Open Access

ARTICLE

Secure Downlink Transmission Strategies against Active Eavesdropping in NOMA Systems: A Zero-Sum Game Approach

Yanqiu Chen, Xiaopeng Ji^*

School of Electronics and Information Engineering, Nanjing University of Information Science and Technology, Nanjing, 210044, China

* Corresponding Author: Xiaopeng Ji. Email:

(This article belongs to this Special Issue: Cyberspace Intelligent Mapping and Situational Awareness)

Computer Modeling in Engineering & Sciences 2023, 136(1), 531-553. https://doi.org/10.32604/cmes.2023.024531

Received 01 June 2022; Accepted 15 September 2022; Issue published 05 January 2023

Abstract

Non-orthogonal multiple access technology (NOMA), as a potentially promising technology in the 5G/B5G era, suffers from ubiquitous security threats due to the broadcast nature of the wireless medium. In this paper, we focus on artificial-signal-assisted and relay-assisted secure downlink transmission schemes against external eavesdropping in the context of physical layer security, respectively. To characterize the non-cooperative confrontation around the secrecy rate between the legitimate communication party and the eavesdropper, their interactions are modeled as a two-person zero-sum game. The existence of the Nash equilibrium of the proposed game models is proved, and the pure strategy Nash equilibrium and mixed-strategy Nash equilibrium profiles in the two schemes are solved and analyzed, respectively. The numerical simulations are conducted to validate the analytical results, and show that the two schemes improve the secrecy rate and further enhance the physical layer security performance of NOMA systems.

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Keywords

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