Abstract: Wireless sensor network is a non-infrastructure network which contains a number of homogeneous or heterogeneous sensor nodes. These sensor nodes have limited battery power. One of the major factor that we have to consider while designing the WSN routing protocol is efficiently use of energy resources. So minimizing the energy consumption and increasing the lifetime of the network is the major issue in the wireless sensor network. Study shows LEACH is one of energy efficient routing protocol. LEACH is a hierarchical clustering based routing protocol which improve the lifetime of the network by distributing of energy load throughout the whole network. This paper will present a brief detail of LEACH protocol and its variants.

Keywords: wireless sensor network (WSN), Low Energy Adaptive Clustering Hierarchy Protocol (LEACH), Q-LEACH, Network lifetime.