Frequency Synchronization Accuracy Estimation in DPLL Networks
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Solution Overview
Problem
Existing methods for estimating frequency synchronization accuracy between slave and master clocks in communication networks are often inaccurate due to clock skews, which can lead to unreliable call handovers and inaccurate network delay measurements, especially in mobile telephone networks where synchronization accuracy is not considered in quality metrics.
Innovation Solution
A method and system that estimate frequency synchronization accuracy using the ratio of the interval of transmitted timing messages and the average progression of the corrected master clock, implemented with a digital phase-locked loop to synchronize the slave clock with the master clock, allowing for real-time monitoring and improved call handover reliability by incorporating frequency accuracy as a quality metric.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If clock skew compensation is performed using conventional methods, then frequency synchronization accuracy can be improved, but the complexity of the synchronization system increases
Solution Approach 1:
The patent extracts the frequency accuracy estimation function from complex clock skew compensation algorithms. By using a simplified ratio-based calculation (ΔT/ΔR) that directly estimates frequency accuracy without requiring full clock skew compensation, the system achieves adequate synchronization accuracy for handover decisions while avoiding the complexity of conventional methods.
Solution Approach 2:
The patent applies partial action by implementing only the essential frequency accuracy estimation needed for handover decisions, rather than performing complete clock synchronization. The system calculates frequency accuracy using the ratio of timing message intervals to corrected master clock progression, which provides sufficient accuracy for the specific application without the overhead of full synchronization protocols.
2Reliability
If frequency synchronization accuracy is monitored in real-time, then call handover reliability is improved, but the processing overhead increases
Solution Approach 1:
The system uses existing timing messages (PTP Sync messages) that are already being exchanged for clock synchronization purposes. By extracting frequency accuracy information from these existing messages through simple ratio calculation, the system achieves real-time monitoring without requiring additional communication overhead or separate measurement mechanisms.
Solution Approach 2:
The patent changes the approach from calculating absolute clock skew values to calculating the ratio of timing intervals to clock progression (ΔT/ΔR). This parameter transformation simplifies the computation while maintaining the ability to estimate frequency accuracy, reducing processing overhead while enabling real-time monitoring for handover reliability.
3Measurement precision
If conventional clock skew estimation methods are used, then synchronization accuracy can be improved, but the measurement precision of network delay is reduced due to system complexity
Solution Approach 1:
The patent extracts only the frequency accuracy component from full clock skew estimation. By using the ratio ΔT/ΔR that directly estimates frequency accuracy without requiring complete skew compensation, the system achieves sufficient synchronization accuracy while minimizing the impact on network delay measurements, as the simplified method introduces less computational error and complexity.
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 provides a simple and effective technique for estimating frequency synchronization accuracy in real-time, enhancing the reliability of call handovers and network delay measurements by continuously and efficiently calculating synchronization accuracy, thereby reducing dropped calls and improving network performance.
Implementation Method 1
The frequency accuracy is estimated using the ratio of the interval of transmitted timing messages and an average progression of a corrected master clock in the same interval. The approach provides a simple and effective technique for estimating frequency synchronization accuracy in real-time
Data Source
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AI summary
This invention relates to methods and systems for estimating and checking synchronization accuracy, in particular frequency synchronization accuracy. It is particularly applicable to synchronization methods and systems which involve a digital phase-locked loop (DPLL) and embodiments provide methods and systems for estimating and tracking how well the DPLL is frequency synchronized to a source frequency. In one embodiment, frequency synchronization accuracy is used as an additional quality metric for mobile call handover between base stations. Call handover is of major importance within any mobile network; without checking frequency synchronization before handover dropped calls and interrupted communication can result.