Simulation And Experimental Verification Of Wireless Optical Transmission Channels In Different Water Environment

Underwater wireless optical communication technology has been gradually applied to high-speed information transmission due to its advantages of high speed,low delay and strong anti-interference.As a medium of light transmission,water has attenuation effect on light wave,and its physical properties and internal material composition have different influence on light transmission characteristics.Research on the characteristics of light transmission channel in complex water environment has important reference value for the design of underwater wireless optical communication system.In this thesis,the optical characteristic theory of underwater channel is firstly introduced,including the empirical formula of absorption coefficient and scattering coefficient,Beer's law,volume scattering phase function and Brillouin scattering theory.At the same time,the principle of Monte Carlo is introduced.On this basis,this thesis combined with the existing Monte Carlo algorithm,aiming at the difference of different water environment,proposed a water environment adaptive light transmission simulation method.This method uses the two information before and after the update of photon to judge the state of the photon and obtain the actual weight and position of the photon,which solves the applicability problem of the channel model in different water areas.Then,using the above model and Brillouin scattering theory,the impact of salinity and zooplankton on the received intensity,receiving time and spatial distribution of energy were simulated and analyzed.Meanwhile,the transmission distance and the misalignment tolerance of transceiver under different turbidity conditions were analyzed.The results show that salinity has little effect on transmission channel characteristics in the blue and green light band.The higher the turbidity,the worse the reception performance.Transceiver misalignment tolerance in clear water is very small.Then,the optical transmission channel characteristics of actual water environment are simulated,and the simulation results under various parameters are given.Finally,underwater wireless optical transmission experiment was carried out in the actual water environment to verify the influence of water environment on the optical transmission channel.