On Optimizing VLC Networks for Downlink Multi-User Transmission: A Survey

TL;DR

This survey reviews recent advancements, challenges, and future directions in optimizing visible light communication (VLC) networks for efficient multi-user downlink transmission, emphasizing resource allocation, security, and energy harvesting.

Contribution

It provides a comprehensive overview of VLC network optimization techniques, including resource management, user association, NOMA, energy harvesting, and security, highlighting open research problems.

Findings

VLC can potentially replace or complement RF networks for high data rate services.

Optimization techniques like resource allocation and user association improve VLC network performance.

Identified key challenges and open problems for future VLC network development.

Abstract

The evolving explosion in high data rate services and applications will soon require the use of untapped, abundant unregulated spectrum of the visible light for communications to adequately meet the demands of the fifth-generation (5G) mobile technologies. Radio-frequency (RF) networks are proving to be scarce to cover the escalation in data rate services. Visible light communication (VLC) has emerged as a great potential solution, either in replacement of, or complement to, existing RF networks, to support the projected traffic demands. Despite of the prolific advantages of VLC networks, VLC faces many challenges that must be resolved in the near future to achieve a full standardization and to be integrated to future wireless systems. Here, we review the new, emerging research in the field of VLC networks and lay out the challenges, technological solutions, and future work predictions. Specifically, we first review the VLC channel capacity derivation, discuss the performance metrics and the associated variables; the optimization of VLC networks are also discussed, including resources and power allocation techniques, user-to-access point (AP) association and APs-to-clustered-users-association, APs coordination techniques, non-orthogonal multiple access (NOMA) VLC networks, simultaneous energy harvesting and information transmission using the visible light, and the security issue in VLC networks. Finally, we propose several open research problems to optimize the various VLC networks by maximizing either the sum rate, fairness, energy efficiency, secrecy rate, or harvested energy.