We study security solutions for dual-functional radar communication (DFRC) systems, which detect the radar target and communicate with downlink cellular users in millimeter-wave (mmWave) wireless networks simultaneously. Uniquely for such scenarios, the radar target is regarded as a potential eavesdropper which might surveil the information sent from the base station (BS) to communication users (CUs), that is carried by the radar probing signal. Transmit waveform and receive beamforming are jointly designed to maximize the signal-to-interference-plus-noise ratio (SINR) of the radar under the security and power budget constraints. We apply a Directional Modulation (DM) approach to exploit constructive interference (CI), where the known multiuser interference (MUI) can be exploited as a source of useful signal. Moreover, to further deteriorate the eavesdropping signal at the radar target, we utilize destructive interference (DI) by pushing the received symbols at the target towards the destructive region of the signal constellation. Our numerical results verify the effectiveness of the proposed design showing a secure transmission with enhanced performance against benchmark DFRC techniques.

中文翻译：

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安全的双功能雷达通信传输：利用干扰增强抵御目标窃听的能力

我们研究双功能雷达通信 (DFRC) 系统的安全解决方案，该系统检测雷达目标并同时与毫米波 (mmWave) 无线网络中的下行链路蜂窝用户进行通信。在这种情况下，雷达目标独特地被视为潜在的窃听者，它可能会监视由雷达探测信号携带的从基站 (BS) 发送到通信用户 (CU) 的信息。发射波形和接收波束成形联合设计以在安全和功率预算约束下最大化雷达的信干噪比 (SINR)。我们应用定向调制 (DM) 方法来利用相长干扰 (CI)，其中可以利用已知的多用户干扰 (MUI) 作为有用信号的来源。而且，为了进一步恶化雷达目标处的窃听信号，我们通过将目标处的接收符号推向信号星座的破坏性区域来利用破坏性干扰 (DI)。我们的数值结果验证了所提出设计的有效性，显示了与基准 DFRC 技术相比具有增强性能的安全传输。