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Experimental Analysis of Area Localization Scheme for Sensor Networks

Vijay Chandrasekhar1, Zhi Ang Eu1, Winston K.G. Seah1,2 and Arumugam Pillai Venkatesh2

1Network Technology DepartmentInstitute For Infocomm Research, A*STAR, Singapore

2National University of Singapore

WCNC2007

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Outline

Introduction Related Work Enhancement To Area Localization Scheme Experimental Setup and Results Conclusions

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Introduction

The location information is important for a large wireless sensor network.

To identify the exact location of every sensor may not be feasible or necessary.

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Introduction

Localization algorithm Range based

Add additional hardware (e.g: GPS) Range-free based

Location information can be obtained RSSI Time of arrival or time difference of arrival Angle of arrival measurements

Probabilistic techniques

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Related Work- ALS Algorithm

Q. Yao, S.K. Tan, Y. Ge, B.S. Yeo, Q. Yin, “An Area Localization Scheme for Large Wireless Sensor Networks”,Proceedings of the IEEE 61st Semiannual Vehicular Technology Conference (VTC2005-Spring), May 30 - Jun 1, 2005, Stockholm, Sweden.

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Related Work- ALS Algorithm

There are three types of nodes in ALS Reference nodes Sensor nodes Sinks

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Related Work- ALS Algorithm

Reference nodes Send out beacon signal to help the sensor nodes

construct their signal coordinates. Equipped with GPS or placed in pre-

determined locations.

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Related Work- ALS Algorithm

Sensor nodes Monitor environment. Use a simple signal coordinate to indicate their

information to the sinks. Only knows its own signal coordinate and attac

h this to the data. Example:

<R1,R2,R3,R4>

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Related Work- ALS Algorithm

Sinks Charge of collecting information from sensor

node and then processing the information. Knows the location of all the reference node

and there respective transmitted power level.

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Related Work- ALS Algorithm

A

B C

D

Reference node

Power Level 1

Power Level 2

<1,0,0,0>

<2,0,0,0>

<0,1,0,0>

<2,2,0,0>

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Related Work- ALS Algorithm

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Related Work- ALS Algorithm

Ideal propagation model

ALS only functions in an ideal radio channel.

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Enhancement To ALS

Shadowing Propagation model

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Enhancement To ALS

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Enhancement To ALS

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Enhancement To ALS

Shadow and fading effects ALS did not consider shadowing and fading.

Use overlapping ranges to construct the signal map.

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Experimental Setup and Results Nodes :MicaZ motes Area size:

Indoor 10m x 10m Multi-purpose hall (MPH)

Outdoor 30m x 30m Open field Park

35 Sensors indoor 30 Sensors outdoor 8 reference nodes

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Experimental Setup and Results

The circular ring between radii √(A/π) and 2√(A/π) is defined as the 1-hop neighboring region of the node.

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Experimental Setup and Results

Summary of experimental results

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Experimental Setup and Results

Actual versus Estimated Locations of Sensors (MPH)

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Experimental Setup and Results

Actual versus Estimated Locations of Sensors (Open Field)

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Experimental Setup and Results

Actual versus Estimated Locations of Sensors (Park with obstacles)

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Experimental Setup and Results

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Conclusions

In this paper, they Modified and implemented the ALS algorithm

on a experimental study. ALS is comparable or better than other

implemented localization scheme, and ALS has lower complexity.

Future works They will incorporate routing protocols on ALS

algorithm.

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