Research On Timing Synchronization Technology Of Visible Light Communication System

With the rapid development of Internet technology,people have higher data transmission rate and transmission quality requirements.However,in the current field of radio communications,because of the rapid increase in data transmission requirements,so that a more limited spectrum of resources is more scarce.Therefore,a communication method using LED flashing signal to transmit data information is proposed,which combines the dual function of lighting and communication,which is called visible light communication.It has no band resources,no harm to the human body and strong confidentiality,etc.advantage.Synchronous technology directly affects the overall performance of the visible light communication system.If the synchronization estimation is not accurate enough,not only can not reliable transmission of information,but also in the receiving end of the system to restore the required information,so the visible light communication system to normal work,synchronization is the foundation.This paper mainly studies the timing synchronization technology.In this paper,after analyzing the characteristics and current situation of visible light communication,the system model is established.Among them,in the LED array driver module,the design of the power supply system with low power consumption,stability,high efficiency and long life,it can be considered as an ideal power supply LED array;modulation used is 16QAM-OFDM,its It is easy to suppress multipath effect,not only can reduce the complexity of the design of the synchronization algorithm,but also can increase the utilization rate of the band.After analyzing the classical algorithms of timing synchronization,such as S& C algorithm,Minn algorithm and Park algorithm,combined with a large number of literatures in this field,we find that the classical algorithm has "correlation peak platform" phenomenon and sub-peak interference influencesymbol accurate location.There are poor real-time and weak real-time and other defects.In this paper,we propose an improved timing synchronization algorithm for their shortcomings.Finally,the S & C algorithm,Minn algorithm,Park algorithm and improved algorithm are applied to the visible light communication system model,and the simulation test of timing estimation is carried out.Timing estimation of mean time difference curve and the analysis of data,the visual difference of the picture and the feasibility of the improved algorithm are used to measure the timing of the time function and the string.Compared with the classical algorithm,the improved algorithm proposed in this paper can accurately locate and maintain good real-time and anti-interference,both in AWGN and RMF channel,after analyzing the simulation results.Especially,under the condition of low SNR,the time-averaged variance of the improved algorithm is close to 0(0.041),and the mean square error of the basic algorithm is much larger than that of the improved algorithm.The research results of this paper have a good prospect in the field of visible light communication.