Vehicle Relay Device gPTP Time Synchronization Ethernet CAN
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Solution Overview
Problem
There is no mechanism for implementing time synchronization between electronic devices connected to communication networks of different communication standards, such as Ethernet and CAN, which are commonly used in vehicle systems.
Innovation Solution
A vehicle electronic system that includes a first electronic device connected to a first communication network, a second electronic device connected to a second communication network, and a relay device that transmits synchronized time information from the first network to the second device, using a generalized Precision Time Protocol (gPTP) for synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a relay device connects multiple communication networks of different standards, then communication versatility is improved, but time synchronization capability deteriorates due to lack of mechanism
Solution Approach 1:
The relay device acts as an intermediary between the first communication network (Ethernet) and the second communication network (CAN). It receives time information from the first network, processes it through the gPTP protocol, and transmits it to the second network. This mediator approach enables time synchronization across different communication standards without requiring direct synchronization between the networks themselves.
Solution Approach 2:
The relay device changes the parameter representation of time information when transmitting between different communication networks. It converts time synchronization parameters from the format used in Ethernet networks to the format required by CAN networks, using the gPTP protocol to manage these parameter transformations and ensure compatibility across different communication standards.
2Measurement precision
If time synchronization is implemented across different communication standards, then measurement precision is improved, but device complexity increases due to protocol integration
Solution Approach 1:
The relay device is designed with multi-functionality to handle both Ethernet and CAN communication protocols simultaneously. It incorporates a gPTP protocol processing unit that can operate with different communication standards, making the device universal rather than specialized for a single protocol. This approach achieves time synchronization precision across networks while avoiding the need for multiple separate synchronization devices.
3Measurement precision
If gPTP protocol is used for time synchronization, then time accuracy is improved, but communication traffic increases due to synchronization messages
Solution Approach 1:
The relay device implements partial action by selectively transmitting time synchronization information only when necessary, rather than continuously broadcasting synchronization messages. It uses the gPTP protocol to determine when synchronization updates are needed, reducing unnecessary communication traffic while maintaining time synchronization accuracy. This approach avoids excessive synchronization messaging that would otherwise increase communication traffic volume.
Data Source
AI summary
Provided is a vehicle electronic system that includes: a first electronic device connected to a first communication network of a first communication standard; a second electronic device connected to a second communication network of a second communication standard; and a relay device connected to the first communication network and the second communication network. The relay device includes a relay device transmission unit that transmits, to the second electronic device, first time information indicating time synchronized in the first communication network.