A Comprehensive Review of Digital Predistortion Techniques for Linearizing Nonlinear Wideband RF Power Amplifiers

The wideband RF power amplifier (PA) is one of the most important and expensive components in modern wireless systems. Unfortunately, wideband PAs suffer from inherent nonlinear distortion and memory effects, which degrade the wireless signal by introducing in-band distortion and out-of-band spectral regrowth. Backing off the analog output power can assure that the PA operates in the linear region, however, this traditional back-off approach leads to low power efficiency due to the high peak-to-average power ratio of the transmitted signals, e.g., multi-carrier UMTS signals or OFDM signals. Digital signal processing (DSP)-based pre-distortion has been proved as a promising approach that can digitally reduce the analogue nonlinear distortion of PAs and significantly enhance the system performance regarding the power efficiency and linearity. This paper presents a comprehensive survey-based tutorial on the digital predistortion (DPD) technique for linearizing nonlinear wideband RF power amplifiers. The surveyed schemes are comparatively analyzed based on three essential aspects of the DPD technique: pre-distortion algorithm validation platform design, behavioral model development, and parameters-extraction implementation. At the end of this paper, a brief discussion on the open issues and challenges is also presented regarding the DPD technique for current advanced and emerging wireless communication systems.