Abstract

—Energy consumption is major constraint in Wireless Sensor Networks (WSNs). Till now, numerous routing protocols have been investigated to achieve the energy efficiency. Earlier communication protocols were proposed, which can have large impact on the overall consumption of these networks.These conventional protocols such as direct transmission, minimum-transmission-energy, multi-hop routing, and static clustering may not be suitable for sensor networks.LEACH was proposed to overcome the problems of conventional protocols. In LEACH, cluster heads are randomly rotated in order to divide energy load among all nodes. There are so many protocols which follows the same operation as LEACH. This paper reviews on hierarchical based clustering and evolutionary protocols for heterogeneous WSNs to provide better energy efficiency.