The Implementation Of Digital Baseband Predistortion Power Amplifier System

The development of wireless communication is causing a new round of change,has a profound change people’s production and life style. Power amplifier is a keycomponent to modern communication system, but the inherent nonlinear characteristics.The nonlinear will severely reduces the performance of communication system, whichwill lead to spectrum regeneration and interfere with adjacent channels, so that thesystem is difficult to meet the requirements. At the same time can lead to distortion atsignal band, make communication system decreases the bit error rate at the receiver.Early communication system using constant envelope technology, such as frequencymodulation, low demands for PA. However, with the strong drive of consumption,modern communication technology has a rapid development, such as the broadbandcode division multiple access technology, orthogonal frequency division multiplexingtechnique, global microwave internet access of application, make signal highpeak-to-average power ratios and high dynamic range, so we must improve thelinearization technology of the power amplifier to meet the requirements of the moderncommunication system. Digital pre-distortion technology is an effective method andlow-cost, which is becoming a hotspot.This paper mainly studies the adaptive digital baseband pre-distortion technologyto realize the linear power amplifier. First of all, introduce some basic parameter ofpower amplifier and non-linearization, and then analyses the power amplifiermemory-less model and memory model, and then to some existing power amplifierlinear technology are analyzed and compared, and finally puts forward some digitalbaseband pre-distortion design scheme.According to the digital baseband pre-distortion scheme requirements, this papercompleted a digital baseband pre-distortion realization on the hardware platform. Forthe involved module, this paper discusses the detail as far as possible all module inFPGA and DSP hardware platform realization process, and present a program at the keypart of the module, and show synthesis results and simulation results for verification.Finally through the dual signal and WCDMA signal to the digital baseband pre-distortion system tests verify the correctness and effectiveness of the scheme. Testresults show that WCDMA signal adjacent channels power improved15dB,16QAMsignal ACPR improved13dB, the testing result is achieved.