Sep 10, 2004 1 Motivation, Genesis & Evolution of the eXtreme Scale Mote (XSM) Prabal Dutta <prabal@eecs>
Dec 19, 2015
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 Reconstruction
Reconstruction Fidelity
Data-centric
Data-driven Messaging
Periodic Sampling
High-latency Acceptable
Periodic Traffic
Store & Forward Messaging
Aggregation
Phenomena Omnichronic
Absolute Global Time
Event Detection
Signal Detection
Detection and False Alarm Rates
Meta-data Centric (e.g. statistics)
Decision-driven Messaging
Continuous “Passive Vigilance”
Low-latency Required
Bursty Traffic
Real-time Messaging
Fusion, Classification
Rare, Random, Short-lived
Relative Local Time
vs.
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 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 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