Unequal clustering routing algorithms in wireless sensor networks: A comparative study

In order to prolong the life span of sensor nodes, wireless sensor nodes are grouped into clusters, and in each cluster at less there is one node act as a cluster head, gathering the sensing data from its cluster member and forwarding to sink or base station. Clustering is the most popular energy efficient technique and provides various advantages like energy efficiency, lifetime, scalability and less delay; clustering has classified into two categories equal cluster size and unequal cluster size. In unequal approach, the size of the clusters are modifying proportionally according to its distance from the base station, where size of the cluster close to BS will be small and whenever the cluster located farther from the base station, the cluster size will be larger. For the importance of this approach and the lack of studies that deal with it in deep details, we are motivated to conduct this study. In this paper, firstly we classified this approach, according to clustering features. Secondly, we classified unequal cluster algorithms in terms of nature of algorithm that used in the clustering. Then we combined these classifications in one comparative table. The main purpose of this work is to discuss the characteristics of protocols according to Features of clustering and clustering algorithms types.