Security Provided by the Physical Layer in Wireless Communications

This article provides an overview of five physical-layer security mechanisms: Physical-Layer Authentication (PLA), Physical-Layer Confidential Communications (PLCC), Physical-Layer Key Generation (PLKG), Physical-Layer Communications with Low Probability of Detection (PLC-LPD), and Physical-Layer Steganography (PLS). We explain the relationship among five physical-layer security mechanisms. Then, we review the features of various physical-layer security mechanisms in terms of the basic idea, properties, assumptions, classification, threat model, and applications, respectively. At last, we introduce five promising plans by combining different physical-layer security mechanisms to further improve the final performance.