Modeling RF Power Amplifiers and Increasing Transmitter Linearity with DPD Using MATLAB

RF power amplifiers lie at the front end of most RF systems, including wireless communications and radar systems, and are critical in ensuring the appropriate range of wireless systems. However, these amplifiers contain non-idealities that can cause performance degradation of the systems they drive when deployed in the real world. To mitigate this performance degradation, you can apply linearization algorithms including DPD as part of the transmitter or receiver chain. DPD algorithms aim to preemptively distort the waveform to be transmitted to counter the nonlinear effects of the power amplifier. Since these wave-forms are often wide-band, they must typically be implemented on FPGA/ASIC to achieve real-time performance.DPD algorithms should be designed in the context of the full system because performance is largely dependent on the system in which it is placed. Simulation provides an early-stage behavioral model of the full system and makes it possible to develop the DPD algorithm early without dependency on hardware. System design and simulation with
Simulink also provides a framework to validate the algorithm and other components later in development and can produce repeatable results that are hard to achieve with real RF hardware in the lab. In addition, you can use Simulink to create bit- and cycle-accurate models of algorithms as they would run on firmware. You can also generate production-quality HDL code from these models.In this paper, we discuss the challenges around RF power amplifier design with a focus on RF imperfections,as well as a workflow for modeling PAs and increasing linearity with DPD.