The advancement in white light-emitting diodes (LEDs) technology makes it the most preferred highly efficient lighting solution. Not only LEDs consume less energy and reduce carbon emissions, but also their average life expectancy is above 10 years, i.e., 50,000 h. Achieving more than 75% of energy savings has encouraged the widespread use of LEDs for indoor and outdoor applications, as well. As a consequence of the huge investments in the LED-based lighting industry, another emerging technology has grown, which is visible light communications (VLC). For instance, LEDs can switch to various light intensity levels at an extremely fast rate, i.e., imperceivable by a human eye, which allows data to be modulated through light, enabling wireless communications [1]. Recent research discusses how LEDs can be used for communication, positioning, and sensing [2]. Adopting VLC enables the use of an ultrawide range of unregulated visible light, offering 10,000 times more bandwidth capacity than radio frequency (RF)-based technologies. Rates of over 10 Gbps have already been demonstrated using LEDs, and an enticing rate of 100 Gbps was reported using laser diodes [3]. This chapter discusses state-of-the-art VLC modulation techniques, potential indoor scenarios, and associated challenges. In the first section, advancements in modulation schemes that are compatible with illumination requirements are highlighted. Such schemes enable the simultaneous offering of multiple wireless services, including communication, sensing, and security, and will even promote more efficient VLC systems. Then, this chapter discusses the possibility of coexisting VLC with RF technologies, followed by recent advancements inVLC-based multiple-input and multiple-output (MIMO) techniques. Finally, the potential of applying deep learning (DL) algorithms to improve the performance of VLC systems is investigated.

Chapter Contents:

• 14.1 Introduction
• 14.2 Novel modulation techniques
• 14.2.1 Mixed-carrier communications
• 14.2.1.1 Binary-level transmission
• 14.2.1.2 Multilevel transmission
• 14.2.1.3 Frame structure
• 14.2.1.4 Spectrum management and interference analysis
• 14.2.1.5 Performance and discussion
• 14.2.2 Lightweight MCC
• 14.2.2.1 FFT-less concept
• 14.2.2.2 Performance evaluation
• 14.3 State-of-the-art VLC topics
• 14.3.1 Security of coexistence with RF technologies
• 14.3.1.1 OFDM inVLC
• 14.3.1.2 SA-OFDM transmission
• 14.3.1.3 SA-OFDM reception
• 14.3.1.4 SA-OFDM performance
• 14.3.2 Augmented MIMO in VLC
• 14.3.2.1 ASM system model
• 14.3.2.2 ASM performance evaluation
• 14.3.3 Deep learning in VLC
• 14.3.3.1 Background
• 14.3.3.2 Autoencoder OFDM-based VLC system
• 14.3.3.3 Autoencoder-based optical camera communications
• 14.4 Conclusion
• References

Inspec keywords: light emitting diodes; lighting; optical modulation; energy conservation; optical communication

Other keywords: radio frequency-based technologies; visible light communications; wireless communications; light intensity levels; extremely fast rate; indoor applications; 000 times more bandwidth capacity; state-of-the-art VLC; unregulated visible light; average life expectancy; preferred highly efficient lighting solution; energy savings; energy-efficient illumination; white light-emitting diodes; bandwidth capacity; efficient VLC systems; RF technologies; green communications

Subjects: Radio links and equipment; Modulation and coding methods; Optical communication; Reliability; Optical communication; Other topics in statistics; Light emitting diodes; Optical beam modulators; Lighting