Communication Control Equipment Time Synchronization via Packet Interval Analysis
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Solution Overview
Problem
In distributed control systems, existing time synchronization methods like IEEE 1588 face challenges with precision due to network intermediary equipment, such as network switches, which cause jitter in time differences between forward and backward delays, making it difficult to maintain accurate synchronization without increasing packet transmission and reception overhead.
Innovation Solution
The communication control equipment uses a time synchronization procedure involving request and acknowledgement packets to measure receiving intervals and detect conflicts, allowing it to determine whether to transmit acknowledgement packets, thereby synchronizing with other equipment without reducing the amount of information transmitted and received.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If IEEE 1588 time synchronization protocol is used with network intermediary equipment, then time synchronization can be achieved, but synchronization precision deteriorates due to jitter in forward and backward delays
Solution Approach 1:
The invention uses delay estimation packets as copies of actual data packets to measure queuing delays. By transmitting these estimation packets and calculating receiving intervals, the system can determine forward and backward delays without requiring special transparent clock equipment, thus maintaining synchronization precision with standard network devices.
Solution Approach 2:
The invention replaces the need for specialized transparent clock hardware with a software-based delay estimation mechanism. By using standard network equipment and calculating delays through packet timing analysis, the system achieves accurate synchronization without relying on expensive specialized hardware.
2Measurement precision
If delay estimation packets are transmitted to measure queuing delay, then synchronization precision can be improved, but packet transmission overhead increases
Solution Approach 1:
The delay estimation packets serve multiple functions: they act as both time synchronization probes and delay measurement tools. By utilizing the receiving interval of these packets to calculate both forward and backward delays, the system achieves comprehensive delay characterization without requiring separate measurement mechanisms, thus avoiding additional overhead.
3Ease of manufacture
If standard network intermediary equipment is used, then system configuration becomes easier, but time synchronization precision deteriorates due to unknown queuing delays
Solution Approach 1:
The system performs self-diagnosis by measuring its own queuing delays using delay estimation packets. By calculating the receiving intervals of these packets at both transmitter and receiver ends, the system automatically determines forward and backward delays without requiring external calibration or specialized equipment configuration, thus maintaining precision with standard equipment.
Data Source
AI summary
Communication control equipment is connected to a plurality of communication control equipment via a network and is configured to be time-synchronized with the plurality of communication control equipment by using a time synchronization procedure using a communication including at least request packets and acknowledgement packets. The communication control equipment includes a receiving-interval measurement section configured to measure a receiving interval of request packets from the plurality of communication control equipment; and a queuing-occurrence determination section configured to detect conflict of the request packets from any of the plurality of communication control equipment on a basis of the receiving interval of the request packets measured by the receiving-interval measurement section. The communication control equipment is configured to determine whether to transmit an acknowledgement packet to the communication control equipment that has transmitted the request packets based on a detection result of the queuing-occurrence determination section.