Energy Saving in Wireless Sensor Networks

A wireless sensor network (WSN) consists of a large number of sensor nodes which are deployed over an area to perform local computations based on information gathered from the surroundings. Each node in the network is equipped with a battery, but it is almost very difficult to change or recharge batteries; therefore, the crucial question is: "how to prolong the network lifetime to such a long time?" Hence, maximizing the lifetime of the network through minimizing the energy is an important challenge in WSN; sensors cannot be easily replaced or recharged due to their ad-hoc deployment in hazardous environment. Considering that energy saving acts as one of the hottest topics in wireless sensor networks, we will survey the main techniques used for energy conservation in sensor networks. The main focus of this article is primarily on duty cycling schemes which represent the most compatible technique for energy saving and we also focus on the data-driven approaches that can be used to improve the energy efficiency. Finally, we will make a review on some communication protocols proposed for sensor networks.