A Lightweight Coefficient Update Method for Linearization of Power Amplifiers With Frequent Power Variation

Abstract

Transmitting power levels of transmitters in modern communication usually change frequently, which complicates the digital predistortion (DPD) linearization of radio frequency (RF) power amplifiers (PAs). By studying the nonlinear behavior of the PAs, we find that there is a certain relationship between the DPD coefficients at different power levels. Therefore, this letter proposes an improved DPD model that uses one compensation factor to accommodate for PA nonlinear behaviors at different power levels. When the PA output power changes, only the compensation factor is recalculated through a simple estimation process. Therefore, the proposed DPD model is suitable for fast updates of model coefficients in scenarios where transmitting powers change frequently. Experimental results demonstrate the effectiveness of the proposed model. Specifically, the proposed model is enough to maintain a −50 dBc adjacent channel leakage ratio (ACLR) when the PA power changes.