29,397 research outputs found
A Survey of Positioning Systems Using Visible LED Lights
© 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.As Global Positioning System (GPS) cannot provide satisfying performance in indoor environments, indoor positioning technology, which utilizes indoor wireless signals instead of GPS signals, has grown rapidly in recent years. Meanwhile, visible light communication (VLC) using light devices such as light emitting diodes (LEDs) has been deemed to be a promising candidate in the heterogeneous wireless networks that may collaborate with radio frequencies (RF) wireless networks. In particular, light-fidelity has a great potential for deployment in future indoor environments because of its high throughput and security advantages. This paper provides a comprehensive study of a novel positioning technology based on visible white LED lights, which has attracted much attention from both academia and industry. The essential characteristics and principles of this system are deeply discussed, and relevant positioning algorithms and designs are classified and elaborated. This paper undertakes a thorough investigation into current LED-based indoor positioning systems and compares their performance through many aspects, such as test environment, accuracy, and cost. It presents indoor hybrid positioning systems among VLC and other systems (e.g., inertial sensors and RF systems). We also review and classify outdoor VLC positioning applications for the first time. Finally, this paper surveys major advances as well as open issues, challenges, and future research directions in VLC positioning systems.Peer reviewe
Experimental Demonstration of Staggered CAP Modulation for Low Bandwidth Red-Emitting Polymer-LED based Visible Light Communications
In this paper we experimentally demonstrate, for the first time, staggered
carrier-less amplitude and phase (sCAP) modulation for visible light
communication systems based on polymer light-emitting diodes emitting at ~639
nm. The key advantage offered by sCAP in comparison to conventional multiband
CAP is its full use of the available spectrum. In this work, we compare sCAP,
which utilises four orthogonal filters to generate the signal, with a
conventional 4-band multi-CAP system and on-off keying (OOK). We transmit each
modulation format with equal energy and present a record un-coded transmission
speed of ~6 Mb/s. This represents gains of 25% and 65% over the achievable rate
using 4-CAP and OOK, respectively.Comment: 6 pages, 9 figures, IEEE ICC 2019 conferenc
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