achieving long-term surveillance in vigilnet
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Achieving Long-Term Surveillance
in VigilNetTian He, Pascal Vicaire, Ting Yan, Qing Cao, Gang Zhou, Lin Gu, Liqian Luo, Radu Stoleru,
John A. Stankovic, Tarek F. Abdelzaher
Department of Computer ScienceUniversity of VirginiaCharlottesville, USA
Motivating Application: Battlefield Surveillance
Other Applications
Wildlife Monitoring
Alarm System
Flock Protection
Border Surveillance
Our Solution: VigilNet
MICA2 / MICAz / XSM Motes
MAC Sensor Drivers
Routing Power Mngt 1
SignalFiltering
TimeSync
Localization GroupMngt
PowerMng 2
Power Mngt 3
ProgrammingAbstractions
TargetClassification
Velocity / TrajectoryInference
Physical
Data-Link
Routing
Middleware
Application
0%
1%
1%99%
Initialization Sleep Event Process
Communication Surveillance
Focus of This Presentation: Power Consumption No power management => 4 days lifetime!
99% of energy consumed waiting for potential targets!
EnergyDistribution
0%
0%2%
2%
Initialization Sleep Event Process
Communication Surveillance
Focus of This Presentation: Power Consumption Power management => 10 months lifetime!
Lifetime x 75
98% of energy consumed in sleep mode!
EnergyDistribution
98%
State of the Art
Topics: Hardware Energy Scavenging Topology Control Sensing Coverage Predefined
Scheduling Data Aggregation Etc…
Practicality? Performance in Real
Deployments? Applicability to
Surveillance System? Combination of
Schemes?
Power Management in VigilNet Turning nodes off as often and as long as possible. Questions:
When to turn nodes off (to save power)? When to wake nodes up (to optimize system performance)? What are the tradeoffs?
Combination of four schemes: Node level power management. Group level power management. Network level power management. On-demand wakeup.
Group Level: Sentry Selection Redundant Coverage!
Group Level: Sentry Selection Redundant Coverage! => Sentry Selection
Group Level: Sentry Selection Load Balancing?
Group Level: Sentry Selection Load Balancing? => Sentry Rotation
Group Level: Sentry Selection Tradeoff: Detection Latency versus Density
Probability ofTarget Detected
Within First1,000m
Number of Nodes inArea 100m x 1,000m
10010 1,000
Area
1,000m 100m
Radius=20mRadius=8mRadius=2m
50 125 500
Sentry Level: Duty Cycle Scheduling Target Takes Time To Go Through the Network.
Sentry Level: Duty Cycle Scheduling Target Takes Time To Go Through the Network.
=> Duty Cycle Scheduling
Sentry Level: Duty Cycle Scheduling Putting It All Together
Sentry Level: Duty Cycle Scheduling Tradeoff: Detection Latency Versus Duty Cycle
Area
1,000m 100m
Probability ofTarget Detected
Within First1,000m
Duty Cycle
40%
100%
0% 20%
1000 Nodes, V=10m/s1000 Nodes, V=30m/s
Network Level: Tripwire Scheduling Exploiting Knowledge About the Target
Network Level: Tripwire Scheduling Exploiting Knowledge About the Target
Network Level: Tripwire Scheduling Tripwire partition based on distance to a base
On-Demand Wakeup
Wakeup
Wakeup PathTo Base StationWakeup Nodes
For FutureDetection
Detection
Details of Wakeup Operation
Sleeping Node: Wakeup x% of the Time
Wakeup Operation: Send Message with Long Preamble
Toggle Period
Sleep 1% Wakeup Sleep
Preamble length = TogglePeriod * BitRate SYNC Bytes DATA CRC
Evaluation by Third Party: Test Field
Mote Field
300m X 200m, 200 motes
Evaluation by Third Party:Interactive Display
Evaluation by Third Party:Detection, Classification, and Tracking
1.Initial Detection
2.Classification
3.Periodic updates
Average Localization Error: 6.24mAverage Velocity Error: 6%
Lifetime Evaluation: Hybrid Simulation
0
10
20
30
40
50
60
70
Time (seconds)
En
erg
y(m
w)
Sentry
NonSentry
Initialization Duration = 5 minutes
Surveillance Duration = 1day
Without system rotation:NonSentry Life Time: 250 daysSentry LifeTime: 7 days
Key Results: Lifetime
Lifetime No Power Management => 4 Days + Sentry Selection and Rotation => 28 Days + Duty Cycle Scheduling => 5 Months
(12.5% Duty Cycle) + Tripwire Service => 10 Months
(16 Tripwires, ¼ Awake) Tracking Performance Penalty
~ 3 to 5 Seconds 0
50
100
150
200
250
300
350
No PM + Sentry + Duty Cycle + Tripwire
Lifetime (days)
Key Results: Detection Performance Penalty ~ 3 to 5 Seconds
Summary
Successfully integrate 4 power management strategies into real system.
Analytical model and extensive simulation to predict system performance under various configurations.
Practical feasibility of tracking system using XSM2s with 10 months lifetime.
My Webpage: www.cs.virginia.edu/~pv9f
Tian’s Webpage:www.cs.umn.edu/~tianhe
Research Group Webpage:www.cs.virginia.edu/~control
Questions?
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