Application Of LED Visible Light Communication System In White Light Pollution Environment

In recent years,with the great progress of the light-emitting diode(LED)in the manufacturing process,luminance efficiency,brightness,control and design,the ability of LED to produce light waves can also be used as a transmission carrier of information in addition to providing conventional lighting.However,the sensitivity of the visible light communication system was greatly affected by the white light pollution,including the sunlight,the incandescent light and the fluorescent light.Therefore,the suppression of the white light pollution is also an important part of the system.Which needs to be fully studied and designed in the system and considered carefully.In this paper,we focus on the problems of modulation,demodulation,coding and decoding of visible light in indoor light pollution.Firstly,the basic theory of VLC system is systematically studied,including the principle and characteristics of white LED,and the principle of visible light receiver.The types and effects of light pollution in indoor environment are discussed,and typical channel of visible optical communication transmission is studied.Secondly,we design and build a VLC simulation system based on OOK-NRZ modulation.Aiming at two typical environmental light pollution experiments,the optical filtering method can effectively reduce the optical noise interference.The influence of visual field angle and transmission distance on transmission performance is evaluated.Finally,two kinds of LED VLC systems are designed.Using two different optical dual-binary modulation schemes,the visible light of 550 nm is transmitted over the 1m distance.The results verify the feasibility of optical dual-binary application in the VLC system,and also verify that the system with DA-ODB modulation scheme has the better transmission performance.At the same time,we also compared the receiving sensitivity and receiving power cost of different wavelengths visible light.The above research results also provide some reference schemes about modulation and demodulation of VLC system.