Accurate Linearization with Low-Complexity Models Using Cascaded Digital Predistortion Systems

Power efficiency is one of the main concerns in modern radio frequency (RF) power amplifier (PA) design. However, efficiency-driven designs typically impose operation of these devices in a compressed mode [1]. When operating in this region, the amplifiers will behave nonlinearly and produce a distorted output signal [1]. This distortion produces new spectral components at the PAs\´ output that are outside the bandwidth of the input signal, so the distorted output signal has a wider bandwidth than the input signal. This bandwidth enlargement effect, called "spectral regrowth," is undesired in RF transmitters due to wireless systems\´ spectral mask regulations [2].