Physical Layer Authentication for 5G Communications: Opportunities and Road Ahead

Resorting to the exploitation of physical attributes, physical-layer authentication (PLA) is a promising technology to supplement and enhance current cryptography-based security mechanisms in wireless communications. in the fifth-generation (5G) communications, many disruptive technologies spring up, such as millimeter-wave communication (mmWave), massive multiple-input and multiple-output (MiMO) and non-orthogonal- multiple-access (NOMA). PLA schemes in 5G networks are facing challenges while exposed to opportunities at the same time. This article seeks to identify the critical technology gaps as well as the feasible enablers in terms of the unique characteristics of 5G networks. The investigation consists of four hierarchical parts. in the first section, existing PLA schemes are reviewed, and the corresponding challenges are discussed in the next section. in the third section, we investigate potential enablers based on the unique characteristics of 5G networks and provide three corresponding PLA case studies. Open problems and research directions on PLA for 5G and beyond are discussed in the last section, including waveform design, feature learning, mobile users, and terahertz communications.