International Journal of Applied Engineering Research ISSN 0973-4562 Volume 13, Number 7 (2018) pp. 4702-4707 © Research India Publications. http://www.ripublication.com 4702 Virtual Tier structured Grid based Dynamic Route Adjustment scheme for mobile sink based Wireless Sensor Networks (VTGDRA) Gaurav Bathla, Rajneesh Randhawa Department of Computer Science, Punjabi University, Patiala, Punjab, India. Abstract Wireless sensor network is one of the emerging fields from past decade for environment sensing and reporting. WSN is expected to be integrated into Internet of Things (IoT) in future trends. Transmission of the aggregated sensed data to Base Station (BS) is termed as routing. This transmission of data is based on limited energy capacity nodes which can neither be charged nor be replaced. So efficient routing scheme is required to be designed which consumes less energy. The sensed data is required to be sent to sink. Sink mobility across the network can be considered as fine strategy to balance the load on the nodes of the network. Proposed scheme virtually divides the network area into four isolated regions (Grids), where each Grid in turn further divided into three tiers based on the distance from the center part of that Grid. After forming the minimum spanning tree among nodes of each Grid, data of each Grid is transmitted to mobile sink node. Proposed scheme proves to have better lifetime with less reconstruction cost than existing techniques. Keywords: Routing, Grid, minimum spanning tree, Wireless Sensor Networks, WSN. INTRODUCTION Wireless Sensor Network (WSN) is a network consists of a large number of Nodes. These sensor nodes (SN) are distributed in some geographical area. WSN’s are used where person cannot interfere in the area of interest. Nodes are deployed in hazardous places, flood effective regions, underwater environments [1]. So, in such unreachable area [2] it is also very difficult to deploy the nodes. In WSN, sensor nodes have limited processing power, communication bandwidth, and storage space. These nodes are equipped with non-chargeable & irreplaceable battery source. Routing is the main concern which can increase the lifetime of the network [3]. Various techniques have been developed since last decades to find out the ways to increase the lifetime of the network. Among all these techniques clustering is found to be the most effective technique to increase lifetime along with lowering the propagation delay. Various Clustering algorithms are classified based on different criteria to effectively utilise this energy. Among that major criterion are cluster head selections, cluster head properties, clustering process [4, 5, 6]. Clustering technique works by forming the cluster of nodes then identify a cluster head. All sensor nodes needs to send data to the respective CH, which further aggregates [7, 8] the data and send it to the base station or the sink node. In this fashion, all nodes can save their energy by sending data to a lower distance. Cluster head selection is based on either the probability factor or on remaining energy of the node. In case of probabilistic election, role of CH is to be rotated after each round otherwise node with highest residual energy is elected as CH. Among proposed techniques, lowering the energy consumption is the major task to tackle. Prime objective is to increase the network lifetime by decreasing the energy consumption. In this paper, a technique based on creating a Grid & then portioning Grid in tiers is proposed and evaluated. This algorithm is divided into three steps Grid formation and partitioning Grid into tiers (static), Grid head selection (dynamic), and routing. Grid head is selected based on residual energy of the nodes. Node with highest residual energy in top most tier is used to aggregate & transmit data to mobile sink. The other sections of paper are divided as follows; the next section presents work done so far in the relevant field. The section following the second one proposes VTGDRA scheme about forming the network and data transmission model along with algorithmic routines. The fourth section is the simulation environment and result comparison with existing techniques. The fifth section concludes the paper. RELATED WORK Extensive research is going to improve network lifetime for wireless sensor networks. Lifetime can be improved by well designing routing techniques. Data dissemination is done in the network and same can be energy efficient by making the sink node mobile. As sink node moves around the periphery, nearest Grid will transmit the data to sink node. Mobility of sink will save energy of the nodes and can be controlled or uncontrolled. In controlled mobility [9-12], speed and direction of the sink is managed by external observer or as per network dynamics. This paper considers controlled mobility of the sink with a particular speed around the periphery. Subsequent paragraphs highlight some of the existing work done in the relevant field. Backbone base virtual Infrastructure (BVI) proposed by oh et al. [13] disseminates data in multi hops. It uses HEED [14] for clustering & tries to minimize the number of clusters. One cluster head (CH) is used to keep track the location of mobile sink. Mobile sink registers itself to the CH via agent node.