Abstract: Energy is one of the scarcest resources in the wireless sensor networks. Most important fact about the energy conservation is deployment of sensor nodes with in network area, so energy which used in network remains balanced throughout the whole network. Clustering algorithm is a kind of key technology used to increase energy efficiency. It can be used to enhance the lifetime and stability period (death of first node) of network by consuming minimum amount of energy. Energy efficient protocol used to characterize the heterogeneous wireless sensor network. It is observed that energy imbalance in wireless sensor networks occurs due to relaying of data from different parts of network towards the sink node, so for improved energy balance instead of using only sensor nodes it is necessary to deploy node with some extra energy with normal sensor nodes to manage such imbalance. In this paper we have survey the previous techniques used for enhancement of energy consumption.

Keywords: wireless sensor networks, connectivity, coverage, node deployment, stability period, energy balance, network lifetime.