Nonlinear Multicarrier Transmitter System With Signal Clipping: Measurement, Analysis, and Optimization

Abstract

Signal clipping is a well-established method employed in orthogonal frequency division multiplexing (OFDM) systems to mitigate peak-to-average power ratio. The utilization of this technique is widespread in electronic devices with limited power or resource capabilities due to its high efficiency and low complexity. While clipping effectively diminishes nonlinear distortion stemming from power amplifiers (PAs), it introduces additional distortion known as clipping distortion. The optimization of system performance, considering both clipping distortions and the nonlinearity of PAs, remains an unresolved challenge due to the intricate modeling of PAs. In this article, we undertake an analysis of PA nonlinearity utilizing the Bessel–Fourier PA model and simplify its power expression through intermodulation product analysis. We mathematically derive expressions for the receiver signal-to-noise ratio and system symbol error rate (SER) for nonlinear clipped OFDM systems. Using these derivations, we explore the optimal system configuration required to achieve the lower bound of SER in practical OFDM systems, taking into account both PA nonlinearity and clipping distortion. The results and methodologies presented in this article contribute to an improved comprehension of system-level optimization in nonlinear OFDM systems employing clipping technology.