This article studies the physical layer security in a multiple-input-multiple-output (MIMO) dual-functional radar-communication (DFRC) system, which communicates with downlink cellular users and tracks radar targets simultaneously. Here, the radar targets are considered as potential eavesdroppers which might eavesdrop the information from the communication transmitter to legitimate users. To ensure the transmission secrecy, we employ artificial noise (AN) at the transmitter and formulate optimization problems by minimizing the signal-to-noise ratio (SNR) received at radar targets, while guaranteeing the signal-to-interference-plus-noise ratio (SINR) requirement at legitimate users. We first consider the ideal case where both the target angle and the channel state information (CSI) are precisely known. The scenario is further extended to more general cases with target location uncertainty and CSI errors, where we propose robust optimization approaches to guarantee the worst-case performance. Accordingly, the computational complexity is analyzed for each proposed method. Our numerical results show the feasibility of the algorithms with the existence of instantaneous and statistical CSI error. In addition, the secrecy rate of secure DFRC system grows with the increasing angular interval of location uncertainty.

中文翻译：

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具有恶意目标的安全雷达通信系统：集成雷达、通信和干扰功能

本文研究了多输入多输出 (MIMO) 双功能雷达通信 (DFRC) 系统中的物理层安全性，该系统与下行链路蜂窝用户通信并同时跟踪雷达目标。在这里，雷达目标被认为是潜在的窃听者，它们可能会窃听来自通信发射机的信息给合法用户。为确保传输保密性，我们在发射机采用人工噪声 (AN) 并通过最小化雷达目标接收的信噪比 (SNR) 来制定优化问题，同时保证信干噪比(SINR) 对合法用户的要求。我们首先考虑目标角度和信道状态信息 (CSI) 都精确已知的理想情况。该场景进一步扩展到具有目标位置不确定性和 CSI 错误的更一般情况，我们提出了稳健的优化方法来保证最坏情况的性能。因此，分析了每种建议方法的计算复杂性。我们的数值结果表明了算法的可行性，同时存在瞬时和统计 CSI 误差。此外，安全DFRC系统的保密率随着位置不确定性角度间隔的增加而增加。我们的数值结果表明了算法的可行性，同时存在瞬时和统计 CSI 误差。此外，安全DFRC系统的保密率随着位置不确定性角度间隔的增加而增加。我们的数值结果表明了算法的可行性，同时存在瞬时和统计 CSI 误差。此外，安全DFRC系统的保密率随着位置不确定性角度间隔的增加而增加。