Analytical and Adaptive Modeling of Nonlinear High Power Amplifiers

Abstract

High‐power amplifiers are used in modern communication systems for their high‐power efficiency. However, these amplifiers have generally nonlinear characteristics, leading to signal distortion and adjacent channel interference. We review the most popular analytical models for these nonlinear characteristics. A special focus is given to adaptive models—mainly neural network approaches—which have emerged as efficient tools for the modeling, identification, and characterization of nonlinear amplifiers.

Performance analysis of nonlinearly amplified M‐QAM signals in MIMO channels

“…However, the characteristics function of amplifiers (see Figure 2 below) are such that at small signal conditions they behave like a linear device while at medium or high signal levels, they introduce significant nonlinear distortions into the transmitted signals [2]. These nonlinear distortions introduce the spectral re-growth, which causes adjacent channel interference (ACI) in a multiuser communication channel [3]. The severities of these HPA nonlinear distortions increase with the efficiency operating points of the amplifiers.…”