Energy-efficient WSN systems

Abstract

Due to increasing number of controllers, sensors and actuators in conventional instrumentation systems, cabling connection complexity has also grown, increasing time and maintenance cost. As a result, the use of IEEE 802.15.4 standard in Wireless Sensors Networks (WSN) have also increased, allowing faster maintenance time, as well as layout changes. In some applications, where there are no reliable sources of energy, the aspect of energy consumption is very important, as in environmental monitoring, mobile applications, agricultural industry and automation of oil wells. This book chapter presents the mainly practices to reduce energy consumption in wireless sensor networks and new techniques. A few of the new power-saving techniques are the Dynamic Scaling Voltage that is a real time reduction of the supply voltage, the Dynamic Modulation Schedule that allows channel characteristics changes according to the need for energy economy, Rational Time Sampling that change the duty cycle of the device dynamically, and the most used and most economical network protocols. A design of an energy-efficient system is presented, show the hardware and software detail of subsystem and communications aspects, emphasizing the control subsystem of charge and discharge, for uses with a solar panels, as well as software optimized for task of network controlling and sensing, both characteristics that leads a reduced consumption of energy. This chapter also presents a consumption estimation method to be used in WSN designs projects that allows the engineer to define the network characteristics as a set of performance requirements and suggests further developments in this area.