An HLA/RTI architecture based on periodic and aperiodic tasks scheduling for real-time improvement

The work takes place in the context of the HLA (High Level Architecture) standard and its application for pursuit of real-time performance. Because of precedence constraint of correlated tasks between federates, it is hard to provide predictable response for all tasks, and it is also difficult to ensure the real-time performance of all tasks, especially aperiodic ones. In the architecture we proposed D-EDF (Double Earliest Deadline First) strategy to schedule overall periodic and aperiodic tasks inside a federate from the point view of task scheduling theory. The policy not only discards some redundant data to ensure the periodic tasks completed effectively before their deadlines, but also schedules aperiodic ones running regularly to improve their real-time responding speed. The simulation results show that the policy can effectively handle the tasks with precedence constraints and consequently improve the real-time performance of RTI.