Visible-light communications and light fidelity

Haas, Harald and Sarbazi, Elham and Marshoud, Hanaa and Fakidis, John; Willner, Alan E., ed. (2019) Visible-light communications and light fidelity. In: Optical Fiber Telecommunications VII. Academic Press, London, pp. 443-493. ISBN 9780128165027

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This chapter starts by explaining the significantly increased interest in visible-light communications (VLC) and light fidelity (LiFi) during the last 10 years. Next, a taxonomy of the various optical wireless communications technologies is provided, and we discuss their key discriminating features. Typical applications for each technology are presented. The important element of the optical wireless propagation channel is discussed in detail. The essential differences to radio-frequency-based wireless communications are highlighted, and we discuss what these differences mean in terms of designing VLC and LiFi systems. The detailed knowledge of the channel allows for an efficient design of the analog optical front ends; thus, various source and receiver technologies are introduced including micro-light-emitting diodes as transmitters, and single-photon avalanche diodes and photovoltaic cells as data receivers. Next, a review of recent advances in digital modulation techniques for intensity modulation/direct detection for single-input single-output channels is provided. The chapter then discusses multichannel data transmission by considering spatial and wavelength domains. The ability to serve randomly moving mobile terminals is a key property of LiFi. The last two sections, therefore, introduce key functions that will enable this. In this context, the latest advancements in multiple access such as nonorthogonal multiuser access are reviewed. The methods to mitigate cochannel interference when multiple closely located light sources transmit different signals to different users are reviewed, along with methods to enable seamless services when users roam through a room or inside a building. The last section summarizes this chapter.


Haas, Harald, Sarbazi, Elham, Marshoud, Hanaa and Fakidis, John ORCID logoORCID:; Willner, Alan E.