Master Station Contention Determination for Time Synchronization
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Solution Overview
Problem
In time synchronization systems, especially when multiple slave stations are connected via a relay device, contention and delay issues arise due to overlapping transmission timings, making it difficult to accurately calculate propagation delay times, which decreases synchronization accuracy.
Innovation Solution
A time synchronization system with a master station that includes contention determination means to identify potential contentions among time synchronization frames received from slave stations and discards frames with potential mutual contention, thereby preventing extended delay times and improving synchronization accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If multiple slave stations transmit time synchronization frames at freely-selected timings, then the system allows flexible transmission timing, but frame loss occurs due to overlap of transmission timings, decreasing time synchronization accuracy
Solution Approach 1:
The master station performs preliminary determination of contention possibility based on receipt timings before processing time synchronization frames. By predicting potential contention scenarios in advance and establishing discard rules beforehand, the system prevents frame loss due to overlap while maintaining transmission flexibility.
2Ease of operation
If slave stations transmit time synchronization frames at freely-selected timings, then transmission timing flexibility is maintained, but contention delay time occurs when frames contend with each other, decreasing time synchronization accuracy
Solution Approach 1:
When contention is detected between time synchronization frames, the system skips processing of the later-received frame and proceeds directly with the earlier frame. This rushing through of contentious frames eliminates waiting time and contention delays, ensuring timely processing without sacrificing transmission flexibility.
3Adaptability or versatility
If time synchronization frames are relayed through a switching hub, then network connectivity is enabled, but fixed delay time and contention delay time increase, making accurate propagation delay calculation difficult
Solution Approach 1:
The invention extracts and removes time synchronization frames that have experienced relay delays or contention delays from the processing sequence. By taking out these problematic frames before they affect propagation delay calculations, the system maintains network connectivity through relay devices while ensuring accurate delay measurements using only frames with known, minimal delays.
Data Source
AI summary
A time synchronization system includes a master station (100) and slave stations (200) communicably connected to the master station (100). The master station (100) includes a contention determiner (114) and a time synchronization frame processing unit (113). The contention determiner (114) determines, based on receipt timings of a plurality of first time synchronization frames transmitted from the respective slave stations (200), whether the plurality of first time synchronization frames have a possibility of contention over relay processing. The time synchronization frame processing unit (113) discards, when the contention determiner (114) determines that the plurality of first time synchronization frames have the possibility of the contention, out of first time synchronization frames that have a possibility of mutual contention, a first time synchronization frame received later.