Development of method for increasing sensitivity in wireless optical data transmission channels in visible wavelength range

The original method for encoding binary data streams based on QPSK quadrature phase shift keying in a wireless optical communication channel in the visible range is suggested. The algorithm for analyzing signals in the receiving tract is presented. It allows to analyze the presence of two or three pulses of different colors at the input, which will signal the presence of interference or the occurrence of "illumination". In addition, the algorithm provides a possibility of dynamic compensation of external "illumination" by changing the gain of the photodetectors and adjusting the brightness of emitting LEDs. The functional scheme of the device for realization of the offered coding method in the wireless channel on the basis of optical radiation has been developed. Given that most photodiodes are sufficiently wide-band in the visible range of light waves, to increase sensitivity of each color channel and selectivity of the receiving tract it is necessary to apply optical filters for each color channel. The most effective are interference filters made of optically transparent materials with different physical characteristics. The approach for calculating optical filters has been presented.