Research On Visible Light Communication Technology Based On Polar Coding And Decoding

In recent years,with the rapid development of artificial intelligence and the Internet of Things,the era of big data intelligence with the Internet of Everything is about to embark on the stage of human history.With the revolutionary technological change,the huge amount of data has brought a severe test to the traditional communication technology.As a new spectrum communication technology,visible light communication can effectively alleviate the problem of the shortage of radio frequency communication frequency band resources and realize a technological supplement to wireless communication.At the same time,visible light communication has the advantage of high-speed transmission,and it has more profound research significance in the future optical networking under 5G/6G technology.Polar codes,as a research hotspot of physical layer channel coding in 5G mobile communication systems,have been theoretically proved to be the only coding method that can "reach" the Shannon limit.It has been selected as a coding scheme for control channels in 5G e MBB scenarios,but few Research the application of polar codes to visible light communications.Relying on the National Natural Science Foundation of China,this thesis has carried out related theoretical analysis and application research of polarization codes in visible light communication systems,and further promoted the practical engineering application of polarization codes.The main research results and innovations are as follows:(1)Introduction and theoretical analysis of visible light communication system and visible light channel characteristics.First,the components of the system are explained,with emphasis on the basic optical characteristics of the optical transmitter and receiver.In order to apply the polarization code to the visible light communication system in the follow-up of the thesis,a simulation model of the visible light channel is built,and the characteristic parameters of the channel in the communication environment are analyzed,and the distribution of noise variance and signal-to-noise ratio under the indoor visible light channel is simulated.(2)In the communication environment of actual engineering,visible light signals are susceptible to short-term occlusion of objects and interference from movement of people during transmission,and random errors and sudden continuity errors will occur in the channel.Aiming at the mixed error codes of this kind of channel,this paper proposes a polarization code cascade scheme specially applied to visible light channels.The simulation experiment results show that,compared with separate polar codes(512,128),the lower bound of the error rate of the BCH-Polar cascade scheme using random interleaving is reduced by about 75%,and the block interleaving scheme is reduced by about 90%.At the same time,the cascade schemes using different outer codes are compared,and the results show that Conv-BI-Polar shows better robustness in combating sudden errors.(3)The research of polarization code in visible light system is still at the stage of theoretical simulation.This article has launched the work of FPGA hardware design and implementation of polarization code codec.By building a board-level experimental platform,it is verified that the polarization code has a certain effectiveness in improving the reliability of the visible light communication link.Compared with uncoded,the visible light system using polarized codes exhibits a 2-3 orders of magnitude reduction in bit error rate.