**1. Introduction**

A sensor based network system that performs wirelessly has given birth to the coinage 'Wireless Sensor Network' or simply 'WSN'. 'WSN' [1] has become essential in many fields including infrastructure, healthcare, agriculture, environment, military defense, automation and so on.

As technological advancement is gaining its momentum day by day, it has been trying to replicate some of the biological receptive and cognitive faculties in order to develop more intelligent devices and systems to overcome real world hindrances. Thus 'sensors' [2] are used to imitate human sense organs to collect information about certain physical parameters like temperature [3], light, speed, movement, moisture etc. for any desired action taken thereafter.

Wireless Sensor Network is a system for the transmission of data through such a networking process which is independent of any physical cables. Here the sensors deployed receive some physical quantities like temperature, pressure, sound, humidity etc. from the environment and process them. They not only monitor the sense but also have the communication capability. Thus we can define Sensor as a device which measures any physical quantity and converts it to such a format which an observer or an instrument can understand (**Figure 1**).

**Figure 1.** *Brief structure of WSN.*
