Near-Field Secure Beamfocusing With Receiver-Centered Protected Zone

Fuente: arXiv
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Autori principali: Liu, Cen, Zhou, Xiangyun, Yang, Nan, Durrani, Salman, Swindlehurst, A. Lee
Natura: Preprint
Pubblicazione: 2025
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author Liu, Cen
Zhou, Xiangyun
Yang, Nan
Durrani, Salman
Swindlehurst, A. Lee
author_facet Liu, Cen
Zhou, Xiangyun
Yang, Nan
Durrani, Salman
Swindlehurst, A. Lee
contents This work studies near-field secure communications through transmit beamfocusing. We examine the benefit of having a protected eavesdropper-free zone around the legitimate receiver, and we determine the worst-case secrecy performance against a potential eavesdropper located anywhere outside the protected zone. A max-min optimization problem is formulated for the beamfocusing design with and without artificial noise transmission. Despite the NP-hardness of the problem, we develop a synchronous gradient descent-ascent framework that approximates the global maximin solution. A low-complexity solution is also derived that delivers excellent performance over a wide range of operating conditions. We further extend this study to a scenario where it is not possible to physically enforce a protected zone. To this end, we consider secure communications through the creation of a virtual protected zone using a full-duplex legitimate receiver. Numerical results demonstrate that exploiting either the physical or virtual receiver-centered protected zone with appropriately designed beamfocusing is an effective strategy for achieving secure near-field communications.
format Preprint
id arxiv_https___arxiv_org_abs_2505_19523
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Near-Field Secure Beamfocusing With Receiver-Centered Protected Zone
Liu, Cen
Zhou, Xiangyun
Yang, Nan
Durrani, Salman
Swindlehurst, A. Lee
Signal Processing
Information Theory
This work studies near-field secure communications through transmit beamfocusing. We examine the benefit of having a protected eavesdropper-free zone around the legitimate receiver, and we determine the worst-case secrecy performance against a potential eavesdropper located anywhere outside the protected zone. A max-min optimization problem is formulated for the beamfocusing design with and without artificial noise transmission. Despite the NP-hardness of the problem, we develop a synchronous gradient descent-ascent framework that approximates the global maximin solution. A low-complexity solution is also derived that delivers excellent performance over a wide range of operating conditions. We further extend this study to a scenario where it is not possible to physically enforce a protected zone. To this end, we consider secure communications through the creation of a virtual protected zone using a full-duplex legitimate receiver. Numerical results demonstrate that exploiting either the physical or virtual receiver-centered protected zone with appropriately designed beamfocusing is an effective strategy for achieving secure near-field communications.
title Near-Field Secure Beamfocusing With Receiver-Centered Protected Zone
topic Signal Processing
Information Theory
url https://arxiv.org/abs/2505.19523