Nanosecond Network Time Synchronization via Self-Receive Back-Coupling
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Solution Overview
Problem
Current network time synchronization methods, such as NTP, often result in significant time biases between nodes, requiring precise calibration and limited precision, especially in mesh networks, which hinders accurate localization and communication protocols.
Innovation Solution
A method for characterizing time bias and propagation delay between nodes using self-receive signals and synchronization signals, allowing for precise clock synchronization within one nanosecond without prior node position information or precise hardware calibration, utilizing standard electronic clock technology and low-frequency bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If NTP or similar network time synchronization methods are used, then time synchronization can be implemented across network nodes, but significant time biases (microsecond to millisecond level) remain between nodes
Solution Approach 1:
The patent segments the time synchronization process into distinct measurement phases: transmitting node records transmit time, receiving node records receive time, and both nodes independently calculate propagation delay. This segmentation allows each node to contribute to the synchronization calculation, reducing cumulative errors and achieving nanosecond-level precision compared to traditional NTP's microsecond to millisecond accuracy.
Solution Approach 2:
The patent implements a feedback mechanism where nodes exchange timing information and calculate time biases based on measured propagation delays. The system continuously refines synchronization by using the calculated time biases to adjust clock offsets, creating a closed-loop feedback system that progressively reduces time synchronization errors to nanosecond levels.
2Measurement precision
If precise hardware calibration and prior node position information are required for accurate time synchronization, then time bias can be reduced, but device complexity and calibration requirements increase significantly
Solution Approach 1:
The patent enables nodes to perform self-calibration by independently calculating propagation delay based on their own transmit and receive time stamps. Each node contributes its timing data to the calculation, allowing the system to determine time biases without external calibration equipment or prior position information, thereby reducing device complexity while maintaining nanosecond-level precision.
Solution Approach 2:
The patent performs preliminary propagation delay measurement through bidirectional signal exchange between nodes before final time synchronization is established. This preliminary action of measuring and calculating time-of-flight allows the system to compensate for propagation effects in advance, enabling accurate synchronization without requiring pre-configured position data or complex hardware calibration.
3Productivity
If traditional time synchronization methods are used in mesh networks, then basic time coordination is achieved, but localization accuracy and communication protocol performance are hindered by significant time biases
Solution Approach 1:
The patent changes the fundamental parameter of time measurement precision from microsecond to nanosecond level by implementing bidirectional time-of-flight calculations. This parameter change enables accurate localization and enhances communication protocol performance by providing the precise timing information required for advanced network operations, directly addressing the limitations of traditional synchronization methods.
Data Source
AI summary
A method includes, at a first node: transmitting a first synchronization signal at a first time according to a first clock of the first node; back-coupling the first synchronization signal to generate a first self-receive signal; calculating a time-of-arrival of the first self-receive signal according to the first clock; and calculating a time-of-arrival of the second synchronization signal according to the first clock. The method also includes, at the second node: transmitting the second synchronization signal at a second time according to a second clock of the second node; back-coupling the second synchronization signal to generate a second self-receive signal; calculating a time-of-arrival of the second self-receive signal according to the second clock; and calculating a time-of-arrival of the first synchronization signal according to the second clock. The method S100 further includes calculating a time bias and a propagation delay between the pair of nodes based on the time-of-arrivals.