AmbShield: Enhancing Physical Layer Security with Ambient Backscatter Devices against Eavesdroppers

Fuente: arXiv
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Main Authors: Zhang, Yifan, Yang, Yishan, Jäntti, Riku, Yan, Zheng, Niyato, Dusit, Han, Zhu
Format: Preprint
Published: 2026
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author Zhang, Yifan
Yang, Yishan
Jäntti, Riku
Yan, Zheng
Niyato, Dusit
Han, Zhu
author_facet Zhang, Yifan
Yang, Yishan
Jäntti, Riku
Yan, Zheng
Niyato, Dusit
Han, Zhu
contents Passive eavesdropping compromises confidentiality in wireless networks, especially in resource-constrained environments where heavyweight cryptography is impractical. Physical layer security (PLS) exploits channel randomness and spatial selectivity to confine information to an intended receiver with modest overhead. However, typical PLS techniques, such as using beamforming, artificial noise, and reconfigurable intelligent surfaces, often involve added active power or specialized deployment, and, in many designs, rely on precise time synchronization and perfect CSI estimation, which limits their practicality. To this end, we propose AmbShield, an AmBD-assisted PLS scheme that leverages naturally distributed AmBDs to simultaneously strengthen the legitimate channel and degrade eavesdroppers' without requiring extra transmit power and with minimal deployment overhead. In AmbShield, AmBDs are exploited as friendly jammers that randomly backscatter to create interference at eavesdroppers, and as passive relays that backscatter the desired signal to enhance the capacity of legitimate devices. We further develop a unified analytical framework that analyzes the exact probability density function (PDF) and cumulative distribution function (CDF) of legitimate and eavesdropper signal-to-interference-noise ratio (SINR), and a closed-form secrecy outage probability (SOP). The analysis provides clear design guidelines on various practical system parameters to minimize SOP. Extensive experiments that include Monte Carlo simulations, theoretical derivations, and high-SNR asymptotic analysis demonstrate the security gains of AmbShield across diverse system parameters under imperfect synchronization and CSI estimation.
format Preprint
id arxiv_https___arxiv_org_abs_2601_09867
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle AmbShield: Enhancing Physical Layer Security with Ambient Backscatter Devices against Eavesdroppers
Zhang, Yifan
Yang, Yishan
Jäntti, Riku
Yan, Zheng
Niyato, Dusit
Han, Zhu
Cryptography and Security
Computers and Society
Passive eavesdropping compromises confidentiality in wireless networks, especially in resource-constrained environments where heavyweight cryptography is impractical. Physical layer security (PLS) exploits channel randomness and spatial selectivity to confine information to an intended receiver with modest overhead. However, typical PLS techniques, such as using beamforming, artificial noise, and reconfigurable intelligent surfaces, often involve added active power or specialized deployment, and, in many designs, rely on precise time synchronization and perfect CSI estimation, which limits their practicality. To this end, we propose AmbShield, an AmBD-assisted PLS scheme that leverages naturally distributed AmBDs to simultaneously strengthen the legitimate channel and degrade eavesdroppers' without requiring extra transmit power and with minimal deployment overhead. In AmbShield, AmBDs are exploited as friendly jammers that randomly backscatter to create interference at eavesdroppers, and as passive relays that backscatter the desired signal to enhance the capacity of legitimate devices. We further develop a unified analytical framework that analyzes the exact probability density function (PDF) and cumulative distribution function (CDF) of legitimate and eavesdropper signal-to-interference-noise ratio (SINR), and a closed-form secrecy outage probability (SOP). The analysis provides clear design guidelines on various practical system parameters to minimize SOP. Extensive experiments that include Monte Carlo simulations, theoretical derivations, and high-SNR asymptotic analysis demonstrate the security gains of AmbShield across diverse system parameters under imperfect synchronization and CSI estimation.
title AmbShield: Enhancing Physical Layer Security with Ambient Backscatter Devices against Eavesdroppers
topic Cryptography and Security
Computers and Society
url https://arxiv.org/abs/2601.09867