A Modified Decomposed Vector Rotation-Based Behavioral Model With Efficient Hardware Implementation for Digital Predistortion of RF Power Amplifiers

Abstract

This paper proposes a novel hardware implementation strategy to achieve low-cost design for digital predistortion of radio frequency power amplifiers (PAs) using a modified decomposed vector rotation-based behavioral model. To make the model hardware friendly, we first modify the model into a subdecomposed format, which significantly reduces the computational complexity in model extraction. We then reassemble the coefficients and propose a simple digital implementation structure for real-time signal processing in the transmit path. A new dual-direction coordinate rotation digital computer design is also proposed to simultaneously calculate both magnitude and ${e}^{j{\theta }_{n}}$ values to facilitate the model implementation. To validate hardware implementation, a wideband signal is employed to evaluate the performance with a Doherty PA. Experimental results show that the proposed approach can achieve comparable performance with much lower system complexity compared with that using the conventional approaches.