The WatchMe Project

1
The WatchMe Project

• Presented by
• Elad Weiss
• Nir Maoz
• Supervised by
• Edward Bortnikov

2
Problem Description

• What is "WatchMe?

3
Location Awareness
You Are Here
Until today
?
4
Location Awareness
You Are Here
Until today
The WatchMe way
And Going Home
?
5
Project Goals
1. A Server-Client Application
2. Static Location Recognition
3. Dynamic Location Recognition
4. Implementation Over SIP
6
Implementation

• Algorithms System Operation

7
Location Pinpointing

• Figuring out your location
• Get the strengths of the access points signals.
• Calculate the distance to each access point.
• Use the triangulation technique to find your
  true location using as many access points as
  possible.

8
Location Pinpointing cont.

• A plot of real signal strengths and their
  corresponding distances from the access point.

9
Location Pinpointing cont.

• A plot of real signal strengths and their
  corresponding distances from the access point.
• We used the equation from another project, and
  changed the constant multiplying the exponent, to
  a function of the signal strength (determined by
  many tests measurements).
• This was later realized to be very much like a
  polynomial curve fit, as shown above.

10
Path Recognition
0
20
40
60
Path Completion Percentage
50
Path Required Activation Percentage
Path X is now active. Your status is X.
11
And for your friends
12
Communication
Server Communication Handler
Client Communication Handler
RTC
SIP
13
Communication cont.
SIP messages content ? in XML!
ltxmlgt ltlocation x5 y4 z3
mapfloor3.jpg /gt lt/xmlgt
ltxmlgt ltheadergtREMOVE_STATUSlt/headergt ltstatus
nameX /gt lt/xmlgt
ltxmlgt ltheadergtADD_STATUSlt/headergt ltstatus
nameX /gt ltpointgt ltsignal ap00-02-2D-08-02
str-50 /gt ltsignal ap00-02-2D-08-61
str-70 /gt ltsignal ap00-02-2D-08-AA
str-60 /gt lt/pointgt ltpointgt ltsignal
ap00-02-2D- ltsignal ap
14
Server structure
Server Communication Handler
Server Data
SQL
Synchronized
Database
15
Call Flow
Thread Assignment
Work Queue
Request 1 SIP method WatchMe header
Server Communication Handler
Request 1
Request 2
Request 3

SIP Request
Request n
Server Application Xrunning on theassigned
thread
16
The Development Process

• Difficulties Solutions

17
Difficulties

• The RTC client implements the SIMPLE protocol,
  which has not been officially published yet.
• Documentation is poor.
• There is no standard for the specifications.
• Some examples
• Offline (SIMPLE) Away (RTC)
• RTC sends SIP MESSAGE requests through a
  session.In SIMPLE, these SIP requests are not
  bound to a session.
• Some headers are critical for RTC to work, but
  RTC seems to forget sending them himself.
• Solution
• Trial Error.
• Some more Trial Error.

18
Difficulties cont.

• The RTC Client doesnt run on an iPAQ.
• Solution
• Switching to a laptop.

19
Difficulties cont.

• Wireless signal detection
• Packages only available for Windows CE and Java.
• There exists a Win32 C package that uses a
  method, which wont be supported in the future.
• Solution
• Writing our own package (WirelessNet.dll).
• We used WMI for accessing the driver.
• Microsoft encourages the use of WMI over other
  methods such as device IOCTL (which we had
  tried).

20
The Development Process

• Conclusions Acknowledgements

21
Accomplishments

• What weve learned
• Dealing with new environmentsiPAQs / Laptops
  with wireless adapters.
• Programming close to the driver level (this was
  not planned).
• New communication protocols
• SIP, SIMPLE (RTC).
• New MIME formats
• XML, SDP, PIDF.
• Programming in various environments and
  languages
• .NET Framework.
• Java
• C
• SQL
• Working with several packages
• JAIN-SIP, RTC, OpenNetCF (though we did not use
  it eventually).

22
Remaining Problems

• The use of signal amplitudes (a.k.a. RSSI) for
  distance determination is highly inaccurate.
• Some interfering factors are
• Background noise.
• Obstacles (such as walls, doors etc).
• Angle confronting the AP.
• Each NIC has its own accuracy.

23
Proposals for the Future

• AM is known to be more prone to interference and
  distortion.
• Possible solutions
• Arranging the APs in such a way, as to get a
  better signal from as many APs as possible.
• A GPS guided laptop, would make the program much
  more realistic, improving the accuracy of
  location path recognition to a great degree.
• Adding a third dimension could help improve
  location determination by a small factor.

24
Proposals for the Future cont.

• iPAQ issues
• WinXP ? WinCE will require the client program to
  use a different GUI, since the one already
  employed, uses a lot of WinXP features, not to be
  found in WinCE.
• The benefit, of course, will be the increased
  mobility.
• Signal detection should be easy to convert since
  WinCE allows you to use OpenNETCFs wireless
  interface.

25
Software We Used

• Microsoft Visual Studio.NET 2003
• Eclipse
• Microsoft Office Visio 2003
• Microsoft PowerPoint 2003
• Microsoft Word 2003
• Adobe Photoshop 7.0
• Notepad

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Related Links

• http//msdn.microsoft.com/ - RTC
• https//jain-sip.dev.java.net/ - JAIN SIP
• http//www.ietf.org/ - RFCs, documents
• http//www.faqs.org/rfcs/rfc3261.html - The SIP
  Protocol
• http//www.microsoft.com/whdc/devtools/ddk/default
  .mspx - DDK
• http//www.google.com/ - Google

27
Acknowledgements

• We would like to thank
• Victor Kulikov
• Yoram Yihyie, Hai Vortman
• Yoel Davidson
• Orit Shteif
• Palram Industries