A Joint Crest Factor Reduction and Digital Predistortion for Power Amplifiers Linearization Based on Clipping-and-Bank-Filtering

Abstract : The power efficiency and the linearity of a power amplifier (PA) depend on its operating point. A high efficiency generally corresponds to poor linearity. To optimize the efficiency/linearity trade-off, crest factor reduction (CFR) techniques are classically implemented along with digital predistortion (DPD) to control the PA operating point. Joint CFR/DPD can be realized with a single model so that the running complexity of the CFR is negligible. This paper fully explores the clipping-and-bank-filtering (CABF) method for joint CFR/DPD and extends it to the multi-carrier case with validation on experimental results. Compared with conventional approaches, it provides either better linearization performance or lower complexity at the same PA operating point. The study is completed with a discussion on the choice of windows in the filter bank. The proposed CABF-based joint CFR/DPD model is then experimentally evaluated on a test bench with two PAs using single-carrier and 2-carrier 20~MHz long term evolution (LTE) signals as the stimulus.