Nowadays, the domain of sensor networks constitutes a very active research field. People are using a lot of
low cost networks. As a result, they are facing an important energy management problem. Consequently, Researchers have tried to ensure long life to networks [1]-[8]. LEACH, PEGASUS, TEEN and APTEEN are pioneers in the reduction of WSN energy consumption. Generally, cluster heads (CH) and nodes close to the station die quickly in sensor networks. Cluster heads consume more than simple nodes. Also, the needed energy for the formation of clusters is very high in sensor networks.
We propose an algorithm that aims at reducing the energy consumption in the formation of clusters and at providing a long life to the homogeneous sensor networks. In this paper, we present this algorithm for energy management in sensor networks. It is based on three thresholds. What we propose is a new way to construct clusters. It will allow having a real vision on the energy available in the sensor network at anytime. Our experimentations have shown a reduction in the energy used in comparaison with other methods.

Wirless WSN Routing