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Optical Wireless Communication Based Indoor Positioning Algorithms: Performance Optimisation and Mathematical Modelling
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Computation 2019, 7(1), 7;

Optical Boundaries for LED-Based Indoor Positioning System

School of Engineering and Built Environment, Glasgow Caledonian University, Glasgow G4 0BA, UK
Institute for Digital Communications, University of Edinburgh, Edinburgh EH9 3JL, UK
Author to whom correspondence should be addressed.
Received: 17 December 2018 / Revised: 5 January 2019 / Accepted: 9 January 2019 / Published: 14 January 2019
(This article belongs to the Special Issue Optical Wireless Communication Systems)
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Overlap of footprints of light emitting diodes (LEDs) increases the positioning accuracy of wearable LED indoor positioning systems (IPS) but such an approach assumes that the footprint boundaries are defined. In this work, we develop a mathematical model for defining the footprint boundaries of an LED in terms of a threshold angle instead of the conventional half or full angle. To show the effect of the threshold angle, we compare how overlaps and receiver tilts affect the performance of an LED-based IPS when the optical boundary is defined at the threshold angle and at the full angle. Using experimental measurements, simulations, and theoretical analysis, the effect of the defined threshold angle is estimated. The results show that the positional time when using the newly defined threshold angle is 12 times shorter than the time when the full angle is used. When the effect of tilt is considered, the threshold angle time is 22 times shorter than the full angle positioning time. Regarding accuracy, it is shown in this work that a positioning error as low as 230 mm can be obtained. Consequently, while the IPS gives a very low positioning error, a defined threshold angle reduces delays in an overlap-based LED IPS. View Full-Text
Keywords: light emitting diodes; indoor localization; optical wireless communications; optical boundary; packet delivery ratio; infrared protocols; overlap light emitting diodes; indoor localization; optical wireless communications; optical boundary; packet delivery ratio; infrared protocols; overlap

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Popoola, O.R.; Sinanović, S.; Popoola, W.O.; Ramirez-Iniguez, R. Optical Boundaries for LED-Based Indoor Positioning System. Computation 2019, 7, 7.

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