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International Journal of Sensors, Wireless Communications and Control, 2016, 6, 4-11
Implementation of Homogeneous LEACH Protocol in Three Dimensional Wireless Sensor Networks Sheena Kohli*, Partha Pratim Bhattacharya and Manish Kumar Jha College of Engineering and Technology, Mody University of Science and Technology, Lakshmangarh, Rajasthan, Pin – 332311, India Abstract: The paper gives the analysis of extending the implementation of Low Energy Adaptive Clustering Hierarchical protocol from the 2D plane to the 3D space in wireless sensor network, having various sensor nodes spread in a particular geographical area or region for collecting the application specific data. The comparison has been shown between the implementation of homogeneous LEACH in 2D plane and 3D space, emphasizing on a node observed from three dimensions, which is more suitable for practical scenarios.
Keywords: 2D plane, 3D space, Cube, Dead node, Hexagon, Network lifetime. 1. INTRODUCTION A wireless sensor network (WSN) comprises of a number of small devices called sensors, which are capable of detecting the environmental events, processing them and sending the data to the main location. The sensors are distributed or spread in the specific geographical area. The sensors are also known as nodes and the main location to which the data is sent is known as the sink or Base Station (BS). Each such sensor network node has typically several parts: a radio transceiver, for transmitting and receiving data, a microcontroller, for processing of data and an energy source, usually a battery. The battery makes these nodes critical in terms of energy efficiency. Due to limited life span of battery; the major issue in sensor networks is to save the energy . Further, the nodes are deployed depending upon the applications, where traditional wired communication is not feasible to be made available. Though the two dimensional (2D) design of wireless sensor networks is implied and considered in most of the applications *Address correspondence to this author at the College of Engineering and Technology, Mody University of Science and Technology, Lakshmangarh, Rajasthan, Pin – 332311, India; Tel: +919784606798; E-mail: [email protected]
as shown in Fig. (1), but it only gives limited results and observations. In such cases, considering the three dimensional (3D) design is more accurate and appropriate. The sensing of the environment in real world applications is in three dimensions only. Generally, it is assumed that all nodes of a network reside on a plane in two dimensional wireless sensor networks design of terrestrial networks. This assumption is not always valid if a network is deployed in e.g. ocean or forests, where nodes of a network are distributed over a three dimensional space. In such cases, the area of interest needs to be studied as three dimensional spaces, being more feasible, practical and analogous to the real world . 2. APPLICATIONS OF THREE DIMENSIONAL WIRELESS SENSOR NETWORKS [2-6] Wireless sensor networks find numerous widespread applications in the areas like: 1) Ocean column monitoring requires the nodes to be placed at different depths of the water, thus creating the three dimensional network. 2) Environment monitoring e.g. wireless sensor networks deployed on the trees of different heights in a forest require 3D design. © 2016 Bentham Science Publishers
Implementation of Homogeneous
International Journal of Sensors, Wireless Communications and Control, 2016, Vol. 6, No. 1
3) 3D wireless sensor network is the obvious choice for monitoring railway tunnels, underground tunnels in the mines and caves in the forests.
from different nodes is known as cluster head (CH) .
4) Structural health monitoring of multi-storey buildings is more efficient in a 3D WSN system to sufficiently monitor the target region.
Low-Energy Adaptive Clustering Hierarchy (LEACH) [10, 11] is one of the most popular energy efficient hierarchical clustering algorithm for wireless sensor networks that was introduced for reducing power consumption. In LEACH, the clustering job is rotated among the nodes, based on some duration. Direct communication is followed by each cluster head (CH) to forward the data to the base station (BS). LEACH is based on fusion or gathering technique that combines the original data into a compressed data that carries only meaningful information to all the individual sensors. LEACH divides a network into several cluster or groups of sensors, which are formed by using localized coordination and control. Given that energy dissipation of the sensor depends on the distance and the data size to be transmitted, LEACH tries to transmit data over short distances and reduce the number of transmission and reception operations. The key features of LEACH involves randomized rotation of the CH and corresponding clusters; local compression to reduce global communication; and localized coordination and control for cluster set-up and operation [12, 13].
5) Sensor nodes deployed in the volcanic region are used to collect weather and image data also prefer the 3D design. 6) For disaster relief management, 3D sensor networks are useful in case of major disasters including earthquakes, storms, flood, fires etc. 7) Moreover, systems have been designed in which wireless chemical sensors are airdropped to collect data about chemical plumes, over a vicinity of the affected area, as a result of hazardous chemical gas leakage from a chemical plant.
Fig. (1). Wireless sensor network.
3. ROUTING AND CLUSTERING IN WIRELESS SENSOR NETWORKS Routing means the way of selecting optimal paths in the networks. There are various routing protocols which are implemented for moving the data packets from source to destination in the wireless sensor networks . One of the major concepts used in routing in the networks is clustering . The term clustering means grouping. The basic idea behind clustering is taking the data from various points and forwarding it further to its destination. The advantage of clustering is that it saves the data from travelling on long paths as well as only the useful data is sent forward, leaving the unimportant data. In wireless sensor networks, the node which collects data
3.1. About LEACH
Considering a 3D network, LEACH uses a randomize rotation of high-energy CH, to give a chance to all sensors to act as CHs and avoid the battery depletion of an individual sensor. The operation of LEACH is divided into rounds, each of which has mainly two phases: (i) first phase is to organize the three dimensional network into clusters and advertise for CH and (ii) second phase for data aggregation, compression, and transmission to the sink or base station. These CHs are selected with some probability and they broadcast their statuses to the other sensors in the network, spread in the three dimensional space. A sensor decides to become a CH based on the desired percentage P of CHs, the current round, and the set of sensors that have not become CH in the past 1/P rounds. If the number of CHs