Experimental Study Of Non-line-of-sight White Light Visible Light Communication System Based On Diffuse Reflection Ligh

Indoor whitelight-based visible light communication technology has attracted the attention of many researchers due to its advantages of low cost,low power consumption,high speed,high confidentiality,free electromagnetic pollution,and wide frequency band,etc.The link of whitelight-based visible light communication can be divided into two models:line-of-sight link and non-line-of-sight link.The signal strength of the line-of-sight link is high,making it easy to achieve low bit error rate communication.However,it also has the disadvantage of small range of signal coverage,which leads to failed communication because of the link obstruction,or reduces the performance of mobile communication.The non-line-of-sight link communication mainly relies on the diffuse reflection of communication signals by walls and other diffusive reflectors.The signal covers a very large range,which can effectively solve the problem of link blocking occurred accidentally in the line-of-sight link.Aiming at the non-line-of-sight link communication,an indoor diffusive reflection spatial link model is established,and the distribution characteristics of diffusive reflection signals are analyzed through simulation.An indoor diffuse reflection optical communication system based on multi-detector fusion is built,and a method of using indoor diffusive reflection light for communication is proposed to solve the problem of link occlusion in the line-of-sight link.The influence of receiving azimuth angle on the received signal is studied experimentally.The signal-to-noise ratio distribution of the received signal based on the single-detector receiving system and the four detectors receiving system is measured respectively.The influence of diffusively reflective surface material on the performance of the light communication system is discussed.The communication performance of the non-line-of-sight link communication system based on four detectors is tested.The application of visible light communication system based on diffusive reflection in smart homes is explored where the motion of a smart car is controlled through the signal from a white light communication system.The experimental results demonstrate that diffuse reflection optical communication can effectively solve the problem of link occlusion in visible light communication.The communication system built in the experiment can achieve a maximum communication rate of 1 Mbps when the line-of-sight link is completely blocked,and the error rate is less than 10^-6.And it is verified that the use of multiple detectors can significantly improve the signal-to-noise ratio distribution of diffuse reflection signals,which can enhance the flexibility and robustness of communication systems.