Advantages of this excellent idea:
1. Visible Light (VL) sources are ubiquitous, IR devices are special
2. IR device beams are narrow-angle, LED Ceiling lights are designed to spread/diffuse light
3. IR emitters normally have lower conversion efficiency and operate at lower power levels
4. Existing VL emitters can be used
1. VL receivers have to contend with far higher levels of ambient interference and saturation effects.
2. The ceiling lights would have to be ON all the time for Communications, resulting in Energy wastage, an antithesis as LEDs are aimed at Green environments
3. The light modulators would have to contend with high power levels and Mains Isolation problems which can be complex for High frequency data modulation .
The Institute is talking about 500 Mbits/sec:
This sounds very similar to "Broadband access over medium and low voltage power-lines and use of white light emitting diodes for indoor communications" by P. Amirshahi and M. Kavehrad of Pennsylvania State University which was published in the IEEE Communications Society CCNC 2006 proceedings. [http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.75.3194&rep=rep1&type=pdf]
Amusing that in this instance high speed communication is viable but very slow data carrier transmission rates would be problematic. Below 30 Hz, the flashing lights would become very annoying). [Also a minor linguistic note: "The optical wireless technology can be deployed in situations where wireless LAN is UNACCEPTABLE / UNDESIRABLE."]
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