Optimal priority assignment for messages on controller area network with maximum system robustness

摘要

Controller Area Network (CAN) is broadly used for in-vehicle networking. Each message on the CAN bus is given a unique identifier as its priority. When more than one node starts to transmit at the same time, the message with the highest priority will be sent. The schedulability of the message set is significantly affected by the priority assignment algorithms employed. To ensure that the CAN system tolerate additional interference, we propose system robustness, a concept to represent the total robustness of the message set. Maximum system robustness of message set problem is NP-hard. We find that assigning a higher priority to the message with small transmission time or low utilization may lead to more system robustness. Based on this, this paper presents four optimal priority assignment approximation algorithms using the Audsley's priority assignment method: TMPA, UMPA, GTMPA, and GUMPA. TMPA and UMPA are heuristic algorithms. GTMPA and GUMPA are greedy algorithms. Experimental results show that, compared with the existing optimal algorithms, TMPA, GTMPA, and GUMPA can improve the system robustness of CAN message sets effectively.