Post on 17-Jan-2016
Advanced Communica-tion Network 2009
2009.06.08
Joint Throughput Optimization for
Wireless Mesh Networks
R97725024 戴智斌 R97725037 蔡永斌
Xiang-Yang Li, Senior Member, IEEE, Ashraf Nusairat, Student Member, IEEE, Yanwei Wu, Student Member, IEEE, Yong Qi, Member, IEEE,
JiZhong Zhao, Member, IEEE, Xiaowen Chu, Member, IEEE, and Yunhao Liu, Senior Member, IEEE
IEEE TRANSACTIONS ON MOBILE COMPUTING, VOL. 8, 2009
Advanced Communica-tion Network 2009 2009.06.08
Outline
Introduction
System Model and Assumption
Problem Formulation
Efficient TDMA Scheduling
Performance Evaluation
Conclusion
Advanced Communica-tion Network 2009 2009.06.08 3
Introduction
Advanced Communica-tion Network 2009 2009.06.08 4
Introduction (1/2)
Wireless mesh network (WMNs) are being
used for extending the Internet
connectivity for mobile nodes.
Many US cities (e.g. Medford, Oregon,
Chaska, Minnesota; Nashville, Illinois; and
Gilbert, Arizona) have deployed WMNs.
Advanced Communica-tion Network 2009 2009.06.08 5
Introduction (2/2)
The major problem of WMNs is the
reduction of capacity due to interference
caused by simultaneous transmissions.
How to optimize joint throughput under
certain fairness constraints via joint
routing, link scheduling, and dynamic
channel assignment.
Advanced Communica-tion Network 2009 2009.06.08 6
System Model and Assumption
Advanced Communica-tion Network 2009 2009.06.08
System Model and Assumption
7
Wireless Mesh Network– MMM for (multihop multiradio multichannel)
– with multiple sink nodes (wireless router with gateway
function)
Internet
Advanced Communica-tion Network 2009 2009.06.08
Assumptions
Different nodes may have…– Multiple radios
– Multiple channels
– Different transmission range and interference
range
– Combined channel
8
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Dynamic Channel Combining
Channel 1
Channel 2
Channel 3
Channel 4
Channel 5
Channel 1
Channel 2
Channel 3
Channel 4
Channel 5
Channel 1
Channel 2
Channel 3
Channel 4
Channel 5
Combining
InterferenceNode 1 Node 2
Advanced Communica-tion Network 2009 2009.06.08
System Model and Assumption
Multiple radios– Virtual nodes and links
10
u
z
v
w
Advanced Communica-tion Network 2009 2009.06.08
System Model and Assumption
Why we need interference models?– PrIM, fPrIM, RTS/CTS, TxIM
11
Sender 1
Receiver 1
Sender 2
Receiver 2
Interference
Advanced Communica-tion Network 2009 2009.06.08 12
Problem Formulation
Advanced Communica-tion Network 2009 2009.06.08
Problem Formulation
Given:– an MMM WMN G = (V,E), flow demand l(u)
from each sourch node u.
Objective– Maximize Fairness
– Maximize Joint Throughput
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Advanced Communica-tion Network 2009 2009.06.08
Maximize Fairness
14
Node 1
Node 4
Node 3
Node 2
Node 6
Node 7
Node 5Mobile Client
Mobile Client
The flow
coming to the node
The flow going out of
the node
Achieved Flow
load demanded
flow achieved of ratio minimum λ
Advanced Communica-tion Network 2009 2009.06.08
MAX Fairness LP
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Advanced Communica-tion Network 2009 2009.06.08
Maximize Joint Throughput
16
Internet
g
iiisp sf
1
)(max
Node NodeNode NodeNode
Node Node Node Node
Node NodeNode NodeNode
Gateway Router
Advanced Communica-tion Network 2009 2009.06.08
MAX Joint Throughput LP
17
Advanced Communica-tion Network 2009 2009.06.08
Interference Free Schedule
Link Scheduling– Give each link a schedule
– list of time slots and corresponding channels
Objective– interference free
18
GL
Advanced Communica-tion Network 2009 2009.06.08
Mixed IP MAX Flow Fairness
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Advanced Communica-tion Network 2009 2009.06.08
LP Flow Fairness
Maximize Fairness
20
Advanced Communica-tion Network 2009 2009.06.08
Maximize Joint Throughput
21
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Efficient TDMA Scheduling
Advanced Communica-tion Network 2009 2009.06.08
Efficient TDMA Scheduling
Centralized scheduling for link
transmission– Assume that T is the number of time slots per
scheduling period.
– We need to schedule time slots for
a virtual link using channel .
23
Advanced Communica-tion Network 2009 2009.06.08
Efficient TDMA Scheduling
Advanced Communica-tion Network 2009 2009.06.08
Links Sorting
Different links sorting algorithm– Our algorithm relies on some special sorting of
the links, which depends on the interference
models.
– No common sorting that works for all
interference models.
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Advanced Communica-tion Network 2009 2009.06.08
Improvement
Parametric searching improve the overall
achieved flow.
26
MCC 1,
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Performance Evaluation
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Impact of Multichannels (1/1)
When channel combining is performed, it provides higher throughput and higher fairness..
Increasing the number of channels per radio increases the throughput and fairness.
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Impact of Multiradios (1/1)
When channel combining is performed, it provides higher throughput and higher fairness..
The bouncing is that the actual number of radios assigned to each node is randomly generated for
each simulation run.
Increasing the number of radios per node “seems to” increase the throughput and fairness.
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Impact of Interference Model (1/1)
With channel combining, the network receives the highest fairness and throughput under PrIM, while it receives the lowest fairness under the
RTS/CTS model and lowest throughput throughput under TxIM.
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Impact of Interference Model (1/1)
Without channel combining, the network receives the highest fairness and throughput
under PrIM, while it receives the lowest fairness and throughput under the RTS/CTS model.
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Conclusion
Advanced Communica-tion Network 2009 2009.06.08 33
Conclusion (1/1)
The main contributions of this paper are– Theoretical performance guarantee for
algorithms.
– Impact of channel combining.
– Realistic models and other restrictions.
Advanced Communica-tion Network 2009
2009.06.08