Real-Time Wireless Routing for Industrial Internet of Things

With the emergence of the Industrial Internet of Things (IIoT), process industries have started to adopt wireless sensor-actuator networks (WSANs) for control applications. It is crucial to achieve real-time communication in this emerging class of networks, and routing has significant impacts on end-to-end communication delays in WSANs. However, despite considerable research on real-time transmission scheduling and delay analysis for such networks, real-time routing remains an open question for WSANs. This paper presents a conflict-aware real-time routing approach for WSANs, leveraging a key observation that conflicts among transmissions involving a common field device can contribute significantly to communication delays in industrial WSANs, such as WirelessHART networks. By incorporating conflict delays into the routing decisions, conflict-aware real-time routing algorithms allow a WSAN to accommodate more real-time flows while meeting their deadlines. Both evaluations based on simulations and experiments on a physical WSAN testbed show that conflict-aware real-time routing can lead to as much as a three-fold improvement in the real-time capacity of WSANs.