数字预失真链路设计与算法研究

发布时间：2018-07-11 13:02

本文选题：功率放大器 + 非线性失真　；参考：《电子科技大学》2015年硕士论文

【摘要】：无线通信新技术的应用提高了频谱利用率,但也增大了传输信号的峰均功率比,当不采用功率回退方法降低射频功率放大器的效率时,具有高峰均功率比的宽带信号通过功放时更易产生非线性失真。效率与线性化程度的内在矛盾为功放线性化技术提出了新的挑战,其中,数字预失真技术由于兼顾功放的效率与线性度,并具有简单、灵活及自适应等特点,成为一种最有潜力的功放线性化方法。本文对数字预失真关键技术进行分析,并根据通信行业标准对数字基带预失真链路进行设计,在已有文献的基础上对预失真算法进行优化改进,降低了功放的非线性失真程度。论文的主要贡献包括:第一,对数字预失真链路进行需求分析与总体方案的制定,在此基础上完成链路的设计与验证,并对链路的影响因素:链路延时估计与补偿、幅度增益调整等问题进行讨论。第二,针对现有的查找表预失真算法精度低、空间需求较多等缺点,提出了一种新的查找表预失真算法,并详细描述了该算法的预调整值获取策略及查找表资源分配策略。当迭代次数为1次,查找表大小为30时,对基带数字功放进行预失真后得到仿真结果:第一邻道功率比、误差矢量幅度、归一化均方误差分别为79.04dBc/73.17dBc、0.0002%、-113.4549dB。第三,基于已设计的数字预失真链路对预失真算法性能进行验证,并借助输入输出特性曲线、功率谱及非线性失真指标等进行分析,仿真结果表明改进后的算法可以有效地改善功放的非线性失真程度,当迭代次数为1次,查找表大小为30时,对功放非线性系统进行预失真处理后得到仿真结果:第一邻道功率比、误差矢量幅度、归一化均方误差分别为62.94dBc/63.55dBc、0.1367%、-57.2709d B。
[Abstract]:The application of the new wireless communication technology improves the spectrum efficiency, but also increases the peak-to-average power ratio of the transmitted signal. When the power back method is not used to reduce the efficiency of the RF power amplifier, Wideband signals with peak to average power ratio are more prone to nonlinear distortion when they pass power amplifier. The inherent contradiction between efficiency and linearization presents a new challenge to the linearization technology of power amplifier. Among them, digital predistortion technology has the characteristics of simplicity, flexibility and self-adaptation due to the consideration of the efficiency and linearity of power amplifier. Become one of the most potential power amplifier linearization methods. In this paper, the key technology of digital predistortion is analyzed, and the digital baseband predistortion link is designed according to the communication industry standard. Based on the existing literature, the predistortion algorithm is optimized and improved to reduce the nonlinear distortion degree of power amplifier. The main contributions of this paper are as follows: first, the requirement analysis and overall scheme formulation of the digital predistortion link are carried out, and the link design and verification are completed on this basis, and the influencing factors of the link are estimated and compensated for the link delay. Amplitude gain adjustment and other issues are discussed. Secondly, aiming at the shortcomings of the existing look-up table predistortion algorithms, such as low precision and more space requirements, a new look-up table predistortion algorithm is proposed, and its pre-adjusted value acquisition strategy and lookup table resource allocation strategy are described in detail. When the number of iterations is 1 and the size of the lookup table is 30, the simulation results are obtained after pre-distortion of the baseband digital power amplifier: the first neighbor power ratio, the amplitude of the error vector, the normalized mean square error are 79.04 dBc / 73.17dBc / 0.0002 / -113.4549dBrespectively. Thirdly, based on the designed digital predistortion link, the performance of the predistortion algorithm is verified, and the input and output characteristic curve, power spectrum and nonlinear distortion index are analyzed. The simulation results show that the improved algorithm can effectively improve the nonlinear distortion of power amplifier. When the iteration number is 1, the lookup table size is 30. The simulation results are as follows: the first adjacent channel power ratio, error vector amplitude and normalized mean square error are 62.94 dBc / 63.55dBcn 0.1367db-1 -57.2709dB.The simulation results are as follows: the first channel power ratio, the error vector amplitude and the normalized mean square error are 62.94 dBc / 63.55dBcn 0.1367db.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN722.75

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