Serial Communications Security Module Error Signaling
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Solution Overview
Problem
Current serial communications protocols, such as CAN, lack the ability to provide detailed information about condition violations on the bus, limiting the effectiveness of remedial actions in response to errors or policy breaches.
Innovation Solution
A security module is introduced that receives data from a serial communications bus, compares it with predefined conditions, and outputs an error-signal with specific parameters, including node and condition identifiers, to enable more informed remedial actions, even in next-generation CAN XL protocols.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If traditional error signaling is used in serial communications, then the protocol remains simple and compatible, but detailed information about condition violations cannot be provided
Solution Approach 1:
The patent embeds multiple levels of error information within the error signal structure. The error signal contains a primary error condition identifier, and each error condition can have associated parameter identifiers that provide additional details about the violation. This nested structure allows detailed error information to be conveyed without requiring a completely new protocol framework.
Solution Approach 2:
The patent extends the traditional binary error signal (error/not error) by adding dimensional depth through multiple identifier fields. Instead of simply indicating an error occurred, the signal now includes error condition identifiers and parameter identifiers that add layers of information, transforming a one-dimensional signal into a multi-dimensional information structure.
2Reliability
If detailed error parameters are transmitted on the bus, then remedial actions can be more appropriate, but the communication protocol becomes more complex
Solution Approach 1:
The security module divides the error signaling function into separate components: error condition identification, parameter identification, and value transmission. Each error condition is segmented into specific parameters with defined values, allowing the system to transmit detailed information while maintaining modular processing at each node.
Solution Approach 2:
The security module acts as an intermediary between the serial communications device and the network nodes. It processes raw error conditions and transforms them into structured error signals with identifiers and parameters, shielding the complexity of error analysis from individual nodes while providing them with actionable information.
3Measurement precision
If error signals include multiple parameter values, then condition identification is more precise, but the signal length increases
Solution Approach 1:
The patent uses parameter identifiers that reference predefined error conditions and their possible values stored in each node's memory. Instead of transmitting all possible parameter values, the system transmits compact identifier values that reference extensive information stored locally at each node, maintaining signal brevity while enabling precise condition identification.
Data Source
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AI summary
A security module (434) for a serial communications device. The security module (434) comprising: a receive data, RXD, input interface (436) for receiving data from a serial communications bus (404); and a transmit data, TXD, output interface (438) for transmitting data to the serial communications bus (404). The security module (434) is configured to: receive a message (540) from the serial communications bus (404) via the RXD input interface (436); compare the message (540) with one or more error conditions; and upon detection that an error condition has been violated, output an error-signal (543) to the serial communications bus (404) via the TXD output interface (438), wherein the error-signal (543) identifies one or more parameters relating to the error condition.