Wake-up radio receiver based power minimization techniques for wireless sensor networks

In a short period of time Wireless Sensor Networks (WSN) captured the imagination of many researchers with the number of applications growing rapidly. The applications span large domains including mobile digital health, structural and environmental monitoring, smart home, energy efficient buildings, agriculture, smart cities, etc. WSN are also an important contributor to the fast emerging Internet of Things infrastructure. Some of the design specifications for WSN include reliability, accuracy, cost, deployment versatility, power consumption, etc. Power consumption is (most often) the dominant constraint in designing such systems. This constraint has multi-dimensional implications such as battery type and size, energy harvester design, lifetime of the deployment, intelligent sensing capability, etc. Power optimization techniques have to explore a large design search space. Energy neutral system implementation is the ultimate goal in wireless sensor networks ensuring a perpetual/greener use and represents a hot topic of research. Several recent advances promise significant reduction of the overall sensor network power consumption. These advances include novel sensors and sensor interfaces, low energy wireless transceivers, low power processing, efficient energy harvesters, etc. This paper reviews a number of system level power management methodologies for Wireless Sensor Networks. Especially, the paper is focusing on the promising technology of nano-Watt wake-up radio receiver and its combination with mature power management techniques to achieve better performance. Some of the presented techniques are then applied in the context of low cost and battery powered toy robots.