Deep Learning Holdover Compensation for Network Clock Synchronization

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Solution Overview

Problem

In networked computer systems, clocks diverge during holdover periods when a reference signal is unavailable, leading to undesirable outcomes due to the inability of existing methods to accurately predict frequency offset values after the holdover period starts.

Innovation Solution

A deep learning model is used to predict the relationship between a first oscillating signal and a second oscillating signal, allowing for adjustments to be made to the first oscillating signal to simulate the second oscillating signal during holdover periods by generating a frequency offset prediction based on temperature data and historical measurements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional holdover methods are used to maintain clock synchronization during reference signal unavailability, then the system can operate without external reference, but the clock divergence increases and synchronization accuracy deteriorates

Engineering Contradiction:
Improveclock synchronization reliabilityVSAvoidfrequency offset prediction accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The system performs preliminary actions by collecting and storing historical frequency offset data and temperature data during normal operation (when reference signal is available). This historical data is prepared in advance and used to train machine learning models before the holdover period begins, enabling accurate predictions during the reference signal unavailability.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system creates a copy of the reference clock's behavior by training a machine learning model to replicate the frequency offset characteristics observed during normal operation. The model learns the relationship between temperature variations and frequency offset, then copies this relationship to predict and compensate for offset during holdover when the actual reference signal is unavailable.

Inventive Principle:
Principle #26Copying

2Duration of action of moving object

If holdover period extends to maintain operation during reference unavailability, then system continuity is maintained, but clock divergence increases and synchronization accuracy deteriorates

Engineering Contradiction:
Improveholdover durationVSAvoidsynchronization accuracy
Core Design Contradiction:
Duration of action of moving objectVSMeasurement precision

Solution Approach 1:

The system implements feedback by continuously monitoring temperature during holdover and feeding this data into the machine learning model. The model uses the current temperature reading along with historical data to generate real-time frequency offset predictions, which are then applied to compensate the local clock. This closed-loop feedback mechanism maintains synchronization accuracy throughout the extended holdover period.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system changes the parameter used for prediction from purely time-based to temperature-based compensation. By recognizing that temperature is the dominant factor affecting crystal oscillator frequency drift, the system uses temperature measurements as the primary input parameter for the machine learning model, enabling accurate long-term predictions during holdover regardless of how much time has elapsed.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If simple holdover compensation methods are used, then system complexity remains low, but the ability to predict frequency offset accurately deteriorates

Engineering Contradiction:
Improvecompensation system complexityVSAvoidfrequency offset prediction accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The system replaces traditional mechanical/mathematical interpolation methods with machine learning-based prediction. Instead of using simple linear extrapolation or polynomial fitting, the system employs trained neural networks or regression models that learn complex non-linear relationships between temperature and frequency offset from historical data, achieving superior prediction accuracy.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system performs self-service by automatically collecting historical data, training the machine learning model, and continuously optimizing its predictions without external intervention. The model learns from the system's own operational data and temperature measurements, enabling it to adapt to specific hardware characteristics and environmental conditions unique to each deployment.

Inventive Principle:
Principle #25Self-service

Data Source

PatentUS20220261032A1Deep learning-based holdover compensation, and related systems, methods and devices
Publication Date: 2022.08.18 MICROCHIP TECHNOLOGY INC
  • US20220261032A1 patent drawing
  • US20220261032A1 patent drawing
  • US20220261032A1 patent drawing

AI summary

In one aspect, a method of adjusting a first oscillating signal, includes generating a relationship prediction responsive to a deep learning model configured to predict a relationship between a fundamental quantity of a first oscillating signal and a fundamental quantity of a second oscillating signal, and applying an adjustment to the first oscillating signal responsive to the relationship prediction to produce an adjusted oscillating signal, wherein the adjusted oscillating signal replaces the second oscillating signal.