For a complete Li-Fi communication system, full duplex communication is required, that is an uplink connection from mobile terminals to the optical AP has to be provided. This can be achieved by using the infrared (IR) transmission, where the mobile terminals can send data using infrared frequency and optical AP receives it to
respond. Since IR Led's are used, Infrared (IR) energy is invisible to the human eye but can be seen by high quality monochrome (black and white) or true day/night CCTV security surveillance cameras.
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Not much detail there, really. The upstream direction is most likely going to use RF, although in principle, light could be used in both directions. Consider, for instance, visible light in downstream, infrared upstream.
https://prezi.com/ph8vfgpbgjdg/the-new-hot-spot/
Like most hyperbole, the demos of LiFi almost always overlook, or should I say deliberately ignore, the upstream direction. And most onlookers are happy to be amazed.
For a complete Li-Fi communication system, full duplex communication is required, that is an uplink connection from mobile terminals to the optical AP has to be provided. This can be achieved by using the infrared (IR) transmission, where the mobile terminals can send data using infrared frequency and optical AP receives it to
respond. Since IR Led's are used, Infrared (IR) energy is invisible to the human eye but can be seen by high quality monochrome (black and white) or true day/night CCTV security surveillance cameras.
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Have a look at this: https://en.wikipedia.org/wiki/Li-Fi
Currently, several variants of 'Li-Fi' are competing: VIS, IR and (near UV), dedicated transmitter LED vs. 're-use' of elements already installed (LED lighting, displays). etc.
Everything is still flowing, even if some standardization exists as well as early adopter products.
I appreciate every one sharing his information. but my key question when Li-Fi using illumination source to broadcast applications. it hard to provide uplink service because it interfere with downlink signal , and the receiver antenna should be direct with transmitter even when mobile is moving,
in another view, we can using bidirectional scheme to separate between transmitter signal and receive signal. but, can i use visible light for downlink services and infrared for uplink service (mobile terminal ) to avoid interference?
thank in advance
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