Research on Scheduling Strategy of AFDX End System Based on Time/Event Trigger

Abstract

To meet different time delay requirements of different data, three scheduling strategies based on event, time and event-time are studied in this paper. The network calculus method is used to derive the maximum delay upper bound of virtual link based on three scheduling strategies, the relationship between the maximum delay upper, virtual link parameters, time scheduleparameters and the frame length is compared, the difference between the alternate scheduling strategy and the Time-Triggered or event-triggered scheduling is studied. The AFDX (Avionics Full-Duplex Switched Ethernet) virtual network model is established toverifythetheory based on OPNET, thedeterminist of theTime-Triggered link, the maximum delay of the event-triggered link and the efficiency of the end system transmission are compared under different scheduling strategies. Also, the applicable occasions of different scheduling strategies are studied. The results show that the event and time alternate scheduling strategy not only ensures the certainty of Time-Triggered link transmission, but also reduces the event triggering. The maximum delay upper bound of the link effectively improves the data processing capability and transmission efficiency, ensures the stability and certainty of the periodic signal transmission, and is suitable for the aviation bus system with different kinds of data with different delay requirements.