Switched FlexRay: Increasing the effective bandwidth and safety of FlexRay networks

With the continued demand for more and innovative functions in series automobiles, significantly higher data-rates and more reliable communication are necessary than traditional automotive bus systems, e.g., the controller area network (CAN), provide. In this paper, we present a novel hardware device for FlexRay networks, which splits the bus into separate branches and operates as a selective central switch. The proposed device is capable of increasing both the available bandwidth and safety of existing FlexRay networks. The bandwidth is increased by enabling the scheduling of multiple messages in parallel on disjoint sets of branches. The device can furthermore serve as a central bus guardian (CBG), protecting the majority of the participants on the network from so-called babbling idiots and short circuits, by isolating a faulty component on its respective branch. The proposed device is fully compatible with the existing FlexRay specifications and transparently extends a system, requiring no modifications to the existing FlexRay bus participants. The architectural challenges of a FlexRay switch/CBG, its subsequent proof-of-concept implementation on an FPGA-platform, and our experimental results are described in detail.