基于子载波加权降低OFDM系统峰均功率比研究

无线通信越来越发展，传输数据速率要求越来越高的，采用传统的传输方法难度比较大。正交频分复用技术（OFDM - Orthogonal Frequency Division Multiplexing ）具有很强的抗干扰能力。OFDM 技术的主要思想是将传输信道分成很多个子信道，它们相互正交，频谱相互交叠。然而 OFDM 系统中有个固有的缺点就是信号存在很大的峰均功率比（ PAPR -Peak to Average Power Ratio），容易导致OFDM 信号的交调失真和系统性能的下降，所以，必须想办法将 OFDM信号的峰均功率比降低。本文进行深入研究 OFDM 系统的基本理论和关键技术;分析了各种降低OFDM PAPR 的方法，其中有预畸变技术、编码类技术和概率类技术三大研究方向。在这个基础上，主要研究了一种基于子载波加权，降低 OFDM 信号峰均功率比的算法。通过理论推导和计算机仿真分析 BER 曲线对 PAPR 的影响，优化加权系数。有效降低 OFDM 信号的PAPR，并且计算量相对较小，具有良好的实用价值。本文中，用 Matlab 变成软件仿真各种降低 PAPR 的算法并进行分析比较各种算法的性能。 59635
毕业论文关键字：正交频分复用；峰均功率比；部分序列传输；子载波加权；Matlab
Title ： Study of Subcarrier-weighted PAPR Reduction   in OFDM system   Abstract： With more and more development of wireless communication, the requirements of transmission rate has become increasingly higher, and it’s very difficult for the traditional transmission method to do it. Orthogonal Frequency Division Multiplexing technology (OFDM) , with its superior anti-interference ability , has involved more and more researchers in this direction. OFDM technology pides the channel into many sub-channels, each channel is orthogonal to each other, and the spectrum overlap, thus improves the channel utilization. However, there is an inherent weakness in OFDM system that the signal has a big Peak-to-Average Power Ratio (PAPR), which will easily lead to the distortion of the OFDM signal and the decline of the system performance, hence, it’s necessary to find ways to lower the PAPR of the OFDM system.   In this thesis, we carry out in-depth study of the basic theory and key technologies of OFDM system; analyze various methods of reducing PAPR of OFDM signal, mainly including pre-distortion technology, coding technology and probability class technology. On this basis, we propose an algorithm based on subcarrier weighted to reduce PAPR of OFDM signal. Through theoretical deduction and computer simulation, we analyze the impact of amplitude weighting coefficient on Bit Error Rate ( BER) and PAPR, and by selecting the weighting coefficients, we can get certain BER and PAPR. Under the guarantee of BER requirement, we can reduce the PAPR of OFDM signal, with a relatively small amount of calculation and a good practical value. In this thesis, we use the Matlab software for simulation of various algorithms in lowering PAPR and analyze the performance of various algorithms.
Keywords: OFDM;    PAPR;    Transmission of part of the sequence;     Subcarrier weighted; Matlab

1 绪论 .. 1

1.1 研究背景 .. 1

1.2 发展现状 .. 2

1.3 研究与论文内容 .. 5

2 OFDM 的基本理论 .. 7

2.1 OFDM系统的基本原理 .. 8

2.1.1 OFDM 系统模型 8

2.1.2 OFDM 信号的实现 .. 9

2.1.3 保护间隔和循环前缀 10

2.2 OFDM 系统的同步 . 11

2.3 信道估计 . 12

2.4 OFDM 系统的峰均功率比 12 基于子载波加权降低OFDM系统峰均功率比研究:http://www.751com.cn/tongxin/lunwen_64916.html