Joint PAPR Reduction and Digital Post-Distortion Transmission Framework for Nonlinear OFDM Systems

Orthogonal Frequency-Division Multiplexing (OFDM) signals inherently exhibit a high Peak-to-Average Power Ratio (PAPR). This forces the Power Amplifier (PA) to operate with large input back-off, resulting in substantial energy waste and posing a serious challenge for green communication. To address this, we propose a novel transmission framework that integrates a nonlinear companding-based PAPR reduction method with the Digital Post-Distortion (DPoD) technique to balance power efficiency and Bit Error Rate (BER) performance. To recover the transmitted signals, a Successive Decision Feedback Nonlinearity Equalizer (SDFNE) is developed at the receiver side. The SDFNE employs a time-domain least squares equalizer with closed-loop iterative feedback to jointly mitigate companding distortion and PA nonlinearity. The proposed framework balances transmitter-side PAPR suppression and receiver-side nonlinear equalization. This enables the PA to operate closer to its saturation point while achieving excellent BER performance. Meanwhile, compliance with spectral emission mask requirements is maintained. Numerical results on diverse PA models demonstrate that the proposed transmission framework with the SDFNE method significantly outperforms conventional nonlinear signal processing methods, including nonlinear companding, digital predistortion, and DPoD. Superior BER performance is achieved in a power-efficient manner, making the proposed framework particularly suitable for resource-constrained communication systems.