Date Added: Mar 2013
In recent times, the technology of Wireless Sensor Network has a great impact on technical fields like wireless communication, information technology, electrical etc. However the major problem faced in this technology is that the sensor nodes run out of energy very quickly. Many routing protocols have been proposed to solve this problem mainly focusing on the accomplishment of minimizing the energy consumption in the sensor system. In this paper, two hierarchical protocols cluster based and chain based protocol for WSNs have been discussed. In both type of protocols some special nodes called cluster heads/chain heads acts as leader for a group of nodes. Each head collects data from its member nodes and forward it to the sink (base station).