In the development of the Internet of Things (IoT), the use of sensors has increased as a way to build smarter cities and industries. The network, consisting of battery-powered sensor nodes, can also be implemented in remote and hazardous environments where cabling and manual maintenance is unfeasible. As the sensors often are deployed remotely and in large quantities or integrated into objects, the battery capacity of the sensors is a limited resource. Therefore, energy management is an important research topic in order to reduce energy consumption.
The industry is currently investigating the use of networked wired and wireless technologies in monitoring, automation, and control. Sensor nodes are commonly used in a control system communicating over a wireless network, in order to regulate the behavior of an actuator based on the measured sensor data. Wireless Networked Control System (WNCS) allows for remote control of the plant and exchange of information in real-time. Due to the potential scalability, large flexibility, and ease of installation and maintenance, the WNCS are widely implemented and researched.
There is a tradeoff between reliability and delay with the energy consumption of the network. An industrial network requires high reliability and low delay while this will have a significant impact on energy consumption in the network.
To prolong the lifetime of the sensor nodes, the energy efficiency can be improved with the implementation of an energy-aware communication protocol. The protocol organizes the nodes into clusters and sends the data through multiple hops between these clusters.
To optimize the energy efficiency under stability constraints, the routing protocol is chosen with this in mind. A routing protocol with multihop transmission minimizes the total energy consumption of the network but may induce greater time delays and packet loss when compared to single-hop transmission.
The goal is to show that by combining a clustering protocol with the control network, it is possible to implement wireless sensor networks in industrial applications where the delays, packet loss, and reliability are critical factors and at the same time prolong the nodes' lifetime.