Controller area network response time analysis and scheduling for advanced topics: offsets, FIFO queues and gateways /

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2015
Alkan, Burak
Controller Area Network (CAN) is the most widely used in-vehicle network for the communication among electronic control units (ECUs). CAN has a priority-based arbitration mechanism and the classical usage of CAN assumes the implementation of priority queues (PQs) on ECUs. Based on this assumption, the literature provides e cient algorithms for the computation of worst-case response times (WCRTs) of messages as well as for the appropriate assignment of priorities to messages in order to meet real-time guarantees such as message deadlines. In contemporary CAN networks there are several extensions to the classical case. First, the addition of new functionality to vehicles requires adding new messages with appropriate priorities to existing CAN networks. Second, FIFO queues (FQs) might be used instead of PQs for easier implementation. Third, due to the everincreasing bus load, CAN networks are usually divided into several segments that are connected via gateways to decrease the contention among messages. Fourth, a further measure is to distribute the message transmission of each ECU over time by assigning transmission o sets to messages. All of the stated extensions require new methods for WCRT analysis and priority assignment on CAN. This thesis has a list of contributions that address the extensions for CAN as listed above. Regarding o set scheduling; di erent schedulability analysis methods for message sets with given o set and priority assignments are incorporated to a previous o set assignment algorithm. Then, a new algorithm which simultaneously assigns the message o sets and priorities is proposed. Regarding ECUs with FIFO queues; the previous schedulability analysis is improved to decrease its run time and then this analysis is used in an algorithm that assigns the priorities to the new messages that extend an existing CAN network. Regarding gateways; an algorithmic priority assignment is proposed for ECUs with priority queues and the schedulability analysis for CAN networks with gateways is extended to FIFO queues. All of the algorithms that are used and developed in this thesis are implemented in C++ to integrate into a novel in-vehicle network analysis and design tool; AUTONET.
Citation Formats
B. Alkan, “Controller area network response time analysis and scheduling for advanced topics: offsets, FIFO queues and gateways /,” M.S. - Master of Science, Middle East Technical University, 2015.