无人机搭载六维可重构智能表面（IRS）辅助的感知通信一体化（ISAC）系统的保密速率最大化
Secrecy Rate Maximization for UAV-Mounted Six-Dimensional Movable IRS-Assisted ISAC Systems
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中文总结 AI 辅助
针对低空ISAC系统的物理层安全局限，提出无人机搭载六维可移动IRS辅助的ISAC系统，采用三模块交替优化框架联合优化多变量，大幅提升保密速率。
中文摘要 AI 辅助
感知通信一体化（ISAC）是6G无线网络的关键使能技术，但其广播特性会在感知目标充当潜在窃听者时引发物理层安全问题。虽然可重构智能表面（IRS）可增强无线传播并提升保密性，但现有安全IRS辅助ISAC设计大多局限于固定部署和无源相位控制，在视距主导的低空场景中空间适应性有限。为解决该局限，本文研究无人机（UAV）搭载六维可移动IRS辅助的安全ISAC系统，其中IRS的位置、朝向和反射系数与基站（BS）波束成形器联合优化，以在通信服务质量（QoS）、功率、单位模和可见性约束下最大化保密速率。由于有源/无源波束成形变量与依赖IRS位置和朝向（姿态依赖）的信道响应耦合，所得问题高度非凸。为高效求解，本文提出三模块交替优化（AO）框架，其中有源波束成形器通过线性化交替方向乘子法（ADMM）更新，IRS姿态通过热启动粒子群优化更新，无源反射向量通过黎曼梯度下降更新。仿真结果表明，所提设计显著优于固定位置和仅朝向的基线方案，凸显联合平移、旋转和相位控制对安全ISAC的重要性。
英文摘要
Integrated sensing and communication (ISAC) is a key enabling technology for 6G wireless networks, but its broadcast nature raises a physical-layer security concern when the sensing target can act as a potential eavesdropper. Although intelligent reflecting surfaces (IRSs) can enhance wireless propagation and improve secrecy, existing secure IRS-assisted ISAC designs are mostly limited to fixed deployments and passive phase control, which offer limited spatial adaptability in line-of-sight-dominated low-altitude scenarios. To address this limitation, we investigate an unmanned aerial vehicle (UAV)-mounted six-dimensional movable IRS-assisted secure ISAC system, where the IRS location, orientation, and reflection coefficients are jointly optimized with the BS beamformer to maximize the secrecy rate under communication quality-of-service (QoS), power, unit-modulus, and visibility constraints. The resulting problem is highly non-convex due to the coupled active/passive beamforming variables and the location-and-orientation-dependent (pose-dependent) channel responses. To solve it efficiently, we develop a three-block alternating optimization (AO) framework, in which the active beamformer, IRS pose, and passive reflection vector are updated via linearized ADMM, warm-started particle swarm optimization, and Riemannian gradient descent, respectively. Simulation results show that the proposed design significantly outperforms fixed-location and orientation-only baselines, highlighting the importance of joint translation, rotation, and phase control for secure ISAC.
