Visible light communication: Difference between revisions
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'''Visible Light Communications''' (VLC) is a data communications medium using [[visible light]] between 400 [[Hertz|THz]] (780 nm; 1 THz = 1000 GHz) and 800 THz (375 nm) (visible light is not injurious to [[vision]]). |
'''Visible Light Communications''' (VLC) is a data communications medium using [[visible light]] between 400 [[Hertz|THz]] (780 nm; 1 THz = 1000 GHz) and 800 THz (375 nm) (visible light is not injurious to [[vision]]). |
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It uses ordinary [[fluorescent lamp]]s (possibly also [[Compact fluorescent lamp | CFL]]s) to transmit signals at 10 kbit/s, or [[LED]]s for up to 500 Mbit/s. Low rate data transmissions at {{convert|1|km|mi|1}} and {{convert|2|km|mi|1}} were demonstrated<ref name="vlcc-sensor">{{cite web |title=Image Sensor Communication |url=http://www.vlcc.net/modules/pico2/index.php?content_id=28 |publisher=VLC Consortium}}</ref><ref name="vlcc-lighthouse">{{cite web |title=Lighthouse Sub Project |url=http://www.vlcc.net/modules/pico3/index.php?content_id=7 |publisher=VLC Consortium}}</ref>. [[RONJA]] achieves full Ethernet speed (10 Mbit/s) over the same distance thanks to larger optics and more powerful LED. |
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It uses ordinary [[compact fluorescent lamp]]s to transmit signals at 10 kbit/s, or [[LED]]s for up to 500 Mbit/s. Specially designed electronic devices receive signals from such light sources. |
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Specially designed electronic devices generally containing a [[photodiode]]<ref name="vlcc-sensor"/> receive signals from such light sources although in some cases a cell phone camera or a digital camera will be sufficient.<ref name="vlcc-about">{{cite web |title=About Visible Light Communication |url=http://www.vlcc.net/modules/pico2/index.php?content_id=1 |publisher=VLC Consortium}}</ref>. 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. Such sensor may provide either a multi-channel communication (down to 1 pixel = 1 channel) or a spatial awareness of multiple light sources.<ref name="vlcc-sensor"/> |
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This technology can be used as a communications medium for [[ubiquitous computing]], because lights are used everywhere. |
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This technology can be used as a communications medium for [[ubiquitous computing]], because light producing devices (such as indoor/outdoor lamps, TVs, traffic signs, commercial displays, car [[Automotive lighting | headlights/tail lamps]]<ref name="vlcc-its">{{cite web |title=Intelligent Transport System - Visible Light Communication |url=http://www.vlcc.net/modules/pico2/index.php?content_id=4 |publisher=VLC Consortium}}</ref> etc.) are used everywhere.<ref name="vlcc-about" /> |
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== History == |
== History == |
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* [[RONJA]] |
* [[RONJA]] |
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* [[Free space optics]] |
* [[Free space optics]] |
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* [[Infrared Data Association | IrDA]] - same principle as VLC but uses [[infrared]] light instead of visible one |
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== External links == |
== External links == |
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Revision as of 02:20, 1 February 2010
 | This article includes a list of references, related reading, or external links, but its sources remain unclear because it lacks inline citations. (February 2009) |
Visible Light Communications (VLC) is a data communications medium using visible light between 400 THz (780 nm; 1 THz = 1000 GHz) and 800 THz (375 nm) (visible light is not injurious to vision).
It uses ordinary fluorescent lamps (possibly also CFLs) to transmit signals at 10 kbit/s, or LEDs for up to 500 Mbit/s. Low rate data transmissions at 1 kilometre (0.6 mi) and 2 kilometres (1.2 mi) were demonstrated[1][2]. RONJA achieves full Ethernet speed (10 Mbit/s) over the same distance thanks to larger optics and more powerful LED.
Specially designed electronic devices generally containing a photodiode[1] receive signals from such light sources although in some cases a cell phone camera or a digital camera will be sufficient.[3]. 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. Such sensor may provide either a multi-channel communication (down to 1 pixel = 1 channel) or a spatial awareness of multiple light sources.[1]
This technology can be used as a communications medium for ubiquitous computing, because light producing devices (such as indoor/outdoor lamps, TVs, traffic signs, commercial displays, car headlights/tail lamps[4] etc.) are used everywhere.[3]
History
First started at Nakagawa Laboratory, in Keio University, Japan in 2003.
Standardization process is conducted within IEEE Wireless Personal Area Networks working group (802.15).
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 100Mbit/s over longer distance using 5 LEDs.[5]
See also
- RONJA
- Free space optics
- IrDA - same principle as VLC but uses infrared light instead of visible one
External links
- VLC consortium
- IEEE 802.15 WPAN Task Group 7 (TG7) Visible Light Communication
Footnotes
- ^ a b c "Image Sensor Communication". VLC Consortium.
- ^ "Lighthouse Sub Project". VLC Consortium.
- ^ a b "About Visible Light Communication". VLC Consortium.
- ^ "Intelligent Transport System - Visible Light Communication". VLC Consortium.
- ^ "500 Megabits/Second with White LED Light" (Press release). Siemens. Jan 18, 2010.
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