RIS-Assisted MIMO CV-QKD at THz Frequencies: Channel Estimation and SKR Analysis

Fuente: arXiv
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Main Authors: Kumar, Sushil, Dash, Soumya P., Ghose, Debasish, Alexandropoulos, George C.
Format: Preprint
Published: 2024
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_version_ 1866908171654660096
author Kumar, Sushil
Dash, Soumya P.
Ghose, Debasish
Alexandropoulos, George C.
author_facet Kumar, Sushil
Dash, Soumya P.
Ghose, Debasish
Alexandropoulos, George C.
contents In this paper, a multiple-input multiple-output (MIMO) wireless system incorporating a reconfigurable intelligent surface (RIS) to efficiently operate at terahertz (THz) frequencies is considered. The transmitter, Alice, employs continuous-variable quantum key distribution (CV-QKD) to communicate secret keys to the receiver, Bob, which utilizes either homodyne or heterodyne detection. The latter node applies the least-squared approach to estimate the effective MIMO channel gain matrix prior to receiving the secret key, and this estimation is made available to Alice via an error-free feedback channel. An eavesdropper, Eve, is assumed to employ a collective Gaussian entanglement attack on the feedback channel to avail the estimated channel state information. We present a novel closed-form expression for the secret key rate (SKR) performance of the proposed RIS-assisted THz CV-QKD system. The effect of various system parameters, such as the number of RIS elements and their phase configurations, the channel estimation error, and the detector noise, on the SKR performance are studied via numerical evaluation of the derived formula. It is demonstrated that the RIS contributes to larger SKR for larger link distances, and that heterodyne detection is preferable over homodyne at lower pilot symbol powers.
format Preprint
id arxiv_https___arxiv_org_abs_2412_18771
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle RIS-Assisted MIMO CV-QKD at THz Frequencies: Channel Estimation and SKR Analysis
Kumar, Sushil
Dash, Soumya P.
Ghose, Debasish
Alexandropoulos, George C.
Information Theory
Signal Processing
In this paper, a multiple-input multiple-output (MIMO) wireless system incorporating a reconfigurable intelligent surface (RIS) to efficiently operate at terahertz (THz) frequencies is considered. The transmitter, Alice, employs continuous-variable quantum key distribution (CV-QKD) to communicate secret keys to the receiver, Bob, which utilizes either homodyne or heterodyne detection. The latter node applies the least-squared approach to estimate the effective MIMO channel gain matrix prior to receiving the secret key, and this estimation is made available to Alice via an error-free feedback channel. An eavesdropper, Eve, is assumed to employ a collective Gaussian entanglement attack on the feedback channel to avail the estimated channel state information. We present a novel closed-form expression for the secret key rate (SKR) performance of the proposed RIS-assisted THz CV-QKD system. The effect of various system parameters, such as the number of RIS elements and their phase configurations, the channel estimation error, and the detector noise, on the SKR performance are studied via numerical evaluation of the derived formula. It is demonstrated that the RIS contributes to larger SKR for larger link distances, and that heterodyne detection is preferable over homodyne at lower pilot symbol powers.
title RIS-Assisted MIMO CV-QKD at THz Frequencies: Channel Estimation and SKR Analysis
topic Information Theory
Signal Processing
url https://arxiv.org/abs/2412.18771