Upload
alyson
View
45
Download
0
Tags:
Embed Size (px)
DESCRIPTION
A Channel Assignment Algorithm for Multi-Radio Wireless Mesh Networks. Stefano Avallone, Ian F. Akyildiz. Computer Communication, Jan. 2008. Outline. Introduction Problem Definition A Flow Rate Computation Method The MCAR Algorithm Performance Evaluation Conclusions. Introduction. - PowerPoint PPT Presentation
Citation preview
A Channel Assignment Algorithm for A Channel Assignment Algorithm for Multi-Radio Wireless Mesh NetworksMulti-Radio Wireless Mesh Networks
Stefano Avallone, Ian F. AkyildizStefano Avallone, Ian F. Akyildiz
Computer Communication, Jan. 2008
OutlineOutline
IntroductionIntroductionProblem DefinitionProblem DefinitionA Flow Rate Computation MethodA Flow Rate Computation MethodThe MCAR AlgorithmThe MCAR AlgorithmPerformance EvaluationPerformance EvaluationConclusionsConclusions
IntroductionIntroduction
Wireless mesh networks consist of a Wireless mesh networks consist of a backbone with mesh routersbackbone with mesh routers
Mesh RouterMesh RouterLow mobility Low mobility Multi-radioMulti-radioTransmission through wireless mediaTransmission through wireless media
IEEE standards define multiple channelsIEEE standards define multiple channels IEEE 802.11a have 12 non-overlapping IEEE 802.11a have 12 non-overlapping
channelschannels IEEE 802.11b/g have 3 non-overlapping IEEE 802.11b/g have 3 non-overlapping
channelschannels
Using multiple channels in multi-radio Using multiple channels in multi-radio WMN greatly improve the network WMN greatly improve the network throughputthroughput
IntroductionIntroduction
IntroductionIntroduction
The channel assignmentThe channel assignmentThe reuse of the same channel in a The reuse of the same channel in a
neighborhood neighborhood The bandwidth available on the network linkThe bandwidth available on the network link
The channel assignment has to preserve The channel assignment has to preserve the network connectivitythe network connectivity
IntroductionIntroduction
The static cannel assignment problemThe static cannel assignment problem Interference awareInterference aware
To minimize the interferenceTo minimize the interference
Traffic awareTraffic awareTo make a given set of flow rate schedulableTo make a given set of flow rate schedulable
IntroductionIntroduction
6
Each node has two radios
IntroductionIntroduction
Each node has two radio
MotivationMotivation
Existing channel assignment Existing channel assignment Only base on information related to node Only base on information related to node
within the interference rangewithin the interference rangeThis may break the radio constraint This may break the radio constraint
Depend on particular traffic profileDepend on particular traffic profile
Problem DefinitionProblem Definition
κ(R1) 1≧
|C| available channel
Problem DefinitionProblem Definition
Interference modelInterference model
u v
rI
rT
ch1
Xch1
ch1
Problem DefinitionProblem Definition
e0
flow rate f(e0)Capacity c(e0)
The conditions ensures that a set of flow rate are schedulable
Depend on channel
assignment
Problem DefinitionProblem Definition
GoalsGoals
Flow Rate ComputationFlow Rate Computation
To compute the flow rates having the To compute the flow rates having the objective to maximal the achievable rateobjective to maximal the achievable rate
At this timeAt this timeChannel assignment is not decideChannel assignment is not decideThe knowledge of the expected traffic demand The knowledge of the expected traffic demand
is unknown is unknown
Flow Rate ComputationFlow Rate Computation
To maximal the throughputTo maximal the throughput Using network throughput instead of the demand Using network throughput instead of the demand
traffic traffic To compute the maximal achievable throughputTo compute the maximal achievable throughput
Channel assignment is not decideChannel assignment is not decide The interference is also unknownThe interference is also unknown In this, the interference is absentedIn this, the interference is absented
The channel assignment is assume to handle the The channel assignment is assume to handle the interference probleminterference problem
Flow Rate ComputationFlow Rate Computation
Maximum the multi-commodity flow Maximum the multi-commodity flow problemproblemNP-completeNP-completeTranslate into single-commodity flow problemTranslate into single-commodity flow problem
Flow Rate ComputationFlow Rate Computation
Mesh aggregation devices
Mesh gateway
Virtual node Virtual node
capacity= ∞
capacity= ∞
Mesh Router
MCAR AlgorithmMCAR Algorithm
Two stagesTwo stagesLinks are grouped based on the flows they Links are grouped based on the flows they
carrycarryFirst stage assure that the number of different First stage assure that the number of different
groups assign to its link does not exceed the groups assign to its link does not exceed the number of radionumber of radio
Each group is assigned a channelEach group is assigned a channel
Link-group BindingLink-group Binding
MCAR AlgorithmMCAR Algorithm
rt
rt
rt
rt
rt
rt
eg1
g1
g2
g1g2
g3
g1
Link-group BindingLink-group Binding
Assume the node has three radio
1
2
3
4R(e) = 1.5 R(e) = 1.2
R(e) = 1.1
R(e) = 1.3 j’
J’’ 3R(e) = 2.3
R(e) = 2.0
Link-group BindingLink-group Binding
g1
g2 g1
g2
R(e) = 1.5
R(e) = 1.2
R(e) = 1.0
R(e) = 1.3
g1
Group-Channel AssignmentGroup-Channel Assignment
Group-Channel AssignmentGroup-Channel Assignment
Group-Channel AssignmentGroup-Channel Assignment
ri
ri
ri
rtrtrt
P(g) : the set of links potentially interference with the link assign to group g
Group-Channel AssignmentGroup-Channel Assignment
ri
ri
rtrtrt S(g,c) : all the link that are assigned
channel c and potentially interference with links of g
εc: all the link that are assigned channel c
Group-Channel AssignmentGroup-Channel Assignment
Performance EvaluationPerformance Evaluation
Compare withCompare withLACA (Load Aware)LACA (Load Aware)BSCA (Balanced Static)BSCA (Balanced Static)
MetricMetric
Performance EvaluationPerformance Evaluation
Transmission range 90m Interference range180m Transmission range 90m Interference range180m Scenario1Scenario1
25 nodes25 nodes300m* 300m300m* 300mTwo radio 60% Three Radio 40%Two radio 60% Three Radio 40%
Scenario2Scenario250 nodes50 nodes400m* 400m400m* 400mTwo radio 20% Three Radio 40% Four Radio 40%Two radio 20% Three Radio 40% Four Radio 40%
Performance Evaluation Performance Evaluation
25 nodes
Capacity fixed to 54Mbps
Performance Evaluation Performance Evaluation
50 nodes
Capacity fixed to 54Mbps
Performance EvaluationPerformance EvaluationCapacity from 6 to 54Mbps
25 nodes
Performance EvaluationPerformance EvaluationCapacity from 6 to 54Mbps
50 nodes
ThroughputThroughput
25 nodes
ThroughputThroughput
50 nodes
DelayDelay
25 nodes
DelayDelay
50 nodes
ConclusionsConclusions
This paper proposedThis paper proposedA Flow Rate ComputationA Flow Rate Computation
Independent from the traffic demandIndependent from the traffic demandMaximal the network throughMaximal the network through
A channel assignment schemeA channel assignment schemeAttempt to make a given set of flow rate Attempt to make a given set of flow rate
schedulable schedulable