Packet Timestamp Synchronization with PDV Compensation
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Solution Overview
Problem
The convergence of time-division multiplexing systems and packet technologies in packet-switched networks introduces significant packet delay variation (PDV) noise, which degrades the precision of clock and time synchronization, particularly in adaptive clock recovery (ACR) and adaptive time recovery (ATR) processes.
Innovation Solution
A synchronization method that compensates for packet delay variation (PDV) noise by predicting a delay prediction value using delay-related data, performing packet selection, and compensating the timestamp difference to enhance synchronization precision and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If adaptive clock recovery (ACR) and adaptive time recovery (ATR) are used for CBR service clock and time recovery over packet switched networks, then clock and time synchronization can be achieved, but packet delay variation (PDV) noise significantly degrades synchronization precision
Solution Approach 1:
The patent applies preliminary action by predicting the packet delay variation before it affects the timestamp difference calculation. The system uses historical delay data and prediction algorithms to estimate future PDV values, then compensates the timestamp differences proactively. This allows the synchronization system to counteract PDV noise before it degrades precision, rather than reacting after the damage is done.
Solution Approach 2:
The patent implements feedback mechanisms by continuously monitoring actual packet delays, comparing them with predicted values, and using the difference to refine future predictions. The system feeds back the compensated timestamp differences to the synchronization algorithm, creating a closed-loop system that continuously improves synchronization precision by learning from past PDV patterns and adjusting compensation strategies accordingly.
2Measurement precision
If packet selection is performed to reduce PDV noise, then synchronization precision can be improved, but the complexity of the synchronization system increases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting prediction parameters such as the prediction window size, filtering coefficients, and compensation factors based on network conditions. Instead of using fixed complex algorithms, the system modifies parameters like the order of delay prediction filters and the weighting factors in timestamp compensation to adapt to varying PDV characteristics, thereby achieving high precision with manageable system complexity.
Data Source
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AI summary
This application discloses a synchronization method, apparatus, and device, and a storage medium. The method includes: obtaining a first timestamp difference of a packet on a target link, where the first timestamp difference is a difference between a sending timestamp and a receiving timestamp of the packet at a first moment; performing packet selection based on the first timestamp difference to obtain a second timestamp difference; obtaining a delay prediction value of the target link at the first moment, compensating for the second timestamp difference based on the delay prediction value to obtain a compensated timestamp difference; and performing time and/or clock synchronization based on the compensated timestamp difference. The second timestamp difference is compensated for based on the delay prediction value, that is, PDV noise introduced to the target link is compensated for. In this way, the PDV noise is reduced, and the compensated timestamp difference more directly reflects frequency offset and phase offset information of a crystal oscillator relative to a frequency reference source, thereby improving synchronization precision and improving synchronization performance.