1 Maintaining Connected Coverage for Wireless Sensor Networks Jehn-Ruey Jiang and Tzu-Ming Sung Department of Computer Science and Infor mation Engineering, National Central University, Taiwan The 28th International Conference on Distributed Computing Systems Workshops ICDCS 2008
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Maintaining Connected Coverage for Wireless Sensor Networks
Maintaining Connected Coverage for Wireless Sensor Networks. Jehn-Ruey Jiang and Tzu-Ming Sung Department of Computer Science and Information Engineering, National Central University, Taiwan. The 28th I nternational C onference on D istributed C omputing S ystems Workshops ICDCS 2008. - PowerPoint PPT Presentation
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1
Maintaining Connected Coverage for Wireless Sensor
Networks
Jehn-Ruey Jiang and Tzu-Ming SungDepartment of Computer Science and Information E
ngineering,National Central University, Taiwan
The 28th International Conference on Distributed Computing Systems Workshops
ICDCS 2008
2
Outline
Introduction Problem Formulation The Density Control Algorithm Simulation Results Conclusion
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Introduction
The wireless sensor network consists of a large number of micro sensors for different application Battlefield surveillance Environment monitoring Animal tracking
The most of the sensors are supported battery distributed over a large area It is hard to recharge
4
Introduction
How to extend the network lifetime is an important problem in WSNs. To deploy high density sensors To use power saving mechanism
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Problem Formulation
Sensors Asynchronous Position-less Density-high Sensing range
Rs Communication r
ange Rc
Rc ≥ 2Rs
The interesting area G
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Problem Formulation
In the high density sensor deployment How to connect the coverage with the least
umber of the sensor? To power saving in the asynchronous
system How to provide a mechanism for sensor to
aware of active sensors’ statuses by asynchronously beaconing
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R. Kershner, “The Number of Circles Covering a Set”,American Journal of Mathematics
The Optimal (Least) Number of Sensors
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The Density Control Algorithm
Two type of the beacon a beacon
:near beacon1/ <α<1
b beacon:far beacon
R3
R
3
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The Density Control Algorithm
The power saving in asynchronous system Monitor interval
Beacon window TI (traffic indication) window n beacon intervals
Non-monitor interval Beacon window TI (traffic indication) window
round
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The Density Control Algorithm
j node can receive the beacon and store to the two type set
A set j can hear i’s a-beacon i is older than j i is oldest among those whose
AB set J can hear I’s b-beacon but not hear a-beacon
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The Density Control Algorithm
(158,a,0) (143,b,0)
(158,a,-1)
(158,a,-2)
In the beacon interval the sensor will
broadcast the beacon with the vector
(time, root, level)
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Simulation Results
Language C Area : 100m x 100m Rc =20 meters Rs = 10 meters Beacon interval 100ms α= 0.7, 0.75, 0.8 and 0.85
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Simulation Results
Optimal hexagon-base deployment
: 42 sensors
The Algorithm : 51 sensors
The cover factor R = 51/42
= 1.21
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Simulation Results
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Simulation Results
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Conclusion
Under the assumption Rc ≥ 2Rs This paper propose the algorithm
Without location information Use two type beacons
Near beacon Far beacon
To approximate the optimal connected hexagonal deployment