WiFi implementation of Wireless Networked Control Systems

This paper studies a Wireless Networked Control System which utilizes the IEEE 802.11b protocol without modifications to communicate between sensors and actuators in a production line environment. OPNET simulations are used to measure the end-to-end delay from sensor to controller and then from controller to actuator. It is observed that the measured delays, including all types of data processing, encapsulation, decapsulation and propagation, meet real-time control network requirements while guaranteeing correct packet reception. The system is then subjected to noise and several worst-case scenarios are analyzed. Simulations indicate that the system is still able to meet the required end-to-end delays. All results are based on a 95% confidence analysis.