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Anonymous Localization of Wireless Terminals in Indoors. Shahrokh Valaee Wireless and Internet Research Lab (WIRLab) Dept of Electrical and Computer Engineering University of Toronto www.comm.utoronto.ca/~valaee
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Anonymous Localization of Wireless Terminals in Indoors Shahrokh Valaee Wireless and Internet Research Lab (WIRLab) Dept of Electrical and Computer Engineering University of Toronto www.comm.utoronto.ca/~valaee Joint work with Chen Feng, Anthea Au, Moshe Eizenman, Sameh Sorour, Sophia Reyes, Sam Markowitz, Deborah Gold, Keith Gordon
Indoor Navigation Opportunistic Localization Workshop - May 2012 [Valaee]
Objective To design an accurate indoor navigation system that can be easily deployed on commercially available mobile deviceswithout any hardware modification. Opportunistic Localization Workshop - May 2012 [Valaee]
Localization Off-line measurements (site survey) On-line localization Coarse localization Fine localization
Motivation Regulations: E911 precision Commercial: shopping mall advertisement Assistive: visually challenged Opportunistic Localization Workshop - May 2012 [Valaee]
Where Am I? Opportunistic Localization Workshop - May 2012 [Valaee]
Fingerprinting Collect fingerprints and store Measure and compare What about privacy? Opportunistic Localization Workshop - May 2012 [Valaee]
Received Signal Strength (RSS) ? Opportunistic Localization Workshop - May 2012 [Valaee]
Fingerprinting • Collect fingerprints by measuring the power from access points • Store the results in a location server • The user: • Fetches fingerprints from the server • Measures the received power from available access points • Compares the measured power with the fingerprints Privacy observed Opportunistic Localization Workshop - May 2012 [Valaee]
Looking for a systematic solution Compressive Sensing A newly developed theory in signal processing for sampling and reconstruction of sparse signals. Opportunistic Localization Workshop - May 2012 [Valaee]
Localization Block Diagram • Two phases: • Offline Phase • Online Phase Opportunistic Localization Workshop - May 2012 [Valaee]
Offline Phase Measure RSS from multiple AP and store the average and variance in the server Opportunistic Localization Workshop - May 2012 [Valaee]
Clustering of Fingerprints • Adjacent points have similar RSS readings • An exemplar can act as a representative for the cluster • Clustering reduces computational complexity • Clustering removes outliers Opportunistic Localization Workshop - May 2012 [Valaee]
Online Phase Retrieve fingerprints from the server Measure the RSS Compare to the fingerprints in two steps Coarse localization Fine localization Opportunistic Localization Workshop - May 2012 [Valaee]
Localization Steps • Coarse Localization • Find the clusters to which I belong • Fine Localization • Locate me inside the clusters Opportunistic Localization Workshop - May 2012 [Valaee]
Anonymous Localization • Localization should be done on the mobile unit • Simple localization algorithm deployable on cellphones • Possibly a three-way solution Two different IDs service Authentication Opportunistic Localization Workshop - May 2012 [Valaee]
Indoor Navigation System Skip the details
Implementation and Field Tests Opportunistic Localization Workshop - May 2012 [Valaee]
Implementation Buildings 4th floor of Bahen Center, University of Toronto Canadian National Institute for Blind (CNIB) Bayview Village Shopping Mall (North Toronto) 440,000 square feet, 110 stores Device Windows Mobile Platform PDA (HP iPAQ windows mobile 2003 pocket PC) Samsung Omnia II smartphone Android Platform HTC Opportunistic Localization Workshop - May 2012 [Valaee]
Test Results (Clustering) Opportunistic Localization Workshop - May 2012 [Valaee]
Localization Error with Tracking Opportunistic Localization Workshop - May 2012 [Valaee]
CDF of Error Opportunistic Localization Workshop - May 2012 [Valaee]
Testing stage- Omnia II Opportunistic Localization Workshop - May 2012 [Valaee]
Testing stage • 30 Subjects • 15 testing group • 15 control group • 3 tests for each subject Opportunistic Localization Workshop - May 2012 [Valaee]
Comparison between 2 groups Opportunistic Localization Workshop - May 2012 [Valaee]
Comparison between 2 groups Opportunistic Localization Workshop - May 2012 [Valaee]
Comparison between 2 groups Opportunistic Localization Workshop - May 2012 [Valaee]
Comparison between 2 groups Opportunistic Localization Workshop - May 2012 [Valaee]
Bayview Village Shopping Center Opportunistic Localization Workshop - May 2012 [Valaee]
Result (positioning system in BV) Opportunistic Localization Workshop - May 2012 [Valaee]
Conclusion • A localization scheme for indoor environment using RSS, Compressive Sensing and Affinity Propagation has been proposed • Localization is done in two steps: coarse localization and fine localization • The solution has been implemented and tested in real environment and used for localization, navigation, and object finding • Since localization is done on the mobile, privacy is satisfied.