Message Reordering for the Reuse of CAN-based Legacy Applications in a Time-Triggered Architecture

Abstract

While CAN is the most widely used communication protocol in present day distributed automotive computer systems, time-triggered architecture will provide the ability to handle the communication needs of future by-wire cars. In addition to hard real-time performance, time-triggered architectures help in managing the complexity of faulttolerance and corresponding formal dependability models, as required for the establishment of ultra-high reliability (failure rates in the order of 10-9 failures/hour). Virtual CAN networks on top of a time-triggered communication protocol are a solution to integrate existing CAN-based legacy applications into such a time-triggered architecture. Thus, there is the possibility to eliminate physical CAN networks, which leads to cost reductions and reliability improvements. In order to ensure that existing CAN-based software works correctly in a time-triggered architecture, a virtual CAN network must provide the temporal behavior of a physical CAN network. For this reason, we develop a solution for establishing in a virtual CAN network the same temporal message order as in a physical CAN network. We present a CAN protocol emulation algorithm and provide validation results based on an implementation in the Time- Triggered Architecture.