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A Novel Physical Carrier Sensing Scheme for enhancing Spatial Reuse in Multihop Wireless Networks. Yongning Zhang, Bassel Alawieh , Chadi Assi Dept. of Science & Engineering, Concordia University in the U.S.A. World of Wireless, Mobile and Multimedia Networks( WoWMoM ), 2008. Outline. - PowerPoint PPT Presentation
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A Novel Physical Carrier Sensing Scheme for enhancing Spatial Reuse in Multihop Wireless Networks
Yongning Zhang, Bassel Alawieh, Chadi Assi
Dept. of Science & Engineering, Concordia University in the
U.S.A.
World of Wireless, Mobile and Multimedia Networks(WoWMoM), 2008
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Outline
Introduction Protocol Simulation Conclusion
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Introduction
Higher CSth
rc
A B C
4
Introduction
lower CSth
rc
A B C
5
Introduction
A B C
d
6
Introduction
A B C
n
r
P
P
rt P
r
P
4
cnntol PPP
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Introduction
A B C
cnt
tol Pr
PP
44
1
4
)(
cnt
ii
PrP
Pr
ri
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Protocol
Scenario 1
A B
Cfailure
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Protocol
Interference from concurrent transmissions Collisions which are due to contending hosts
which initiate their transmissions simultaneously
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Protocol
transmits T times A times are successful Pc is collision probabilities Pe is error probabilities Nbusy and Nidle represent respectively the number of
time slots in which a node senses the channel as busy/idle
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Protocol
Pc is collision probabilities Pe is error probabilities
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Protocol
If Pe is above a certain threshold PF ,a node decreases its CSth.
If Pe is below a certain threshold PS, a node increases its CSth.
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Protocol
Scenario 2
A B
Cfailurefailure
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Protocol
A B C
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Protocol
A B C
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Protocol
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Protocol
Switch from 4-way to 2-way handshake
If this transmission is successful, the 2-way handshake will be activated for the next transmission attempt.
otherwise, a node will keep on using the 4-way handshake until the transmission is successful.
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Simulation
Simulator : Qualnet Propagation model : 2-ray mode Routing protocol : AODV
Dynamic CCA adaptation : 11Mbps Spatial Backoff : default CS th=-84dbm
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Simulation
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Simulation
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Simulation
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Simulation
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Conclusion
The paper proposed a novel scheme that balances
the tradeoff between collision and spatial reuse in multihop wireless networks.