Physical layer security (PLS) is one of the major concerns in modern mobile communication systems and has got special attention in millimeter-wave (mmWave) communication systems. The principal objective of this study is to construct a hybrid precoder that can secure the mmWave communication systems by incorporating the finest techniques to obtain a secure precoder and combiner for the legitimate receiver and to ensure minimum information leakage towards illegal-user. In this context, firstly, a traditionally coordinated precoder and combiner design algorithm is exploited in the analog domain to protect the legitimate receiver, and then, iterative geometric mean decompositions (IGMD) scheme is applied to obtain a digital precoder and combiner. Moreover, artificial noise (AN) is also transmitted towards illegal-user that further alleviates the privacy of the system. Finally, we compared our results with our latest proposed algorithm for a secure hybrid precoder system based on the generalized triangular decomposition (GTD) method and a recent algorithm presented in the literature. The simulation studies confirmed that the IGMD based approach considerably degrades the eavesdropping capabilities of the undesired user and provides significantly better secrecy rate performance as much as 3.5 bps/Hz than its counterparts.

物理层安全性（PLS）是现代移动通信系统中的主要问题之一，并且在毫米波（mmWave）通信系统中得到了特别的关注。这项研究的主要目的是构建一种混合预编码器，它可以通过结合最先进的技术来确保mmWave通信系统的安全，从而为合法接收者获得安全的预编码器和组合器，并确保将最少的信息泄露给非法用户。在这种情况下，首先，在模拟域中利用传统的协调式预编码器和组合器设计算法来保护合法接收器，然后，采用迭代几何均值分解（IGMD）方案来获得数字预编码器和组合器。而且，人工噪声（AN）也向非法用户传输，这进一步减轻了系统的隐私性。最后，我们将结果与基于广义三角分解（GTD）方法的安全混合预编码器系统中最新提出的算法以及文献中提出的最新算法进行了比较。仿真研究证实，基于IGMD的方法大大降低了不希望的用户的窃听能力，并提供了比同类用户更好的保密率性能，高达3.5 bps / Hz。