基于TD-LTE标准的高速移动通信系统中的多普勒频移估计

发布时间：2018-02-06 04:18

本文关键词： 多普勒频移高速移动铁路场景 TD-LTE协议　出处：《北京交通大学》2014年硕士论文　论文类型：学位论文

【摘要】：摘要：LTE作为首个全球推行的通信协议,现在已经广泛投入商业使用。本文的目的在于研究TD-LTE协议标准下高速铁路场景的多普勒频移估计。在高速场景下,移动台速度越快,信道的时变性越大,并且由于周边环境随着移动台的移动而变化,信道还呈现一定的非平稳特性。通过仿真,现有LTE导频图案在高速条件已经不能在接收端完全的信道估计。此外,多普勒频移还造成频域子载波的偏移,使子载波能量下降并相互干扰(ICI)。由此看出多普勒频移估计的重要性。对多普勒频移的研究能够提高对信道的认识,提高信道估计算法和ICI消除算法的准确性。本文以此思路展开对多普勒频移估计的研究,主要工作内容和创新点可以分为以下几个方面： (1)现有OFDM系统多普勒频移估计算法主要有时域自相关的估计思路和频域功率谱估计思路。本文通过仿真分析表明三种估计算法在LTE系统中的估计性能。 (2)多普勒功率谱在多普勒频域估计方法起到关键性作用。本文结合实际铁路场景,分析了各个场景信道特征和场景对应的多普勒功率谱。 (3)LTE下行物理层以OFDM技术为基础,具有自己规范的系统带宽、帧结构、导频图案等参数。LTE测试协议给出了2种MIMO信道,以抽头延迟线模型为基础的EPA模型和以基于几何图形的随机MIMO模型ITU模型。论文分析了MATLAB语言编写的LTE物理层仿真器,并依照测试协议,检测仿真器是否达到协议标准。 (4)使用合理的信道模型仿真实际信道,验证了多普勒估计算法在高速移动铁路场景中应用的可行性。通过本文的研究,给出了三种基于TD-LTE标准、高速铁路场景和多天线条件下能够正确估计的多普勒频移估计算法,并通过仿真分析为高速铁路专用移动通信网络设计及优化提供一定的依据和参考。
[Abstract]:As the first communication protocol in the world, LTE is the first one to be implemented in the world. The purpose of this paper is to study the Doppler frequency shift estimation of high-speed railway scene under the TD-LTE protocol standard. The faster the mobile station is in the high-speed scenario. The more time-varying the channel, and because the surrounding environment changes with the mobile station, the channel also presents a certain non-stationary characteristics. The current LTE pilot pattern can no longer be fully estimated at the receiver at high speed. In addition, the Doppler shift results in the offset of the subcarrier in the frequency domain. The subcarrier energy is reduced and the ICI is interfered with each other, which shows the importance of Doppler shift estimation. The study of Doppler frequency shift can improve the understanding of the channel. Improve the accuracy of channel estimation algorithm and ICI elimination algorithm. In this paper, the Doppler frequency shift estimation is studied in this paper. The main contents and innovations can be divided into the following aspects: 1). The existing Doppler frequency shift estimation algorithms for OFDM systems mainly include time-domain autocorrelation estimation and frequency-domain power spectrum estimation. 2) Doppler power spectrum plays a key role in Doppler frequency domain estimation. In this paper, the channel characteristics of each scene and the corresponding Doppler power spectrum of the scene are analyzed in combination with the actual railway scene. The downlink physical layer is based on OFDM technology. It has its own standard system bandwidth, frame structure, pilot pattern and other parameters. LTE test protocol gives two kinds of MIMO channels. EPA model based on tap delay line model and random MIMO model ITU model based on geometry. This paper analyzes the LTE physical layer simulator written in MATLAB language. And according to the test protocol, check whether the simulator meets the protocol standard. Finally, a reasonable channel model is used to simulate the actual channel, which verifies the feasibility of the Doppler estimation algorithm in the high-speed mobile railway scene. Through the research in this paper, three Doppler frequency shift estimation algorithms based on TD-LTE standard, high-speed railway scene and multi-antenna are presented. Through the simulation analysis, it provides a certain basis and reference for the design and optimization of the special mobile communication network of high speed railway.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN929.5

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