Different Digital Predistortion Techniques for Power Amplifier Linearization

Linearity and high efficiency are crucial requirements for any power amplifier. However, power amplifiers have high efficiency levels when they are in non-linear regions. To overcome this issue there have been many suggestions in literature, one of the most successful methods is digital predistortion method. Digital predistortion (DPD) method’s low resource usage and fairly easy algorithm draws a lot of researcher’s attention. Many different methods are suggested for DPD algorithms. Volterra series based methods draws even more attention due to its flexibility and easy implementation. However, deciding which method to use for DPD purposes is not completed even when Volterra series based method is chosen. There are many different Volterra series based methods which differ from each other. This paper examines 5 different Volterra based methods for DPD purposes and tests them in 2 different PAs with LTE signals. Also forward behavioral modelling performance of these 5 methods are also examined for each PA with same signals. In chapter 1 needed theoretical information is explained about power amplifier characteristics. In chapter 2, the five chosen methods are examined in detail and corresponding parameters are explained. In chapter 3, forward behavioral modelling setup and the way to model power amplifiers is explained. In chapter 4, setup and the digital predistortion algorithms are explained. In the 5th chapter the results of both behavioral modelling and DPD is shown and comments on the results are given.