Experiment and numerical evaluation of bit error rate for free-space communication in turbulent atmosphere

Influenced by atmospheric turbulence, performance of the free-space optical (FSO) communication system fluctuates greatly. Research on evaluating system error performance according to parameters of system and atmosphere is a subject of current interest. Based on the optical turbulence channel and photoelectric detection model, a mathematic simulation model of error performance for the FSO communication system was modified, and an expression of bit error rate (BER) for the FSO communication system through turbulent atmosphere was proposed. Results of simulation were compared with former models and experimental data obtained in weak turbulence, and the model characterizes factors in turbulence, such as intensity fluctuation, variable shot noise, etc. Simulations showed that the results simulated by the modified model were more consistent with experimental data in most cases, and the detection threshold should be adjusted according to real atmosphere and signal intensity. The presented model could lead to an efficient performance evaluation and provide reference to correlative researches.

► Modified model to evaluate bit error rate of the free space optical communication system through atmospheric turbulence is proposed.
► Noise should be considered as variable of irradiance intensity.
► Accuracy of calculation relies on irradiance probability density function.
► Optimum threshold decreases with increasing scintillation index and irradiance intensity.
► Simulation results show good agreement with experimental data in most cases.