WiPrint 3D Printing Your Wireless Coverage Justin Chan, Changxi - - PowerPoint PPT Presentation

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WiPrint 3D Printing Your Wireless Coverage Justin Chan, Changxi - - PowerPoint PPT Presentation

Jan 29, 2023 228 likes •584 views

WiPrint 3D Printing Your Wireless Coverage Justin Chan, Changxi Zheng*, Xia Zhou Dartmouth College, *Columbia University 1 Problem 1 Rx Tx Performance 2 Problem 2 Security 3 Problem Statement -35 -40 -45 -50 -55 -60

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WiPrint 3D Printing Your Wireless Coverage

Justin Chan, Changxi Zheng*, Xia Zhou Dartmouth College, *Columbia University

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Problem 1 Performance

Tx Rx

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Problem 2 Security

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Problem Statement

How to create custom signal maps?

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  • 35 -40 -45 -50 -55 -60 -65 -70 -75

RSS (dBm)

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Existing Solution

Bulky Expensive (~$9000) Cumbersome

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Solution: Soda Cans?

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Solution: 3D Printed Reflectors Flexible Cheap (~$50) Lightweight

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Fabrication

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Fabrication

Concave reflector Square-wave reflector

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Fabrication

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Search for optimal reflector shape Fabricate

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Roadmap

Modeling Compute reflector Evaluate results 12

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Roadmap

Modeling Compute reflector Evaluate results 13

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Ray Tracer

Input:

  • Environmental layout
  • Router location
  • Reflector shape

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Output: Predicted signal map

Ray Tracer

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  • 35 -40 -45 -50 -55 -60 -65 -70 -75

RSS (dBm)

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Propagation Model

  • Site-specific models
  • Solving wave equations

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Propagation Model

Θi Θr

Specular Refmection

Θi Θr

Difraction tion

Transmission

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Roadmap

Evaluate results Compute Reflector Modeling 18

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Shape Of A Reflector

Set of points

Interpolated to polynomial

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Objective Function For High-Res Input

  • Mean absolute error
  • Find reflector to optimize fitness function

Desired Predicted

Ray tracer

Reflector

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Simulated Annealing

  • Randomized algorithm for global optimization

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Low-Res Map

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Scoring Low-Res Maps

  • Red cells

– The higher the signal, the better the red score

  • Black cells

– The lower the signal, the better the black score

  • Maximize both red and black scores

http://gymnastjudge.com/wp-content/uploads/2012/01/scoring42.png 23

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Pareto Optimal Solution

Red Red score Black score A point where we cannot improve a one objective function without causing a decrease in another

  • bjective function

Pareto Optimal Solution 24

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Pareto Simulated Annealing

  • Give weights to objective functions
  • Maximize weighted sum
  • Vary weights, allows exploration along the

frontier

Red Red score Black score 25

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Roadmap

Modeling Compute Reflector Evaluate results 26

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Without reflector With reflector

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  • 35 -40 -45 -50 -55 -60 -65 -70 -75

RSS (dBm)

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Baseline Measurements

5 10 15 20 25 7 14 y (m) Estimated Measured 5 10 15 20 25 x (m) 7 14 y (m)

5 10 15 20 25 7 14 y (m) Estimated Measured 5 10 15 20 25 x (m) 7 14 y (m)

Router in center Router in corner

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  • 35 -40 -45 -50 -55 -60 -65 -70 -75

RSS (dBm)

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Reflectors

5 10 15 20 25 7 14 y (m) Estimated Measured 5 10 15 20 25 x (m) 7 14 y (m) 5 10 15 20 25 7 14 y (m) Estimated Measured 5 10 15 20 25 x (m) 7 14 y (m)

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Concave reflector Square wave reflector

  • 35 -40 -45 -50 -55 -60 -65 -70 -75

RSS (dBm)

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Future Work

  • Other waves frequencies
  • Different reflector materials
  • More advanced 3D ray tracer
  • System of multiple reflectors

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Intuitive and novel solution to both performance and security problems

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Questions?

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5GHz Router

5 10 15 20 25 7 14 y (m)

  • 80
  • 70
  • 60
  • 50
  • 40

RSS (dB) 5GHz 2.4GHz 5 10 15 20 25 x (m) 7 14 y (m)

  • 80
  • 70
  • 60
  • 50
  • 40

RSS (dB) 5 10 15 20 25 7 14 y (m)

  • 80
  • 70
  • 60
  • 50
  • 40

RSS (dB) 5GHz 2.4GHz 5 10 15 20 25 x (m) 7 14 y (m)

  • 80
  • 70
  • 60
  • 50
  • 40

RSS (dB)

No reflector Concave reflector

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Simulator Error

0.2 0.4 0.6 0.8 1 5 10 15 20 25 30 CDF Error (dBm) Ray tracing Ray w/o diffraction ITU Uniform 0.2 0.4 0.6 0.8 1 5 10 15 20 25 30 CDF Error (dBm) Ray tracing Ray w/o diffraction ITU Uniform

TX in center TX in corner

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Simulator Error

0.2 0.4 0.6 0.8 1 5 10 15 20 25 30 CDF Error (dBm) Ray tracing Ray w/o diffraction ITU Uniform 0.2 0.4 0.6 0.8 1 5 10 15 20 25 30 CDF Error (dBm) Ray tracing Ray w/o diffraction ITU Uniform

Concave reflector Square-wave reflector