Typical worst case response-time analysis and its use in automotive network design

For some automotive applications, worst case performance guarantees are too expensive, but a minimum level of performance must be formally guaranteed. For such applications, we have developed an approach called Typical Worst Case Analysis (TWCA) which can formally bound the number of violations of the computed response-time guarantee in a given time window. In this paper, we demonstrate how it can be used to analyze a real CAN bus with complex load patterns. We investigate the effects of these load patterns and show how the necessary parameters can be derived and verified from traces and specifications. We compare the results to the commonly used base load approximation — like a 50%-limit for cyclic load — showing superior accuracy and expressiveness.