New Cloud-Based Service for Broadcasting and Identification for Solving Data Traffic Re-Using for Mobile Communications

In recent decades, the majority of mobile communications data traffic has relied on RF technology. Even if optimization efficiency for use or reuse is implemented, there are limits to the growing traffic demand for RF communications. Visible light communications (VLC) is a new technology that can work with RF to overcome these limitations. The standard for VLC was published in 2011 as IEEE 802.15.7, which specifies specifications for the MAC layer and PHY layer. This standard is one of the first for this technology. The light emission decoding operation at the receiver in IEEE 802.15.7 is mainly based on photo detectors. However, with the development of image sensors (photodiode arrays) in smart devices, changes to the IEEE 802.15.7 specification are being considered. This expansion will primarily focus on communications with image sensors, called optical camera communications (OCC). In this paper, we analyze the performance of camera communication systems based on different types of image sensor architectures. We then propose OCC-ID, a novel streaming service application that uses camera communication and a cloud model. The proposed architecture is a general implementation scenario for camera communications. Optical camera communication has great potential in future wireless communications due to the advantages of VLC and business trends. A revision of the IEEE 802.17.5 standard is currently under study. However, OCC's issues regarding timing, data rate, and interference still need to be resolved. Synchronization is an important issue because the signal received from the camera is a discrete image from the transmitter without any feedback information and because camera communication applications are based on a transmission topology. Roller blinds have more advantages in terms of timing than overall blinds. In this study, we present and evaluate the performance of two image detection techniques, namely rolling shutter and global shutter. The performance of the two image sensors and their considerations will play an important role in the standard's contribution. Finally, we propose a new service application for OCC based on cloud architecture, called OCC-ID. Invisible identification can be accomplished using visible light communications, camera communications, and cloud computing technology. The ID is integrated into the optical channel using OOK or OOK frequency shift modulation. The receiver uses the camera to decode the information embedded in the LED and then transmits it to the cloud server transmission link based on the detected ID. The OCC-ID system shows the advantages of dynamic content management compared to traditional identification systems

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

Optically gated beating-heart imaging

The constant motion of the beating heart presents an obstacle to clear optical imaging, especially 3D imaging, in small animals where direct optical imaging would otherwise be possible. Gating techniques exploit the periodic motion of the heart to computationally "freeze" this movement and overcome motion artefacts. Optically gated imaging represents a recent development of this, where image analysis is used to synchronize acquisition with the heartbeat in a completely non-invasive manner. This article will explain the concept of optical gating, discuss a range of different implementation strategies and their strengths and weaknesses. Finally we will illustrate the usefulness of the technique by discussing applications where optical gating has facilitated novel biological findings by allowing 3D in vivo imaging of cardiac myocytes in their natural environment of the beating heart

Fast Characterization of Dispersion and Dispersion Slope of Optical Fiber Links using Spectral Interferometry with Frequency Combs

We demonstrate fast characterization (~1.4 microseconds) of both the dispersion and dispersion slope of long optical fiber links (~25 km) using dual quadrature spectral interferometry with an optical frequency comb. Compared to previous spectral interferometry experiments limited to fiber lengths of meters, the long coherence length and the periodic delay properties of frequency combs, coupled with fast data acquisition, enable spectral interferometric characterization of fibers longer by several orders of magnitude. We expect that our method will be useful to recently proposed lightwave techniques like coherent WDM and to coherent modulation formats by providing a real time monitoring capability for the link dispersion. Another area of application would be in stabilization of systems which perform frequency and timing distribution over long fiber links using stabilized optical frequency combs.Comment: 3 pages, 3 figures, Minor changes to tex

Feedforward data-aided phase noise estimation from a DCT basis expansion

This contribution deals with phase noise estimation from pilot symbols. The phase noise process is approximated by an expansion of discrete cosine transform (DCT) basis functions containing only a few terms. We propose a feedforward algorithm that estimates the DCT coefficients without requiring detailed knowledge about the phase noise statistics. We demonstrate that the resulting (linearized) mean-square phase estimation error consists of two contributions: a contribution from the additive noise, that equals the Cramer-Rao lower bound, and a noise independent contribution, that results front the phase noise modeling error. We investigate the effect of the symbol sequence length, the pilot symbol positions, the number of pilot symbols, and the number of estimated DCT coefficients it the estimation accuracy and on the corresponding bit error rate (PER). We propose a pilot symbol configuration allowing to estimate any number of DCT coefficients not exceeding the number of pilot Symbols, providing a considerable Performance improvement as compared to other pilot symbol configurations. For large block sizes, the DCT-based estimation algorithm substantially outperforms algorithms that estimate only the time-average or the linear trend of the carrier phase. Copyright (C) 2009 J. Bhatti and M. Moeneclaey