Communication Apparatus Guard Time Arbitration for Synchronization
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Solution Overview
Problem
Conventional communication systems experience increased delay times and reduced synchronization accuracy when relaying cyclically transmitted communication frames, particularly due to network delays that do not exceed the threshold, leading to deteriorated synchronization accuracy.
Innovation Solution
A communication apparatus with a frame relaying unit, a frame transmitting unit, and a transmission-frame arbitrating unit that regulates output during a guard time period, ensuring the arrival of communication frames in a fixed cycle, thereby preventing delays and maintaining synchronization accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a communication frame is relayed during network operation, then network communication functionality is maintained, but delay time increases and synchronization accuracy deteriorates
Solution Approach 1:
The patent applies preliminary action by determining in advance whether to set a guard time before relaying a communication frame. The arbitration unit checks if another communication frame is being transmitted at the expected arrival timing of the cyclically transmitted frame, and proactively sets the guard time before the relay operation to prevent delay, rather than reacting after delay occurs
Solution Approach 2:
The patent implements dynamics by making the guard time setting dynamic rather than fixed. The guard time is set selectively based on real-time network conditions - specifically when the arbitration unit detects that another communication frame transmission overlaps with the expected arrival time of the cyclically transmitted frame. This dynamic adjustment prevents unnecessary guard time settings while ensuring protection when needed
2Measurement precision
If a guard time is set to prevent relay delay, then synchronization accuracy is improved, but transmission of other communication frames is regulated
Solution Approach 1:
The patent applies partial action by setting the guard time only for the specific period necessary to prevent relay delay - namely, during the time window when another communication frame transmission overlaps with the expected arrival of the cyclically transmitted frame. The guard time is not set continuously or excessively, but only partially when the arbitration unit detects the overlapping transmission condition, thus balancing synchronization protection with transmission efficiency
Data Source
AI summary
A slave unit that is a communication apparatus according to the present invention includes: a frame relaying unit that receives, among communication frames received by a reception port, a communication frame to be relayed to the other apparatus and outputs the received communication frame to a transmission port; a frame transmitting unit that generates a communication frame and outputs the communication frame to the transmission port; and a transmission-frame arbitrating unit that regulates output of the communication frame to the transmission port performed by the frame transmitting unit in a guard time that is a period including a time period in which arrival of the communication frame transmitted in a network in a fixed cycle is expected.