Optical Wireless and Visible light communication techniques

Abstract

The growth of broadband internet services has led to an increase in traffic demand carried by telecommunication networks. This has resulted in the development of wireless technologies which can deliver ultra-high data rates. Optical wireless communication (OWC) is one such technology that uses light as the medium for transmitting data. OWC operates in the 390-1600 nm band consisting of a variety of technologies such as infrared communication (IR), free space optics (FSO), visible light communication (VLC), and Light Detection and Ranging (LiDAR). VLC is a relatively new and emerging technology that uses visible light to transmit data, making use of the Light Emitting Diodes (LEDs) that are ubiquitous in homes, offices, and public spaces. VLC has several advantages over wireless radio communication technologies, such as security, lack of interference with other wireless technologies, low latency and it is used in areas where radio frequencies are restricted. The thesis work aims to provide an insight into the classification of OWC for both indoor and outdoor systems based on the transmission range and its various applications mainly focusing on the indoor systems. The different types of modulation techniques used in VLC are discussed and VLC IEEE 802.15.7 standardization along with the link performance measurement of Li-Fi using measurement tools in a university environment. The result of the link performance experiment shows that distance is a non-neglectable factor in a LiFi system when determining the transmission rate in an indoor environment. It was noted during the course of the experimental measurement that the presence of interference from other light sources influences the transmission rate for both uplink and downlink as recorded in this experiment.