We all know that Light Emitting Diode (LED), convert electrical energy into light on the basis of recombination of electrons and holes that release energy quants in the form of photons which have frequency dependent on the material from which the semiconductor layer is made. As a semiconductors it can be turned on and off at high speeds, which can be used for directly sequenced coding, part of an orthogonal coding is also possible because on LED’s we can control to some extent the level of photon emission, that is light intensity.
In addition, LEDs are available in several different color shades, which allows the application of color separation filters corresponding to the reception so Space Time Coding (STC) be carried applied, i.e. each color can become a separate channel.
Light due to its dualistic nature in addition to its quantum also inherent all EM waves characteristics, and can be polarized. The standard IEEE 802.15.7-2011 foresaw the possibility of the existence of 3 different Physical Layer (PHY) operational mode in which will provide bit rate up to 96Mbit/s for optical clock rate of 24MHz and 16-Color Shift Keying (16-CSK) modulation (PHY III Optical Mode)
Knowing all of that we can try and make color and polarization filtering of separated color chanels.
Blue filter pass blue and portion of green LED light.
Red is doing oposite.
Setup with color stickers :)