Column Matrix Selection And Mapping Method For Optical Camera Communication

With the rapid development of communication technology,the limited spectrum resources of traditional RF communication have been unable to meet the increasing needs of users for bandwidth.Visible light communication(VLC)technology is widely concerned because of its uncontrollable visible light band,simultaneous illumination and data transmission.Light emitting diode(LED)is often used as the signal source of the transmitter because of its low power consumption,high response,transmission and lighting functions,and complementary metal oxide semiconductor(CMO S)is often used as the receiver because of its portability,easy to build-in,wide range of reception and low price.Therefore,the visible light camera communication(OCC)system has become one of the hot spots in VLC technology research.In this paper,aiming at the"blooming"effect,flicker and other problems in visible camera communication,combined with practical application scenarios,the main work is as follows:1.A column matrix selection method based on LED energy diffusion is proposed and verified in traditional OCC system.The proposed method can not only avoid the influence of"blooming"effect,but also improve the contrast of light and dark stripes.The experimental results show that the proposed column matrix selection method can effectively avoid the"blooming"effect,and the error rate of the system under the same conditions is far lower than the traditional column method.When the illumination intensity is 700 lux and the distance is 30 cm,the error rate of column matrix selection method based on LED energy diffusion is increased from 2.5 x 10^-4 to 8.82 × 10^-6compared with the traditional column matrix selection method.2.A flicker free method based on automatic column matrix selection is proposed and verified in traditional OCC system.The experimental results show that the error rate of the proposed scheme is not affected by the sensitivity(ISO).When the exposure time is 1/17200s,the sensitivity is 140 and the voltage of LED is 4V,the best receiving distance of the camera is 0.4-0.7m.3.This paper proposes an effective mapping scheme of visible light communication based on LED and smart phone,which is verified by experiments in traditional OCC system.The proposed method not only can achieve fast location,but also does not need extra processing time.Under the same conditions,the BER performance of the automatic column matrix selection scheme and the traditional column matrix selection scheme are compared.The experimental results show that the best receiving distance is 0.5-1.0m when the exposure time is 1/12800s and the sensitivity is 160.Under the same condition,at the speed of 0.5-0.9m/s,the bit error rate is not affected.