Visible Light Communication Based On NOMA-OFDM System Research

Visible Light Communication(VLC)is a new-generation communication method that uses visible light waves as the communication medium to exchange high-speed data through LED light sources,photodetectors and other devices.In situations where traditional wireless communication methods cannot be used,there are better Application scenarios.DC-Bised Optical Orthogonal Frequency Division Multiplexing(DCO-OFDM)is a commonly used model for VLC systems,but it is limited by the 3dB bandwidth and nonlinearity of LEDs,and it is difficult to achieve higher communication speeds in multi-user systems.Communication reliability.The paper applies Non-orthogonal Multiple Access(NOMA)to the VLC system in indoor multi-user scenarios to improve the communication performance of the visible light communication system.Based on the analysis of the principles of VLC and NOMA and the research status at home and abroad,the related technologies of NOMA applied to the VLC system were studied in depth,the VLC system model based on NOMA-OFDM was designed,and the performance simulation and experimental test platform were built.The specific content includes:1.Theoretical study of the channel characteristics of indoor VLC system,simulation analysis of path loss,and establishment of indoor VLC system channel gain model,to provide a basis for the realization of power allocation in the NOMA-OFDM-based VLC system.2.Based on the theoretical research and analysis of Orthogonal Frequency Division Multiplexing(OFDM)and NOMA,based on the channel gain model and the fixed power allocation algorithm,a VLC system based on NOMA-DCO-OFDM is designed,Realize multi-user communication,and improve spectrum efficiency and communication rate.At the same time,the dirty paper coding,Turbo coding,and serial interference cancellation technology(SIC)in NOMA are used to improve the reliability of the communication system.Based on the designed system model and algorithm,a simulation platform was established,and the system performance simulation experiment was carried out.3.On the basis of theoretical analysis and simulation experiments,the VLC system transceiver circuit system based on NOMA-OFDM was designed and implemented,and arbitrary signal generators,digital oscilloscopes and other equipment were used to build a platform environment for functional testing and communication performance experiments.The theoretical analysis and design were verified by experiments.Theoretical analysis,simulation,and actual test experiments show that when NOMA is applied to an indoor VLC system,the communication speed is significantly improved when the bandwidth and users are certain,and the combined rate is less affected by the number of users;the two-user simulation experiment shows the bit error rate At 10-4,user 1 has a performance improvement of about 5.1dB,user 2 has a performance improvement of about 2.1dB,and communication reliability is significantly improved;based on the experimental platform,the test results and theoretical analysis of the impact of different power allocation ratios on reliability It is basically the same as the simulation.