Improved Gravitational Search Algorithm for Hotspot Problem in Wireless Sensor Networks

Abstract

Energy conservation of sensor nodes (SNs) is the major concern of wireless sensor networks (WSNs) as those are operated by small batteries with a limited power. In a clustered WSN, cluster heads (CHs) collects local information such as temperature, humidity, pressure etc. from the member SNs aggregate it and send to the sink through few intermediate CHs. Here, the CHs that are closer to the sink are over burdened as they are responsible for forwarding more number of packets than the farther CHs that tends to exhaust their energy quickly. This results in network partitioning and this problem well known hot spot or energy hole problem. In this paper, a Gravitational Search Algorithm (GSA) approach based clustering and rout- ing algorithms are proposed to address the hot spot problem. In clustering, we select few efficient SNs as CHs from the normal SNs with respect to certain cost function. We design an algorithm for CH selection based on GSA and assign the remaining SNs to the CHs based on another derived cost function. Then, a GSA based routing algorithm is presented with respect to the routing cost function. These algorithms are intended to develop to enhance the lifetime of network with efficient encoding schemes of GSA. The proposed algorithms are simulated on various scenarios of WSNs by varying number of SNs. The results of the proposed algorithms are com- pared with few well known algorithms to show the supremacy in terms network lifetime, residual energy and number of alive SNs.