Fig. 1. The structure of single-layer NN structure

Fig. 2. The characteristics of activation function

Fig. 3. The characteristics of Softmax function

Fig. 4. The structure of CNN

Fig. 5. The structure of RNN

Fig. 6. The structure of LSTM NN

Fig. 7. The structure of GAN

Fig. 8. The structure diagram of BiLSTM optical fiber communication model^[33]

Fig. 9. The structure of DNN^[34]

Fig. 10. The structure of DCNN^[35]

Fig. 11. The structure of IPCA-DNN^[37]

Fig. 12. The structure of SBRNN^[38]

Fig. 13. The basic schematic diagram of sliding window^[38]

Fig. 14. The structure of LDBP^[40]

Fig. 15. The structure of CNN+RNN^[41]

Fig. 16. The structure of AdaNN^[42]

Fig. 17. The schematic diagram of sliding window^[42]

Fig. 18. The structure of ANN+Adaboost algorithm^[43]