Secure Bus Telegram CRC Adaptation for Higher User Data Throughput
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Solution Overview
Problem
Current secure bus systems in industrial automation, such as PROFIsafe and AS-i Safety at Work, require a high number of bits for CRC data, limiting the amount of user data that can be transmitted securely due to fixed bit error probabilities and CRC calculation methods, which do not allow for efficient data throughput while maintaining security standards.
Innovation Solution
An apparatus and method that evaluates error rates in received secure telegrams using a CRC check, allowing for a reduced CRC data requirement by adjusting the CRC calculation method based on the determined error rate, enabling more user data to be transmitted per secure telegram while ensuring secure communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed CRC calculation method based on expected bit error probabilities is used, then security standards are maintained, but the amount of user data that can be transmitted per telegram is reduced
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed CRC calculation method to a dynamic adaptation mechanism. The system continuously monitors the actual bit error rate of the communication bus and adjusts the CRC polynomial and degree accordingly. This allows the CRC parameters to adapt in real-time to changing communication conditions, optimizing the balance between security requirements and data transmission capacity.
Solution Approach 2:
The patent implements parameter changes by modifying CRC calculation parameters (polynomial coefficients and degree) based on measured error rates. Instead of using a predetermined fixed CRC configuration, the system dynamically changes these parameters to match actual communication quality, thereby reducing excessive CRC overhead while maintaining adequate error detection capability for secure communication.
2Reliability
If a high number of bits are allocated for CRC data, then error detection capability is improved, but the quantity of user data that can be transmitted is limited
Solution Approach 1:
The patent applies partial action by allocating only the necessary portion of bits for CRC data based on actual error rates rather than using a fixed maximum allocation. The system determines the minimal sufficient CRC overhead required for the current communication conditions, avoiding excessive error detection capability that would unnecessarily reduce user data capacity.
3Productivity
If the CRC data bits are reduced to increase user data transmission, then data throughput is improved, but security compliance may be compromised
Solution Approach 1:
The patent implements feedback by continuously monitoring the actual bit error rate of the communication bus and using this information to adjust CRC parameters. The system measures the error rate, compares it against thresholds, and dynamically modifies the CRC polynomial and degree to maintain security compliance while optimizing data throughput based on real-time communication conditions.
Data Source
AI summary
An apparatus includes a communication device and an evaluation unit, wherein the communication device can be linked to a communication bus and can receive secure telegrams by way of the communication bus, and wherein a secure telegram includes user data and CRC data in each instance. In at least one embodiment, in order to improve the communication within the secure bus system, the evaluation unit can determine an error rate from received secure telegrams by way of a CRC check and if a threshold value of the error rate stored in the evaluation unit is exceeded, can effect a secure state of the apparatus.