Abstract
One of the mechanisms used to enlarge the lifetime of Wireless Sensor Networks (WSN) and to provide more efficient functioning procedures is clustering. By assuming roles within a cluster hierarchy, the nodes in a WSN can control the activities they performed and therefore, reduce their energy consumption. However, the election of when to act as a data provider (saving energy) and when to act as a gateway (cluster head) between the nodes and the base station is not a simple task. To make this decision it is necessary to take into account aspects like power level signal, transmission schedules and networking functioning (proactive or reactive). In this paper we study some basic concepts related to the clustering process in WSN and presenting a comparison survey between different clustering protocols.