The wireless sensor network is characterized by its density in number of deployed sensors. In reality, sensors in the same region collect and forward, in general, the same information. In order to conserve nodes energy, it is necessary to keep active a set of nodes while others can sleep. In this paper, we present a new topology control protocol (GECP) for wireless sensor network that extends the network lifetime by minimizing the energy consumption as well as ensuring the network connectivity. GECP exploits the sensor redundancy in the same region by dividing the network into a set of groups and allowing only to one sensor node to be active in each group. The group formation process is based only on exchanged messages between one-hop neighbors.