Delay Bounds for CAN Communication in Automotive Applications

As a widespread automotive network, CAN (Controller Area Network) buses are deployed in modern cars to fulfill the demands of more than 90 collaborating electronic control devices. For safety critical applications, fast and reliable data transfer is indispensable, since often hard real-time transmission deadlines have to be met to assure a safe operation of the vehicle. Therefore, deterministic performance evaluation methods are inevitable for the validation of systems that must guarantee hard delay bounds and timeliness of information processing. One recent deterministic modeling approach is Network Calculus, which allows to determine worst case transmission times. Based on real-world communication CAN bus data, we generate appropriate modeling elements for the Network Calculus as arrival and service curves that reflect all priorities of CAN traffic. While the highest priority traffic on a CAN bus is known to have real-time properties, the results of this paper provide closed and easily applicable formulas to determine delay bounds of messages on all priority levels.