CAN Transceiver Arbitration Loss Detection
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Solution Overview
Problem
In Controller Area Network (CAN) bus systems, malicious nodes can hijack or disrupt data transmission by sending dominant bits after losing arbitration, leading to potential safety risks, such as failures in critical vehicle systems like anti-lock braking during skidding on icy roads.
Innovation Solution
A transceiver is configured to detect nodes that have lost arbitration and send a predefined bit pattern, such as a CAN Error Frame, to prevent further transmission by malicious nodes, utilizing a white list to verify message identifiers and a black list to block unauthorized messages, and disabling nodes that attempt to send or receive unauthorized data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a node sends a dominant bit after losing arbitration, then the node can attempt to hijack the bus control, but this disrupts normal CAN bus communication and creates spurious transmissions
Solution Approach 1:
The transceiver monitors the CAN bus to detect when a node sends a dominant bit after losing arbitration. Upon detection, the transceiver sends a predefined bit pattern (error frame) back to the node, creating a feedback loop that corrects the spurious transmission and restores proper bus control reliability
Solution Approach 2:
The harmful spurious transmission attempt by the node is converted into a beneficial error detection opportunity. The transceiver uses the detected dominant bit as trigger to send an error frame, which both corrects the spurious transmission and provides feedback to the node about its improper behavior
2Reliability
If the transceiver continuously monitors the CAN bus for arbitration losses, then spurious transmissions can be detected and corrected, but this increases the complexity of the transceiver
Solution Approach 1:
The transceiver uses its existing arbitration monitoring capabilities to detect spurious transmissions. The same hardware and software resources used for normal CAN bus operation are leveraged to detect when a node sends a dominant bit after losing arbitration, eliminating the need for separate dedicated monitoring circuitry
Solution Approach 2:
The transceiver performs multiple functions using its existing architecture: normal data transmission, arbitration monitoring, spurious transmission detection, and error frame generation. This multi-functionality approach maintains reliability while avoiding additional complexity
3Reliability
If the transceiver sends error frames to nodes that lost arbitration, then spurious transmissions are prevented, but this may cause unnecessary node disablement
Solution Approach 1:
The transceiver implements a counter that tracks the number of times a node sends spurious dominant bits. Instead of immediately disabling the node upon first detection, the system allows a certain number of partial correctures (error frames) before triggering node disablement. This partial action approach prevents over-reaction to minor transmission issues while maintaining security
Data Source
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AI summary
A transceiver for sending and receiving data from a controller area network (CAN) bus is disclosed. The transceiver is configured to detect if a node, after losing an arbitration, has sent a dominant bit on the CAN bus. The transceiver is further configured to send a predefined bit pattern on the CAN bus after receiving the dominant bit from the node.