Extending Network Lifetime of Clustered-Wireless Sensor Networks Based on Unequal Clustering

In wireless sensor network (WSN), sensor nodes are partitioned into clusters in order to gather information more efficiently in terms of energy consumption. In clustered networks, each node transmits acquired data to a cluster-head which the nodes belong to. After a cluster-head collects all the data from member nodes, it transmits the data to the base station (sink) in aggregated manner. This data transmission occurs through other cluster-heads in a multi-hop network environment. The sensor nodes closer to the base station consume more energy, because the network traffic increases as it approaches the base station. As a result, cluster-heads close to the sink tend to die earlier because of the heavy inter-cluster traffic. This problem is named as hotspots problem. To solve this problem, decrease the cluster sizes as they approach the base station by reducing cluster range radius, that is cluster-head closer to the base station has less intra-cluster work, then it can contribute more to inter-cluster data forwarding. A fuzzy logic approach is adopted in order to handle uncertainties in cluster-head radius estimation. The proposed algorithm is compared with fuzzy energy-aware unequal clustering algorithm (EAUCF). The experiment results shows that proposed algorithm performs better in terms of number of dead nodes and residual energy. Therefore, proposed algorithm is stable and energy efficient clustering algorithm to be utilized in any application. Index Terms wireless sensor network, clustering, network lifetime, network traffic.