Network Node Synchronization Using Running Average Timing
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Solution Overview
Problem
Time-triggered communication systems in safety-critical applications face challenges in maintaining synchronization between interconnected networks, leading to potential jitter in message delay, especially when clock correction values are not received by network nodes.
Innovation Solution
A computer node system that allows synchronization in small steps by monitoring and adjusting clock rates and phase offsets between networks through independent synchronization units within a gateway node, enabling nodes to maintain synchronization even without immediate inter-connected network timing information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If clock correction values are transmitted from inter-connected networks to maintain synchronization, then frequency and phase synchronisation between networks is improved, but network reliability deteriorates when correction values are not received due to potential loss of local synchronisation
Solution Approach 1:
The patent applies preliminary action by having network nodes continuously monitor the timing of received data packets and calculate time differences in advance, maintaining a running average of these differences. This pre-computed timing information is ready for immediate use when clock correction values are received, allowing the node to adjust its transmission timing proactively rather than reactively, thus maintaining synchronization reliability even during periods when correction values are not received.
Solution Approach 2:
The patent implements feedback by continuously measuring the time difference between when data packets are received from the inter-connected network and when they should have been received according to the node's internal clock. This measured time difference is fed back into the system to continuously update the running average, which then feeds back into the transmission timing adjustment, creating a closed-loop feedback mechanism that maintains synchronization without requiring continuous external correction values.
2Measurement precision
If clock correction values are used to synchronise nodes with inter-connected networks, then inter-network synchronisation is improved, but local synchronisation may be lost if correction values are not received
Solution Approach 1:
The patent introduces an intermediary mechanism - a running average of time differences - that mediates between the inter-connected network timing and the local network timing. Instead of directly applying clock correction values to the local network clock, the system uses this intermediary average to gradually adjust transmission timing. This intermediary buffers the impact of external timing corrections, allowing smooth transitions that maintain local synchronisation stability while still achieving inter-network synchronisation.
Solution Approach 2:
The patent applies partial action by adjusting transmission timing based on a running average of time differences rather than making full corrections based on each individual clock correction value received. This partial adjustment approach prevents over-correction that could destabilize local synchronisation, while still progressively aligning the node with inter-connected network timing over multiple correction cycles.
3Measurement precision
If time difference measurements are performed between network clocks, then synchronisation accuracy is improved, but message delay jitter increases by the length of a whole communication cycle
Solution Approach 1:
The patent applies preliminary action by continuously monitoring and calculating time differences between network clocks in advance, building up a running average of these differences over multiple communication cycles. This pre-computed timing information allows the node to adjust its transmission timing based on accumulated data rather than waiting for complete communication cycle delays, thereby reducing message delay jitter while maintaining synchronisation accuracy.
Data Source
AI summary
A computer node comprising a synchronization unit for comparing network timing information for a first network with network timing information for a second network and for communicating to the first network the sign of the difference between the first network timing information and the second network timing information to allow the first network to alter its network timing information using the sign of the difference to allow the network timing difference between the first network and the second network to be reduced.