  Energy saving to prolong the network life is an important design issue while
developing a new routing protocol for wireless sensor network. Clustering is a
key technique for this and helps in maximizing the network lifetime and
scalability. Most of the routing and data dissemination protocols of WSN assume
a homogeneous network architecture, in which all sensors have the same
capabilities in terms of battery power, communication, sensing, storage, and
processing. Recently, there has been an interest in heterogeneous sensor
networks, especially for real deployments. This research paper has proposed a
new energy aware clustering protocol (EACP) for heterogeneous wireless sensor
networks. Heterogeneity is introduced in EACP by using two types of nodes:
normal and advanced. In EACP cluster heads for normal nodes are elected with
the help of a probability scheme based on residual and average energy of the
normal nodes. This will ensure that only the high residual normal nodes can
become the cluster head in a round. Advanced nodes use a separate probability
based scheme for cluster head election and they will further act as a gateway
for normal cluster heads and transmit their data load to base station when they
are not doing the duty of a cluster head. Finally a sleep state is suggested
for some sensor nodes during cluster formation phase to save network energy.
The performance of EACP is compared with SEP and simulation result shows the
better result for stability period, network life and energy saving than SEP.
