Wireless sensor networks (WSNs) have been widely used in industrial systems. Industrial systems demand a high degree of reliability and real-time requirements in communications. In many industrial wireless sensor networks applications, flows with different levels of criticality coexist in the system. When errors or exceptions occur, high-criticality flows must be guaranteed reliably and in real time. However, only a few works focus on mixed-criticality industrial systems. Concerning this issue, in the current study, we study mixed-criticality industrial systems and propose a supply/demand bound function analysis approach based on earliest deadline first scheduling. In addition, our method considers both source routing and graph routing. At the beginning, when the system is in low-criticality mode, source routing considers the schedulability of each flow. When errors or exceptions occur, the system switches to high-criticality mode, and network routing turns to graph routing to guarantee that important flows can be scheduled. By estimating the demand bound for mixed-criticality systems, we can determine the schedulability of industrial systems. Experiments indicate the effectiveness and efficacy of our approach.

This work was published on IEEE Access,2017:1-12. titled  Bounding the Demand of Mixed-Criticality Industrial Wireless Sensor Networks.