Experimental controller tuning and QoS optimization of a wireless transmission scheme for real-time remote control applications

In this paper an experimental optimization of a wireless (802.11b) transmission scheme, coupled to the tuning process of the controller parameters, for real-time control applications is presented. In congested wireless networked controlled systems (WNCS), there is considerable loss of data-packets in the transmission process between the client and server-sides. Accordingly the quality of service (QoS) suffers and the system's performance deteriorates. An integrated framework is proposed, that monitors the QoS-factor and: a) adjusts the data re-transmission attempts, and b) periodically tunes the controller's parameters. Experimental studies on a WNCS-prototype are used for the optimization procedure. These studies indicate the need for a compromise between the achieved QoS, the network's throughput, and the selected sampling period.