Method and Analysis for the Improvement of Preemption Performance in IEEE 802.1 TSN

The application of a program-based control method using an Electronic Control Unit (ECU) for mechanical control has improved the reliability and performance of vehicles. However, vehicle network structures are becoming increasingly complex. Consequently, the current central gateway method is in the process of changing from a domain-based structure to a zone-based network. The Institute of Electrical and Electronics Engineers IEEE 802.1 group announced Time-Sensitive Networking (TSN) in line with the changing vehicle network system. TSN uses the IEEE 802.1Qav, IEEE 802.1Qbv, and IEEE 802.1Qbu protocols to achieve bounded low latency. Estimating the guard band area is essential when applying the IEEE 802.1 Qav protocol. This is because if the audio, video, and text frames are long or the transmission time is insufficient, the scheduled traffic area, where the control data are transmitted, might be invaded by the guard band area. A preemption function can be used to prevent such problems; however, to do so, additional processing time is required to divide or recombine frames. In addition, it is necessary to separate the divided frames and the required header for the re-assembly process. Subsequently, the preemption function can be used to minimize the guard band area, reduce the number of preemption occurrences, and increase the efficiency of the network. In this study, to solve the above-mentioned problem, we propose a method to explore the frame preemption and to reduce the number of preemptions that may occur in a specific situation. As a result, the number of preemption occurrences could be reduced by 87% by applying the proposed method.