Subscriber Station Abort Mechanism for Serial Bus Priority Arbitration
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Solution Overview
Problem
Current serial bus systems, such as those using the CAN protocol, face limitations in data transfer rate and payload data capacity, particularly in high-bandwidth applications, and struggle with efficiently handling priority messages and errors.
Innovation Solution
A subscriber station with a communication control device that can abort lower-priority messages to prioritize higher-priority frames, allowing for increased data transfer rates and payload capacity up to 4096 bytes per frame, while maintaining error robustness, by using designated break points and signalization within the frame.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If data transfer rate is increased beyond 1 Mbit/sec using CAN FD, then bandwidth is improved, but payload data length is limited to 64 bytes which is too short for some applications
Solution Approach 1:
The patent segments the data transmission into multiple frames, where each frame can carry a portion of the total payload. The communication control device manages frame segmentation and reassembly, allowing the system to achieve both high data transfer rates and extended payload capacity by transmitting large data sets across multiple sequential frames rather than being limited to a single 64-byte payload.
2Productivity
If lower-priority messages are transmitted, then bus occupancy is improved, but high-priority messages intended to convey critical states may be blocked
Solution Approach 1:
The patent implements dynamic priority arbitration where the communication control device continuously monitors message priorities and can abort lower-priority transmissions when higher-priority messages are detected. This dynamic adjustment of transmission priorities ensures that critical messages are never blocked while maximizing bus utilization during normal operation when only low-priority messages are present.
Solution Approach 2:
The communication control device acts as an intermediary between the message queue and the transmit/receive device, mediating priority conflicts by deciding whether to abort current transmissions based on incoming message priorities. This intermediary layer enables intelligent priority management that balances bus occupancy with reliability requirements.
3Reliability
If error frames are used to handle transmission errors, then error robustness is improved, but net data transfer rate decreases due to additional overhead
Solution Approach 1:
The patent merges error handling functionality into the existing frame structure rather than using separate error frames. The communication control device incorporates error detection and correction mechanisms within the data frames themselves, eliminating the need for additional error frames and thereby maintaining high net data transfer rates while preserving error robustness.
Data Source
AI summary
A subscriber station for a serial bus system is described. The subscriber station includes a communication control device for generating a message to serially transmit on the bus system, and/or for reading a message that has been serially received by the subscriber station on the bus system. The communication control device is configured to decide whether there exists, for aborting a serial transmission of the frame onto the bus line which is currently being carried out, an abortion criterion according to which a serial transmission of a higher-priority frame for a message is more important than the serial transmission of the frame onto the bus line which is currently being carried out, and to provide in the frame currently being serially transmitted, on the basis of the decision that has been made, a signalization as to whether or not the frame currently being serially transmitted is to be aborted.