Physical-Layer Security Improvement with Reconfigurable Intelligent Surfaces for 6G Wireless Communication Systems

Abstract

Recently, reconfigurable intelligent surfaces (RISs) have received much interest from both academia and industry due to their flexibility and cost-effectiveness in adjusting the phase and amplitude of wireless signals with low-cost passive reflecting elements. In particular, many RIS-aided techniques have been proposed to improve both data rate and energy efficiency for 6G wireless communication systems. In this paper, we propose a novel RIS-based channel randomization (RCR) technique for improving physical-layer security (PLS) for a time-division duplex (TDD) downlink cellular wire-tap network which consists of a single base station (BS) with multiple antennas, multiple legitimate pieces of user equipment (UE), multiple eavesdroppers (EVEs), and multiple RISs. We assume that only a line-of-sight (LOS) channel exists among the BS, the RISs, and the UE due to propagation characteristics of tera-hertz (THz) spectrum bands that may be used in 6G wireless communication systems. In the proposed technique, each RIS first pseudo-randomly generates multiple reflection matrices and utilizes them for both pilot signal duration (PSD) in uplink and data transmission duration (DTD) in downlink. Then, the BS estimates wireless channels of UE with reflection matrices of all RISs and selects the UE that has the best secrecy rate for each reflection matrix generated. It is shown herein that the proposed technique outperforms the conventional techniques in terms of achievable secrecy rates.

Eavesdropping Risk Evaluation on Terahertz Wireless Channels in Atmospheric Turbulence

“…Physical layer techniques, such as cooperative nodes, noise randomness and multi-antenna techniques, are usually developed to reduce eavesdropping risk from modern wireless communication systems [44]. Our model and findings can be useful helpful for testing new methods to minimize risk for eavesdropping.…”

Resource Allocation Using Reconfigurable Intelligent Surface (RIS)-Assisted Wireless Networks in Industry 5.0 Scenario

“…The algorithm showed significant improvements in EE of the D2D network. In [20], the authors used RIS surface to enhance the security of the physical layer in the 6G wireless network. The performance showed a significant improvement in security using RIS.…”

RIS-Aided Physical Layer Security With Full-Duplex Jamming in Underlay D2D Networks

“…Simultaneously, academia and industry have shown tremendous interest to unlock the superior advantages of RIS, and enhance the several performance metrics of the networks, such as sum-secrecy rates, energy efficiency, and spectral efficiency. Different application scenarios of RIS have been introduced, including device-to-device (D2D) communication [21], mmWave communication [22], coordinated multipoint (CoMP) transmission [23], simultaneous wireless information and power transfer (SWIPT) [24], and PLS [25]- [27]. In specific to PLS, [25] adjusted the phase shifts and transmit powers to enhance the PLS performance in RIS-assisted twoway communications.…”

“…The authors in [26] presented the secrecy maximization problem in RIS-assisted multiuser twoway communications by utilizing the signals of the users for degrading the eavesdropping capability. Moreover in [27], the proposed RIS-based channel randomization technique improved the secrecy performance for a downlink cellular wire-tap network. The application of PLS was also extended to the D2D communications underlaying cellular networks where the system interference was utilized to enhance the secrecy performance [28], [29].…”