Physical-Layer Security for 5G and Beyond

Recently, the physical layer has gained a more prominent role on the security context of wireless networks due to its potentiality on providing more effective solutions to safeguard confidentiality and privacy for 5G-and-beyond networks. Physical-layer security (PLS) techniques are recognized to offer powerful features that can complement and enhance cryptography-based mechanisms, by considering the unique properties of wireless channels. Even though physical-layer security has been intensively studied in the past decade, novel scenarios expected for future networks impose big challenges for the full acceptance of PLS techniques as a component of the security solutions of 5G-and-beyond networks. This article provides a brief overview of the information theoretic fundamentals of secrecy and secrecy metrics. The most recognized PLS techniques are described, and the challenges and issues regarding some well-known 5G technologies are also provided.