Energy Efficient Routing for Wireless Sensor Networks-A hierarchical Approach

The popularity of Wireless Sensor Networks (WSN) has increased tremendously in recent time due to growth in Micro-Electro-Mechanical Systems & wireless communication technology. These Wireless sensor networks can be used for various applications, such as military, health & habitat monitoring, object tracking, fire detection, agriculture, and security. The main purpose of such networks is to collect information from the environment and deliver the same to the applications to determine characteristics of the environment or to detect an event. The sensor nodes are usually resource deficient with energy being the most critical of all the resources. These nodes in a wireless sensor networks are connected typically to a powerful controlling node called the base station. The base station is assumed to be connected to a stable power source and is not considered energy deficient, whereas all other nodes are battery powered. So, efficient use of energy resources in sensor nodes could extend the lifetime of the wireless sensor networks. The activity of sensing does not require much energy, it is the communication required for the delivery of the sensed data which causes most drainage of a sensor's battery. Therefore, the issue of energy saving is considered primarily in transmission and dissemination of data in sensor networks. Clustering techniques are important to save energy in a wireless sensor networks. It conserves communication bandwidth by avoiding redundant exchange of messages among nodes. It schedules activities in the cluster so that nodes can switch to the low-power sleep mode most of the time and reduces their rate of energy consumption