HV-ECU Retransmission Control for CAN Data Loss
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Solution Overview
Problem
In CAN communication systems, repeated transmission errors can lead to data loss as higher-priority data retransmissions prevent lower-priority data from being transmitted within a predetermined communication period, especially when errors persist.
Innovation Solution
A communication apparatus and system that inhibits retransmissions when the number of transmission errors exceeds a threshold within a communication period, releasing the inhibition at the start of the next period to ensure data reception, thereby preventing data loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If retransmitting process is repeated when transmission error occurs, then transmission reliability is improved, but data loss occurs due to communication period expiration
Solution Approach 1:
The patent dynamically adjusts the retransmission behavior based on the communication period status. When a transmission error is detected, the system checks whether the current communication period has expired. If expired, retransmission is inhibited to prevent data loss; if not expired, retransmission proceeds to ensure reliability. This dynamic decision-making resolves the contradiction between maintaining transmission reliability and preventing data loss.
Solution Approach 2:
The patent implements a feedback mechanism where the system continuously monitors the communication period status and transmission error conditions. Based on this feedback, the retransmission control is adjusted in real-time. The communication period management unit provides feedback about period expiration status to the retransmission control unit, which then decides whether to allow or inhibit retransmission, thereby balancing reliability and data loss prevention.
2Reliability
If retransmission is performed for high-priority data, then transmission error recovery is improved, but lower-priority data transmission is delayed
Solution Approach 1:
The patent structures data transmission around periodic communication cycles with defined periods. Each communication period has a specific purpose and time constraint. By aligning retransmission decisions with these periodic boundaries, the system ensures that retransmissions of high-priority data do not indefinitely block lower-priority data. When the communication period expires, the system transitions to the next period, automatically resolving the blocking issue and ensuring timely transmission of all priority levels.
Data Source
AI summary
A hybrid vehicle electronic control unit (HV-ECU) includes a communication unit and a retransmission control unit. The communication unit performs a retransmitting process of data when a transmission error of the data is detected. The retransmission control unit inhibits the retransmitting process in a corresponding communication period and releases the retransmitting process when the corresponding communication period ends and the next communication period starts if the number of times that a transmission error is detected in a predetermined communication period is larger than a transmission stop determination threshold value.