Physical layer security is a promising approach that can benefit traditional encryption methods. The idea of physical layer security is to take advantage of the propagation medium’s features and impairments to ensure secure communication in the physical layer. This work introduces a comprehensive review of the main information-theoretic metrics used to measure the secrecy performance in physical layer security. Furthermore, a theoretical framework related to the most commonly used physical layer security techniques to improve secrecy performance is provided. Finally, our work surveys physical layer security research over several enabling 5G technologies, such as massive multiple-input multiple-output, millimeter-wave communications, heterogeneous networks, non-orthogonal multiple access, and full-duplex. We also include the key concepts of each of the technologies mentioned above. Also identified are future fields of research and technical challenges of physical layer security.

物理层安全性是一种有前途的方法，可以使传统的加密方法受益。物理层安全性的思想是利用传播介质的功能和缺陷来确保物理层中的安全通信。这项工作对用于测量物理层安全性保密性能的主要信息理论指标进行了全面回顾。此外，提供了与最常用的物理层安全技术相关的理论框架，以提高保密性能。最后，我们的工作对几种可行的5G技术进行了物理层安全性研究，例如大规模多输入多输出，毫米波通信，异构网络，非正交多路访问和全双工。我们还包括上述每种技术的关键概念。还确定了物理层安全性的未来研究领域和技术挑战。