Performance Analysis and Low-Complexity Beamforming Design for Near-Field Physical Layer Security

Fuente: arXiv
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Autori principali: Zhang, Yunpu, Fang, Yuan, You, Changsheng, Zhang, Ying-Jun Angela, So, Hing Cheung
Natura: Preprint
Pubblicazione: 2024
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author Zhang, Yunpu
Fang, Yuan
You, Changsheng
Zhang, Ying-Jun Angela
So, Hing Cheung
author_facet Zhang, Yunpu
Fang, Yuan
You, Changsheng
Zhang, Ying-Jun Angela
So, Hing Cheung
contents Extremely large-scale arrays (XL-arrays) have emerged as a key enabler in achieving the unprecedented performance requirements of future wireless networks, leading to a significant increase in the range of the near-field region. This transition necessitates the spherical wavefront model for characterizing the wireless propagation rather than the far-field planar counterpart, thereby introducing extra degrees of freedom (DoFs) to wireless system design. In this paper, we explore the beam focusing-based physical layer security (PLS) in the near field, where multiple legitimate users and one eavesdropper are situated in the near-field region of the XL-array base station (BS). First, we consider a special case with one legitimate user and one eavesdropper to shed useful insights into near-field PLS. In particular, it is shown that 1) Artificial noise (AN) is crucial to near-field security provisioning, transforming an insecure system to a secure one; 2) AN can yield numerous security gains, which considerably enhances PLS in the near field as compared to the case without AN taken into account. Next, for the general case with multiple legitimate users, we propose an efficient low-complexity approach to design the beamforming with AN to guarantee near-field secure transmission. Specifically, the low-complexity approach is conceived starting by introducing the concept of interference domain to capture the inter-user interference level, followed by a three-step identification framework for designing the beamforming. Finally, numerical results reveal that 1) the PLS enhancement in the near field is pronounced thanks to the additional spatial DoFs; 2) the proposed approach can achieve close performance to that of the computationally-extensive conventional approach yet with a significantly lower computational complexity.
format Preprint
id arxiv_https___arxiv_org_abs_2407_13491
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Performance Analysis and Low-Complexity Beamforming Design for Near-Field Physical Layer Security
Zhang, Yunpu
Fang, Yuan
You, Changsheng
Zhang, Ying-Jun Angela
So, Hing Cheung
Signal Processing
Information Theory
Extremely large-scale arrays (XL-arrays) have emerged as a key enabler in achieving the unprecedented performance requirements of future wireless networks, leading to a significant increase in the range of the near-field region. This transition necessitates the spherical wavefront model for characterizing the wireless propagation rather than the far-field planar counterpart, thereby introducing extra degrees of freedom (DoFs) to wireless system design. In this paper, we explore the beam focusing-based physical layer security (PLS) in the near field, where multiple legitimate users and one eavesdropper are situated in the near-field region of the XL-array base station (BS). First, we consider a special case with one legitimate user and one eavesdropper to shed useful insights into near-field PLS. In particular, it is shown that 1) Artificial noise (AN) is crucial to near-field security provisioning, transforming an insecure system to a secure one; 2) AN can yield numerous security gains, which considerably enhances PLS in the near field as compared to the case without AN taken into account. Next, for the general case with multiple legitimate users, we propose an efficient low-complexity approach to design the beamforming with AN to guarantee near-field secure transmission. Specifically, the low-complexity approach is conceived starting by introducing the concept of interference domain to capture the inter-user interference level, followed by a three-step identification framework for designing the beamforming. Finally, numerical results reveal that 1) the PLS enhancement in the near field is pronounced thanks to the additional spatial DoFs; 2) the proposed approach can achieve close performance to that of the computationally-extensive conventional approach yet with a significantly lower computational complexity.
title Performance Analysis and Low-Complexity Beamforming Design for Near-Field Physical Layer Security
topic Signal Processing
Information Theory
url https://arxiv.org/abs/2407.13491