Secure transmission in backhaul NOMA systems: A physical layer security design with untrusted user and eavesdropper

• Published in: Digital communications and networks Vol. 10; no. 4; pp. 1001 - 1013
• Main Authors: Le, Chi-Bao, Do, Dinh-Thuan, Voznak, Miroslav
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.08.2024; KeAi Communications Co., Ltd
• Subjects: Non-orthogonal multiple access (NOMA); Power allocation; Secure outage probability; Wireless backhaul; Wireless backhaul; Secure outage probability; Power allocation; Non-orthogonal multiple access (NOMA)
• ISSN: 2352-8648; 2352-8648
• DOI: 10.1016/j.dcan.2022.12.005

In order to improve the Physical Layer Security (PLS) perspective, this paper aims to empower function of PLS by considering a backhaul Non-Orthogonal Multiple Access (NOMA) system in two practical situations. In the proposed schemes, the untrusted user intercepts information transmitted to the far user, or the external eavesdropper overhears confidential information sent to the far user in the context of NOMA technique. Unlike the conventional NOMA systems, this paper emphasizes the actual situations of the existence of actual illegal users and legitimate users, especially the reasonable use of relay selection architecture to improve the confidentiality performance. To evaluate the security properties of the proposed scheme, a comprehensive analysis of the Security Outage Probability (SOP) performance is first performed, and then the corresponding SOP asymptotic expressions are derived for real scenarios related to eavesdroppers and untrusted users. Numerical results are performed to verify the analysis in terms of the secure performance metric.