Room lighting could be used to offer an alternative to radio waves for wireless communications. There are several organisations around the world working on using LED lighting to provide Li-Fi, a competitor for Wi-Fi.

Old Light Through New Windows
            The idea behind visible light communications (VLC) pre-dates radio transmissions and has existed for over a century. Alexander Graham Bell, who was born in Edinburgh, used modulated sunlight to send a wireless phone message in 1880 using an invention he called the Photophone.

            Using LEDs, Haas has managed to reach speeds of 100Mbps (Mbits per second), somewhat less than a Japanese competitor, Outstanding Technology, which has a similar system peaking at 160Mbps. Even the Japanese achievement is a standstill speed compared to a Fraunhofer Institute for Telecommunications team in Germany, sponsored by Siemens, that holds the VLC record at 800Mbps but considers 500Mbps to be more sustainable. To achieve these speeds, the team used an Ostar LED, one of the brightest LEDs on the market, and one that can match the required modulation speeds.

            The applications appear to be there and several have been touted. The system could be an alternative public network used in airports and other areas where radio transmissions are kept to a minimum. It could also be used in domestic and business situations where radio cannot penetrate thick walls or traverse areas of high electrical activity.

            The light can also be shaded to enhance security and prevent the kind of "street leakage" that occurs when Wi-Fi signals project to the outside of a building.

VLC is a maturing technology but it could be over five years before it is ready for market.