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IEEE Vehicular Technology Conference

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Antenna Actuation for Radio Telemetry in Remote Sensor Networks University of California at Los Angeles David Browne, Vishwa Goudar, Henrik Borgstrom, Michael Fitz ... – PowerPoint PPT presentation

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Title: IEEE Vehicular Technology Conference


1
Antenna Actuation for Radio Telemetry in Remote
Sensor Networks
  • University of California at Los AngelesDavid
    Browne, Vishwa Goudar, Henrik Borgstrom, Michael
    Fitz, William Kaiser

2
Remote Sensor Networks
  • Three characteristics
  • Nodes deployed sparsely over large geographic
    regions
  • Nodes gather local data on a natural phenomenon
  • Nodes need to communicate sensor data

Example UCLA Broadband Seismic Network Array
(Thanks to Igor Stubailo and John Propst for
graphics.)
3
Remote Sensor Networks
  • Goal
  • Enable telemetry of sensor data between nodes

Known solution Radio telemetry over
omni-directional or sector antenna
  • Benefits
  • ad hoc deployment
  • self assembling
  • self healing
  • Limitations
  • Poor range
  • Low energy efficiency

Better solutionHighly-directional antennas with
rotational actuation
4
Benefits of Directional Antenna
  • Measured Path Loss 40dB/decade is typical
  • Range improvement
  • Omnidirectional 80dB loss _at_ 130m
  • 15dBi Directional 80dB loss _at_ 750m
  • Efficiency improvement
  • A link over 15dBi antennas is 1000x more energy
    efficient

azimuth
azimuth elevation
5
Actuated Network Assembly
Initial antenna orientation
Antenna orientation after articulation
6
The First Contact Problem
  • Missing information
  • Direction to other nodes.
  • Search coordination
  • Energy Considerations
  • search depletes energy
  • global vs. local maxima

Q How to shorten the first contact search? A
coordination geolocation.
7
Wideband vs. Narrowband Radios
  • 802.11b Radio
  • 2.44 GHz
  • 20MHz Bandwidth
  • 100m range (omni)
  • UCLA Narrowband Radio
  • 220 MHz
  • 4 kHz
  • 2 mile urban range (omni)

8
Search Strategies
9
Field Test Results
10
Field Test Conclusions
  • Blind vs. Geolocation and/or Coordination ?
    reduced search duration from 1.5 hours to 15min
  • Coordination only? search times are independent
    of range.
  • Geolocation only ? excellent short range (0m
    500m) search times (10s) ? exponentially
    deteriorating performance after 500m
  • Coordination Geolocation ?excellent range
    independent search times (10s)

11
Conclusions on Directional Antenna Actuation
  • Benefits common with omni/sector solutions
  • ad hoc deployment
  • self assembly
  • self healing
  • Advantages over omni/sector solutions
  • range
  • energy efficiency
  • Disadvantage latency due to actuation
  • latency due to actuation ? Importance of
    minimizing search time.

12
Whats Next
13
End of PresentationQuestions and Comments
14
Search Algorithms
  • A. Blind Search (baseline)
  • 802.11b radios search for gtthreshold coordinate.
  • Exhaustive search for the global maximum.
  • Upper bounds all strategies.
  • B. Coordinated Search
  • Coordination via LR radios.
  • Nodes begin 180º out of phase.
  • Nodes complete one rotation.
  • Link guaranteed within one rotation.
  • Lower bound for coordination.
  • C. Blind Search Geolocation
  • Random walk (speed dwell).
  • 802.11b radios search for gtthreshold coordinate.
  • GPS coordinates exchanged over 802.11 radios for
    LOS alignment.
  • D. Coordination Geololation
  • GPS coordinates exchanged over LR radios .
  • Immediate LOS alignment.

15
( Coordinates gt Threshold) vs. Range
16
Strategy C Simulation
17
The Link Search Space
  • Simulated Link Search Space

Measured Link Search Space
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