Author : Ab Wahid Bhat and Dr. Abhiruchi Passi

Wireless sensor networks (WSN) are increasingly finding their way in diverse applications be it the realization of IoT or real-time monitoring of the environment, health, defense, and even domestic ones. A wireless sensor network consists of a large number of small self-configurable sensor nodes that are capable of performing functions of sensing, processing, and communication of information. Sensor nodes are inherently constrained in terms of energy, computational and communicational capabilities. Most of the sensor nodes are battery-powered with a limited supply of energy. The battery of a sensor node is hard/ impossible to be replaced once deployed. Lifetime of a sensor node or sensor network is concerned with energy, and it is strictly constrained. Most of the energy of a sensor node is consumed during communication, therefore; energy efficiency should be the prime focus while designing the hardware and software of wireless sensor networks. Clustering is an energy optimization technique that can increase the energy efficiency and prolong the network lifetime. Various aspects of clustering presented in this paper include different types of cluster-based networks, clustering process and evaluation metrics. A brief insight into present trends on clustering is also included.

Keywords: Wireless sensor Networks (WSN), unique constraints, lifetime, clustering, load balancing and quality of service.