MEEP: Multihop Energy Efficient Protocol For Heterogeneous Wireless   Sensor Network
  Energy conservation of sensor nodes for increasing the network life is the most crucial design goal while developing efficient routing protocol for wireless sensor networks. Recent technological advances help in the development of wide variety of sensor nodes. Heterogeneity takes the advantage of different types of sensor nodes and improves the energy efficiency and network life. Generally sensors are deployed randomly and densely in a sensing region so short distance multihop communication reduces the long distance transmission in the sensor network. In this research paper MEEP (multihop energy efficient protocol for heterogeneous sensor network) is proposed. The proposed protocol combines the idea of clustering and multihop communication. Heterogeneity is created in the network by using some nodes of high energy. Low energy nodes use a residual energy based scheme to become a cluster head. High energy nodes act as the relay nodes for low energy cluster head when they are not performing the duty of a cluster head to save their energy further. Protocol also suggests a sleep state for nodes in the cluster formation process for saving energy and increasing the life of sensor network. Simulation result shows that the proposed scheme is better than other two level heterogeneous sensor network protocol like SEP in energy efficiency and network life. 
Surender Kumar, Manish Prateek, N.J. Ahuja, Bharat Bhushan
cs.NI