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Interplay of Spatial Reuse and SINR-determined Data Rates in CSMACA-based, Multi-hop, Multi-rate Wirless Networks. Ting-Yu Lin and Jennifer C. Hou Department of Computer Science University of Illinois at Urbana-Champaign. IEEE INFOCOM 2007. Outline. Introduction - PowerPoint PPT Presentation
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Interplay of Spatial Reuse and SINR-determined Data Rates in CSMACA-based, Multi-hop, M
ulti- rate Wirless Networks
Ting-Yu Lin and Jennifer C. HouDepartment of Computer Science University
of Illinois at Urbana-Champaign
IEEE INFOCOM 2007
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Outline
Introduction Network Model and Signal Propagation/In
terference Model Network Capacity as A Function of Tcs, SI
NR and β[i] Validation of Analytic Model Conclusions
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Introduction
How does the collision be avoided in CSMA-CA-based wireless network? Physical carrier sense Binary exponential back off
mechanism Data rate adjustmentNetwork throughput : 1. Transmission time
2. Spatial reuse
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Spatial reuse
Tuning the carrier-sensing threshold Tcs Spatial reuse Computes the accumulated interference Tcs vs. Data rate Increase simultaneous transmissions
Within carrier sense range
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Network Model and Signal Propagation/Interference Model
Network Model Multi-hop Multi-rate Based on IEEE 802.11 DCF
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Network Assumption
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Virtual transmission time
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Network Capacity as A Function of Tcs, SINR and β[i]
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Attempt Probability
is derived in Calí’s model
Radio propagation
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Interference
dpg
dcs
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Interference Model
1st –tier interference nodes
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SINR vs. β[i]
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Collision Zone
Extra interference By simultaneous transmissions within the dc
s
SINR perceived at the receiver >β[i] Accumulative interference
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Revision all accumulated interference
Prcv (≧ Isim,dcz,dcs+ Icon,dcs,dpg +η) *β
, ,
[ ]con dcs dpg
GDPi
I
Spatial Reuse
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Numerical Results-1
Setting 500 nodes 500*500 m2
1125 Bytes/packet DSR =50m dpg=302m
dcs = 153m CW=64
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Numerical Results-2_1
200 nodes 500*500 m2
dcs=153 m CW =64~128
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Numerical Results-2_2 62 nodes 500*500 m2
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Numerical Results-2_3 10 nodes 500*500 m2
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Experiments with Settings (Tcs, CW, r)
Tcs : Optimal value r= 6 or 54
Number of nodes: 25 125
Field : 500*500 Single hop CBR conn
ection (225Bytes)
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Validation of Analytic Model
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Conclusions In this paper
Investigate Relation between PHY- and MAC-layer parameters
Derive Analytic model about the characters of IEEE 802.11
DCF A corresponding SINR
Achieve Spatial reuse Sustainable data rates