Physical Layer Security Design for Polar Code Construction

• Published in: Cryptography Vol. 6; no. 3; p. 35
• Main Authors: Zeng, Yao, Tang, Yuxi, Xiang, Luping
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.07.2022
• Subjects: Algorithms; channel quality indicator (CQI); Codes; Coding theory; Communications systems; Confidentiality; Construction; Data encryption; Data security; Design; Error correction; Methods; Mobile communication systems; Pattern generation; physical layer security (PLS); polar codes; Reciprocity; Security; Time division; Transmitters; Wireless communication systems; Wireless communications; China
• ISSN: 2410-387X; 2410-387X
• DOI: 10.3390/cryptography6030035

In contrast to the network security that relies on upper-layer encryption for the confidentiality and authenticity of communications, physical layer security (PLS) exploits the uniqueness and randomness of the physical channel to encrypt information and enhance the security of the system. In this paper, we study the PLS of a polar-coded wireless communication system. To be more specific, we leverage the unique properties in polar code construction and propose a channel quality indicator (CQI)-based frozen-bit pattern generation scheme. The transmitter employs the Gaussian approximation algorithm to generate the corresponding frozen bit pattern according to the instantaneous CQI of the legitimate link. At the receiver, by leveraging the full channel reciprocity in the time-division duplex (TDD) mode, we can map the CQI to the corresponding frozen bit pattern and correctly decode the received bits. By contrast, the eavesdropper was unable to have the knowledge of the legal channel, and hence cannot determine the frozen bit pattern of the polar-coded bit sequence. Our simulation results demonstrate that by adopting the proposed PLS key generation scheme, Eve was hardly able to correctly decode a complete frame, leading to a high block error rate (BLER), while Bob was able to attain a 10−5 BLER.