Analysis of Message Transmission Time Based on CAN Bus Stuffing Mechanism

Abstract

The main performance index in CAN bus is closely related to the transmission time (message length) of the transmission message. As the CAN bus adopts the bit-stuffing mechanism, the transmission time of the message in the CAN bus is random variable with the change of the message data. Based on the inherent potential bit-stuffing mechanism of the CAN bus, this paper studied stuffing-bit from the point of probability of stuffing. CAN bus bit-stuffing model was constructed with standard format data frame as an example. The stuffing-bit probability distribution curves of standard frame with different bytes were obtained by simulation. By analyzing the simulation curves, it was found that the worst-stuffing-bit-method used in the previous computation was difficult to reflect the random characteristics of the message transmission time. Combined with the stuffing-bit probability distribution curves, the statistical characteristics of standard frame message transmission time were deduced through formula, which will provide theoretical basis for further research on the random characteristics of CAN bus performance index.