Fig. 1. Wireless ultraviolet NLOS single scattering channel model

Fig. 2. Wireless ultraviolet channel estimation scheme based on deep neural network

Fig. 3. Basic structure of a single neuron

Fig. 4. Training phase flow chart of DE-DNN

Fig. 5. PDF curves of received optical signal intensity under different parameters. (a) Communication distance; (b) elevation angle of transceiver; (c) turbulence intensity

Fig. 6. Influence of elevation angle on transmission attenuation

Fig. 7. Variation curves of transmission attenuation with communication distance under different turbulence intensities

Fig. 8. MSE curves under different DNN model structures. (a) Number of hidden layers; (b) Number of neurons per hidden layer

Fig. 9. Comparison of the convergence speed of two optimization algorithms

Fig. 10. Channel response coefficient estimation results of different algorithms

Fig. 11. Comparison curves of channel estimation performance of different algorithms. (a) MSE; (b) BER

Fig. 12. Influence of turbulence intensity on the estimation performance of DE-DNN