Network Node Delay Marking for Time Synchronization Accuracy
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Solution Overview
Problem
In communication networks, especially those using LTE-based radio access technologies, accurate time and phase synchronization is challenging due to variance in send, access, propagation, and receive times, which leads to unpredictable delays and synchronization offset inaccuracies, particularly in packet switched networks where existing solutions require complex upgrades or are not fully supported by all network nodes.
Innovation Solution
Implementing a synchronization report module and offset calculation module in network nodes to detect and mark synchronization packets with delay indications, allowing boundary clock nodes and ordinary clock nodes to differentiate and omit delayed packets, thereby improving time synchronization accuracy without requiring extensive network upgrades.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If PTP messages are distributed from a centralized Grandmaster entity through multiple hops, then network coverage and synchronisation reach are improved, but time synchronisation accuracy deteriorates due to accumulated delay and delay variation
Solution Approach 1:
The patent divides the network into multiple segments, each with its own synchronisation master node that independently determines delay values for its local segment. This segmentation allows each segment to be synchronised with high accuracy while collectively covering a large network area, resolving the contradiction between network coverage and time synchronisation accuracy.
2Measurement precision
If transparent clock nodes are deployed to compensate for delay, then time synchronisation accuracy is improved, but device complexity and network upgrade requirements increase
Solution Approach 1:
The patent enables ordinary clock nodes and boundary clock nodes to independently determine delay values using locally available information from PTP messages, without requiring complex transparent clock functionality or network-wide upgrades. Each node serves itself by calculating delay based on timestamps received in standard PTP messages, simplifying the overall system while maintaining accuracy.
3Measurement precision
If delay compensation mechanisms are implemented, then time synchronisation accuracy is improved, but protocol complexity and processing overhead increase
Solution Approach 1:
The patent uses feedback from PTP message timestamps to enable nodes to determine delay values. The synchronisation process incorporates delay information feedback into the offset calculation, allowing nodes to compensate for delay without requiring complex additional protocols or processing mechanisms.
Data Source
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AI summary
Method and arrangement for providing delay information to synchronisation packets passing a transport network node. In a transport network node synchronisation packets propagate from a synchronisation master node towards boundary clock nodes. The synchronisation packets pass the transport network node, in which the 5 synchronisation packets are received 400, and a level of delay is determined 402. Furthermore, when the level of delay for the synchronisation packets is above a threshold, the synchronisation packets are marked 404 with a delay indication. The received synchronisation packets are sent 406 to the boundary clock node or ordinary clock node, whether or not they are marked. 10 By implementing functionality for determining a level of delay of synchronisation packets in intermediate transport network nodes, and mark passing synchronisation packets with delay indications, boundary clock nodes and ordinary clock nodes may differentiate the received synchronisation packets based on the delay identifications. 15 Thereby, improved accuracy may be achieved when calculating time synchronisation offsets.