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ABSTRACTABSTRACT

we proposed a simple and efficientwe proposed a simple and efficient

approach for the placement of multipleapproach for the placement of multiple

sinks within largesinks within large--scale WSNs.scale WSNs.The objective is to determine optimalThe objective is to determine optimal

sinks positions that maximize the networksinks positions that maximize the network

lifetime by reducing energy consumptionlifetime by reducing energy consumption

related to data transmissions from sensorrelated to data transmissions from sensor

nodes to different sinks.nodes to different sinks.

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INTRODUCTIONINTRODUCTION

A sensor network is a static ad hoc networkA sensor network is a static ad hoc networkcomposed of hundreds or thousands ofcomposed of hundreds or thousands ofsensor nodes.sensor nodes.

Each sensor node is equipped with a sensingEach sensor node is equipped with a sensingdevice, a low computational capacitydevice, a low computational capacityprocessor, a shortprocessor, a short--range wireless transmitterrange wireless transmitter--receiver and a limited batteryreceiver and a limited battery--suppliedsuppliedenergy.energy.

It collects data from the surroundingIt collects data from the surroundingenvironment and forward it towards a closeenvironment and forward it towards a closebase station.base station.

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EXISTING SYSTEMEXISTING SYSTEM

The existing protocols and mechanismsThe existing protocols and mechanisms

are not scalable.are not scalable.

They are mostly conceived and adapted toThey are mostly conceived and adapted torelatively small networks.relatively small networks.

In particular, centralised approaches,In particular, centralised approaches,

where data from each sensor is sent to awhere data from each sensor is sent to a

central base station, are not efficient andcentral base station, are not efficient and

can not scale for large wireless sensorcan not scale for large wireless sensor

networks.networks.

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PROPOSED SYSTEMPROPOSED SYSTEM The use of multiple base stations is oneThe use of multiple base stations is one

possible solution for largepossible solution for large--scale WSNs.scale WSNs.

The idea is to shorten the path betweenThe idea is to shorten the path between

each sensor node and the nearest baseeach sensor node and the nearest basestation, to save energy consumption forstation, to save energy consumption fortransmission operations.transmission operations.

To achieve this efficiency, the multipleTo achieve this efficiency, the multiple

base stations should be optimally placedbase stations should be optimally placedwithin the sensed area.within the sensed area.

Graph theory technique is used to partitionGraph theory technique is used to partitionthe network.the network.

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SYSTEM REQUIREMENTSSYSTEM REQUIREMENTS

SOFTWAREREQUIREMENTSSOFTWAREREQUIREMENTS

Java 1.5Java 1.5

HARDWAREREQUIREMENTSHARDWAREREQUIREMENTS

Windows 2000,XpWindows 2000,Xp

4gb RAM4gb RAM

20gb hard disk/ ROM20gb hard disk/ ROM

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SYSTEM ANALYSISSYSTEM ANALYSIS

Model formulationModel formulation

---- The objective is to partition theThe objective is to partition the

connected graph into connected balancedconnected graph into connected balancedsubgraphs(in terms of number of nodes).subgraphs(in terms of number of nodes).

---- This partitioning technique shouldThis partitioning technique should

be applied as much as required accordingbe applied as much as required according

to the targeted size for the subto the targeted size for the sub--networksnetworks

and taking into account the number ofand taking into account the number of

available sinks to be placed.available sinks to be placed.

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start

Model formulation

(Nodes creation)

Problem resolution

(partitioning the

network)

Graph partitioning

approach

Collecting data from

node to sink

stop

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DFDDFD

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MODULESMODULES

Nodes Creation.Nodes Creation.

Dividing the network into subnetworksDividing the network into subnetworks

based onbased on Graph Partitioning Approach.Graph Partitioning Approach.Sink placement technique.Sink placement technique.

Downloading data from nodes to sink.Downloading data from nodes to sink.

Results.Results.

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MODULES DESCRIPTIONMODULES DESCRIPTION

NODES CREATION:NODES CREATION:

-- The Sensor Nodes were created forThe Sensor Nodes were created for

visual representation according to the uservisual representation according to the user

wish (based on cowish (based on co--ordinates).ordinates).

-- The data can be uploaded for theThe data can be uploaded for the

nodes from the database.nodes from the database.

-- We can also upload different values toWe can also upload different values to

different nodes.different nodes.

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GRAPH PARTITIONING APPROACH:GRAPH PARTITIONING APPROACH:

-- Maximally Balanced ConnectedMaximally Balanced ConnectedPartition problem (MBCP) isPartition problem (MBCP) is

used here.used here.

-- SubSub--networks are formed in terms ofnetworks are formed in terms ofnumber of sensors.number of sensors.

-- This technique should be appliedThis technique should be applied

according to the size for the subaccording to the size for the sub--networksnetworksand no.of sinks to be placed on theand no.of sinks to be placed on the

network.network.

-- The final result should be pow(2,n)The final result should be pow(2,n)

where n is the no.of artitionin iterations.where n is the no.of artitionin iterations.

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SINK PLACEMENT TECHNIQUE:SINK PLACEMENT TECHNIQUE:

-- The sinks are deployed according toThe sinks are deployed according toeach subeach sub--network.network.

-- polynomial approximation concept ispolynomial approximation concept is

used.used.

-- To select the neighbouring nodesTo select the neighbouring nodes

within the same subwithin the same sub--network the sortingnetwork the sorting

list of nodes is calculated based on thelist of nodes is calculated based on the

distance of nodes.distance of nodes.

-- The sinks are placed in such a wayThe sinks are placed in such a way

that,they are movable around its partition.that,they are movable around its partition.

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DOWNLOADINGDATA FROM NODESDOWNLOADINGDATA FROM NODES

TO SINK:TO SINK:

-- To collect the data from the nodes,inTo collect the data from the nodes,in

existing concepts the data will passexisting concepts the data will pass

through their parent nodes to reach thethrough their parent nodes to reach the

sink.sink.

-- Thus the parent nodes will lose theirThus the parent nodes will lose their

energy very soon compare to leaf nodes.energy very soon compare to leaf nodes.

-- In proposed the sink will move to theIn proposed the sink will move to the

nodes place to collect the data with in thenodes place to collect the data with in the

partition.partition.

-- Thus we can avoid the energy of eachThus we can avoid the energy of each

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RESULTS:RESULTS:

-- To prove that our proposed approach isTo prove that our proposed approach isefficient the results are calculated andefficient the results are calculated and

compared for the energy loss of thecompared for the energy loss of the

nodes.nodes.

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ALGORITHMIC DESIGNALGORITHMIC DESIGN

MBCP problem:MBCP problem:Bw (Bw (V1,V2) = min ( w(V1), w(V2))V1,V2) = min ( w(V1), w(V2))

Subject toSubject to

1. (1. (V1,V2) is a partition ofV into nonV1,V2) is a partition ofV into non--emptyemptydisjoints setsdisjoints sets V1 andV2such that subV1 andV2such that sub--

graphs ofGgraphs ofGinduced byinduced by V1 andV2areV1 andV2are

connected.connected.2.2. w(V1)=sum(Vs) in the the partition.w(V1)=sum(Vs) in the the partition.

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TESTINGPLANTESTINGPLAN

The test cases should be planned beforeThe test cases should be planned before

testing begins. Then as the testingtesting begins. Then as the testing

progresses, testing shifts focus in anprogresses, testing shifts focus in an

attempt to find errors in integrated clustersattempt to find errors in integrated clustersof modules and in the entire system.of modules and in the entire system.

-- Each module is tested seperately byEach module is tested seperately by

unit testing.unit testing.-- The purpose is to exercise theThe purpose is to exercise the

different parts of the module code todifferent parts of the module code to

detect the errors.detect the errors.

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Sensor NetworksSensor Networks

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5/17/20115/17/2011 Prasant MohapatraPrasant Mohapatra 2020

OutlineOutline

Introduction and IssuesIntroduction and Issues

Architecture and ApplicationsArchitecture and Applications

LocalizationLocalization

Routing and IntercommunicationRouting and Intercommunication

MAC LayerIssuesMAC LayerIssues

Security IssuesSecurity Issues

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What are Sensor Networks?What are Sensor Networks?

A group of wireless nodes or embedded devicesA group of wireless nodes or embedded devices

Collectively the nodes sense, collect, andCollectively the nodes sense, collect, andanalyze dataanalyze data

The sensor nodes are small, low power,The sensor nodes are small, low power,inexpensive, and have high SNR.inexpensive, and have high SNR.

The network usually consists of a large numberThe network usually consists of a large numberof dense nodes distributed at randomof dense nodes distributed at random

They can be deployed in any kind of terrain withThey can be deployed in any kind of terrain with

hostile environment; places where traditionalhostile environment; places where traditionalwired network cannot be deployedwired network cannot be deployed

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Sensor Network ArchitectureSensor Network Architecture

SINK

TASK

MANAGER

Internet/

Satellite

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Sensor Node ArchitectureSensor Node Architecture

Sensor nodes include a combination ofSensor nodes include a combination of

Microelectromechanical systems (MEMS)Microelectromechanical systems (MEMS)

such as sensing devices, actuators, RFsuch as sensing devices, actuators, RF

components, and CMOS building blockscomponents, and CMOS building blocks

Low power computing and wirelessLow power computing and wireless

networking supportnetworking support

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Architecture of a Sensor NodeArchitecture of a Sensor Node

Sensing

UnitA/D

Processor

Memory

Trans-

ceiver

Software

Battery Power

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Applications of SensorApplications of Sensor

NetworksNetworksSurveillance and securitySurveillance and securityEnvironmental monitoringEnvironmental monitoring

Transport monitoringTransport monitoringPrecision agriculturePrecision agriculture

Smart spacesSmart spaces

Manufacturing and inventory controlManufacturing and inventory controlOther specialized tasksOther specialized tasks

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Operational ChallengesOperational Challenges

Ad hoc deployment: should be able toAd hoc deployment: should be able todiscover the topology and selfdiscover the topology and self--configureconfigurefor intercommunicationfor intercommunication

Dynamically adapt to changes in topologyDynamically adapt to changes in topologydue to node failures and environmentaldue to node failures and environmentalconditionsconditions

Automatic configuration/reconfigurationAutomatic configuration/reconfigurationUntethered for energy and communicationUntethered for energy and communication

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Localization IssuesLocalization Issues

What is Localization?What is Localization?

Why is it important?Why is it important?

CategorizationCategorizationSome Localization MechanismsSome Localization Mechanisms

GPSGPS

Beacon based rangingBeacon based ranging Range free methodsRange free methods

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What is Localization?What is Localization?

A mechanism for discoveringA mechanism for discovering

spatial relationships betweenspatial relationships between

objectsobjects

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Why is Localization Important?Why is Localization Important?

Sensor Network Data is typicallySensor Network Data is typicallyinterpreted based on a sensors locationinterpreted based on a sensors location

report event originsreport event origins

giving raw sensor readings a physical contextgiving raw sensor readings a physical context

Temperature readingsTemperature readings temperature maptemperature map

objects trackingobjects tracking

Enables dataEnables data--centric network designcentric network design assist with routingassist with routing

evaluate network coverageevaluate network coverage

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CategorizationCategorization [Bulusu00][Bulusu00]

CoarseCoarse--grained Localizationgrained Localization

Proximity to a given reference pointProximity to a given reference point

E

.g.,A

ctive BadgeE

.g.,A

ctive BadgeFineFine--grained Localizationgrained Localization

Coordinates estimationCoordinates estimation

E.g., Distance to a given reference pointE.g., Distance to a given reference point

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FineFine--Grained LocalizationGrained Localization

Ranging based methodsRanging based methods

TimingTiming

Signal StrengthSignal Strength

Directionality BasedDirectionality Based

Ranging free methodsRanging free methods

E.g.: Centroid based, DVE.g.: Centroid based, DV--hop, APIThop, APIT

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Ranging (Distance Measuring)Ranging (Distance Measuring)

TechniquesTechniquesTime based methodsTime based methods

Time ofArrival (ToA), TDoATime ofArrival (ToA), TDoA

Used with radio, IR, acoustic, ultrasoundUsed with radio, IR, acoustic, ultrasound


Uses received signal strength indicator (RSSI)Uses received signal strength indicator (RSSI)

readings and wireless propagation modelreadings and wireless propagation model

Directionality basedDirectionality based Angle ofArrival (AoA) measured with directionalAngle ofArrival (AoA) measured with directional

antennas or arraysantennas or arrays

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TimingTiming

Time of flight of communication signalTime of flight of communication signal

Signal PatternSignal Pattern

Global Positioning SystemGlobal Positioning System Local Positioning SystemLocal Positioning System

Pinpoints 3DPinpoints 3D--iDiD

Different modalities of communicationDifferent modalities of communication

Active BatActive Bat

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Attenuation of radio signal increases withAttenuation of radio signal increases with

increasing distanceincreasing distance

RADARRADAR

Wall Attenuation Factor based SignalWall Attenuation Factor based Signal

Propagation ModelPropagation Model

RF mappingRF mapping

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Directionality Based FineDirectionality Based Fine--

Grained

Localization

Grained

LocalizationSmall Aperture Direction FindingSmall Aperture Direction Finding

Used in cellular networksUsed in cellular networks

Requires complex antenna arrayRequires complex antenna array

DisadvantagesDisadvantages

CostlyCostly

Not a receiver based approachNot a receiver based approach

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Basic Concepts in RangingBasic Concepts in Ranging

TrilaterationTrilateration

TriangulationTriangulation

MultiMulti--laterationlateration Considers all available beaconsConsiders all available beacons

A

B

Cab

c

c

C

b

B

a

A

sinsinsin!!

)cos(2

)cos(2

)cos(2

222

222

222

aBCCBC

bBCCAB

cABBAC

Sines Rule

Cosines Rule

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Localization MechanismsLocalization Mechanisms

GPSGPS

Beacon based rangingBeacon based ranging

Range free methodsRange free methods

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Global Positioning System (GPS)Global Positioning System (GPS)

[Getting93][Getting93]

Started in 1973, built in 1993Started in 1973, built in 1993

WideWide--area radio positioning systemarea radio positioning system

RangingRanging--based methodbased method Using Timing ofArrival (ToA)Using Timing ofArrival (ToA)

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GPS System ArchitectureGPS System Architecture

Constellation of 24Constellation of 24

NAVSTAR satellitesNAVSTAR satellites

made by Rockwellmade by Rockwell

Altitude: 10,900 nauticalAltitude: 10,900 nauticalmilesmiles

Orbital Period: 12 hoursOrbital Period: 12 hours

At least five satellites inAt least five satellites in

view from every point inview from every point inthe Globethe Globe

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How GPS WorksHow GPS Works

The basis ofGPS isThe basis ofGPS istrilateration" from satellitestrilateration" from satellites

Distance measuring based on ToADistance measuring based on ToA

accurate timing is importantaccurate timing is important

Along with distance, you need to know exactlyAlong with distance, you need to know exactlywhere the satellites are in spacewhere the satellites are in space

High orbits and careful monitoring are the secretHigh orbits and careful monitoring are the secret

Finally you must correct for any delays the signalFinally you must correct for any delays the signal

experiences as it travels through the atmosphereexperiences as it travels through the atmosphere

A Fourth satellite used for correction purposeA Fourth satellite used for correction purpose

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GPS ot Al a s Appli a lGPS ot Al a s Appli a l

Man ont xts ou annot hav GPS on v r Man ont xts ou annot hav GPS on v r

nodnod

form fa torform fa tor

n rgn rg

ostost

o stru tionso stru tions

Beacon based approaches for sensor networks

Ranging based v.s. ranging free

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Beacon Based Location DiscoveryBeacon Based Location Discovery

Known LocationUnknown Location

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Beacon Based Location DiscoveryBeacon Based Location Discovery

No need ofGPSNo need ofGPS

No infrastructure supportNo infrastructure support

Ad hoc deployableAd hoc deployable

Use RSSI for measuring node separationUse RSSI for measuring node separation

But how should the beacons be placed?But how should the beacons be placed?

Distributed LocalizationDistributed Localization

Iterative multilaterationIterative multilateration

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Localization ApproachLocalization Approach

Single hop beaconingSingle hop beaconing

Iterative multilaterationIterative multilaterationDynamic estimate theDynamic estimate the

wireless channel parameterswireless channel parameters

Can be done in conjunctionCan be done in conjunctionwith routingwith routing

Beacon

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AdvantagesAdvantages

Data packets also act as beacon signalsData packets also act as beacon signals

Location discovery is almost freeLocation discovery is almost free

DistributedDistributed

relies on neighborhood informationrelies on neighborhood information

Fault tolerantFault tolerant

However, Ranging still requires expensive circuits!

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Range Free MethodsRange Free Methods

Centroid approach [Bulusu00]Centroid approach [Bulusu00]

Adaptive beacon placement [Bulusu01]Adaptive beacon placement [Bulusu01]

SelfSelf--configuring localization [Bulusu03]configuring localization [Bulusu03]

DVDV--hop [Niculescu01]hop [Niculescu01] AoA approach [Niculescu03]AoA approach [Niculescu03]

APIT [He03]APIT [He03]

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Centroid Based ApproachCentroid Based Approach[Bulusu00][Bulusu00]

Multiple nodes serve as reference pointsMultiple nodes serve as reference points

(Beacons)(Beacons)

Reference points transmit periodic beaconReference points transmit periodic beacon

signals containing their positionssignals containing their positions

Receiver node finds reference points in its rangeReceiver node finds reference points in its range

and localizes to the intersection of connectivityand localizes to the intersection of connectivity

regions of these pointsregions of these points

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ModelModel

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Centroid Based LocalizationCentroid Based Localization

DisadvantagesDisadvantages

D

esign using a idealized radio model withD

esign using a idealized radio model withperfect spherical radio propagationperfect spherical radio propagation

Assume a regular grid of nodes with knownAssume a regular grid of nodes with known

location information to serve as Beaconslocation information to serve as Beacons

(Xest, Yest) = (avg(Xi1++Xik), avg(Yi1++Yik))

k = No. of beacon nodes within connectivity range

Xi1Xik Yi1Yik: Beacon nodes locations

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Impact of Beacon PlacementImpact of Beacon Placement

Beacons uniformly placed:SMALLER mean granularity

Beacons randomly placed:LARGER mean granularity

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CONCLUSIONCONCLUSION

we proposed the use of graph partitioningwe proposed the use of graph partitioning

techniques to obtain smaller and balancedtechniques to obtain smaller and balanced

subsub--networks over which existing sinknetworks over which existing sink

placement techniques that are optimizedplacement techniques that are optimized

for small to medium scale WSNs.for small to medium scale WSNs.

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REFERENCESREFERENCES

S. Tilak, A. Murphy and W. Heinzelman,S. Tilak, A. Murphy and W. Heinzelman,"Non"Non--Uniform Information DisseminationUniform Information Dissemination

for Sensor Networks,.for Sensor Networks,.

http://users.sdsc.edu/~sameer/pubs/Samehttp://users.sdsc.edu/~sameer/pubs/Sameer_Tilak.pdf.er_Tilak.pdf.

S. R. Gandham et al., Energy EfficientS. R. Gandham et al., Energy Efficient

Schemes for Wireless Sensor NetworksSchemes for Wireless Sensor Networks

With Multiple Mobile Base Stations,.With Multiple Mobile Base Stations,.

http://www.eecs.berkeley.edu/~dtse/ton_mhttp://www.eecs.berkeley.edu/~dtse/ton_m

ob_final_3.pdf.ob_final_3.pdf.

sensor 1234

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