Deploying Sensors for Maximum Coverage in Sensor Network

Ruay-Shiung ChangShuo-Hung WangNational Dong Hwa University　IEEE International Wireless Communications & Mobile Computing Conference 2007 (IWCMC 2007)

Outline Introduction Self-Deployment by Density Control

(SDDC) Simulation Conclusion

Introduction In the Wireless Mobile Sensor Network

The application of survivors searching efficiently search quick deployment large search area

The deployment should be considered about the sensing coverage the network communication

Introduction

　?

Introduction

Introduction

Introduction There is the problem of deciding the

moving position The network partition The overlapping sensing coverage

Goal To deploy the sensor nodes with

larger sensing coverage unconnected networks

Assumption Each Sensor

can get the data of obstacles positions measures the free area knows the neighbors’ distance and angle by [8]

the communication range > the sensing range Cx=2Sx

has one unique ID

[8]Relaxation on a mesh: a formalism for generalizedlocalization", Proceedings of the IEEE/RSJ InternationalConference on Intelligent Robots and Systems (IROS01),pages 1055--1060, Wailea, Hawaii, Oct 2001

obstacle

Self-Deployment by Density Control

At the initialization The node exchange the ID with the

neighbors To decide the cluster-header

1

3

2

obstacle

Node id 1 2 3

Cluster statusNode status

Any pair of cluster headers are not in the communication range

Undecided Undecided Undecided

Not deployed

Not deployed

Not deployed

Clusterheader member member

The cluster header Divides the communication into k

equal area calculates the density in

communication range The virtual force

the neighbor nodes The obstacles

Self-Deployment by Density Control

1

3

2

obstacle

Density K: the parameter of division the

communication area Km : the measure of division of node’s

communication area

m

aa K

NDen

m

tt K

NDen 1

3

2

obstacle

area2area3

area4

area5

area6 area7

area8

area1

The theoretical number is calculated by the related work.

Density

22227rKN m

t

The Geometrical Foundation of Natural Structure: A Source Book of Design 　R. Williams 　 Dover Pub. Inc., New 　 York, 1979.

krR

rKN m

t

1**227

227

2

2

22

If R=2r , k=8 Nt=0.41

There are 3 neighbors in the communication

Density Ratio of actual number and theoretical number

The ratio of occupied area measure is defined

m

mmo K

OKR

The free area

t

a

mt

mam N

NKNKNR

//

The obstacle area ratio mm OK obstacle area

Virtual Force Each node calculates the force within

it’s communication area

i

mi Dis

RF

1

3

2

obstacle

area2area3

area4

area5

area6 area7

area8

area1

o

oo Dis

RF

The Distance between the node i to nodes j

The Distance between the node to obstacle

Fi

Fo

Self-Deployment by Density Control

In the cluster each node calculate the virtual force

oicom FFF

2

1

2

1

)()(

m

kyk

m

kxkcom FFF

2

1

2

11

)(

)(tan

m

kyk

m

kxk

F

F

Self-Deployment by Density Control

The node get the new position and angle from the virtual force The node

Node status : not deployment Send the sug_msg to the neighbors

New position and angle Wait a ask_msg from other neighbor If there is no ask_msg feedback, node still waits a random time interval.

com

com

FRDis

DisRF

Self-Deployment by Density Control

Sensors change the node status “not deployment“ to “deployed” adjust their position until the density lower than the Nt can not moving because the obstacle or other sensors Moving distance is small than the threshold β

Self-Deployment by Density Control

The cluster header will communicate with the neighbor cluster header To compare with the cluster density ratio

Density ratio > neighbor’s ratioAll cluster move to the neighbor cluster

Density ratio <threshold εThe cluster stop moving

Simulation Simulator : Stage multi-agent simulator Sensor nodes: 10-100 System parameter

Density ratio threshold : 0.125 Distance threshold: 1.25m

The moving speed : 0.6m/s The detection distance of obstacle : 5m

Simulation

Simulation Results

Conclusion This paper proposes the Self-Deployment by

Density Control (SDDC) algorithm which deploys the sensor node quickly.

The simulation result shows that the algorithm is useful in spread the sensor nodes efficiently.