Research And Application Of Spatial Modulation Technology In Visible Light Communications

In recent years,with the continuous deepening of big data and cloud computing applications and the continuous advancement of the Internet of Things,the demand for high-speed communication,especially for wireless high-speed communication,is growing rapidly.However,with the continuous development of the communication industry for decades,electromagnetic spectrum which below 10 GHz and has good communication characteristics has been widely used by various wireless technologies and it will be exhausted.In order to meet the needs of people for high-speed,high-quality communication,and to solve the shortage of electromagnetic spectrum,visible light communications technology came into being.Compared with traditional RF communication,visible light communications have the advantages of wide spectrum,no electromagnetic interference and green environmental protection.This paper achieves the following work for visible light communications:Firstly,the research background and significance of visible light communications are expounded from various aspects,and the research status and the possible future development directions of visible light communications are summarized.Secondly,the visible light communication system 1s elaborated,its basic composition and communication principle are introduced,and the transceivers,channel models and modulation technologies used in system are also introduced.1 Thirdly,the principles of spatial modulation,generalized spatial modulation,quadrature spatial modulation and enhanced spatial modulation and their spectral efficiency are introduced in detail.At the same time,an improved generalized spatial modulation(iGSM)is proposed to solve the spectral efficiency problem caused by the inability to effectively utilize all LEDs in traditional generalized spatial modulation.This paper also studies the performance of iGSM from various aspects.Firstly,it compares the spectral efficiency between iGSM and different modulation techniques.Secondly,it compares the BER performance between iGSM and traditional generalized spatial modulation.Finally,the effect of transceivers distance in communication system on iGSM performance is studied.The research results show that iGSM can improve spectral efficiency while guaranteeing BER performance.Fourth,the two sets of visible light communication hardware systems built by the laboratory,including the digital transmission system and the video transmission system,are introduced in detail.Firstly,the system overview of these two systems is carried out.After that,the transceivers and the components used in these two systems are introduced.Finally,the working states of these two systems are displayed and the results are analyzed.