A Novel Method to Linearize Power Amplifiers with Reduced Sampling Rate Required for DPD Processing and DACs

Digital predistortion (DPD) is widely applied to linearize power amplifiers (PAs) for wireless communication systems. A predistorted signal is usually associated with spectral regrowth, just like a nonlinear-distorted signal of PA output. To generate such predistorted signal, a high sampling rate, which is usually five times the source signal bandwidth, is required in a DPD-enabled transmitter for both the digital-signal-processing (DSP) and digital-to-analog converter (DAC). This paper investigates a novel approach to significantly reduce the required sampling rate for both the DSP of predistortion and DAC. The main idea is to generate nonlinear components of the predistorted signal by utilizing the nonlinearity of devices such as the DAC. Hence, the DPD only needs to perform a linear operation on the source signal, and the required sampling rate could be reduced to the same as the source signal bandwidth. For a DPD-enabled transmitter, this novel DPD approach is a potential solution for reducing the cost and power consumption, which are spent on the high-sampling-rate DAC and DSP unit.