SINR) and sensing Signal-to-Clutter-plus-Noise Ratio (SCNR) constraints. A fractional-programming-based alternating optimization algorithm is developed to solve this problem for fully digital arrays, where successive convex approximation (SCA) and semidefinite relaxation (SDR) are leveraged to handle non-convex constraints. Furthermore, the minimum number of dedicated sensing beams is analyzed via a worst-case rank bound, upon which the proposed beamforming design is further extended to the hybrid analog-digital (HAD) array architecture, where the unit-modulus constraint is addressed by manifold optimization. Simulation results demonstrate that only a small number of sensing beams are sufficient for both sensing and jamming AEs, and the proposed designs consistently outperform strong baselines while also revealing the communication-sensing trade-off.