Receiver-Assisted Nonlinear Compensation of Power Amplifier for PD-NOMA

Nonorthogonal multiple access (NOMA) can further improve spectral efficiency by sharing a single radio resource among multiple users to meet the increase in demand. However, in practical NOMA wireless communications, the nonlinear distortions introduced by the power amplifier (PA) cannot be ignored and thus affect the bit error rate (BER) of users. Existing nonlinear compensation methods, such as random Fourier feature (RFF)-based solution, are suitable for compensating for the narrowband signals. With the increase of signal bandwidth, the compensation effect of the model and identification method used in this method decreases. To address this issue, this letter proposes a post-compensation method based on the preamble. In this method, we introduce the preamble as training data to identify the nonlinearity of the wireless communications system. The experimental results show that the proposed method can effectively compensate for the nonlinear distortion of large-bandwidth signals and significantly reduce the users' BER.