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Schedulability analysis for CAN bus messages of periodically-varying size
Ref: CISTER-TR-220501       Publication Date: 27 to 29, Apr, 2022

Schedulability analysis for CAN bus messages of periodically-varying size

Ref: CISTER-TR-220501       Publication Date: 27 to 29, Apr, 2022

Abstract:
Abstract—Conventional CAN bus schedulability analysis assumes that all messages with a given identifier have the same worst-case length. In this paper we extend that analysis to a more general model in which messages with a given identifier may have different lengths, that vary according to a known periodic pattern. That is, for some positive integer S, we assume that the length of message instances n and n + S with the same id is the same. By leveraging such patterns, where present, our new analysis allows for a more efficient use of CAN bus bandwidth than the application of conventional analysis, which can be pessimistic. This may be interesting when a given node sends the values of multiple signals with different periods. In such a scenario, the conventional CAN schedulability analysis would require either the use of different ids for different signals (assuming there are enough of them), which leads to a higher bandwidth overhead because of the reduplication of message headers, or using only one id, but pessimistically always assuming the maximum possible length of the message, for safety reasons.

Authors:
Ishfaq Hussain
,
Konstantinos Bletsas
,
Muhammad Ali Awan
,
Eduardo Tovar
,
Pedro Souto


18th IEEE International Conference on Factory Communication Systems (WFCS 2022) (WFCS2022), Deterministic and Predictable Industrial Communication.
Virtual, Italy.



Record Date: 4, May, 2022