Low-complexity weighted regular perturbation model-based symbol rate power profile estimation

In this work, we propose a low-complexity fiber longitudinal power profile estimation (PPE) method operating at the symbol rate, based on the weighted first-order regular perturbation model (WRP1). The WRP1 model introduces inter-symbol nonlinearity into the nonlinear operator by incorporating nonlinear phase rotation caused by both the current symbol and its adjacent symbols. Evaluated in a 130 GBaud DP-16QAM 3-span × 50 km numerical transmission system, the proposed WRP1-based PPE achieves accurate power estimation with a mean absolute error (MAE) of 0.56 dB across all positions and 0.02 dB MAE at erbium-doped fiber amplifier (EDFA) positions. This accuracy is comparable to the extensively studied waveform-level PPE that employs 2 samples per symbol of oversampled data. Moreover, the WRP1-based PPE reduces computational complexity by over 52% compared to waveform-level PPE, which is conducive to the practical implementation of PPE technology. Furthermore, additional numerical simulations verify that the proposed WRP1-based PPE is robust across different transmission scenarios, including variations in transmission distance, modulation format, launch power, and insertion loss.