A solar-aware wireless sensor network based on low energy adaptive clustering hierarchy: www.reein.org

National Exhibition and Seminar (Title : Climate Change Mitigation : Role of Renewables) on Renewable Energy . Dhaka, Bangladesh, 24-25 March, 2008

Focus on Climate Change Mitigation: Role of Renewable

A solar-aware wireless sensor network based on low energy adaptive clustering hierarchy

An Overview of Wireless Sensor Network

The components of a sensor node

Sensor Networks Communication Architecture

Network Layer Routing Protocols

Hierarchical Based Routing Protocol

• When sensor density increases single tier networks cause

– Gateway overloading

– Increased latency

– Large energy consumption

To allow the system to cope with additional load and to

be able to cover a large area of interest without

degrading the service, networking clustering has been

pursued in some routing approaches.

– Uses Multi - hop communication within a cluster

– Performs data aggregation and fusion on data to reduce number of transmitted messages to the sink

– Maintain the energy reserves of nodes efficiently

Examples

• LEACH – Low-Energy Adaptive Clustering Hierarchy

• Power-Efficient GAthering in Sensor Information Systems (PEGASIS)

– Hierarchical PEGASIS

• Threshold sensitive Energy Efficient sensor Network protocol (TEEN)

– Adaptive Threshold TEEN (APTEEN)

• Energy-aware routing for cluster-based sensor networks

• Self-organizing protocol

Low-Energy Adaptive Clustering Hierarchy (LEACH)

• Randomized, adaptive, self-configuring cluster formation;

• Localized control for data transfer;

• Low-energy media access control;

• Data compression and aggregation process

LEACH Algorithm Details

Set-up Phase

• Cluster-head advertisement

• Cluster set-Up

• Transmission schedule creation

Steady-state Phase

• Data transmission to cluster heads

• Signal processing (Data fusion)

• Data transmission to the base station

Two phases that describe the operation of LEACH

Solar-aware LEACH [sLEACH]

• use of renewable energy sources such as solar power prolong the lifetime of a sensor network

• letting nodes powered by solar energy to perform the most energy demanding tasks

• choosing solar-powered nodes as clusterheads is feasible and energy savings

Thus LEACH can be extended to become solar

aware, a new version of LEACH, sLEACH

• Sensor nodes transmit their remaining energy level and position to the base station. They also transmit their solar status (if a node is powered by solar energy or by battery).

• Solar-driven nodes that have a high remaining energy level have a high chance of becoming cluster head. Clusterheads, chosen by the base station remain as clusterheads for a certain time called round.

OMNeT++, Discrete Event Simulator

• Allow the design of modular simulation models

• Object-oriented approach allows flexibility in the simulation kernel

• Offer an extensive simulation library

• Model components are compiled and linked with the simulation library and one of the user interface libraries to form an executable program

• Simulation kernel uses C++ to be embedded in larger applications

• Models are built with NED and omnetpp.ini and do not use scripts

Building Simulation Programs

An OMNeT++ simulation model physically

consists of the following parts:

• NED language topology description(s). These are files with the .ned suffix.

• Message definitions, in files with .msg suffix.

• Simple modules implementations and other C++ code, in .cpp files on Windows

Network Description File (.ned) Window

Setting Module Parameters in the Configuration File: omnetpp.ini

• solar.trRange = 190;

• solar.numNodes = 100;

• solar.xMax = 1000;

• solar.yMax = 1000;

• solar.rounds = 280;

• solar.frames = 10;

• solar.solarOn = 1;

• solar.sunDuration = 600;

• solar.sunNodes = 5;

Model of Scenario for Simulation

Analyzing Simulation Results

Simulation results with sun Duration=600

Simulation results with sun Duration=1200

Simulation results with sunDuration=2400

Output scalars are used to compare designed network model behavior under various parameter settings which is shown in the following

Frames 10, Sun-Duration 600

solar.sunNodes 5 10 15 25

• solar on 120F/142H 144F/157H 152F/173 162F/168H

• solar off 104F/118H 107F/124H 117F/113H 133F/146H

Frames 10, Sun-Duration 1200

solar.sunNodes 5 10 15 25

• solar on 128F/150H 159F/176H 165F/193H 192F/211H

• solar off 107F/123H 120F/139H 129F/142H 136F/159H

Frames 10, Sun-Duration 2400

solar.sunNodes 5 10 15 25

• solar on 140F/155H 170F/190H 188F/199H 213F/235H

• solar off 110F/127H 132F/146H 147F/165H 160F/177H

Improvement of solar-aware LEACH over the standard LEACH protocol

A solar aware sensor network has been presented. The network model has been verified through experimentation and found

• For longer sun-Duration the energy dissipation per node decreases with respect to time.

• When the node is solar powered, the number of rounds (until the first node dies) increase with increased sun-Nodes.

These features led to design solar-aware LEACH [sLEACH]. So, letting

sensor nodes powered by solar energy to perform the most energy

demanding tasks in sensor networks significantly extends the lifetime of

sensor networks.