Analysis Of The Influence Of Atmospheric Turbulence On The Performance Of Partially Coherent Laser Communication

Atmospheric laser communication system has attracted considerable attention as its advantages. However, the performance of Atmospheric laser communication system is affected by atmospheric turbulence. In order to ensure the stability of communication system, it is significant to research the influence of atmospheric turbulence.Due to the unneglectable atmospheric turbulence effect, the fundamental roles of atmospheric turbulence is introduced, the formula for calculating the intensity scintillation, beam wander, beam spreading and angle-of-arrival fluctuation was analyzed in atmospheric turbulence from weak to strong. In order to research the influence of atmospheric turbulence on the laser propagation effectively, based on power spectrum method, a transmission process of the laser propagation through atmospheric turbulence was simulated with the multi-phase screen method. Using a partially coherent beam as light source and different modulations, the influence of the scintillation and beam spreading on the BER in laser communication system is analyzed. Then, in PPM modulation, the BER of partially coherent beam propagation through atmospheric turbulence channel with different correlation radius is analyzed. Based on the correcting error ability of RS code, using RS code in PPM modulation system, it can improve the performance of communication system effectively. The analysis indicates that the simulation results are corresponded with the theoretical results. The off-axis scintillation index is effectively reduced by using a partially coherent beam as source, and the BER becomes lower as the light source coherent radius decrease. Thus by using a partially coherent laser as source with PPM modulation, it can decrease the influence of atmospheric turbulence on BER and improve effectively the performance of laser communication system. By choosing RS code as channel code method of Atmospheric laser communication system, it can decrease the BER of laser communication system and improve the performance of communication system effectively.These studies have great significance and practical value in the development and application of Atmospheric laser communication system.