Research On Key Technologies Of High-speed Multi-color Visible Light Communication Systems

In recent years,with the rapid development,the numbers of mobile communication users are growing and the band resources of radio frequency become more and more crowded.Visible light has high frequency,short wavelength,wide bandwidth,large communication capacity and so on.These factors make the visible light communication(VLC)become a hot research topic in the indoor wireless communication.This paper studies the key technology of multi-color indoor VLC system,including HARQ and AMC.The paper gives suitable plans in the VLC system and the simulation results to verify the performance of the algorithms.At last,the paper provides the implementation FPGA scheme of the indoor multi-color VLC system.Firstly,this paper introduces the research background of the VLC technology and summarizes the latest research of VLC.Then,the paper briefly introdeces the VLC system and the basic principle,including the system model,transmitting and receiving circuit and so on.And introduces the channel model of basic indoor VLC system.Then,the paper introduces the VLC system based on DCO-OFDM and the basic principle of multi color VLC system.Secondly,the paper discusses the HARQ scheme in the indoor VLC system.At the beginning,the paper introduces the HARQ,including ARQ and FEC.Then this paper studies the suitable HARQ scheme for indoor VLC system and compares the differences between the two schemes.One is the scheme based on type I HARQ,the other is the scheme based on Chase-HARQ.Results shows that the scheme based on type I HARQ compared to the system without HARQ,the performance of FER is better and the performance of pass rate is close.The scheme based on Chase-HARQ compared with the previous scheme,the performance is greatly improved despite of larger receiver buffer and higher system complexity.Thirdly,the paper discusses the AMC scheme in the indoor VLC system.At the beginning,this paper describes the water filling algorithm and introduces the principle of adaptive OFDM system.Then this paper introduces the traditional AM algorithms and compares their simulation results.Nextly,the adaptive mod-ulation coding(AMC)is introduced.And this paper proposes a AMC implementation scheme:the simple packet AMC algorithm based on the SNR threshold.Compared with the SBLA algorithm,the transmission rate is improved despite of higher system complexity.Finally,the scheme is verified in the hardware platform of the indoor VLC system.Finally,on the basis of the basic theory of visible light in the previous chapters,this paper introduces the hardware demonstration platform of the indoor VLC system.This paper gives an overview of the hardware demonstration platform.And then this paper describes the FPGA design scheme,mainly describes the FPGA baseband processing module of the transmitor and receiver in the hardware demonstration platform.Finally,A presentation of our demo system is given,and each devices in the system is introduced.