Advanced Doherty Architecture

For modulated signals with a high peak-to-average power ratio (PAPR), the transmitter has to be operated with its average output power backed off for an acceptable linearity at the expense of low efficiency. To achieve high efficiency and high linearity at the same time, both an efficiency enhancement technique and a linearization technique should be utilized. A powerful and reliable linearization technique, digital predistortion (DPD), is currently the most favored method for the linearization of base-station amplifiers [1]–[3]. Possible efficiency enhancement techniques are the hybrid envelope elimination and restoration/envelope tracking technique (H-EER/ET) and the Do-herty technique.