Date Added: Aug 2012
Due to the necessity of saving energy cost in low-powered devices, extending the lifetime of a sensor node powered by battery in both homogeneous and heterogeneous Wireless Sensor Networks (WSNs) is area of interest. To save battery power in sensor networks, many research works including Low Energy Adaptive Clustering Hierarchy (LEACH) and its variants use clustering techniques to reduce energy spent by keeping most of the nodes in sleeping mode but making a good Quality of Service (QoS). However, LEACH lacks on optimizing the network life time due to loosing huge energy of sensor nodes selected as cluster heads for communications. In contrast, relay node based schemes use independent powerful relay nodes as cluster heads to save energy of the low energy sensor nodes.