Network Time Synchronization via Phase Reference Signals
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Solution Overview
Problem
Existing methods for synchronizing time of day values in data transfer networks face challenges due to varying transfer delays and asymmetrical data paths, which affect the accuracy of timestamp-based synchronization.
Innovation Solution
Utilizing phase reference signals, such as PPS signals from GPS systems, to create a difference variable indicating the timing phase difference between the network element's time of day value and the phase reference signal, allowing for accurate synchronization by estimating the time of day value based on the phase reference signal's timing phase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If timestamp-based synchronization is used, then time synchronization can be achieved, but accuracy deteriorates due to varying transfer delays and asymmetrical data paths
Solution Approach 1:
The patent introduces phase reference signals as an intermediary mechanism to mediate the synchronization between network elements. Instead of directly comparing timestamps between nodes (which suffers from transfer delay variations), the phase reference signal serves as a common reference that both transmitting and receiving elements can use to calculate time differences, thereby eliminating the impact of asymmetrical data paths and variable transfer delays on synchronization accuracy
Solution Approach 2:
The patent changes the synchronization parameter from absolute timestamp comparison to phase difference measurement. By measuring the phase difference between the transmitted phase reference signal and the locally generated phase reference signal, the system transforms the synchronization problem into a relative measurement task that is immune to transfer delay variations, thus improving both accuracy and reliability
2Measurement precision
If phase reference signals are used for synchronization, then synchronization accuracy is maintained despite transfer delay variations, but device complexity increases due to additional signal processing requirements
Solution Approach 1:
The patent implements self-service by having each network element generate its own phase reference signal locally. This eliminates the need for complex external synchronization equipment or centralized control systems. Each element independently measures the phase difference between its locally generated signal and the received signal, performing self-synchronization that maintains accuracy while minimizing additional device complexity
Data Source
AI summary
The invention relates to transferring of a time of day value between network elements of a data transfer network. It has been surprisingly detected that the phase reference signals available to various network elements can be utilized in the synchronization of time of day values between these network elements. In the solution according to the invention, a first network element sends to a second network element a difference variable (401, 402, 403) that indicates how much the timing phase of the time of day value maintained in the first network element differs from the timing phase of the phase reference signal available to the first network element. In the second network element that receives the message, an estimate of the time of day value is formed (404, 405) based on the difference variable and the timing phase of the phase reference signal available to the second network element.