Abstract
FlexRay is a communication protocol that combines event- and time-triggered communication to increase the schedulability and flexibility of message scheduling in current car systems. Because safety and reliability are particularly crucial for automotive systems, the response times of signals transmitted by electronic control units must be under their deadlines. Therefore, this study analyzed the timing of messages by using an integer linear program. Furthermore, to increase the bandwidth utilization, the slot-multiplexing (SM) mechanism that is allowable in protocol specification was adopted to schedule messages in the dynamic segment of the FlexRay protocol, and this mechanism was also considered in the timing analysis. The proposed method was applied to a Society of Automotive Engineers benchmark to ensure that all messages were transmissible. Finally, the improvement in bandwidth was assessed by comparing the bandwidths of the SM and non-SM models.