Physical layer security incorporates security features embedded in the communication channels without the need to exchange cryptographic keys. Interest in exploiting such mechanisms has been increasing rapidly for 5G and beyond, due to the low overhead and low-latency properties of such encoding. Although phased arrays, by their nature of the focused beams to users, introduce secrecy, they are still vulnerable to eavesdropping at the sidelobes. In this article, we present a class of spatio-temporal modulated arrays (STMAs) with custom CMOS integrated circuits (ICs) and packaged antennas operating in the 71–76-GHz range that creates secure cones in space by preserving signal fidelity in the intended direction while emulating a time-varying channel outside the secure cone. At unintended directions, the architecture intentionally spectrally aliases signals to create noise-like features and scrambles constellations with a one-to-many mapping (including infinite constellation splitting), making it challenging to invert the mapping by eavesdroppers. Through the architecture, the secure cone can be reconfigured in space on demand and narrowed when we increase the number of elements. We also show how reconfigurable time modulation (such as through frequency chirping) can create a non-repetitive mapping of the constellation to protect against colluding attacks.

中文翻译：

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通过时空毫米波发射机阵列的定向调制实现物理层安全


物理层安全性结合了嵌入通信通道中的安全功能，无需交换加密密钥。由于此类编码的低开销和低延迟特性，对于 5G 及更高版本利用此类机制的兴趣正在迅速增加。尽管相控阵由于其向用户聚焦波束的性质而引入了保密性，但它们仍然容易在旁瓣处被窃听。在本文中，我们提出了一类时空调制阵列 (STMA)，具有定制 CMOS 集成电路 (IC) 和在 71-76 GHz 范围内运行的封装天线，通过在预期的范围内保持信号保真度，在空间中创建安全的锥体。方向，同时模拟安全锥体外部的时变通道。在意想不到的方向上，该架构故意对信号进行频谱混叠，以创建类似噪声的特征，并通过一对多映射（包括无限星座分裂）来扰乱星座，从而使窃听者很难反转映射。通过该架构，安全锥体可以根据需要在空间中重新配置，并在我们增加元件数量时缩小。我们还展示了可重新配置的时间调制（例如通过频率啁啾）如何创建星座的非重复映射以防止串通攻击。