| In 3G communication systems,in order to pursue a high transmission data rates, it requires to increase system bandwidth. The modulation of 3G system, such as orthogonal frequency division multiplexing (OFDM), will lead to their signals with high PAPR which non-linear distortion have a greater impact on. On the other hand,with the issuance of 3G licenses, operators became a growing concern about somethings, such as the large-scale construction of the network communication systems, improving power amplifier efficiency and reduce investment costs. Therefore the linearization technique for power amplifier is necessary.Chapter 1 of this thesis, first proposed the necessity of the linearization technique for power amplifier and discusses the development of digital pre-distortion technology; chapter 2 bases the analysis of nonlinear characteristics of RF power amplifiers and its technical indicators for non-linear characteristics, and then proposes the basic ideas about how to set up non-linear RF power amplifier model; chapter 3 discusses the basic principles, structures of the digital predistortion technology as well as CFR technology. It analyses the feasibility of the adaptive digital pre-distortion system. chapter 4 gives a feasible optimization scheme on fulfilling algorithms for digital pre-distortion technology, including algorithm and simulation using MATLAB. Simulation results show us that pre-distortion results for the power amplifier with non-memory effect are satisfactory. chapter 5 researchs the digital pre-distortion technology, hardware circuit design and explores the working methods for the various functional modules. Finally the test results show that this DPD scheme is feasible. For WCDMA signal, ACPR can be improved more than 10dBc, so it can put into use; chaper 6 of the text are summarized. |
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