高速移动MIMO-OFDM系统信道估计

发布时间：2018-03-04 02:06

本文选题：高速移动　切入点：MIMO-OFDM　出处：《杭州电子科技大学》2014年硕士论文　论文类型：学位论文

【摘要】：正交频分复用(Orthogonal Frequency Division Multiplexing，OFDM)技术具有抗多径干扰能力强、频谱利用率高、数据传输速率快和实现比较简单等优点，因而在无线通信领域引起了广泛的关注，并成为3G/4G标准的核心技术之一。多输入多输出(Multiple Input MultipleOutput，MIMO)技术在不增加系统带宽和天线总发射功率的前提下成倍的提高无线通信系统的容量和频谱效率。MIMO-OFDM技术融合了MIMO和OFDM技术的优点，，并被标准化组织确认为第四代移动通信系统的关键技术。随着高速铁路的快速发展，移动通信用户对高速移动环境下高速数据业务的需求日益增加，因此对高速移动环境下的OFDM和MIMO-OFDM系统的研究成为当务之急。本文针对高速移动环境下的OFDM和MIMO-OFDM系统的信道估计算法进行了深入研究。首先，本文分析了高铁环境下无线信道的特性，并详细分析了一种适合高铁环境的新莱斯衰落信道仿真模型；其次，针对高速移动OFDM系统中的子载波间干扰(Inter carrierinterference，ICI)进行了详细的分析,并在新莱斯衰落仿真信道模型下对各种常见的信道估计算法和插值算法分别进行了仿真对比与分析；再次，为了提高速移动OFDM系统的信道估计的精度，本文提出了一种基扩展模型(Base expansion model，BEM)联合反馈分组离散傅里叶变换(Discrete Fourier Transform，DFT)的信道估计算法，该算法通过BEM信道估计得到载波间干扰(Inter-Carrier Interference，ICI)系数项，并消除ICI得到反馈信息，再由分组DFT信道估计算法二次消除ICI和其他干扰项，仿真结果证实该算法可以有效的提高系统整体的性能；最后，为了提高高速移动MIMO-OFDM系统信道估计的性能，本文在传统的最优MIMO-OFDM系统导频序列基础上，提出了一种适用于高速移动MIMO-OFDM信道估计的导频序列，在插入该导频序列后MIMO-OFDM系统每一对收-发天线对可以看成是独立的SISO-OFDM系统，此时可以采用BEM信道估计算法得到每一对收-发天线之间的信道响应，再由MIMO检测模块获得各天线的输入信号估计值，并估计得到每对收-发天线上的ICI系数项，进而计算出反馈信号，最后利用分组DFT信道估计算法二次消除ICI和其他干扰项，仿真证实基扩展模型联合反馈分组离散傅里叶变换的信道估计算法适用于高速移动的MIMO-OFDM系统。
[Abstract]:Orthogonal Frequency Division Multiplexing OFDM (OFDM) technology has attracted wide attention in the field of wireless communication because of its strong ability to resist multipath interference, high spectral efficiency, fast data transmission rate and simple implementation. It has become one of the core technologies of 3G / 4G standard. Multi-Input-Multiple Input multiple output Mimo (MIMO-OFDM) technology has been integrated to improve the capacity and spectral efficiency of wireless communication system without increasing system bandwidth and antenna total transmit power. The advantages of MIMO and OFDM technology, With the rapid development of high-speed railway, the demand of mobile communication users for high-speed data services in high-speed mobile environment is increasing. Therefore, the research of OFDM and MIMO-OFDM systems in high speed mobile environment becomes urgent. In this paper, channel estimation algorithms for OFDM and MIMO-OFDM systems in high speed mobile environment are studied. Firstly, the characteristics of wireless channel in high-speed railway environment are analyzed, and a simulation model of Neo-Rice fading channel suitable for high-speed railway environment is analyzed in detail. In this paper, the inter carrier interference (ICI) in high speed mobile OFDM system is analyzed in detail, and a variety of common channel estimation algorithms and interpolation algorithms are compared and analyzed respectively under the simulation channel model of New Rice fading. Thirdly, In order to improve the accuracy of channel estimation for fast moving OFDM systems, this paper presents a channel estimation algorithm based on Base expansion Model (BEM) and discrete Fourier transform (DFT) combined feedback packet discrete Fourier transform (DFT). In this algorithm, the inter-carrier interference coefficient term is obtained by BEM channel estimation, and the feedback information is eliminated by ICI. Then the ICI and other interference items are eliminated twice by the packet DFT channel estimation algorithm. Simulation results show that the proposed algorithm can effectively improve the overall performance of the system. Finally, in order to improve the performance of channel estimation for high-speed mobile MIMO-OFDM systems, this paper is based on the traditional optimal pilot sequence of MIMO-OFDM systems. A pilot sequence suitable for high-speed mobile MIMO-OFDM channel estimation is proposed. After inserting the pilot sequence, each pair of transceiver antenna pairs in the MIMO-OFDM system can be regarded as an independent SISO-OFDM system. At this time, the channel response between each pair of transceiver antennas can be obtained by using BEM channel estimation algorithm, and then the input signal estimation value of each antenna can be obtained by the MIMO detection module, and the ICI coefficient term on each pair of transceiver antennas can be estimated. Then the feedback signal is calculated. Finally, the ICI and other interference items are eliminated twice by using the packet DFT channel estimation algorithm. The simulation results show that the channel estimation algorithm based on the basis extension model combined with the feedback packet discrete Fourier transform is suitable for the high-speed moving MIMO-OFDM system.
【学位授予单位】：杭州电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN919.3

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