Abstract
While wireless sensor networks (WSN) are increasingly equipped to handle more complex functions, in-network processing still require the battery powered sensors to judiciously use their constrained energy so as to prolong the effective network life time.There are a few protocols using sensor clusters to coordinate the energy consumption in a WSN. To cope with energy heterogeneity among sensor nodes, a modified clustering algorithm is proposed with a three-tier sensor node setting. Simulation has been conducted to evaluate the new clustering algorithm and favorable results are obtained especially in heterogeneous energy settings.