Optical Spectrum Estimation Technique for Optical Interference Cancellation in High Speed Transmission MISO-OCVLC Environment

In this paper, we have studied the multiple light source image sensing technology for high speed transmission in optical camera CCD sensor based visible light communication system. To improve transmission capacity in optical camera communications via image sensors, different data must be transmitted simultaneously from each LED. However, multiple LED light source environments for high-speed transmission can cause interference between adjacent LEDs. In this case, since the visible light communication system generally uses intensity modulation, when a plurality of LEDs transmit data at the same time, it is difficult to accurately detect the respective LEDs due to the light scattering interference of the adjacent LEDs. In order to solve these problems, we propose spectral estimation technique and pixel image signal processing technique for each LED. A threshold value is generated based on the center value of the spectrum at the center of each LED, and only the LED which is sensed above the reference value is recognized independently by the ISP. If the spectral level is below the center value, that LED is recognized as off because it is affected by the light spread of adjacent LEDs. This technique accurately recognizes multiple LED pixels and improves the total average bit error rate and throughput of the MISO-OCVLC (Optical Camera Visible Light Communication) system.