A method for optimization of static slot length for maximum utilization of bandwidth in Flex ray protocol

Most of the mechanical and hydraulic parts, nowadays, are replaced by electronic control units in automobile industry. The number of infotainment and multimedia applications has an increasing trend. Hence, the number of Electronic control units and signals in a cyber physical system like vehicles are increased and a high bandwidth protocol for communication between distributed embedded controllers is required. Flexray provides time triggered static segment for the transmission of time critical periodic data and a priority based scheduling of frames in a dynamic segment for transmission of event triggered signals. Number of Electronic control units connected to the Flexray protocol depends on the time units allocated to a particular node. If it can be optimized for maximum utilization, then more electronic control units can be connected to one Flexray bus. In this paper, a method for optimization of static slot length for maximum utilization of every cycle in the hyper period of periodic tasks satisfying its worst case deadline is presented. A linear integer programming problem is developed from its non linear constraints and number of Electronic control units that can be connected for the communication length is also obtained.