Performance Evaluation And Analysis Of Link Key Technologies Of Visible Light Communication

As a new technology in wireless communication area,visible light communication(VLC)is a potential key technology of 6G.In VLC,information is carried with light intensity and conversions between electrical signals and optical signals are through photoelectric devices.This thesis evaluates and analyzes the performance of link key technologies of visible light communication to provide reference for their direction selection.The specific contents of the study are as follows:First of all,this thesis studies three typical optical OFDM technologies,combines them with the complete process of PDSCH to carry out link-level simulation,evaluates their performance and conducts comparison and analysis in AWGN channel.Simulation results show that the SNR-BLER performances of ACO-OFDM and DCO-OFDM are basically similar when the code rate and the average power of transmitted signals are the same,but the power utilization of DCO-OFDM is low,and the spectrum utilization of ACO-OFDM is about half of that of DCOOFDM.LACO-OFDM maintains the advantage of ACO-OFDM with high power utilization and improves the frequency spectrum utilization through stratification.However,due to interlayer interference,the more layers,the worse the reliability of the system.Then,LED lamps and channel are modeled in specific indoor simulation scenarios to evaluate and analyze the performance of DCOOFDM,ACO-OFDM and LACO-OFDM in visible light channel.The simulation results are similar to those in AWGN channel,but the reliability performance of visible light communication system decreases obviously when the propagation characteristics of visible light and the actual application scenarios are considered.Finally,the effect of LED frequency response on the performance of DCO-OFDM system and ACO-OFDM system is studied.Taking ACOOFDM as an example,the effect of 3dB cutoff frequency of LED chip on system performance is studied.Simulation results show that the reliability of the system decreases when the LED frequency response is considered,and the lower the 3dB cutoff frequency of the LED chip,the greater the impact on reliability.Meanwhile,under the premise of considering the LED frequency response,the effect of DC bias on the performance of DCO-OFDM system is simulated and analyzed.The results verify that a large DC bias can effectively reduce the clipping noise and improve the reliability of the system.