Power amplifier is one of the most important module of transceiver design. Linearity and efficiency are the two main areas of improvement in power amplifier design. Fifth generation (5G) mobile communication is one of the most important application of power amplifier, which require power amplifiers that are extremely linear and efficient. In this paper, review of different efficiency enhancement and linearization techniques has been undertaken. Basic architecture, advantages, and challenges of efficiency enhancement techniques—outphasing, Doherty, and envelope tracking—have been discussed. Linearization techniques—feedback, feedforward, and predistortion—have also been discussed in this paper.

中文翻译：

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功率放大器的效率增强技术和线性化技术综述

功率放大器是收发器设计中最重要的模块之一。线性和效率是功率放大器设计的两个主要改进领域。第五代（5G）移动通信是功率放大器最重要的应用之一，它需要极其线性和高效的功率放大器。在本文中，已经对不同的效率增强和线性化技术进行了回顾。已经讨论了效率增强技术的基本体系结构，优点和挑战（过时，Doherty和包络跟踪）。本文还讨论了线性化技术（反馈，前馈和预失真）。