Research On Broad-Band Digital Pre-distortion Technology

While wireless communication systems have deep in the full access to 3G andstarted the process to 4G. The use of digital pre-distortion (hereinafter referred to as DPD)on the transmitter power amplifier linearization is a key technology. Power amplifier is akey component that affect system performance and coverage, and nonlinear is one of theinherent characteristics of power amplifier. Nonlinear will cause spectra lre-growth, andresulting in adjacent channel interference, so that stray can not reach agreement with thestandard requirements. Nonlinear can also cause in-band nonlinear distortion, bringingthe problem of increases bit error rate.In order to ensure the power amplifier linearity and efficiency, a variety of methods canbe used for linearization of power amplifier, such as feedback, feed forward and digitalpre-distortion method. In all of these linearization techniques, digital pre-distortion is acost-effective technology.In response to improve power amplifier efficiency and power amplifier linearization,the main research work carried out in this article are as follows:1. Combined with Agilent’s Advanced Design System software (ADS) and Freescale’spower amplifier empirical model and completed the Doherty amplifier design based onload-pull theory. provides valuable experience and a clear direction for improvement forfollow-up study.2. Compared to a variety of pre-distortion model by using of direct training method ,focusing on the look-up table in the baseband pre-distorter adding adaptive equalizer toremove the power amplifier memory technology, and the structure of the algorithm issimplified. Finally, testing the effect of the algorithm through MATLAB simulation.