Date Added: Jul 2012
One of the main problems in wireless sensor networks is information collection. How the sensor nodes can send efficiently the sensed information to the sink since their number is very large and their resources are limited? Clustering provides a logical view, much more effective than the physical view, which extends the lifetime of the network and achieves the scalability objective. Although the assumption that all sensor nodes can communicate directly with each other or with the sink is not always valid because of the limited transmission range of the sensor nodes and the remoteness of the sink.