Abstract: Wireless sensor network consists of sensor nodes which are powered by battery; to communicate with each other for environment monitoring. Energy efficiency is the main issue in wireless sensor networks. Therefore, to maximize network lifetime and achieve maximum reliability and scalability, routing techniques have been developed. LEACH is the conventional hierarchical clustering protocol widely used in WSNs. This paper reviews the taxonomy of WSN routing protocols and also highlights issues in LEACH protocol along with disadvantages. The objective of this paper is to provide brief detail of some LEACH improved versions. Finally this paper compares some features of LEACH protocol variants.

Keywords: WSN, LEACH, HEED, LEACH-C, Network lifetime.