Adding artificial noise for code rate matching in continuous-variable quantum key distribution

TL;DR

This paper introduces a novel method of adding artificial noise to quantum key distribution data to match code rates with channel SNR, potentially outperforming traditional puncturing and shortening techniques especially in challenging high-loss, high-noise conditions.

Contribution

The paper proposes a new approach of adding artificial noise for code rate matching in CV-QKD, offering an alternative to puncturing and shortening with improved performance in certain scenarios.

Findings

Method competes with puncturing and shortening techniques.

Outperforms traditional methods in high-loss, high-noise scenarios.

Enables better reconciliation efficiency in challenging quantum channels.

Abstract

The reconciliation step of continuous-variable quantum key distribution protocols usually involves forward error correction codes. Matching the code rate and the signal-to-noise ratio (SNR) of the quantum channel is required to achieve the high reconciliation efficiencies that are crucial for long distance links. Puncturing and shortening is a way to adapt the code rate to the SNR at the cost of a slightly reduced reconciliation efficiencies. Instead of adapting the code rate to the SNR, we propose to add a controlled amount of artificial noise to the measured data, so that the resulting SNR could be reduced to match the given code rate. We show that our method can compete with puncturing and shortening and even outperform it in high-loss, high-excess noise scenarios.