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Introduction to Simulating radio propagation models and COOJA ARM

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Maximum values used by ray tracer. May become very time-consuming ... User may track ray paths from a transmitter to a point. Uses the current formula settings ... – PowerPoint PPT presentation

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Title: Introduction to Simulating radio propagation models and COOJA ARM


1
Introduction toSimulating radio propagation
modelsand COOJA ARM
2
One radio
REFRACTION
REFLECTION
DIFFRACTION
  • receiving a radio signal
  • Typically 4 different categories
  • Problem
  • What happens to the radio signal?
  • (And how is sound quality affected?)

SCATTERING
3
WSN radio model types
  • Unit Disk Graph
  • COOJAs Standard Radio Medium
  • Bit Error Ratio (BER)
  • Collected statistical data (or empirical models)
  • Ray tracing

4
COOJA ARM
  • Advanced Radio Medium
  • Advanced when compared to Standard )
  • Radio propagation models introduction
  • How ARM works

5
Wikis definitions
  • Radio Propagation
  • ... is a term used to explain how radio waves
    behave when they are transmitted, or are
    propagated from one point on the Earth to
    another.
  • Radio Propagation Model
  • ... characterization of radio wave propagation
    as a function of frequency, distance and other
    conditions.

6
Empirical models
  • Lots of different models exist
  • Outdoor
  • City, Terrain, Rain, Earth curvature
  • Okumura model built using data collected in Tokyo
  • Indoor
  • ITU Model for indoor Attenuation
  • Log Distance Path Loss Model
  • Typical parameters frequency, distance, number
    of floors, coefficients tuned to different
    environments etc.
  • Above models based on empirical data

7
Analytical approach
  • Based on ray tracing
  • Calculates multi-path effects
  • Used in COOJA ARM

8
Small-scale vs. Large-scale
  • Small-scale effects
  • Sum of many received signal from different
    directions
  • Often Gaussian random
  • Scattering
  • Large-scale effects
  • Shadowing
  • Reflections

9
Free Space Propagation Model
  • (FSPL)
  • Predicts signal strength for LOS paths

Antenna gains
Wavelength
Distance
Transmitted vs. received power
10
Ray tracing in ARM
  • 2D positions
  • Supports attenuating obstacles
  • Only rectangles
  • Refractions
  • Reflections
  • Diffractions
  • Potential support
  • Scatterings

11
Using ARM
  • Registers two plugins
  • Changing formula parameters
  • Visualizing radio coverage
  • Listens to all radios in the simulation
  • Transmitted power
  • Antenna gains
  • Packet lengths
  • SNR threshold
  • (Channel)

12
Formula Viewer
13
Formula Viewer
14
Formula Viewer
15
Formula Viewer
16
Formula Viewer
17
Area Viewer
  • Shows radios, obstacles and channel propagation

18
Area Viewer
  • Obstacles are set by analyzing the background
    image

19
Area Viewer
  • User may track ray paths from a transmitter to a
    point
  • Uses the current formula settings

20
Area Viewer
  • Show surroundings of transmitter
  • Signal strength
  • SNR ratio
  • Probability of reception
  • Delay spread

21
Area Viewer
  • Received signal strength vs. Probability of
    reception

22
Future work
  • Validate models
  • Parameter estimation / Model calibration
  • From actual measurements
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