Gateway Message Forwarding for CAN-Ethernet Integration
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Solution Overview
Problem
The integration of CAN and Ethernet networks in vehicles often results in message omission due to the slower boot time of Ethernet controllers, which have separate application processors and complex software stacks, leading to delayed message forwarding.
Innovation Solution
A vehicle message transmission method involving a gateway that receives network management messages from the CAN network, sends a wakeup pulse to the Ethernet network, converts and stores CAN messages, and transmits them to Ethernet nodes only after a TCP connection is established, ensuring messages are forwarded without omission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the gateway forwards a message to the Ethernet controller immediately when receiving the message from the CAN controller, then the message transmission speed is improved, but message omission occurs due to the boot time of the Ethernet controller
Solution Approach 1:
The gateway performs preliminary actions by sending a wakeup pulse to the Ethernet controller before forwarding the actual message. This wakeup pulse triggers the Ethernet controller to start its booting procedure in advance, ensuring that the controller is ready to receive and process the message without omission. The message is then forwarded only after confirming the Ethernet controller is operational, thus resolving the contradiction between fast transmission and reliable delivery.
2Reliability
If the gateway waits for the Ethernet controller to complete booting before forwarding messages, then message omission is prevented, but message transmission delay increases
Solution Approach 1:
The gateway sends a wakeup pulse as a preliminary action to initiate the Ethernet controller's booting process before the actual message needs to be transmitted. This allows the controller to start its initialization sequence in advance, reducing the waiting time when a message needs to be forwarded. The gateway then forwards the message only after confirming the controller is ready, thus minimizing delay while ensuring reliable delivery.
Solution Approach 2:
The wakeup pulse acts as an intermediary signal between the gateway and the Ethernet controller. This intermediary mechanism allows the gateway to asynchronously trigger the controller's booting process without blocking the message forwarding path. The controller can initialize at its own pace while the gateway maintains message readiness, reducing overall transmission delay while ensuring the controller is ready when the message arrives.
3Device complexity
If the gateway uses a simple forwarding mechanism without connection establishment, then the transmission process is simplified, but message delivery cannot be guaranteed when the Ethernet node is not ready
Solution Approach 1:
The gateway implements a feedback mechanism by establishing a TCP connection with the Ethernet node before forwarding messages. The connection establishment process provides feedback about the node's readiness status. Only when the TCP connection is successfully established does the gateway forward the message, ensuring reliable delivery. This feedback-based approach maintains relatively simple forwarding logic while guaranteeing message delivery through connection verification.
Data Source
AI summary
An in-vehicle message transmission method includes receiving a network management (NM) message from a Controller Area Network (CAN) network, transmitting a wakeup pulse to an Ethernet network in response to the NM message, storing an Ethernet message into which a CAN message received from the CAN network is converted in a gateway, and transmitting the Ethernet message to an Ethernet node when a Transmission Control Protocol (TCP) connection with the Ethernet node to receive the Ethernet message is established.