Virtual Time-Stamping Apparatus for High-Precision Network Synchronization
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Solution Overview
Problem
Current network synchronization techniques, such as NTP, lack precision for applications requiring high accuracy, particularly in multimedia streaming services, and existing hardware-based solutions for PTP are cumbersome and costly due to the need for extensive hardware support for multiple Ethernet ports.
Innovation Solution
A virtual time-stamping apparatus that measures time stamp values at the interface between Layers 2 and 3, using a difference extraction unit, minimum filter, and delay variation calculation unit to estimate and synchronize with a master clock, reducing the need for extensive hardware and providing precise time synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If hardware-based PTP solutions are used to achieve high-precision time synchronization, then measurement precision is improved, but device complexity and cost increase due to the need for extensive hardware support for multiple Ethernet ports
Solution Approach 1:
The patent creates a virtual time-stamping apparatus that copies the function of physical time stamping hardware by measuring time stamp values at the interface between Layers 2 and 3 using software-based processing. This virtual implementation achieves high-precision time synchronization without requiring extensive physical hardware support for multiple Ethernet ports, thereby reducing device complexity while maintaining measurement precision.
Solution Approach 2:
The patent replaces the mechanical hardware-based time stamping system with a software-based virtual time-stamping apparatus. By using difference extraction units, minimum filters, and delay variation calculation units implemented through software algorithms, the system achieves precise time measurement and synchronization without the need for complex hardware infrastructure, thus resolving the contradiction between precision and complexity.
2Ease of operation
If NTP is used for time synchronization in packet networks, then ease of operation and cost-effectiveness are improved, but measurement precision deteriorates due to precision limitations in typical Internet environments
Solution Approach 1:
The patent changes the parameter of time measurement precision by implementing virtual time-stamping that measures time stamp values at the interface between Layers 2 and 3. This allows the system to achieve microsecond-level precision similar to hardware-based PTP while maintaining the software-based ease of operation and cost-effectiveness. The minimum filter and delay variation calculation units enable precise synchronization without sacrificing operational simplicity.
Data Source
AI summary
An apparatus includes a difference extraction unit to extract a difference between a second time stamp value, which is obtained by adjusting a first time stamp value that is measured at a time of arrival of a synchronization message transmitted by the master at a Layer 3 to be synchronized in frequency with a clock of the master, and a third time stamp value, which is measured at a time of departure of the synchronization message from the master; a minimum filter to select a minimum from one or more difference values extracted by the difference extraction unit; and a delay variation calculation unit to estimate a time of arrival of a current synchronization message at the Layer 3 based on the selected minimum and calculate a delay variation.