WiFi Usability

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WiFi Usability

• Reg Arvidson

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Idea

• Track signal variances throughout the day
• Get a feel for the usability of a WiFi access
  point (or location)
• Present this as a map to easily spot lagging
  areas

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Implementation

• Create a client program to collect WiFi/GPS data
  and submit to a server
• Server catalogues data into a database while
  waiting to serve map requests
• Clients can request a map from the server showing
  WiFi data for GPS points

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High-Level Architectural View
Client
Server
GPS
WiFi
GPS/WiFi Data
Map!
If it was only that easy
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Client View (Data Collection)
COM_Access
GPS Serial Data
GPS_Parser
WiFiGPSDataUnit
cURL
Internet
WLAN_Access
WiFi Signal Data
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Server View (Data Collection)
Internet
Apache Web Server
postdata.php
MySQL Database
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Server View (Data Service)
Internet
Apache Web Server
index.php
MySQL Database
testdisp.php
kml.kml
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Client View (Data Service)
Your favorite web browser! http//shyguy2.mine.nu
Or Google Earth http//shyguy2.mine.nu/kml.kml
Internet
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Data Collection

• Flag a GPS fix if at least 3 satellites in view
• Utilize fix data to time 5 second intervals
• If fix, poll WiFi interface for access points
• Tag SSID and signal strength to GPS fix
• If internet available, submit data, else store
  for later!
• Runs in background, works even when using any
  access point or the Internet

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cURL Library

• Created a URL to pass data to PHP script
• http//shyguy2.mine.nu/postdata.php?datetime1234
  lon-84.5675lat23.4326ssidUCFsig23...
• cURL library allows easy usage of GET
• If GET fails then we leave data in buffer and try
  again later

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Data Buffering

• A cURL failed GET leaves data in a buffer
• Allows roaming off the network, across town,
  local pub, etc
• Upon reconnecting with friendly access point will
  push data to server

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Displaying Mapped Data

• Going to homepage, index.php, triggers creation
  of KML file, kml.kml through use of testdisp.php,
  with all collected data from MySQL database
• Automatically loads map using this freshly
  created KML file
• Mapped data shows signal strength of SSID tagged
  to a GPS point, marker colors reflect signal
  strength
• Can also load KML into Google Earth for a much
  more interactive view

13
Problems

• Laptop Died
• Created new database
• Recovery of project files
• Rebuilt for new target machines
• Recollection of data
• Lack of data (due to stated death)

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Improvements

• Can easily add additional data in minutes
• Security algorithm (if used), for example
• Better data transfer method
• Direct connection to SQL server for instance
• DATA DATA DATA DATA DATA

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Questions?

• ?