功率放大器数字预失真建模研究
发布时间：2018-08-20 12:55
【摘要】：步入移动互联网时代,宽带移动通信设备成为每个人生活中不可缺少的一部分。有了这些移动通信设备,移动通信用户可以使用社交软件和周围的世界保持着联系,利用新闻客户端获悉最新的新闻资讯,通过视频、音频应用享受当下的美好时光。移动通信用户的这些需求大大刺激了总信息传输量的增长,在频谱资源有限的现实条件下,迫切需要开发和利用有更高频谱利用率的调制技术,如OFDM,以达到在有限的频谱资源上传输更多的信息的目的。频谱利用率高的调制技术调制出非恒定包络的信号,这种信号在通过功率放大器(简称功放)这种通信设备中非常常见的电子器件时,由于功放的非线性特性,输出的信号会发生非线性失真,造成码间干扰和频谱扩展,严重影响了信号的正常传输。上述问题的解决办法是采用功率放大器的线性化技术,消除功放非线性带来的影响。预失真技术是功放线性化技术的一个重要分支,随着数字信号处理技术的发展,它逐步得到业界的青睐和重视。这篇论文对数字预失真技术展开了研究,主要的工作如下:(1)分析了功放产生非线性失真的原因,主要从谐波失真和互调失真两个方面进行了说明。(2)对常见的功放的行为模型进行了介绍,分别列出了无记忆和有记忆功放行为模型,分析了各种模型的适用场合。(3)针对无记忆和有记忆两种功放,分别应用了相应的预失真技术,分析了预失真参数的辨识方法。如无记忆预失真技术中,查找表技术里的极坐标预失真和增益预失真,给出了求解查找表项的迭代公式,同时详细阐述了非迭代地初始化查找表项的方法。记忆预失真技术中,给出了记忆多项式进行参数辨识的最小二乘法的求解过程。(4)介绍了两种自适应的学习结构,阐述了两种自适应算法的原理,提出了一种预失真结构框图,然后对无记忆多项式和有记忆多项式两种预失真技术进行了仿真研究,结合模型准确度评价指标归一化均方误差和误差矢量幅度,功率谱图以及相邻信道功率比等,对仿真实验的结果进行了分析,验证了预失真技术的有效性。
[Abstract]:In the era of mobile Internet, broadband mobile communication equipment has become an indispensable part of everyone's life. With these mobile devices, mobile users can use social software to keep in touch with the world around them, take advantage of news clients to get the latest news, and use video and audio applications to enjoy the good times. These demands of mobile communication users greatly stimulate the growth of total information transmission. Under the realistic conditions of limited spectrum resources, it is urgent to develop and utilize modulation technology with higher spectral efficiency. Such as OFDM, to achieve the purpose of transmitting more information on limited spectrum resources. The modulation technology with high spectral efficiency modulates the unsteady envelope signal. When the signal passes through the power amplifier (power amplifier), which is a very common electronic device in the communication equipment, it is due to the nonlinear characteristics of the power amplifier. Nonlinear distortion will occur in the output signal, resulting in inter-symbol interference and spectrum spread, which seriously affects the normal transmission of the signal. The solution to the above problem is to use linearization technology of power amplifier to eliminate the nonlinear effect of power amplifier. Pre-distortion technology is an important branch of power amplifier linearization technology. With the development of digital signal processing technology, it is gradually favored and valued by the industry. The main work of this thesis is as follows: (1) the causes of nonlinear distortion in power amplifier are analyzed. Mainly from the harmonic distortion and Intermodulation distortion two aspects are explained. (2) the common behavior models of power amplifier are introduced, and the memoryless and memorized amplifier behavior models are listed respectively. The applications of various models are analyzed. (3) for memoryless and memoryless power amplifiers, the corresponding predistortion techniques are applied, and the identification methods of predistortion parameters are analyzed. For example, in the memoryless predistortion technique, polar coordinate predistortion and gain predistortion in look-up table technology, the iterative formula for solving the look-up table items is given, and the method to initialize the look-up table items without iteration is described in detail. In memory predistortion technique, the process of solving the least square method for parameter identification by memory polynomial is given. (4) two adaptive learning structures are introduced, the principles of two adaptive algorithms are expounded, and a predistortion structure block diagram is proposed. Then, two kinds of pre-distortion techniques, memoryless polynomial and memoryless polynomial, are simulated and studied. The normalized mean square error and error vector amplitude, power spectrum and adjacent channel power ratio are combined with the model accuracy evaluation index. The simulation results are analyzed to verify the effectiveness of the predistortion technique.
【学位授予单位】：武汉理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN722.75
本文编号：2193675
[Abstract]:In the era of mobile Internet, broadband mobile communication equipment has become an indispensable part of everyone's life. With these mobile devices, mobile users can use social software to keep in touch with the world around them, take advantage of news clients to get the latest news, and use video and audio applications to enjoy the good times. These demands of mobile communication users greatly stimulate the growth of total information transmission. Under the realistic conditions of limited spectrum resources, it is urgent to develop and utilize modulation technology with higher spectral efficiency. Such as OFDM, to achieve the purpose of transmitting more information on limited spectrum resources. The modulation technology with high spectral efficiency modulates the unsteady envelope signal. When the signal passes through the power amplifier (power amplifier), which is a very common electronic device in the communication equipment, it is due to the nonlinear characteristics of the power amplifier. Nonlinear distortion will occur in the output signal, resulting in inter-symbol interference and spectrum spread, which seriously affects the normal transmission of the signal. The solution to the above problem is to use linearization technology of power amplifier to eliminate the nonlinear effect of power amplifier. Pre-distortion technology is an important branch of power amplifier linearization technology. With the development of digital signal processing technology, it is gradually favored and valued by the industry. The main work of this thesis is as follows: (1) the causes of nonlinear distortion in power amplifier are analyzed. Mainly from the harmonic distortion and Intermodulation distortion two aspects are explained. (2) the common behavior models of power amplifier are introduced, and the memoryless and memorized amplifier behavior models are listed respectively. The applications of various models are analyzed. (3) for memoryless and memoryless power amplifiers, the corresponding predistortion techniques are applied, and the identification methods of predistortion parameters are analyzed. For example, in the memoryless predistortion technique, polar coordinate predistortion and gain predistortion in look-up table technology, the iterative formula for solving the look-up table items is given, and the method to initialize the look-up table items without iteration is described in detail. In memory predistortion technique, the process of solving the least square method for parameter identification by memory polynomial is given. (4) two adaptive learning structures are introduced, the principles of two adaptive algorithms are expounded, and a predistortion structure block diagram is proposed. Then, two kinds of pre-distortion techniques, memoryless polynomial and memoryless polynomial, are simulated and studied. The normalized mean square error and error vector amplitude, power spectrum and adjacent channel power ratio are combined with the model accuracy evaluation index. The simulation results are analyzed to verify the effectiveness of the predistortion technique.
【学位授予单位】：武汉理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN722.75
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