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Motivation, Genesis & Evolution of the eXtreme Scale Mote (XSM). Prabal Dutta . Crossbow Technology Mike Grimmer Ohio State Emre Ertin Hui Cao U.C. Berkeley Joe Polastre Cory Sharp Rob Szewczyk Virginia Lin Gu MITRE Ken Parker DARPA. Acknowledgements. Data Collection - PowerPoint PPT Presentation
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Sep 10, 2004 1
Motivation, Genesis & Evolutionof the eXtreme Scale Mote (XSM)
Prabal Dutta <prabal@eecs>
Sep 10, 2004 2
Acknowledgements
• Crossbow Technology– Mike Grimmer
• Ohio State– Emre Ertin– Hui Cao
• U.C. Berkeley– Joe Polastre– Cory Sharp– Rob Szewczyk
• Virginia– Lin Gu
• MITRE– Ken Parker
• DARPA
Sep 10, 2004 3
Motivation: Data Collection vs. Event Detection
Data Collection
Signal ReconstructionReconstruction Fidelity
Data-centricData-driven Messaging
Periodic SamplingHigh-latency Acceptable
Periodic TrafficStore & Forward Messaging
AggregationPhenomena Omnichronic
Absolute Global Time
Event Detection
Signal DetectionDetection and False Alarm RatesMeta-data Centric (e.g. statistics)Decision-driven MessagingContinuous “Passive Vigilance”Low-latency RequiredBursty TrafficReal-time MessagingFusion, ClassificationRare, Random, Short-livedRelative Local Time
vs.
Sep 10, 2004 4
Differing Energy Usage Patterns
Sep 10, 2004 5
Extreme Scale Requirements
• Biggie-size “A Line in the Sand” (like PEG) Network Scale by 100x (10,000 nodes) Detection range by 6x (10m) Lifetime 8x (720hrs 1000hrs) *
• Other areas also affected, but not covered– Topology– Classification– Tracking– Routing– Time Synchronization– Localization– Application– Visualization
Sep 10, 2004 6
LITeS Concept of Operations
RadarTarget
Detected
Magnetic Target
Detected
Sep 10, 2004 7
Requirements (of the hardware platform)
• Functional– Detection, Classification (and Tracking) of:
Civilians, Soldiers and Vehicles
• Reliability– Recoverable: Even from a Byzantine program image
• Performance– Intrusion Rate: 10 intrusions per day– Lifetime: 1000 hrs of continuous operation (> 30 days)– Latency: 10 – 30 seconds– Coverage: 10km^2 (could not meet given constraints)
• Supportability– Adaptive: Dynamic reconfiguration of thresholds, etc.
Sep 10, 2004 8
Genesis: The Case for a New Platform
• Cost– Eliminate expensive parts from BOM– Eliminate unnecessary parts from BOM– Optimize for large quantity manufacturing and use
Network Scale by 100x (10,000 nodes)– Reliability: How to deal with 10K nodes with bad image
Detection range by 6x (10m)– New sensors to satisfy range/density/cost tradeoff
Lifetime 8x (720hrs 1000hrs)– Magnetometer: Tstartup = 40ms, Pss = 18mW– UWB Radar: Tstartup = 30s, Pss = 45mW– Optimistic lifetime: 6000mWh / 63mW < 100 hrs– Must lower power
• Radio– Fix anisotropic radiation and impedance mismatch
Sep 10, 2004 9
Hardware Evolution
Telos =Low-power CPU +802.15.4 Radio +Easy to useSleep-Wakeup-Active
MICAzMICA2 - CC1000 +802.15.4 RadioSleep-Wakeup-Active
XSMMICA2 + Improved RF +Low-power sensing + RecoverabilityPassive Vigilance-Wakeup-Active
XSM2XSM + Improvements +Bug Fixes
Sep 10, 2004 10
The eXtreme Scale Mote
• Key Differences between XSM and MICA2– Low-power Sensors– Grenade Timer– Radio Performance
Sep 10, 2004 11
Sensor Suite
• Passive infrared– Long range (15m)– Low power (10s of micro Watts)– Wide FOV (360 degrees with 4 sensors)– Gain: 80dB– Wakeup
• Microphone– LPF: fc = 100Hz – 10kHz– HPF: fc = 20Hz – 4.7kHz– Gain: 40dB – 80dB (100-8300)– Wakeup
• Magnetometer– High power, long startup latency– Gain: 86dB (20,000)
Sep 10, 2004 12
Low-power Sensing through Duty-cycled Operation
• Motivation– Low-latency, high-power
sensors– High-latency, low-power
signal conditioning• Components
– Unbalanced clock• Tsetup phase• Tsampe phase• Thold phase
– S/H switch– S/H capacitor– S/H unity-gain buffer
Sep 10, 2004 13
Reliability through the Grenade Timer
• Motivation• Basic idea presented by
Stajano and Anderson• Once started
– You can’t turn it off– You can only speed it up
• Our implementation:
Sep 10, 2004 14
XSM RF Performance
Sep 10, 2004 15
Conclusions and Future Work
• Improve (or obviate) sensor wakeup circuits– Lower false-alarm rate– Low-power (zero-power?) wakeup
• Reduce sensing power (op amp FET ASIC)• Decrease signal processing power consumption
– Consider space, time, message (and energy) complexity
Sep 10, 2004 16
Discussion