Improving Physical Layer Security for Reconfigurable Intelligent Surface aided NOMA 6G Networks

TL;DR

This paper investigates physical layer security enhancements in RIS-aided NOMA 6G networks, proposing joint beamforming and power allocation schemes to counter internal and external eavesdropping, demonstrating significant secrecy performance improvements.

Contribution

It introduces novel joint beamforming and power allocation schemes for RIS-aided NOMA networks to enhance physical layer security against various eavesdropping scenarios.

Findings

Increasing reflecting elements improves secrecy more than adding transmit antennas.

Proposed schemes outperform existing methods in simulation.

Optimal power allocation enhances security in eavesdropper scenarios.

Abstract

The intrinsic integration of the nonorthogonal multiple access (NOMA) and reconfigurable intelligent surface (RIS) techniques is envisioned to be a promising approach to significantly improve both the spectrum efficiency and energy efficiency for future wireless communication networks. In this paper, the physical layer security (PLS) for a RIS-aided NOMA 6G networks is investigated, in which a RIS is deployed to assist the two "dead zone" NOMA users and both internal and external eavesdropping are considered. For the scenario with only internal eavesdropping, we consider the worst case that the near-end user is untrusted and may try to intercept the information of far-end user. A joint beamforming and power allocation sub-optimal scheme is proposed to improve the system PLS. Then we extend our work to a scenario with both internal and external eavesdropping. Two sub-scenarios are considered in this scenario: one is the sub-scenario without channel state information (CSI) of eavesdroppers, and another is the sub-scenario where the eavesdroppers' CSI are available. For the both sub-scenarios, a noise beamforming scheme is introduced to be against the external eavesdroppers. An optimal power allocation scheme is proposed to further improve the system physical security for the second sub-scenario. Simulation results show the superior performance of the proposed schemes. Moreover, it has also been shown that increasing the number of reflecting elements can bring more gain in secrecy performance than that of the transmit antennas.