Vehicle Network Time Synchronization via Link Delay Verification
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Solution Overview
Problem
Current vehicle network technologies, such as CAN and FlexRay-based networks, fail to meet the higher transmission rate and system expandability requirements of advanced vehicle systems like telematics and infotainment systems, and the MOST-based network is costly to implement.
Innovation Solution
An Ethernet-based vehicle network is used, with a method for verifying time synchronization among communication nodes by transmitting and receiving frames containing link delay and transmission time information to determine synchronization states and perform necessary adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If Ethernet-based network is used to achieve high transmission rate and system expandability, then transmission rate and adaptability are improved, but device complexity increases due to the need for time synchronization verification mechanisms
Solution Approach 1:
The patent implements time synchronization verification by having the master node proactively send verification requests to slave nodes before actual data transmission. The slave nodes prepare their link delay information in advance, and the master node calculates time differences beforehand, ensuring synchronization is established prior to communication operations.
Solution Approach 2:
The patent employs feedback mechanisms where slave nodes return their link delay information to the master node in response to verification requests. The master node uses this feedback to calculate time differences and determine synchronization status, continuously monitoring and adjusting the time synchronization state across the network.
2Measurement precision
If time synchronization verification is performed among all communication nodes, then time synchronization accuracy is improved, but communication overhead increases due to additional frame transmissions
Solution Approach 1:
The patent extracts the time synchronization verification function from general data communication, using dedicated verification request frames and verification result frames. This separation allows the synchronization protocol to operate independently from data traffic, enabling precise time measurement without completely intertwining synchronization overhead with data communication overhead.
Solution Approach 2:
The verification request frames and verification result frames serve multiple purposes: they establish time synchronization, measure link delays, and verify synchronization status across different communication nodes. This multi-functionality reduces the need for separate dedicated synchronization channels or additional specialized messaging protocols.
3Measurement precision
If link delay information is collected from all slave nodes to verify time synchronization, then synchronization verification accuracy is improved, but information processing complexity increases
Solution Approach 1:
The master node acts as an intermediary that centralizes the time synchronization verification process. It collects link delay information from all slave nodes, performs the time difference calculations, and determines the synchronization status. This centralized approach simplifies information processing compared to distributed verification, as the master node coordinates all synchronization activities and processes information in a single location.
Data Source
AI summary
Methods for time synchronization among communication nodes in a vehicle network are disclosed. An operation method of a first communication node includes: transmitting a first frame requesting verification of time synchronization to a second communication node; receiving a second frame including information indicating a link delay time of the second communication node from the second communication node; receiving a third frame including information indicating a transmission time of the second frame from the second communication node; and verifying time synchronization between the first and second communication nodes based on the information included in the received second and third frames.