NeTS: Small: RUI: Hybrid Visible-Light and Radio-Frequency Communications with Integrated Medium-Access Control

Franklin W. Olin College Of Engineering, Needham MA

Investigators

Abstract

The explosion in demand for wireless communications has resulted in the crowding of the electromagnetic spectrum. To service the exponentially increasing demand forecast for the near future, new technologies and frequency bands need to be considered. One such technology is Visible-Light-Communications (VLC), where light-emitting diode (LED) based lighting systems can be used to transmit data while also providing illumination. The visible-light spectrum provides a very large bandwidth of electromagnetic spectrum that has the potential to help alleviate the spectral crunch. This proposed effort addresses the challenge of tightly integrating VLC communications with Radio-Frequency (RF) communications, where the RF channel is used only when a VLC link cannot be established, and for upstream data transmissions between users and access points since the upstream link poses a number of challenges for VLC including significant glare that would result from high-powered lights on mobile devices, and high power consumption. The PI proposes to develop practical, efficient protocols and algorithms for hybrid VLC-RF communications systems. The PI works in an undergraduate-only institution and will work with undergraduate students in this project. Additionally, the PI plans to work with a youth teacher program to educate middle- and high-school aged children on the fundamentals of digital communications, using VLC as an example technology. Successful completion of this project will be a major step towards making VLC-RF systems practical which will help service the increased demand for wireless data communications in the future, and help train the next generation of engineers. The PI proposes to design, develop, and implement in hardware, hybrid RF-VLC systems with integrated Medium-Access Control (MAC), which also provide illumination. The proposed program will involve 1) designing, simulating and implementing a VLC-RF MAC protocol; 2) developing and integrating into the system, physical layer algorithms that exploit channel information that can realistically be obtained through MAC protocol interactions; and 3) optimizing the MAC protocol for Room-Division Multiplexing (RDM). The fact that the proposed systems will have integrated MACs, enables practical VLC-RF systems for which physical layer implementation is decoupled from higher layers, which is an important principle of modular communications system designs. Optimizing the system for RDM can potentially increase data rates significantly due to the higher spectral re-use on the VLC enabled downlink of the hybrid system. Successful completion of this project will help make VLC a practical and modular communications system, which can lead to improved internet access, particularly in dense urban environments.