The increasing number of local control units in automotive systems led to growing emphasis on developing and using multiplex systems. For reasons of price and robustness the use of asynchronous and slow multiplex systems is preferred.
Since the communication volume now reaches critical dimensions in peak load situations during the use of those systems, new concepts on different communication levels have to be developed.
Due to the use of many different message types (wide range of message length) and the statistical dependence of the communication behaviour of control units (e.g. question-answer-combinations), the application of standard methodologies is only partly suitable for a performance analysis of automotive multiplex systems.
In this paper a simulation concept is proposed, which combines the different methodologies used for modelling embedded control units (finite state machines), multiplex systems (queuing theory) and external input (statistical approximation based on real data).
Finally first analysis results and deduced proposals for an optimised communication protocol are presented.