Configuring loosely time-triggered wireless control software

Abstract

In many wireless control networks, sensor data and controller data are exchanged periodically, which requires periodic packet transmissions between the physical plant and the controller. As an alternative, event-triggered control paradigms imply that data is only exchanged when there are significant changes in the state of the plant, e.g., because of disturbances. This is the nature of many IoT scenarios and requires that a receiving device has to listen to the channel for incoming packets during all times. However, especially in mobile networks, in which all devices are battery-powered, continuous scanning would drain the battery quickly and hence, reception needs to be duty-cycled. When optimizing such duty-cycled operation, significant energy savings are possible using intelligent software-enabled communication scheduling. In this paper, we propose a wireless transmission scheme that supports loosely time-triggered control. When optimizing the scheduling of transmissions and reception windows in the communication protocol, our proposed scheme allows for energy-efficient communication without requiring strict clock-synchronization between the devices. We show that such a scheme is practical and can greatly reduce the energy consumption in event-triggered control applications.