Schedulability Comparisons between Priority Queue and FIFO Queue for CAN Messages with Offsets

The Controller Area Network (CAN) is a widely used in-vehicle network and its schedulability is particularly important. In a CAN system, implementing the priority queues is better than FIFO queues with respect to the schedulability, which is widely recognized by users. In this paper, we investigate whether and how much implementing the priority queues is better than FIFO queues when the offset assignment for CAN messages is conducted. Our results show that usually the priority queues are better, whereas the FIFO queues are better in some specific situations. Furthermore, we propose a new scheduling method for obtaining the advantages of both queues, which improves the schedulability effectively.