NEST Midterm Wireless OEP Demo

1. NEST Midterm Wireless OEP Demo David Culler Eric Brewer, David Wagner Shankar Sastry NEST PI Meeting July 14, 2003

2. composition services coordination services synthesis services Role of MidTerm demo in the program Challenge Application SW platform HW platform sensors actuators processing storage communication NEST midterm Demo

3. Platform Timeline • 6/01 Start of Program Platform Proposal • 1/02 Delivered 1000 Micas + TinyOS kits to program projects • 7/02 Projects demo working components OEP demos NEST-Tracker • 2/03 OEP demos NEST-Tracker composable framework • Collect services from projects • SOCOMM and UW demos • 7/03 Mid-Term Demo on OEP2 • Show feasibility of platform and middleware • … • Challenge Application NEST midterm Demo

4. Outline • Introduction • Overview of the Demo • OEP2 HW/SW Platform • Component Services • Mini-demos • Time synchronization • Ranging • Localization • Sensing • Routing • Demo NEST midterm Demo

5. Overview of the midterm demo NEST midterm Demo

6. Establish active sensor field • Establish spatial and temporal co-ordinates • Minimize time-to-deploy • Self-localization (ultra-sound ranging) from few Anchor nodes • Functional heterogeneity • Time synchronization to establish rough clock NEST midterm Demo

7. Regionalized Entity Detection • Local signal processing of magnetometer readings • Generate local sighting of strength s at time t • Node with max s over time window elected leader • Aggregates sightings into entity position estimate • Communicate entity detect to entity authority (EA) NEST midterm Demo

8. Self-Organized Routing Structure • Sensor nets: 1-all bcast + all-1 data collection • Tree construction (bcast, gradient reinforcement, QoS) • NEST: any-to-few mobile NEST midterm Demo

9. Entry Detection and Tracking • Power management, Distributed sensing, sentry service (UVA), multihop N-1 routing NEST midterm Demo

10. Pursuer Challenges • Multiple entities in the field • Disambiguation? • Mobile destination, multicast “upward” • Navigation, control, … NEST midterm Demo

11. Disambiguation and Hierarchy • Node Heterogeneity • Stationary sensor field nodes • uniform, limited resources, short-range connectivity • Functional specialization • Anchored vs localized • Landmark nodes • Mobile Pursuer Nodes • Greater computing resources • Alternative sensing modes & localization mechanisms • Alternative communication channels • Hierarchy of knowledge • Sensor field nodes detect entities, maintain routing state • Pursuer nodes maintain entity relationships • Map of pursuers and evader • Inter-pursuer coordination • Entities disambiguated at high levels in hierarchy NEST midterm Demo

12. Routing Service Challenge • Mobile ad hoc routing (eg, MANET) have focused on any-to-any independent paths ala internet • Protocols involve extensive discovery and state maintenance • DSDR, AODV, … • either state proportional to size of net or partial flood on any new connection • Sensor nets dominated by 1-to-N (broadcast) and N-to-1(data collection or aggregation) • simple tree routing structures • cost-based topology formation with data-driven reinforcement • Simple cases of directed diffusion • Here, entity leader (any) routes to few pursuers (anywhere) • Want simple, bounded-state routing structures • Small mobility cost NEST midterm Demo

13. Landmark-based Routing • Build routing tree (forest) to landmark node(s) • Entity leader routes up to landmark • Each Pursuer EA handshakes w/ close sensor node (crumb) • Path to landmark forms “crumb trail” • Routes up to landmark, beam-form down to multiple EAs • Incremental crumbs Alternative routing services: PARC NEST midterm Demo

14. Pursuer Control • Localizes within field coordinates • Multiple sources: GPS, Ultra-sound, RSSI • Obtains entity detections from sensor field • Obtains other pursuer positions • Pursuer channel or sensor field • Isolates evader position • Maintains map • Tracking and estimation • Navigates toward evader • Control loop: head-and-run till next update • Target based on estimate from evader track • Coordination and collision avoidance with other pursuer • When close, STOP Alternative Control Services: OSU NEST midterm Demo

15. Overall Demo Operation • Sensor field established coordinate grid and time • Sensor field waits in quiescent “sentry state” • Command/Monitor is stationary EA • Plus snooping display for visibility of internal operation • Evader enters field is detected and tracked • Pursuers enter field • Entity detection, routed to landmark, beamed to EAs • Pursuers distinguish evader from self entities • Navigate in co-ordination to pursuer • Stop when pursuer gets within 1 cell of evader or evader leaves field NEST midterm Demo

16. acoustic ultrasound mag dot OEP2 Hardware Platform • Main board: Mica2 dot • Atmega microcontroller, Flash, clock • CC1000 frequency agile FSK radio • Small form-factor • Xbow based on Mica • Sensor Board: magnetometer • Honeywell mag with 2-stage amplification • Set/reset circuit (5v) • 4-port digital Pot for biasing and filtering • Power Subsystem • Dual-voltage booster/regulator board w/ rechargeable battery • Controllable 5 v • Adapter board for conventional recharger • Ranging boards • UltraSound • Acoustic • Enclosure • Corresponding Micro-climate and occupancy detector “stack NEST midterm Demo

17. Power Board • Dual 3.3V and 5V supply • independently controlled • 3550mAh capacity at 1.2V on rechargables • drawing 25mA constant current (tested in lab) • operation down to 0.8V • ~50uA current at 1.2V in sleep state with boost converter on NEST midterm Demo

18. Enclosure Design reflector Exposed components Watertight compartment ultrasound main mag sense power battery Collision absorption NEST midterm Demo

19. OEP2 Software Platform • TinyOS 1.1 + NesC 1.1 • Rich Component Composition Language • ChipCon radio stack • Network Programming • Race detection • TOSSIM + TinyViz • Abstract Timer • Robust Multihop Data Collection • TinyDB NEST midterm Demo

20. Localization Span Tree Route test Mag position Power ctrl Mgmt Reset Net pgming nbr-hood messaging sense Timer Config Higher-Level Node Service Architecture appln services Service Coordination Network services routing Intra-mote services Hardware abstraction NEST midterm Demo

21. Localization Span Tree Route test Mag position Power ctrl Mgmt Reset Net pgming nbr-hood sense Config TinyOS Core Components • Network Stack • ChipCon • UART • I2C • Magnetometer • Abstract Timer • One-shot • periodic Service Coordination routing Timer messaging Hardware abstraction NEST midterm Demo

22. Localization Span Tree Route test Mag position Power ctrl Mgmt Reset Net pgming nbr-hood sense Configuration Service • Query & Set variables • Any service can register ‘config’ variable • Late binding • Limited virtualization Service Coordination routing Timer messaging Config Hardware abstraction NEST midterm Demo

23. Localization Span Tree Route test Mag position Power ctrl Mgmt Reset Net pgming nbr-hood sense Config Routing • Protocol stack • Outbound queue • Multihop • Broadcast Service Coordination routing Timer messaging Hardware abstraction NEST midterm Demo

24. Localization Span Tree Route test Mag position Power ctrl Mgmt Reset Net pgming sense Config Neighborhood Tuple Space • Data sharing abstraction • Per-node logical tuple space • Get/Set field • Abstract neighbor relation • Flexible publish/sync policy var2 var1 var3 id Service Coordination routing nbr-hood Timer messaging Hardware abstraction NEST midterm Demo

25. Localization Span Tree Route test Mag position Mgmt Reset Net pgming nbr-hood sense Config Power Control Service • Provides start/stop/awake control for each component • Protocol and sequencing Service Coordination Power ctrl routing Timer messaging Hardware abstraction NEST midterm Demo

26. Localization Span Tree Route test Mag position Power ctrl Net pgming nbr-hood sense Config Reset and Mgmt Services • Service protocol to bring components to a clean, initialized state • Health and status commands • Blink • ping Service Coordination Reset Mgmt routing Timer messaging Hardware abstraction NEST midterm Demo

27. Localization Span Tree Route test Mag position Power ctrl Mgmt Reset Net pgming nbr-hood sense Config Service Coordination Schedule application services and underlying resources • Provides start/stop • One AS active at any time • Additional constraints • Mag/Msg interaction Service Coordination routing Timer messaging Hardware abstraction NEST midterm Demo

28. Span Tree Route test Mag position Power ctrl Mgmt Reset Net pgming nbr-hood sense Config Localization Service • Build field-relative coordinate grid • Range measurements • Propagate to determine multihop ranges from anchors • Compute estimated positions Localization Service Coordination routing Timer messaging Hardware abstraction NEST midterm Demo

29. Localization Route test Mag position Power ctrl Mgmt Reset Net pgming nbr-hood sense Config Spanning Tree Service • Build routing tree (forest) from Landmark nodes • Low-contention, signal-strength determined tree • New bcast • Collect readings till quiet • Filter based on RSSI • Min hop (filtered) with max strength • Retransmit after delay Span Tree Service Coordination routing Timer messaging Hardware abstraction NEST midterm Demo

30. Localization Span Tree Mag position Power ctrl Mgmt Reset Net pgming nbr-hood sense Config Routing Test Service • Route from node A to B via landmark • Execute mgmt cmd Route test Service Coordination routing Timer messaging Hardware abstraction NEST midterm Demo

31. Localization Span Tree Route test Power ctrl Mgmt Reset Net pgming nbr-hood sense Config Mag Service • Collect mag stream • EWA into threshold detector • Bcast in trigger • Leader election • Estimate position as center of mass • Route via landmark to EA Mag position Service Coordination routing Timer messaging Hardware abstraction NEST midterm Demo

32. Entity Authorities • Maintain “crumb trail” to landmarks • Collect entity detections via LM routng • Collection position estimates • GPS, node RSSI, mag entities, ultrasound • Collection other pursuer positions • Alternative channel or LM routing • Maintain entity map • Execute navigation control • Coordinate strategies NEST midterm Demo

33. Mini Demos NEST midterm Demo

34. TimeSynch Mini-Demo • Vanderbilt NEST midterm Demo

35. Time Sync • Cross-layer optimization provided by platform • Eliminates typical large variance on send-delay • Timestamp outgoing msg after mac delay • Timestamp incoming • UCLA demo’d RBS timesynch • Vanderbilt provided simple multihop direct method • Example: • Ring of nodes maintaining exclusive slots NEST midterm Demo

36. Sensing Mini-Demo NEST midterm Demo

37. Sensing: Magnetometer Detection • Based on a 2 stage amplification with a potentiometer-controlled bias • Set/Reset circuit • improved accuracy & no drift • 50 uJ of energy per operation; • 5 mW at 128 Hz • Improved resolution • 130 uGauss on a 10-bit Atmel ADC • Range - 4 gauss (Earth's magnetic field = 0.5 gauss) • Software-tunable RC filter • adaptive sampling and control • allows for sampling between 5MHz (sensor BW) and 10 Hz without aliasing • Further advances with OSU techniques HoneyDot NEST midterm Demo

38. Ranging and Localization Mini-Demo NEST midterm Demo

39. Ranging Board • Lessons from sounder, UCLA ultrasound, VU ranging • Dedicated Atmega 8, like motor-control board • Dual proc TinyOS with UART link • TX • Command Processor • Generate 25 KHz 10v signal (range) • RX • Triggered by radio chirp • Analog switch • Starts Atmega 8 timer • Analog compare amplified recv with digital pot threshold. • Completes timer • Signals time-stamped event 25 KHz US Transceiver tone Atmel 8 digital pot UART AM channel Main TinyOS Mote NEST midterm Demo

40. Ultra-Sound Ranger • UCLA Ultra-sound provides good directional ranging • High frequency, high amplitude pulse • PEG requires ranging in the plane • Rob Szewczyk designed variant of UCLA cone • Vanderbilt showed good acoustic ranging with high sample rate and sophisticated processing • Dual TinyOS approach off-loads sampling • Relatively simple processing • 5 cm accuracy in the plane • 5 m range • Demo: display range of roving node reflector ultrasound NEST midterm Demo

41. Localization for Ease of Deployment • Few anchor nodes at known positions • Range between pairs of nodes • Propagate range estimates to get distance estimates from anchors • Calculate estimated location from set of anchors • Least squares fit • All three of these steps on-mote and entirely distributed => behavior of algorithm => live demonstration on 9-node array outside NEST midterm Demo

42. 13 10 15 14 12 11 9 5 7 6 8 3 2 1 4 Localization NEST midterm Demo

43. Localization Accuracy NEST midterm Demo

44. Localization Accuracy NEST midterm Demo

45. Localization Accuracy NEST midterm Demo

46. Live Localization Demo • 3x3 grid with 4 anchors Red = Anchor Blue = Actual Green = Estimated 2-hop NEST midterm Demo

47. Routing Mini Demo • Goal: route information to the pursuers • Challenge: pursuers are mobile • Need to route from one mobile entity (motes near evader) to another (motes near the pursuer) • Two solutions: • “Landmark routing” -- landmark keeps track of the pursuer and forwards messages from the evader motes • “Constrained Broadcast” – multicast to possible locations of the pursuer (Xerox PARC) NEST midterm Demo

48. Routing Mini-Demo • Any-to-one  global re-broadcast • Any-to-mobile  repeated re-broadcast NEST midterm Demo

49. Berkeley Landmark Routing • Crumb-trail allows landmark to forward to mobile • Avoids repeated re-broadcast • Question: is this too fragile? NEST midterm Demo

50. Statistics • Bandwidth: #received/sec • Delivery Rate: # received/# sent • Energy Cost: # transmissions • Latency: time received – time sent NEST midterm Demo