Serial Bus User Station Header Check Sum Verification
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Solution Overview
Problem
Current serial bus systems, such as CAN FD, face issues with error detection due to variable frame lengths and bit stuffing, leading to reduced data transmission rates and increased complexity, which affects communication reliability and efficiency.
Innovation Solution
A user station with a communication control device that generates transmission signals with fixed stuff bits and computes header and frame check sums, ensuring correct frame length detection and eliminating the need for a stuff bit counter, thereby enhancing error robustness and data rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If variable data field length is used in CAN FD, then data transmission flexibility is improved, but error detection reliability deteriorates due to incorrect frame length decoding
Solution Approach 1:
The patent divides the frame check sum verification into two separate stages: header check sum verification for the first communication phase (arbitration phase) and frame check sum verification for the second communication phase (data phase). This segmentation allows each phase to be verified independently with appropriate check sums, preventing error propagation and improving overall error detection reliability while maintaining variable data field length flexibility.
2Adaptability or versatility
If dynamic bit stuffing is used to accommodate variable frame lengths, then adaptability is improved, but device complexity increases due to stuff bit counter requirements
Solution Approach 1:
The patent extracts the bit stuffing function from the dynamic variable-length mechanism and replaces it with fixed stuff bits at defined positions in the header. This eliminates the need for complex stuff bit counters that track dynamic stuffing, while maintaining frame length adaptability through the variable data field. The fixed stuffing approach simplifies the transmitter and receiver design significantly.
3Reliability
If stuff bit counter is implemented for frame length safeguarding, then error detection is improved, but data transmission rate decreases due to overhead
Solution Approach 1:
The patent performs preliminary verification of the header check sum in the first communication phase before full frame transmission. This allows early detection of header errors and enables the receiver to prepare for the expected frame length, eliminating the need for stuff bit counters during data reception. The preliminary action reduces overhead and maintains high data transmission rates while ensuring frame length safeguarding.
Data Source
AI summary
A user station for a serial bus system. The user station includes a communication control device for controlling a communication of the user station with another user station, and a transceiver device for transmitting a transmission signal, generated by the communication control device, onto a bus, so that for a message that is exchanged between user stations of the bus system, the bit time of a signal transmitted in the first communication phase is different from a bit time of a signal transmitted in the second communication phase. The communication control device generates the transmission signal according to a frame in which fields for a header check sum and a frame check sum. The communication control device computes the header check sum from all bits in the header of a frame that is formed for the message, except for fixed stuff bits that have been inserted into the header.