Validation of in-vehicle-protocol network topologies

Abstract

Network systems in vehicles represent very high complex systems. As such, topologies typically become very complex and in their layout criticality a major topic to be considered. Analysis of almost one hundred different topologies of vehicle manufactures worldwide led to the conclusion that less than 50 % of these layouts had been non-critical, if tolerances of all the parameters involved had been considered in their realistic worst-case scenario. C&S group developed a methodology based on electrical network topology components modelling for a couple of years together with the major German vehicle OEMs. As such, line models had been developed along with other models for the components being involved such as transceivers, termination coupling circuits, common mode chokes, electrostatic protection elements, etc. Along with the OEM specification of the desired topologies, simulations of these modelled topologies had been executed. The result of the simulation shows the electrical signal behaviour of the communication passing through the network. Signal distortion emerges due to the discrete components and the topology geometry itself and leads to signal ringing and reflections which may corrupt the individual bits to be transmitted and received. C&S simulation technology observes these corrupted bits and identifies the reason leading to the problem observed.