  Clustering in wireless sensor networks (WSNs) is an important technique to
ease topology management and routing. Clustering provides an effective method
for prolonging lifetime of a WSN. This paper proposes energy efficient
multi-level clustering schemes for wireless sensor networks. Wireless sensor
nodes are extremely energy constrained with a limited transmission range. Due
to large area of deployment, the network needs to have a multi-level clustering
protocol that will enable far-off nodes to communicate with the base station.
Simulation is used to analyze the proposed protocols and compare their
performance with existing protocol EEMC. Simulation results demonstrate that
our proposed protocols are effective in prolonging the network lifetime.
