Control-Aware Adaptive Routing for Industrial Wireless Sensor-Actuator Networks

Abstract

The recent adoption of Wireless Sensor-Actuator Networks (WSANs) in industrial control systems makes it possible to build and maintain infrastructure at low cost. Unlike conventional wireless networks, WSANs have strict constraints to ensure the control performance and stability of physical systems. The main goal of the WSANs research is to maximize the control performance of the WSANs considering the stringent requirements of the control system and external disturbances caused by the harsh industrial environments. In this paper, we propose a control-aware adaptive routing for industrial WSANs. The proposed routing scheme aims to improve the performance of the control system in the conditions that the packet delivery ratio (PDR) of routing paths is not constant due to the unpredictable external interference of WSANs. The criticality of control packet is decided by importance of control commands in consideration of real-time control performances. The control command packet generated by the controller has a different purpose depending on the criticality. High criticality packets are transmitted over the optimal path with the highest PDR measured among the multiple paths. Low criticality packets not only convey control commands to the actuator but are also used to measure the PDR of each path. In addition, an algorithm to detect changes in PDR keeps the PDR of each path up to date. It is possible to improve the performance of the control system by maintaining the maximum probability that the high criticality packets are delivered successfully in a given network situation. The simulation results demonstrate the performance of the proposed routing algorithm.