Ray Tracing 2'0 Wireless LAN Deployment Tool

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• Ray Tracing 2.0
• Radio Propagation Simulation Software

Presented By Matthew Taylor Ni Yi-Feng Tuan
Truong Project Advisor Dr. Jacques Beneat
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Motivation Goals

• Better techniques for wireless LAN deployment
  (save time save money)
• Indoor as well as Outdoor
• Increase speed and friendliness of existing
  program

• Convert from MATLAB to C code to increase speed
• Including diffraction to simulate outdoor
  situations
• Take measurements to verify program predictions

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Ni Yi-Feng

• Converting the MATLAB code from last year into C
  code.
• Increase performance hopefully by a factor of
  1000. (When we compute the MATLAB program, it
  runs very slow. )

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The floor plan is modified in the form of a line
with 18 numbers. The first six numbers are used
as options, like variables. The rest of twelve
numbers formed a plane unit.
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• This is a basic floor plan when we run the
  MATLAB.
• Data house_1fl.flp (we have 92 planes in this
  case)
• MATLAB has ability to provide multiple views.

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No Reflection
Two Reflection
Three Reflection
One Reflection

• What is the differences between multiple
  reflections?

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Power (mini-watt)
Time (nano-second)

• This is a power delay profile. First reflection
  displays in red lines, and the second reflection
  displays in blue linesand so on.
• Take a look at the first red line, which tells us
  that the ray path bounces in the shortest time
  consumption and travels in the shortest distance.
  The signal corresponds to the stronger power
  signal.

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• The ray tracing program in C language build as a
  rt_full.cpp file and a xxx.flp file.
• The rt_full.cpp has approximately 1,000 lines of
  code.
• The xxx.flp is combined with options and floor
  plan.
• And in option part of xxx.flp is modified with
  texts, which is easier for users to change their
  options. (see the figure)
• In this way, the ray tracing program is condensed
  with less related files, which provides
  convenience and efficiency.

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Geo_viewer.m

• Image_em.m
• -properties along path
• reflection loss
• transmission loss
• free space loss

.flp file .rcx file
Image_geo.m -find the paths reaching
RX. (Reflections Transmissions)
path.txt file .opt file
.raw file
Power_rt.m
MATLAB ONLY
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Geo_viewer.m

• Rt_full.cpp
• Compute paths
• -reflections/transmissions
• -(diffractions)
• 2. Properties alone paths
• -reflection loss
• -transmission loss
• -free space loss

_path.txt file
.flp file
.raw file
Power_rt.m
Imbedded with C and MATLAB
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The Powerful Sample Generator
C\Documents and Settings\Administratorgt
receiver_nbym_matrix jucketthall This is a n-by-m
matrix sample generator. Please specify your
floor plane regions x_axis 220
y_axis 90 How many rows of receiver positions
do you want to generate? rows (in
x-direction) 4 How many columns of receiver
positions do you want to generate?
columns (in y-direction) 3 What program are you
going to use to execute all the generated
samples? Program Name rt_full
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Sample took
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Future Work for C

• Modify the format of the _path.txt file so that
  MATLAB can plot the ray paths.
• Implement diffraction into C program.

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Diffraction

• Include diffraction in the program
• Takes into account more outdoor situations

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Diffraction

• Steps
• Fresnel Zone
• Half screen
• Conducting screen
• Right-angle wedge

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The Fresnel Zone

• The Fresnel zone is a very important area when
  considering the path loss of an antenna.

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Diffraction and Absorbing Half Plane
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Absorbing half plane screen

• 2 Separate Regions
• Illuminated
• Shadow
• Boundary Region
• Equation

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Absorbing half plane screen simulation
10 Meters
TX
10 Meters
10 Meters
-30 Meters
RX
Wall
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Dielectric wedge

• The dielectric wedge has 3 zones
• 1 Incident Plane Wave
• 2 ISB Incident Shadow Boundary
• 3 Reflected Plane Wave

Magnitude of diffraction field
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UTD Equation
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Comparison Between the MATLAB simulation and the
book figure
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Animation of Matt and Tuan taking Diffraction
Measurements
Animation of Matt and Tuan taking Diffraction
Measurements
Cabot
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MATLAB Simulation
Cabot
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Future Work

• Create a method for automatically finding corners
  in the floor plan file that would be used to
  diffract rays.

Building
Tx
Rx
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Radio Channel Measurements

• Indoor to Outdoor, Diffracting around corner, and
  the Upper Parade Ground
• UP Floor Plan File for Ray Tracing
• Verifying Ray Tracing Program and Diffraction
  Program

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Measurement Hardware Software
Net Stumbler 4.0 - signal strength (Graphical
Numerical) - signal to noise ratios

• IEEE 802.11a 5.4 GHz Wireless LAN

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Indoor MeasurementFree Space Propagation

• Partridge Hall
• - Every five meters
• - Theoretical received power (Red Line)
• Actual power received (Blue Stars)

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Outside Measurement
Free Space Propagation - Outdoors in open area -
Every five meters

• Diffraction Propagation
• Around the corner of the Goodyear Hall
• - Hugh power lost from diffraction
• - Greater loss at steeper angles

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Floor Plan Files for the UP

• - Record the X, Y, Z coordinates for every corner
  of each building
• Enter the data into the floor plan file (UP.flp)
• Use MATLAB to plot the image above

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Maximum Free Space Propagation

• The transmitter (AP) is at Goodyear Hall
• The receiver (RX) moves toward Jackman Hall
• Total of 245 meters

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DIFFRACTION MEASUREMENTS

• Diffracting around Cabot 085
• Use diffraction program to check the validity of
  the software
• The data shows the signal strength decreasing

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RECEIVING SIGNAL FROM INSIDE

• Setup the transmitter (AP) inside the building
• Moved the laptop to several locations outside
• Stronger signal strength if receiver is right in
  front of the transmitter
• The transmitter sends signals through walls and
  doors

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RECEIVING OUTSIDE SIGNAL

• Setup the transmitter on the upper parade ground
• Typical location for doing inside and outside
  measurements
• Receiver is at the front door of every building

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Results for the Measurements on the Upper Parade
Ground

• There is low signal strength enter into each
  building
• The receiver is inside and far away from the
  transmitter
• The signal strength is produced by 1 transmitter
• Imagine if there are 3, 6, or 9 transmitters
  having the same frequency
• The receiving signal strength for the receiver
  inside the building will be higher

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Final Conclusions

• Speed up the processing by a factor of 1000 is
  possible.
• A Diffraction formula was found and implemented
• The measurement results show that it is possible
  to deploy a wireless LAN on the Upper Parade
  ground

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Questions or Comments