Integrated end-to-end timing analysis of networked AUTOSAR-compliant systems

As Electronic Control Units (ECUs) and embedded software functions within an automobile keep increasing in number, the scale and complexity of automotive embedded systems is growing at a very rapid pace. Hence, the automotive industry has been developing the Automotive Open System Architecture (AUTOSAR) to harness the reusability of common interfaces to communication buses, real-time operating systems and services. These common interfaces foster ease of adoption, interoperability, maintainability, predictability, and analyzability. However, realizing such standards also requires strong support from end-to-end design tool chains. In this paper, we describe some key analytical components that together characterize the end-to-end timing properties of hierarchical bus structures composed of FlexRay, CANbus and LINbus. Our analysis shows that the practical constraints imposed by standards such as AUTOSAR can lead to higher levels of schedulable resource utilization. This reduces both the overall component count and cost, while facilitating easy enhancements. Our analytical results show (a) how a schedulable utilization of 100% can be obtained for time-triggered FlexRay static segments under AUTOSAR compliance, (b) average-case schedulable utilization of 87% for the event-triggered CAN bus, and (c) similarities between LINbus and FlexRay analyses. We generalize the analytical results from different bus technologies, by exploiting their common underlying structure to enable an integrated end-to-end timing analysis of hierarchical heterogeneous networks. These together yield an end-to-end framework to analyze heterogeneously networked AUTOSAR-compliant automotive systems.