LAUSR

Predistortion techniques can be categorized into digital predistortion (DPD) and analog predistortion (APD), which are always implemented separately in their own domains. The baseband-domain mean square error (MSE) is the design target of DPD, and the RF-domain inter-modulation distortions (IMDs) are applied for APD. In this letter, we propose a hybrid MSE-IMDs based DPD framework that optimizes the above two criteria simultaneously. Specifically, to make the joint optimization possible, we define a new IMDs metric which can capture the DPD model coefficients. The classic recursive least square (RLS)-based DPD scheme is improved to balance the MSE and IMDs metrics without increasing the complexity.