Improving the Covertness in the Physical-Layer Authentication

• 来源期刊: 中国通信（英文版）
• 年，卷（期）: 2021,（3）
• 所属期刊栏目: COMMUNICATIONS THEORIES & SYSTEMS
• 页码范围: 122-131
• 页数: 10页
• 语种: 英文

摘要

A well-designed Physical-Layer Authen-tication (PLA) scheme should consider three proper-ties: covertness, robustness, and security. However, the three properties always cause some dilemmas, e.g., higher covertness leading to lower robustness. This paper concerns the problem of improving the covert-ness without sacrificing the robustness. This problem is important because of the following reasons: reduc-ing the errors in recovered source message, improving the security, and ease of constructing a multi-factor au-thentication system. In this paper, we propose three covert PLA schemes to address the problem. In the first scheme, we improve the covertness by reducing the modification ratio on the source message based on an encoding mechanism. In the second scheme, we improve the covertness by optimizing the superim-posing angle, which maximizes the minimum distance between the tagged symbols and the boundary line of the demodulation decision for the source message. In the third scheme, referred to as the hybrid scheme, we further improve the covertness by jointly using the ad-vantages of both the above two schemes. Our exper-imental results show that when the SNR at a legiti-mate receiver is 25 dB, as compared with the prior scheme, the first scheme improves the covertness by 17.74％, the second scheme improves the covertness by 28.79％, and the third scheme improves the covert-ness by 32.09％, while they have similar robustness as that of the prior scheme.