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Location Service for Mobile Device. New Ideas Increasing proliferation of 802.11 base stations and PC card use 802.11 wireless LAN infrastructure to determine mobile device location inside building - PowerPoint PPT Presentation
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A CS395T Course Project MobileComputing &
WirelessNetworks
Spring 2002C
ourse
we
b site
: http://w
ww
.cs.ute
xas.e
du
/use
rs/ygz/39
5T
-02
S • In
structor: D
r. Yon
gg
uan
g Z
han
g (yg
z@cs.u
texa
s.ed
u)
Key Design/Approach Data collation: mapping the service area in
advance for an accurate signal map Algorithm 1: best matching: O(n2) Algorithm 2: multidimensional search
O(log(n)) GUI (see above)
New Ideas Increasing proliferation of 802.11 base
stations and PC card use 802.11 wireless LAN infrastructure to determine mobile device location inside building
Signal strength can be measured and there is a correlation between signal strength and distance
Signal strengths from multiple base stations can triangulate the exact location
Location Service for Mobile Device
Results/Lesson Learned Implemented in Linux Tested in ACES 6th floor
–Beacon stations: 2–Service granularity: 10 feet
Accuracy: 90% of the time: within 15 feet Lesson learned:
–802.11 Linux driver does not support “promiscuous” mode to pick up beacons from multiple basestations
–Resolved to ad-hoc mode
Project team: Ravishankar Chamarajnagar, Jeff NapperURL: http://www.cs.utexas.edu/users/ravshank/mobile_project/project.html
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