Date Added: Feb 2013
Wireless Sensor Networks (WSNs) is considered as most recent technology for data gathering. The sensor devices are made up of hundreds or thousands of sensor nodes deployed over a huge geographical area. Due to the limited power of the Wireless Sensor Networks (WSNs), the network lifetime becomes a critical issue in WSN's. To enhancing the lifetime, clustering is becoming a most active branch of routing technology in WSNs. In this paper, the authors present a fine review on clustering protocols. In addition, they outline the objectives of clustering for WSNs. Finally, they summarize and conclude the paper.