Hierarchical Clustering for Heterogeneous Energy Harvesting Wireless Sensor Networks (WSNs)

Abstract

Wireless Sensor Networks are composed of tiny electronic device sensor nodes and are capable of sensing the information of external environment. Sensor nodes are also capable of computing and transmitting the information to end users with the help of sink node. Sensor nodes are dependent on the battery being used in it. Battery get depleted very fast because node has to perform computation as well as communication operations. Energy efficiency is major challenging problems in wireless sensor networks (WSNs). In this paper, we have focused on optimized location of cluster heads (CHs) for energy efficiency in a hybrid WSN (that consists of both mobile and static sensors). LEACH is a very good method for clustering in a WSN consisting solely of static sensors with uniform energy capabilities. Our proposed clustering schemes suggest simple and static clustering strategy for a hybrid WSN and we explore whether their performance is improved relative to LEACH. Mobile sensors act as CHs and also harvest energy from their harvesting module. Our proposed schemes divide the total network covered area into cells based upon different criterion. In the first approach, named as the regular grid (RG) approach, a CH is simply placed in the center of each cell. The Minimax Grid (MG) attempts at improving the lifetime by relocating the CH from cell center to the center of the smallest enclosing circle. The more complicated KM approach first divides the network into clusters and then solves a facility location problem to assign the role of CHs to the mobile sensors. Simulation results show that RG, MG and KM perform better than LEACH algorithm in terms of energy consumption and consequently increases the lifetime of network. The relative improvement of KM and MG over RG is marginal as the number of energy harvesting (EH) sensors increase in network.