Quantum Key Distribution Time Stamp Compression
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Solution Overview
Problem
The sifting processing in quantum key distribution systems is limited by the high amount of time stamp communication required, which restricts the increase in secure key rate due to physical limitations of the communication channel, and existing compression techniques do not sufficiently enhance the processing rate.
Innovation Solution
A communication device is configured with a photon detector, a measurer, and a difference generator to detect photons and generate difference time stamp information, reducing the amount of time stamp communication by transmitting only the difference between previous and current detection times through a classical communication channel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the receiver transmits time stamp information for each detected photon to the transmitter, then the sifting processing can be performed accurately, but the amount of communication data increases, limiting the secure key rate
Solution Approach 1:
The patent extracts only the essential information needed for sifting processing by transmitting difference values between time stamps rather than complete time stamp data. This selective extraction of necessary information reduces communication data volume while maintaining the accuracy required for matching transmitted and received photon sequences.
Solution Approach 2:
The patent changes the parameter representation from absolute time stamp values to relative difference values. By transforming the data format from complete time stamps to time differences, the communication efficiency is improved while the essential temporal relationship information is preserved for accurate sifting processing.
2Productivity
If the band of the communication channel for time stamp communication is widened to increase secure key rate, then higher-speed quantum key distribution can be achieved, but hardware structure and cost problems arise
Solution Approach 1:
The patent changes the data parameter from full time stamp values to compressed difference values, which reduces the communication bandwidth requirement. This parameter transformation allows the existing communication hardware to operate at higher speeds without requiring upgrades to wider bandwidth channels, thereby increasing secure key rate while avoiding hardware complexity and cost increases.
3Productivity
If the number of detected photons per unit time is increased to improve secure key rate, then high-speed quantum key distribution is achieved, but the amount of time stamp communication required increases, reaching the physical limit of the communication channel
Solution Approach 1:
The patent extracts only the essential temporal difference information needed for sifting processing rather than transmitting complete time stamp data for each photon. This extraction approach reduces the communication data volume proportionally, enabling the system to handle higher photon detection rates without exceeding the communication channel's physical capacity.
Solution Approach 2:
Instead of transmitting the complete time stamp information from absolute reference, the patent inverts the approach by transmitting only the difference or change in time stamps. This inverted methodology reduces the information quantity while preserving the essential temporal relationship needed for correlating transmitted and received photons at high speeds.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces the communication bandwidth required for time stamp information, enabling higher-speed sifting processing and thus enhancing the secure key rate in quantum key distribution systems.
Implementation Method 1
a photon detector configured to detect photons transmitted from the other communication device through the quantum communication channel
Data Source
AI summary
According to an embodiment, a communication device is connected to another communication device through a quantum communication channel and a classical communication channel to share an encryption key. The device includes a photon detector, a measurer, a difference generator, and a transmitter. The photon detector is configured to detect photons transmitted from the other communication device through the quantum communication channel. The measurer is configured to measure time when each photon is detected by the photon detector as time stamp information. The difference generator is configured to generate difference time stamp information as a difference between time obtained by adding particular information to the time indicated by the time stamp information previously measured by the measurer and time indicated by the time stamp information subsequently measured by the measurer. The transmitter is configured to transmit the difference time stamp information to the other communication device through the classical communication channel.