An Unequal Cluster-Based Routing Protocol for Wireless Heterogeneous Sensor Networks

Abstract

Hierarchical clustering provides an effective way to prolong the lifetime of wireless sensor networks. However, when cluster heads use multi-hop forwarding model for inter-cluster communication, the area around the sink is burdened with heavy traffic load, which introduces uneven energy consumption and causes energy-hole problem. In this paper, an Unequal Cluster-based Routing Protocol (UCRP) is proposed to alleviate the energy-hole problem in wireless heterogeneous sensor networks. In UCRP, by evenly dividing the network into multi-layer rings, three kinds of nodes with different initial energy namely normal nodes, advanced nodes and super nodes, are grouped into clusters with unequal sizes. In order to obtain the optimal number of cluster heads and the balanced average energy consumption, a mathematical method is developed to calculate the optimal cluster radius for each cluster. Based on the optimal cluster radius, an unequal clustering algorithm and a cluster-based routing protocol are proposed to balance the energy consumption in each cluster. Both theoretical analysis and simulation results indicate that UCRP effectively balances energy consumption and improves network throughput.