A Frequency-Domain Anti-Aliasing Digital Predistortion with Low Feedback Sampling Rate for Power Amplifiers Linearization

The soaring data of mobile communication services has resulted in energy consumption and environmental pollution. Enhancing the power efficiency of power amplifiers (PAs) is crucial for improving energy utilization and achieving green communication. Due to the inherent characteristics of PAs, when operating at high power efficiencies, PAs produce nonlinear distortions that lead to in-band distortion and out-of-band spectral leakage that pollute adjacent channels. To mitigate this nonlinearity, this paper proposes a frequency-domain (FD) antialiasing frequency-selective digital predistortion (FDAFS-DPD) scheme for Orthogonal Frequency Division Multiplexing (OFDM) systems. After analyzing the regularity of spectral aliasing caused by undersampling, we proposed the FDAFS-DPD model. The proposed FDAFS-DPD model can distinguish the FD information within the mixing in-band. In contrast to traditional time-domain nonlinear models, the FDAFS-DPD model enables direct selection of the target subcarriers to be corrected. Experimental results show that, compared to without DPD, with the proposed FDAFS-DPD scheme, the lower adjacent channel leakage ratio improves from –29.8 dBc to –35.3 dBc.