Variable Bandwidth Allocation Scheme for Energy Efficient Wireless Sensor Network
SeongHwan Cho, Kee-Eung KimKorea Advanced Institute of Science and Technology (KAIST),
Samsung Advanced Institute of Technology
ICC 2005ICC 2005
SpeakerSpeaker:: Shih-Yun, HsuShih-Yun, Hsu
OutlineOutlineIntroductionGoalAssumptionEnergy consumption vs BandwidthVariable Bandwidth Allocation (VBA)Bandwidth Allocation AlgorithmSimulation ResultsConclusions
IntroductionIntroductionThe characteristics of the sensor network
Small packets (hundreds of bits)Short transmission range (< 10m)Low mobilityYears of lifetime with small energy resourceDistributed redundantly
Cluster
IntroductionIntroductionAn Application-Specific Protocol Architecture
for Wireless Microsensor NetworksIEEE Trans. on wireless communications, 2002
TDMA scheme with DSSS in a clusterAvoiding inter-cluster interference
AdvantageEnergy efficient
Disadvantage Increases the packet sizeAggravates time synchronization problems
IntroductionIntroduction[5][6][7] are aimed at a general sensor network
with multi-hop routingDo not consider
Bandwidth utilization to minimize energy consumption
GoalGoalProposes a mechanism
ClusteringVariable bandwidth allocationTime-frequency slot assignment
AssumptionAssumption There are many frequency bands available The network environment bases on cluster structure
Energy consumption vs BandwidEnergy consumption vs Bandwidthth6 sensors100 bits packet100 bpsUsing hybrid FDM-TDM methodFrame time = 10ms
Energy consumption vs BandwidEnergy consumption vs Bandwidthth
Energy consumption vs BandwidEnergy consumption vs Bandwidthth
RE: event rate
Nsync: the number of synchronizations per second
ρ: the error in the reference crystal oscillator
,
,
,
total tx rx sync
E tx sync rx sync
E tx rx syncguard
P P P
R E N E
R E ET
Energy consumption vs BandwidEnergy consumption vs Bandwidthth
,
max
total E tx rx sync
tx
P R E EM
TNR
M: the number of channels available N: the total number of sensors Rmax: the maximum event rate of the sensors
Energy consumption vs BandwidEnergy consumption vs Bandwidthth
Energy consumption vs BandwidEnergy consumption vs Bandwidthth
Variable Bandwidth Allocation (VBA)Constant bandwidth allocation (CBA)
Allocates equal amount of frequency bands to the clusters regardless of its node density
Variable Bandwidth Allocation (VBA)
Variable Bandwidth Allocation (VBA)
Variable Bandwidth Allocation (VBA)
Bandwidth
Time
Variable Bandwidth Allocation (VBA)
1 1
min ( )
Cluster iN n
network ii k
P P k
,( )( , )
i E tx rx sync
guard
P k R E ET i k
,
( , ) ( , )
j i
guard jj C C
T i k dist k A
Bandwidth Allocation AlgorithmSingle macrocluster slot assignmentPairwise joint macrocluster slot assignmentGlobal network slot allocation
Bandwidth Allocation Algorithm Single macrocluster slot assignment
Bandwidth Allocation Algorithm Pairwise joint macrocluster slot assignment
Bandwidth Allocation Algorithm
A B C
Θ1 Θ2
Bandwidth Allocation Algorithm
A B C
Θ1 Θ2
Θj= Θ2 , nj=3Θi= Θ1 , ni=2
ni < nj
BTframe
Bandwidth Allocation Algorithm
A B C
Θ1 Θ2
Θj= Θ1 , nj=2Θi= Θ2 , ni=3
ni > nj
Tframe B
Bandwidth Allocation Algorithm Global network slot allocation
Bandwidth Allocation Algorithm
Simulation ResultsSimulation Results25 clusters and 750 sensor nodesAveraging 100 different simulations for each
standard deviation
Simulation ResultsSimulation Results
Simulation ResultsSimulation Results
ConclusionsConclusionsA variable fine-grain bandwidth allocation sch
eme is proposed for a collaborative sensor network with multiple clusters
This scheme reduces the power consumption of the network by exploiting the fact that power consumption from synchronization can be reduced if more bandwidth is available
Thank You!!Thank You!!
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