Research On LED Intelligent Traffic Optical Communication System Based On MIMO Technology

Visible Light Communication(VLC)has made up for the shortcomings of poor communication and poor environmental protection of RF communication,and it has become the next generation of communication technology.VLC uses the high response of Light Emitting Diode(LED)to emit a fast bright and dark flashing beam,which take into account the dual role of lighting and information transmission.Due to the popularity of LED traffic lights in transportation facilities and lighting applications,VLC technology has broad application prospects in the field of intelligent transportation.However,the main problem that hinders the application of VLC technology in the field of intelligent transportation is that the turbulence effect in the channel environment has a high error rate in the vehicle and LED traffic light communication system.To this end,this paper has carried out a series of researches on how to reduce the turbulence effect and high communication error rate,and focuses on the BER performance of VLC communication system based on MIMO technology in the turbulent channel environment.Finally,the experiment is verified.The work of this paper is as follows:Firstly,this paper introduces several influencing factors of atmospheric channel environment,focusing on the formation of atmospheric turbulence,the form of influence and based on the characteristics of stochastic changes of atmospheric turbulence,the modified Kolmogorov power law spectrum model has used random phase screen to simulate its randomness.Meanwhile,it build an LED illumination model,analyze and compare the light intensity distribution of the LED beam after passing through a random phase screen with different turbulence intensity.This laid the foundation for the subsequent suppression of turbulence effects.Secondly,the basic principles of MIMO technology and related theoretical knowledge such as space-time block code are introduced.It analyses the effects of channel state on the MIMO channel capacity of different transmit and receive antennas are known.The simulation results show that the different states of the channel have a great impact on the performance of the MIMO communication system.In this paper,based on the channel environment where the channel state is known and the multiple links are independent of each other,the basic theory of MIMO diversity combining is expounded and the VLC system model based on MIMO technology is constructed.The MIMO communication system of different transmitting and receiving antennas and the bit error rate performance under diversity conditions is analyzed and compared.The simulation results show that the BER of the MIMO system is positively correlated with the number of transmitting and receiving antennas,whether it is transmit diversity or receive diversity.Thirdly,the influence of different turbulence intensities on the BER performance of MIMO-VLC systems with different transmit and receive antennas is analyzed and compared in the VLC system based on MIMO technology.The simulation results show that MIMO technology can ease the effects of turbulence when turbulence intensity is determined and improve the performance of communication system.Finally,according to the simulation results,the experimental results are verified.The relationship between BER and communication distance of 1×4 and 1×1 MIMO-VLC systems is analyzed and compared in the channel environment with moderate turbulence intensity.The conclusion that MIMO diversity technology can ease the effect of turbulence and improve the performance of communication.