Improving Performance of Controller Area Network (CAN) by Adaptive Message Scheduling

Controller Area Network (CAN) has been widely used in many distributed control applications. The low capacity of CAN and usually strict constraints under which it is used in real-time applications limit its applicability. This paper presents a new approach for scheduling messages on CAN based on online adaptation of message offsets, which results in significantly shorter average message response times compared with approaches which guarantee response times. This allows much higher utilization of CAN, resulting in increased effective capacity, and enables its use in applications in which more expensive faster protocols would be required otherwise. Since the average message response times are reduced, the approach is particularly attractive for soft real-time applications. In addition, the paper proposes a method for self-initialization of the CAN-based system on its start-up, which reduces response times from the very start of the system. The proposed approach is very simple and requires modest resources for its implementation, with no change of the standard CAN infrastructure. We demonstrate the performance improvements by comparing the approach with other approaches.