Development of the Physical Layer and Signal Integrity Analysis of FlexRay™ Design Systems

Future automotive applications, like high-speed control in power train or drive-by-wire systems, demand large bandwidth, deterministic communication behavior, and fault tolerance. FlexRay, a new standard communication system, is ideally suited to safety applications as well as applicable to the role of a central backbone in future ECU network architectures. The FlexRay physical layer specification is kept very generic to provide the network designer with a wide range of possibilities for optimization of the network implementation. Due to the highly transient behavior of the system, the developer of the network physical layer cannot manually predict the behavior of an entire FlexRay topology. To analyze design concepts like topologies, terminations, and ECU architectures much earlier in development phase, simulation is the only choice. Simulation can be used to predict physical behavior and to verify the physical layer implementation of a FlexRay network while accounting for component and environmental variations. Accordingly, the developer can use simulation in the design of a robust network to investigate the influence and interoperability of new components and ECU interfaces with the goal of improving quality in automotive networks. Using virtual prototypes or production networks in conjunction with Robust Design methods, the developer can analyze network extensions (e.g. through automated wire length variations) and verify the impact of device tolerances. This paper describes the required elements for simulating the FlexRay physical layer, including simulation models, simulation scenarios, and post-processing mechanisms needed to sufficiently evaluate system behavior.