QKD Information Reconciliation Using Above-Shannon Error Correction
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Solution Overview
Problem
Conventional QKD systems face limitations in reach due to noise thresholds and code rates below the Shannon capacity, making them less effective for longer distances and practical applications.
Innovation Solution
A device and method that utilizes an error correction code with a code rate exceeding the Shannon capacity and incorporates a multi-step error correction and detection process to optimize data blocks, allowing for higher code rates and increased reach.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional error correction codes with code rates below Shannon capacity are used, then reliability is maintained, but the reach and key generation rate of QKD systems are limited
Solution Approach 1:
The patent changes the fundamental parameter of code rate from being below Shannon capacity to exceeding it. By using error correction codes with code rates greater than the Shannon capacity for the observed noise characteristics, the system achieves both improved reach and maintained reliability through the novel multi-step reconciliation protocol
2Length of moving object
If higher code rates are used to increase reach, then the distance over which secure communication can be maintained increases, but the probability of uncorrected errors increases
Solution Approach 1:
The patent segments the error correction process into multiple distinct steps: an initial error correction step using high-rate codes, followed by iterative error detection and correction steps. This segmentation allows the system to tolerate uncorrected errors from the first step while ensuring final reliability through subsequent correction steps
Solution Approach 2:
The patent implements feedback mechanisms where error detection information from each step is used to determine whether additional correction steps are needed. The system continuously monitors error patterns and adjusts the correction process accordingly, ensuring that reliability is maintained even when using high code rates
3Reliability
If conventional multi-step error correction protocols are used, then reliability is improved, but code efficiency remains below one
Solution Approach 1:
The patent fundamentally changes the code rate parameter to exceed Shannon capacity, enabling code efficiency greater than one. This is achieved by carefully selecting error correction codes whose code rates are higher than the mutual information between transmitter and receiver, while maintaining reliability through the structured multi-step protocol
Data Source
AI summary
In accordance with an embodiment, a method includes: obtaining Quantum Key Distribution (QKD) data; dividing the QKD data into a set of data blocks, wherein each data block of the set of data blocks of the device corresponds to a data block of a remote device; determining, based on a Bit Error Rate (BER) or a Signal to Noise Ratio (SNR), an error correction code, where the error correction code is configured such that a code rate of the error correction code is larger than a Shannon capacity for noise exhibited by the QKD data, or that the error correction code, after decoding the QKD data, leaves errors in corrected QKD data with a probability of at least 98%; performing an error correction step; and performing an error detection step. The error correction step and the error detection step are performed in any order.