OFDM系统峰均比抑制算法研究

发布时间：2018-05-20 19:05

本文选题：正交频分复用 + 峰均比　；参考：《东北大学》2012年硕士论文

【摘要】：正交频分复用(OFDM, Orthogonal Frequency Division Multiplexing)技术因其具有较高的频谱利用率、能有效对抗多径衰落、消除符号间干扰等优势已成为未来第四代多媒体移动通信系统的关键传输技术之一,在天线、导航、航空航天等领域具有广阔的应用前景。然而,OFDM技术传输过程中存在峰均比(PAPR, Peak-to-Average Power Ratio)较高的问题,对功率放大器、A/D转换器等设备的线性范围提出很高的要求,严重影响整个通信系统的运行成本和效率。因此,研究峰均比抑制技术具有深刻的理论意义和应用价值。本文深入研究了OFDM系统的基本原理,详细介绍了各部分的实现及系统基本参数的选择,针对其特点阐述了OFDM系统中的关键技术,概括了OFDM系统的主要优缺点,重点分析了高峰均比问题产生的原因及其对系统性能的影响。在此基础上,详细分析了峰均比抑制的各类技术,包括预畸变技术、编码类技术和概率类技术,并简单介绍了三类技术中的典型算法,为峰均比抑制算法的提出提供理论基础。本文重点研究了选择性映射(Selected Mapping, SLM)算法,针对SLM算法中需要传送额外边带信息的缺点,本文提出了基于边带信息隐藏的SLM算法,该算法通过在发送端插入导频符号,在接收端利用导频符号本身携带的信息来确定随机相位序列,从而避免传输边带信息,节省了带宽资源。进一步考虑改善系统峰均比性能,本文提出了基于子块分割的SLM算法,该算法采用不同的分割方式对数据流进行分块,通过对不同子块分别进行相位优化,选择具有最小峰均比性能的组合信号进行传输,显著扩大相位因子搜索空间,从而获得良好的峰均比性能。仿真实验证明了所提两种算法的有效性。
[Abstract]:Orthogonal Frequency Division Multiplexing (OFDM) and Orthogonal Frequency Division Multiplexing) (orthogonal Frequency Division Multiplexing) (OFDM) have become one of the key transmission technologies in the fourth generation multimedia mobile communication systems in the future because of their high spectral efficiency, which can effectively resist multipath fading and eliminate inter-symbol interference. Navigation, aerospace and other fields have a broad application prospects. However, the problem of high peak to average ratio (PAPR), Peak-to-Average Power Ratio (peak to average ratio) exists in the transmission process of OFDM.The linear range of power amplifier / A / D converter is very high, which seriously affects the operation cost and efficiency of the whole communication system. Therefore, the study of PAPR suppression technology has profound theoretical significance and application value. In this paper, the basic principle of OFDM system is deeply studied, the realization of each part and the selection of system basic parameters are introduced in detail. According to its characteristics, the key technologies in OFDM system are expounded, and the main advantages and disadvantages of OFDM system are summarized. The reason of peak to average ratio problem and its influence on system performance are analyzed. On this basis, various techniques of PAPR suppression, including predistortion, coding and probabilistic techniques, are analyzed in detail. The typical algorithms of the three kinds of techniques are briefly introduced, which provide a theoretical basis for the PAPR suppression algorithm. This paper focuses on the selective mapping selected Mapping (SLM) algorithm. In view of the disadvantages of the SLM algorithm which needs to transmit extra sideband information, this paper proposes a SLM algorithm based on sideband information hiding, which inserts pilot symbols at the sending end. The random phase sequence is determined by using the information carried by the pilot symbols at the receiving end, thus avoiding the transmission of sideband information and saving bandwidth resources. In order to improve the PAPR performance of the system, a new SLM algorithm based on sub-block segmentation is proposed in this paper. The algorithm uses different segmentation methods to divide the data stream into blocks and optimizes the phase of different sub-blocks. A combination signal with minimum peak-to-average ratio (PAPR) is selected for transmission and the phase factor search space is significantly expanded to obtain good PAPR performance. Simulation results show the effectiveness of the proposed two algorithms.
【学位授予单位】：东北大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TN929.53

【参考文献】