On Secrecy Performance of RIS-Assisted MISO Systems over Rician Channels with Spatially Random Eavesdroppers

Fuente: arXiv
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Main Authors: Shi, Wei, Xu, Jindan, Xu, Wei, Yuen, Chau, Swindlehurst, A. Lee, Zhao, Chunming
Format: Preprint
Published: 2023
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author Shi, Wei
Xu, Jindan
Xu, Wei
Yuen, Chau
Swindlehurst, A. Lee
Zhao, Chunming
author_facet Shi, Wei
Xu, Jindan
Xu, Wei
Yuen, Chau
Swindlehurst, A. Lee
Zhao, Chunming
contents Reconfigurable intelligent surface (RIS) technology is emerging as a promising technique for performance enhancement for next-generation wireless networks. This paper investigates the physical layer security of an RIS-assisted multiple-antenna communication system in the presence of random spatially distributed eavesdroppers. The RIS-to-ground channels are assumed to experience Rician fading. Using stochastic geometry, exact distributions of the received signal-to-noise-ratios (SNRs) at the legitimate user and the eavesdroppers located according to a Poisson point process (PPP) are derived, and closed-form expressions for the secrecy outage probability (SOP) and the ergodic secrecy capacity (ESC) are obtained to provide insightful guidelines for system design. First, the secrecy diversity order is obtained as $\frac{2}{α_2}$, where $α_2$ denotes the path loss exponent of the RIS-to-ground links. Then, it is revealed that the secrecy performance is mainly affected by the number of RIS reflecting elements, $N$, and the impact of the number of transmit antennas and transmit power at the base station is marginal. In addition, when the locations of the randomly located eavesdroppers are unknown, deploying the RIS closer to the legitimate user rather than to the base station is shown to be more efficient. Moreover, it is also found that the density of randomly located eavesdroppers, $λ_e$, has an additive effect on the asymptotic ESC performance given by $\log_2{\left({1}/{λ_e}\right)}$. Finally, numerical simulations are conducted to verify the accuracy of these theoretical observations.
format Preprint
id arxiv_https___arxiv_org_abs_2312_16814
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle On Secrecy Performance of RIS-Assisted MISO Systems over Rician Channels with Spatially Random Eavesdroppers
Shi, Wei
Xu, Jindan
Xu, Wei
Yuen, Chau
Swindlehurst, A. Lee
Zhao, Chunming
Information Theory
Signal Processing
Reconfigurable intelligent surface (RIS) technology is emerging as a promising technique for performance enhancement for next-generation wireless networks. This paper investigates the physical layer security of an RIS-assisted multiple-antenna communication system in the presence of random spatially distributed eavesdroppers. The RIS-to-ground channels are assumed to experience Rician fading. Using stochastic geometry, exact distributions of the received signal-to-noise-ratios (SNRs) at the legitimate user and the eavesdroppers located according to a Poisson point process (PPP) are derived, and closed-form expressions for the secrecy outage probability (SOP) and the ergodic secrecy capacity (ESC) are obtained to provide insightful guidelines for system design. First, the secrecy diversity order is obtained as $\frac{2}{α_2}$, where $α_2$ denotes the path loss exponent of the RIS-to-ground links. Then, it is revealed that the secrecy performance is mainly affected by the number of RIS reflecting elements, $N$, and the impact of the number of transmit antennas and transmit power at the base station is marginal. In addition, when the locations of the randomly located eavesdroppers are unknown, deploying the RIS closer to the legitimate user rather than to the base station is shown to be more efficient. Moreover, it is also found that the density of randomly located eavesdroppers, $λ_e$, has an additive effect on the asymptotic ESC performance given by $\log_2{\left({1}/{λ_e}\right)}$. Finally, numerical simulations are conducted to verify the accuracy of these theoretical observations.
title On Secrecy Performance of RIS-Assisted MISO Systems over Rician Channels with Spatially Random Eavesdroppers
topic Information Theory
Signal Processing
url https://arxiv.org/abs/2312.16814