卫星信道下OFDM调制与信道估计研究

发布时间：2018-07-05 11:03

本文选题：OFDM + MQAM　；参考：《西安电子科技大学》2014年硕士论文

【摘要】：OFDM技术早于20世纪50年代提出,但是由于当时实际应用中实现的复杂度太高,还有其它一些原因没能够引起广泛的重视,所以一直没有发展起来。如今,经过几十年的发展和深入研究,OFDM已经成为一种可以保证数据高速传输的技术,同时也可以有效对抗多径信道产生的ISI的影响。OFDM具有频谱利用率高、抗多径的能力强、容易用IFFT和FFT实现、传输数据速率高、信道均衡简单等优点,在综合无线接入领域得到了广泛的应用。并且由于DSP技术的发展,MQAM高速调制技术的应用,信道编码技术以及软判决技术的成熟,都使得OFDM技术在如今的移动通信领域得到了深入的应用。本篇论文是在给定的S频段卫星信道的各项参数的情况下进行OFDM系统的设计,并且对于系统的一些关键问题进行独立研究。文章前两章是OFDM技术的一些基本信息,包括发展状况以及技术原理和使用环境等,后三章是本文的主要研究成果。具体如下：根据信道的参数对系统所使用的信道进行设计与建模；系统的具体搭建流程；OFDM符号的设计,具体对导频的插入格式做了详细的讨论；数据比特调制方式MQAM应用于OFDM系统中的性能分析；还有频率偏移对系统造成的具体影响,以及相位噪声对系统影响的具体分析,相位噪声导致的影响又包括星座图旋转和发散两类；最后对信道估计的算法进行的比对和研究,具体到信道估计对多径、频偏、相噪以及噪声的估计情况。所有的研究都基于MATLAB平台进行仿真以及验证,最后对这些问题整合进行了综合研究,采取合适的数据比特调制方式、采用最优的导频插入格式、选用最佳的信道估计方法,最终综合同步以及信道编码等模块,在卫星信道参数下使系统的整体误码率性能达到最优。
[Abstract]:OFDM technology was put forward in the 1950s, but because of the high complexity of practical application at that time, there are some other reasons can not attract widespread attention, so it has not been developed. Nowadays, after decades of development and in-depth research on OFDM, it has become a technology that can guarantee the high-speed transmission of data. At the same time, it can effectively counteract the influence of ISI generated by multipath channels. OFDM has high spectral efficiency and strong anti-multipath capability. It is easy to be implemented by Ifft and FFT. It has the advantages of high data rate and simple channel equalization. It has been widely used in the field of integrated wireless access. Because of the development of DSP technology, the application of MQAM high speed modulation technology, the maturity of channel coding technology and soft decision technology, OFDM technology has been deeply applied in the field of mobile communication. In this thesis, the OFDM system is designed under the given parameters of the S-band satellite channel, and some key problems of the system are studied independently. The first two chapters are some basic information of OFDM technology, including the development situation, the technical principle and the use environment, etc. The last three chapters are the main research results of this paper. The main contents are as follows: the channel used in the system is designed and modeled according to the parameters of the channel, and the design of OFDM symbols is discussed in detail, and the pilot insertion format is discussed in detail. The performance analysis of the data bit modulation MQAM in OFDM system, the specific influence of frequency offset on the system, and the effect of phase noise on the system are discussed. The effects caused by phase noise include rotation and divergence of constellation. Finally, the comparison and research of channel estimation algorithms are carried out, especially the estimation of channel estimation for multipath, frequency offset, phase noise and noise. All the researches are based on MATLAB platform for simulation and verification. Finally, the integration of these problems is comprehensively studied, adopting the appropriate data bit modulation method, adopting the optimal pilot insertion format, and selecting the best channel estimation method. Finally, by synthesizing the synchronization and channel coding modules, the overall BER performance of the system is optimized under the satellite channel parameters.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN929.53

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