OFDM系统符号定时同步研究及实现

发布时间：2018-06-07 19:24

本文选题：OFDM + 符号定时同步算法　；参考：《电子科技大学》2014年硕士论文

【摘要】：近年来,正交频分复用技术广受人们的关注,其优点主要有灵活的资源分配和抗噪声性能以及抵抗多路径干扰性能良好。在下一代的4G无线通信系统中它已成为了核心关键技术。而OFDM作为一种含有多个子载波的系统,同步误差对系统的影响十分巨大,因此在目前的通信领域中,同步已经成为了一个研究热点。首先,本文概述了课题研究的背景,包括正交频分复用技术的发展历程及其主要的优缺点和目前该课题的研究面貌,然后分别介绍了OFDM系统的基本传输模型和数学信号模型,并且详细分析了各类同步误差对系统性能造成的影响,进一步表明了同步问题对于OFDM系统的重要性。其次,本文主要研究了OFDM符号定时同步算法。在数据辅助型算法的基础上,提出了两种改进的符号定时算法,它们克服了SchmidlCox算法和Minn算法中定时测度曲线存在导致估计模糊的平台现象和多尖峰现象,同时相比Park算法在不同信道中有了更优异的性能表现,两种提出的算法都只存在一个尖峰,它们都是基于在接收端匹配滤波的思想,因此提高了符号定时同步的精度。最后,本文对IEEE802.11a物理层参数和帧结构做了简要的描述,然后介绍了基于该标准的几种符号定时同步算法,并且进行了仿真分析。在此基础上将这两个模块分别在FPGA上进行了实现,并与软件仿真进行了比较,证明了算法的可行性,然后与系统的其他模块在硬件上进行了联调,分析了实验数据。
[Abstract]:In recent years, orthogonal Frequency Division Multiplexing (OFDM) technology has attracted much attention. Its main advantages are flexible resource allocation, anti-noise performance and good resistance to multi-path interference. It has become the key technology in the next generation 4G wireless communication system. As an OFDM system with multiple subcarriers, synchronization error has a great impact on the system. Therefore, synchronization has become a research hotspot in the field of communication. Firstly, this paper summarizes the background of the research, including the development of orthogonal Frequency Division Multiplexing (OFDM) technology, its main advantages and disadvantages, and the present situation of the research, then introduces the basic transmission model and mathematical signal model of OFDM system, respectively. The effect of various synchronization errors on the system performance is analyzed in detail, which further shows the importance of synchronization problem to OFDM systems. Secondly, this paper mainly studies OFDM symbol timing synchronization algorithm. On the basis of data aided algorithm, two improved symbolic timing algorithms are proposed. They overcome the platform phenomenon and multi-spike phenomenon in SchmidlCox algorithm and Minn algorithm due to the existence of timing measure curve. At the same time, compared with Park algorithm in different channels, there is only one spike in both algorithms, which are based on the idea of matched filtering at the receiver, so the precision of symbol timing synchronization is improved. Finally, this paper briefly describes the physical layer parameters and frame structure of IEEE 802.11a, then introduces several symbol timing synchronization algorithms based on this standard, and carries out simulation analysis. On this basis, the two modules are implemented on FPGA, and compared with the software simulation, the feasibility of the algorithm is proved, and then the hardware is combined with other modules of the system, and the experimental data are analyzed.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN929.53

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