Research on Optimal Scheduling Period of Flexray Based on Jitter - free Transmission

The scheduling period (SP) is an important parameter for building an in-vehicle communication network based on FlexRay bus. In this paper, we analyze the impact of SP on the bus bandwidth utilization and transmission jitter, study the method of assignment of bus period with jitter constraints, investigate necessary conditions should be meet when jitter-free transmission is demanded and establish mathematical model for the optimal SP. Considering there are many long period messages on in-vehicle communication network and much of bandwidth is wasted by them, we put forward an integer period extended model (IPEM) and present the structure of the modified period scheduling table and corresponding software architecture as well, thus the long period message can be transmitted with a period larger than SP and the bandwidth demanded is reduced dramatically. At last, the model is verified by various kinds of message sets and the result of simulation indicates that our method is effective. Copyright © 2014 IFSA Publishing, S. L.