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Publications have been coming from Nakagawa Laboratory, ByteLight filed a patent on a light positioning system using LED digital pulse recognition in March 2012. ABI research forecasts that it could be a key solution to unlocking the $5 billion "indoor location market". Recently, VLC-based indoor positioning systems have become an attractive topic. gave a live demonstration of high-definition video being transmitted from a standard LED lamp, and proposed the term Li-Fi to refer to a subset of VLC technology. In July 2011 a presentation at TED Global. Cloud, Minnesota, signed a contract with LVX Minnesota and became the first to commercially deploy this technology. The VLC standardization process is conducted within the IEEE 802.15.7 working group. In January 2010 a team of researchers from Siemens and Fraunhofer Institute for Telecommunications, Heinrich Hertz Institute in Berlin demonstrated transmission at 500 Mbit/s with a white LED over a distance of 5 metres (16 ft), and 100 Mbit/s over longer distance using five LEDs. This research suggested that VLC could be deployed as a perfect last-mile solution in the future. In 2006, researchers from CICTR at Penn State proposed a combination of power line communication (PLC) and white light LED to provide broadband access for indoor applications. Since then there have been numerous research activities focussed on VLC.
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More recent work began in 2003 at Nakagawa Laboratory, in Keio University, Japan, using LEDs to transmit data by visible light. This pre-dates the transmission of speech by radio. when the Scottish-born scientist Alexander Graham Bell invented the photophone, which transmitted speech on modulated sunlight over several hundred meters. The history of visible light communications (VLC) dates back to the 1880s in Washington, D.C. 2.3.2 Variable Pulse Position Modulation.2.2 Multi-Carrier Modulated Transmission.2.1 Single-Carrier Modulated Transmission.VLC can be used as a communications medium for ubiquitous computing, because light-producing devices (such as indoor/outdoor lamps, TVs, traffic signs, commercial displays and car headlights/taillights ) are used everywhere.
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Such a sensor may provide either multi-channel (down to 1 pixel = 1 channel) or a spatial awareness of multiple light sources. The image sensor used in these devices is in fact an array of photodiodes (pixels) and in some applications its use may be preferred over a single photodiode. Specially designed electronic devices generally containing a photodiode receive signals from light sources, although in some cases a cell phone camera or a digital camera will be sufficient.
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Systems such as RONJA can transmit at full Ethernet speed (10 Mbit/s) over distances of 1–2 kilometres (0.6–1.2 mi). The technology uses fluorescent lamps (ordinary lamps, not special communications devices) to transmit signals at 10 kbit/s, or LEDs for up to 500 Mbit/s over short distances. VLC is a subset of optical wireless communications technologies. Visible light communication ( VLC) is a data communications variant which uses visible light between 400 and 800 THz (780–375 nm). Visible light is only a small portion of the electromagnetic spectrum.