New Design Techniques for Improved Visible Light Communications

Recently, visible light communication, in which rapidly flashing visible light (of 390-750 nm wavelength) is used to transmit information, has been gaining considerable attention among both academia and industry. It is a promising technology for the creation of a new generation of high-speed indoor personal area networks, wireless local area networks, and vehicular networks. The use of this technology is further motivated by an increasing need for faster wireless data connections for commercial and medical applications and a demand for practical communication solutions where radio frequency technology cannot be used. Progress in the area is being accelerated by the improvements in the output power, lifetime, bandwidth and cost of light-emitting diodes, which are typically used as the light source of choice in visible light communication systems. These light sources have much larger bandwidth than that of RF systems, and therefore, this technology can potentially accommodate more users and achieve higher data rates. A further benefit is limited interference from other frequency bands, both licensed and unlicensed. Moreover, as lighting is ubiquitous, there is an exciting opportunity to create a unified, cost-effective lighting and communications infrastructure that simultaneously combines energy-efficient illumination with fast, free-space data communications. Another notable advantage of visible light communication is enhanced security. Specifically, because light cannot propagate through walls and is better confined in an enclosed region, such as a room, it offers the prospect of more secure data exchange than radio frequency electromagnetic waves. This technology is also a promising solution to the health concerns related to the use of radio frequency and infrared communications at high transmit powers. This research proposal will develop a suite of new techniques that can improve the efficiency and performance of visible light systems, with the aim of enhancing key metrics such as signal to noise ratio, coverage, information security, data-transmission speed, spectral efficiency and bit error rate. This effort will target new approaches to visible light modulation schemes as well as new algorithms for adjusting the angles of coverage and directivity of light emitting diodes for efficient noise mitigation and mobility alleviation in hybrid lighting-communications technology. The research proposal will develop new hybrid radio frequency-visible light communication designs to improve the spatial coverage and enhance the information secrecy in future heterogeneous wireless networks. It will also construct sophisticated theoretical tools for modeling and simulating visible light systems and providing quantitative analysis of their key performance metrics.