Modeling And Performance Analysis Of Visible Light Communication Channels Based On Intelligent Reflecting Surface

Visible light communication technology uses light in visible band as the carrier of information transmission,which is a communication mode of direct transmission of optical signals.In this paper,we mainly study the visible light communication system between the street lamp and the vehicle.Aiming at whether the communication link is blocked,this paper mainly establishes the line-of-sight communication model between the street lamp and the vehicle and the non-line-of-sight communication system model assisted by the intelligent reflecting surface,and studies the system performance.The details are as follows:(1)This paper establishes a line-of-sight communication model between street lamps and vehicles.The communication channel between the street light and the vehicle is modeled accurately,including the height of the street light,the distance between the street light and the vehicle,and the size of the vehicle photodetector.The channel loss in near-field channel is analyzed,including path loss,atmospheric turbulence and pointing error.The bit error rate,outage probability and block error rate of the line-of-sight communication system are deduced.The transmission performance of the system is verified by simulation,including the influence of the distance between the street lamp and the vehicle and the height of the street lamp on the bit error rate,the influence of the outage threshold on the outage probability,and the influence of the number of bits on the block error rate.(2)The non-line-of-sight communication model assisted by intelligent reflecting surface is established in this paper.When the line-of-sight communication link is blocked,intelligent reflecting surface is considered to assist vehicle communication.The intelligent reflecting surface can control the amplitude and phase of each reflected signal and adjust the reflected signal in real time according to the channel state information.The bit error rate,outage probability and block error rate of non-line-of-sight communication system assisted by intelligent reflecting surface are deduced,and the influence of physical parameters in non-lineof-sight transmission on system performance is verified.At the same time,the influence of monopole M-ary pulse amplitude modulation and binary phase shift keying modulation on the bit error rate of the system is analyzed.Through simulation,it is concluded that changing the modulation order of monopole M-ary pulse amplitude modulation can change the bit error rate performance of the system,which can quickly reduce the bit error rate performance.(3)Based on the above content,the non-orthogonal multi-access assisted line-of-sight communication model and non-line-of-sight communication model are established.According to the statistical characteristics of the channel,the expression of the signal to noise ratio statistics is derived,the achievable capacity of orthogonal and non-orthogonal multi-access is compared,and the bit error rate of near and far vehicles in the non-orthogonal multi-access assisted communication system is analyzed and simulated.In the non-line-of-sight communication model assisted by non-orthogonal multiple access,the ergodic rate and the asymptotic performance of high signal to noise ratio of vehicles near and far are simulated.Considering the hardware limitations of intelligent reflecting surface,the influence of phase error on the bit error rate of vehicles near and far is analyzed.The simulation results verify the theoretical analysis.