Academic literature on the topic 'Visible light wireless communications'

Visible light communication (VLC) allows the dual use of light-emitting diodes (LEDs) for wireless communication purposes in addition to their primary purpose of illumination. As in any other communication system, realistic channel modelling is a key for VLC system design, analysis and testing. In this paper, we present a comprehensive survey of indoor VLC channel models. In order to set the background, we start with an overview of infrared (IR) channel modelling, which has received much attention in the past, and highlight the differences between visible and IR optical bands. In the light of these, we present a comparative discussion of existing VLC channel modelling studies and point out the relevant advantages and disadvantages. Then, we provide a detailed description of a site-specific channel modelling approach based on non-sequential ray tracing that precisely captures the optical propagation characteristics of a given indoor environment. We further present channel models for representative deployment scenarios developed through this approach that were adopted by the Institute of Electrical and Electronics Engineering (IEEE) as reference channel models. Finally, we consider mobile VLC scenarios and investigate the effect of receiver location and rotation for a mobile indoor user. This article is part of the theme issue ‘Optical wireless communication’.

Visible Light Communication (VLC) using a Light Fidelity system, as proposed by a German physicist—Harald Haas, provides transmission of data through illumination by sending data through an LED light source that varies in intensity that can be controlled and adjusted such that it appears as normal light to the naked human eye. Here the property of persistence of vision of the human eye is exploited for additional application of a free, sustainable and green source that can be used for wireless communication at very fast data rates. This paper focuses on developing a low cost Li-Fi based system and analyses its performance with respect to existing wireless technology. Wi-Fi is great for general wireless coverage within buildings, whereas Li-Fi is ideal for high density wireless data coverage in confined area and for relieving radio interference issues. Li-Fi based system provides better bandwidth, efficiency, availability and security than Wi-Fi and has already achieved higher data rates. By leveraging the low-cost nature of LEDs and lighting units there are many opportunities to exploit this medium, from public internet access through day-to-day light sources which have their primary purpose of only emitting light. This project envisions a future where data for communication devices will be transmitted through the visible spectrum thus de-clogging the currently overused RF spectrum.

Abstract In this conceptual paper, we discuss the concept of hospital of the future (HoF) and the requirements for its wireless connectivity. The HoF will be mostly wireless, connecting patients, healthcare professionals, sensors, computers and medical devices. Spaces of the HoF are first characterized in terms of communicational performance requirements. In order to fulfil the stringent requirements of future healthcare scenarios, such as enhanced performance, security, safety, privacy, and spectrum usage, we propose a flexible hybrid optical-radio wireless network to provide efficient, high-performance wireless connectivity for the HoF. We introduce the concept of connected HoF exploiting reconfigurable hybrid optical-radio networks. Such a network can be dynamically reconfigured to transmit and receive optical, radio or both signals, depending on the requirements of the application. We envisage that HoF will consist of numerous communication devices and hybrid optical-radio access points to transmit data using radio waves and visible light. Light-based communications exploit the idea of visible light communications (VLC), where solid-state luminaries, white light-emitting diodes (LEDs) provide both room illumination as well as optical wireless communications (OWC). The hybrid radio-optical communication system can be used in principle in every scenario of the HoF. In addition to the hybrid access, we also propose a reconfigurable optical-radio communications wireless body area network (WBAN), extending the conventional WBAN to more generic and highly flexible solution. As the radio spectrum is becoming more and more congested, hybrid wireless network approach is an attractive solution to use the spectrum more efficiently. The concept of HoF aims at enhancing healthcare while using hospital resources efficiently. The enormous surge in novel communication technologies such as internet of things (IoT) sensors and wireless medical communications devices could be undermined by spectral congestion, security, safety and privacy issues of radio networks. The considered solution, combining optical and radio transmission network could increase spectral efficiency, enhancing privacy while reducing patient exposure to radio frequency (RF). Parallel radio-optical communications can enhance reliability and security. We also discuss possible operation scenarios and applications that can be introduced in HoF as well as outline potential challenges.