Advanced techniques for enhancing performance in visible light communication systems

Abstract

With the increase in high-speed-data demand for the upcoming fifth generation (5G) and beyond communication systems visible light communications (VLC) has emerged as a low-cost, green, and secure technology complementary to the currently congested traditional radio frequency (RF) communications owing to its wide license-free spectrum. In VLC, data transmission is achieved by modulating the intensity of light emitted from light-emitting diodes (LEDs). Using LEDs as transmitters, VLC enables simultaneous data communication and illumination. Despite VLC’s promise as a viable supplement to RF-based communication systems, the performance of a VLC system is significantly limited by several factors, such as: (a) multiplicative fading distortion due to user mobility and multipath between receiver and transmitter, (b) nonlinear characteristics of an LED, (c) presence of thermal and ambient noise, (d) absence of a direct link, and (e) limited coverage as visible light can not penetrate obstacles and is reflected back due to the high penetration loss. Moreover, the illumination requirements of LEDs pose a challenge to the practical deployment of VLC. The aforementioned VLC channel impairments significantly degrade the achievable bit error rate (BER) performance, and cause a significant performance-gap between the promised and the achieved sum rate of VLC based systems.