Vehicle Network Time Synchronization via Timestamped Offset Calculation
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Solution Overview
Problem
In-vehicle communication networks face challenges in synchronizing nodes due to packet-based communication, making it difficult to coordinate simultaneous events or activations across devices, such as sensor data capture and simultaneous illumination of brake lights, as commands may take different times to reach each device through the switch fabric network.
Innovation Solution
A system and method for time synchronizing nodes in a vehicle switch fabric network involves transmitting a synchronization request message with a unique ID and timestamp, allowing neighboring nodes to calculate and share timer offset values, enabling coordinated timing across the network for message transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If packet-based communication is used in the switch fabric network, then communication flexibility and device independence are improved, but timing synchronization between nodes deteriorates
Solution Approach 1:
The system performs preliminary timing calibration by measuring the actual transmission time of synchronization messages between nodes and calculating offset values before actual coordinated operations. This advance preparation allows nodes to compensate for network variability in subsequent simultaneous activations and data captures.
Solution Approach 2:
The system implements a feedback mechanism where nodes exchange synchronization messages with timestamps, measure round-trip times, and calculate timing offsets. This continuous timing information feedback enables nodes to adjust their local clocks and coordinate future actions accurately despite packet-based communication variability.
2Adaptability or versatility
If commands are transmitted through the switch fabric network, then device independence and network flexibility are improved, but command transmission time varies between different devices, making simultaneous activation difficult
Solution Approach 1:
The system performs preliminary timing calibration by measuring the actual transmission time of synchronization messages between nodes and calculating offset values before actual coordinated operations. This advance preparation allows nodes to compensate for network variability in subsequent simultaneous activations and data captures.
Solution Approach 2:
The system dynamically adjusts timing offsets based on measured network conditions. Instead of using fixed transmission time assumptions, nodes continuously measure actual message travel times and update their offset values to adapt to changing network loads and conditions, enabling accurate simultaneous activation despite variable transmission times.
3Device complexity
If nodes operate independently without time synchronization, then system simplicity is maintained, but coordination of simultaneous events becomes impossible
Solution Approach 1:
The system introduces a timing offset calculation mechanism as an intermediary layer between independent node operation and coordinated action. Rather than requiring complex centralized control or tightly coupled node designs, nodes exchange synchronization messages and use calculated offsets to independently coordinate their actions, maintaining operational simplicity while achieving reliable event coordination.
Data Source
AI summary
A system and method for time synchronizing nodes in a switch fabric network of a vehicle. A synchronization request message is transmitted from a requesting node to a neighboring node. At the time the synchronization request message is sent, the requesting node will store a unique message identification associated with the request message as well as a first timestamp that is associated with the time that the synchronization request message was transmitted by the requesting node. The neighboring node will receive the synchronization request message and store a second timestamp associated with the time that the synchronization request message was received by the neighboring node. Thereafter, the neighboring node will transmit to the requesting node a synchronization response message that includes the message identification and the second timestamp. The requesting node will then calculate a timer offset value that is based on the first timestamp and the second timestamp. The timer offset values may then be shared with other nodes in the network so that a summed offset may be used to transmit network messages across a plurality of nodes.