AI 中文总结
研究卫星通信链路易被窃听问题，提出CPWC系统，利用IRS协作及基于OFDM的RSCS方法增强隐蔽性。基于实际信道模型推导约束，通过AO-SDR和SQP算法优化，提升隐蔽速率，所提系统在隐蔽速率上优于多种基准方案。
AI 中文摘要
卫星通信作为地面网络的有效补充，因其覆盖范围广和高度灵活性而备受关注。然而，卫星链路的固有开放性使其极易被窃听，带来重大安全挑战。本文提出一种卫星隐蔽精确无线通信（CPWC）系统，多个智能反射面（IRS）协作辅助卫星传输，确保机密信息能传送给合法用户且不被窃听者察觉。为进一步增强隐蔽性，开发了基于正交频分复用（OFDM）的随机子载波选择（RSCS）方法来将信号能量集中到目标接收器。在实际卫星-地面信道模型下，基于相对熵和检测错误概率推导了CPWC系统的闭式隐蔽性约束。在相对熵约束和卫星功率约束下，通过基于交替优化（AO）的半定松弛（SDR）迭代算法最大化隐蔽速率并获得高质量可行解。以该解为热启动，进一步施加检测错误概率约束并通过基于序列二次规划（SQP）的算法优化波束形成器。数值结果证明了所提CPWC系统的有效性，基于检测错误概率的方案在隐蔽速率方面优于二阶锥规划（SOCP）基准、随机相移设计、一位IRS量化方案以及无精确通信（PC）的SDR基线。
英文摘要
Satellite communication (SatCom), as an effective complement to terrestrial networks, has attracted considerable attention from both academia and industry owing to its wide coverage and high flexibility. However, the inherent openness of satellite links renders them highly vulnerable to eavesdropping, thereby posing significant security challenges. In this paper, we propose a satellite covert precision wireless communication (CPWC) system, where multiple intelligent reflecting surfaces (IRSs) cooperate to assist satellite transmissions, ensuring that confidential information is delivered to legitimate users while remaining undetectable to wardens. To further enhance covertness, an orthogonal frequency division multiplexing (OFDM)-based random subcarrier selection (RSCS) method is developed to concentrate the signal energy at the intended receiver. Under a practical satellite-terrestrial channel model, we derive closed-form covertness constraints for the CPWC system based on relative entropy and detection error probability. Under the relative-entropy constraint and the satellite power constraint, we maximize the covert rate by an alternating-optimization (AO) based semidefinite relaxation (SDR) iterative algorithm and obtain a high-quality feasible solution. Using this solution as a warm start, we further impose the detection-error-probability constraint and refine the beamformer through a sequential quadratic programming (SQP) based algorithm. Numerical results demonstrate the effectiveness of the proposed CPWC system, where the detection-error-probability-based scheme outperforms the second-order cone programming (SOCP) benchmark, the random-phase-shift design, the one-bit IRS quantized scheme, and the SDR baseline without precise communication (PC) in terms of covert rate.
Comments16 pages, 12 figures
