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Please use this identifier to cite or link to this item: http://hdl.handle.net/1807/17260

Title: A Cognitive Radio Tracking System for Indoor Environments
Authors: Kushki, Azadeh
Advisor: Plataniotis, Konstantinos N.
Venetsanopoulos, Anastasios N.
Department: Electrical and Computer Engineering
Keywords: Positioning
Localization
Location determination
Geolocation
WLAN Positioning
Fingerprinting
Nonparametric Information Filter
Cognitive Dynamic System
Location-based services
Received signal strength
Issue Date: 26-Feb-2009
Abstract: Advances in wireless communication have enabled mobility of personal computing services equipped with sensing and computing capabilities. This has motivated the development of location-based services (LBS) that are implemented on top of existing communication infrastructures to cater to changing user contexts. To enable and support the delivery of LBS, accurate, reliable, and realtime user location information is needed. This thesis introduces a cognitive dynamic system for tracking the position of mobile users using received signal strength (RSS) in Wireless Local Area Networks (WLAN). The main challenge in WLAN positioning is the unpredictable nature of the RSS-position relationship. Existing system rely on a set of training samples collected at a set of anchor points with known positions in the environment to characterize this relationship. The first contribution of this thesis is the use of nonparametric kernel density estimation for minimum mean square error positioning using the RSS training data. This formulation enables the rigorous study of state-space filtering in the context of WLAN positioning. The outcome is the Nonparametric Information (NI) filter, a novel recursive position estimator that incorporates both RSS measurements and a dynamic model of pedestrian motion during estimation. In contrast to traditional Kalman filtering approaches, the NI filter does not require the explicit knowledge of RSS-position relationship and is therefore well-suited for the WLAN positioning problem. The use of the dynamic motion model by the NI filter leads to the design of a cognitive dynamic tracking system. This design harnesses the benefits of feedback and position predictions from the filter to guide the selection of anchor points and radio sensors used during estimation. Experimental results using real measurement from an office environment demonstrate the effectiveness of proactive determination of sensing and estimation parameters in mitigating difficulties that arise due to the unpredictable nature of the indoor radio environment. In particular, the results indicate that the proposed cognitive design achieves an improvement of 3.19m (56\%) in positioning error relative to memoryless positioning alone.
URI: http://hdl.handle.net/1807/17260
Appears in Collections:Doctoral
The Edward S. Rogers Sr. Department of Electrical & Computer Engineering - Doctoral theses

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