STTR Phase I: High-Speed Indoor Wireless Networking Using Visible Light Communications

The broader impact/commercial potential of this project is bringing numerous economic and social benefits to the public: advance the security of information and communication, decrease public health risk, and overall increase the quality of life all around the world. VLC has the potential to significantly increase the speed of Internet connection in multiuser indoor environments due to the broad bandwidth of the visible light. Commercializing the VLC technology will not only be a big step toward energy saving and provide stronger justification and desire for implementing economical LED systems, but also will increase the speed and security of wireless data communications. It will offer a huge energy saving for the nation since energy is already used for lighting, and thus does not require separate expenditure for communications. It will also increase the quality of life for those who are concerned about the impacts of Wi-Fi on their health, and any group of people including children and pregnant women can use it for Internet connection without any concern about the effect of electromagnetic waves. VLC can replace the controversial Wi-Fi technology in schools, hospitals, kindergartens and any other place that health issues are of major concerns. This Small Business Technology Transfer Research (STTR) Phase I project is to develop the technology for visible light communication (VLC) system that achieves high data-rates using low-cost commercial light emitting diodes (LED). VLC is a potential alternative data communication technique for wireless applications that uses optical energy to provide simultaneously lighting needs and data transmission. The idea in this technology is to transmit the data using the lighting systems that are already used for the illumination of indoor environments. Spectrally efficient coding and modulation techniques with dimming feature support will be developed based on combinatorial designs to modulate LEDs. Multi-input multi-output (MIMO) will be explored to increase the transmission speeds since each user receives signals from multiple LEDs. Solutions to address technical problems of using LEDs intended for lighting in commercial VLC systems, such as LED heating, LED nonlinearity and controlling large LED-arrays with low-cost small circuits will be explored. The techniques developed in the Phase I of this proposal can also be employed along with faster but more expensive LEDs and photo-detectors to achieve Gbps streaming in VLC systems. Furthermore, tri-chromatic LEDs can be used to achieve a three-fold increase in the data-rate by modulating each color independently.