Research On Modeling And Characteristics Of Visible Light Communication Channel In Indoor Scenes

With the development of information technology,the demand of wireless communication for data is increasing.The previous communication technology can not meet the requirements of the information age.Due to the high efficiency,energy saving and environmental protection advantages of LED lamps with the development of technology,in recent years,Visible Light Communications(VLC)technology with LED as a light source has become one of the research hotspots in the field of wireless communication.Indoor VLC has also become one of the hotspots of research.Effective analysis of indoor visible channel characteristics can provide a better reference for the design of VLC system.Therefore,indoor VLC channel modeling and analysis of its characteristics are of great significance in practice.This paper mainly focuses on indoor scene modeling,visible light communication channel characteristics and indoor light source layout optimization.1.According to the principle of computer graphics and the actual layout of indoor scenes,a three-dimensional indoor scene model composed of point-surface structure is established,and different diffuse reflectance coefficients are set according to the roughness of different objects to form an efficient storage mode of three-dimensional model.Based on Lambert radiation model,the channel propagation mode of visible light communication in indoor scenes is studied.The object surface or wall surface is divided into differential elements.The diffuse reflection of light signal on differential surface is regarded as a new radiation source.The channel characteristic prediction model of indoor scene is established by judging the occlusion of light propagation process.According to the channel modeling method of interactive representation of independent reflection elements,the indoor visible light multiple diffuse reflection is calculated.Thus,an accurate and fast channel prediction model for visible light communication in indoor scenes is established.2.Based on the channel prediction model for visible light communication of indoor scene,the effects of different differential cell sizes and indoor scene on the channel characteristics of indoor visible communication system are analyzed.Combining the indoor scene model and the channel propagation prediction model of visible light communication,the distribution of channel parameters such as illumination,light power,impulse response,root mean square delay spread and signal-to-noise ratio are calculated and simulated,and some simulation results are compared and verified.It provides a reliable theoretical support for VLC channel prediction in real indoor environment.3.The optimization of light source layout in indoor visible light communication system based on improved genetic algorithm(IGA)is studied.Because genetic algorithm is advantageous to global optimization and has good global optimization ability,but it has some shortcomings such as slow convergence speed and poor local optimization ability.Simulated annealing algorithm(SAA)has strong local search ability and can accelerate convergence speed.By combining IGA and SAA and improving them according to the light source layout problem of indoor scene.Finally,an evolutionary algorithm for optimizing the layout of light sources in indoor scenes is obtained.According to the optimization results,the influence of light source layout on indoor visible channel characteristics is analyzed.