Message scheduling on static segment of FlexRay networks

FlexRay is a hybrid in-vehicle communication protocol whichcarries out the transmission of time-triggered data in the static segment as well as event-triggered data in the dynamic segment. In this paper, we study the problem of scheduling static messages with precedence relations in FlexRay protocol. Our objective is to obtain the minimum number of used slots. To this end, a scheme for transformation of the precedence constrained message scheduling problem to a Strip Packing Problem is proposed. In thisproblem a set of rectangles must be placed within a strip. The goal is to place the rectanglesso that they do not overlap and so that the height ofthe area covered by rectangles is minimized. However, since Strip Packing Problem cannot solely deal with flexray specifications and precedence relations between items we introduce new constraints called FlexRay Constraints. We elaborate on a Linear Integer Programming that obtains the optimal solution. We study our approach based on a case study involving someadvanced automotive control applications.