Sep 10, Motivation, Genesis & Evolution of the eXtreme Scale Mote (XSM) Prabal Dutta

Sep 10, 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, 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, Differing Energy Usage Patterns

Sep 10, 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, LITeS Concept of Operations Radar Target Detected Magnetic Target Detected

Sep 10, 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, 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: T startup = 40ms, P ss = 18mW –UWB Radar: T startup = 30s, P ss = 45mW –Optimistic lifetime: 6000mWh / 63mW < 100 hrs –Must lower power Radio –Fix anisotropic radiation and impedance mismatch

Sep 10, Hardware Evolution Telos = Low-power CPU Radio + Easy to use Sleep-Wakeup-Active MICAz MICA2 - CC Radio Sleep-Wakeup-Active XSM MICA2 + Improved RF + Low-power sensing + Recoverability Passive Vigilance-Wakeup-Active XSM2 XSM + Improvements + Bug Fixes

Sep 10, The eXtreme Scale Mote Key Differences between XSM and MICA2 –Low-power Sensors –Grenade Timer –Radio Performance

Sep 10, 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 ( ) –Wakeup Magnetometer –High power, long startup latency –Gain: 86dB (20,000)

Sep 10, 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, 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, XSM RF Performance

Sep 10, 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, Discussion