本文關鍵詞： 多普勒頻移 高速移動 鐵路場景 TD-LTE協(xié)議　出處：《北京交通大學》2014年碩士論文　論文類型：學位論文

【摘要】：摘要：LTE作為首個全球推行的通信協(xié)議,現(xiàn)在已經廣泛投入商業(yè)使用。本文的目的在于研究TD-LTE協(xié)議標準下高速鐵路場景的多普勒頻移估計。在高速場景下,移動臺速度越快,信道的時變性越大,并且由于周邊環(huán)境隨著移動臺的移動而變化,信道還呈現(xiàn)一定的非平穩(wěn)特性。通過仿真,現(xiàn)有LTE導頻圖案在高速條件已經不能在接收端完全的信道估計。此外,多普勒頻移還造成頻域子載波的偏移,使子載波能量下降并相互干擾(ICI)。由此看出多普勒頻移估計的重要性。對多普勒頻移的研究能夠提高對信道的認識,提高信道估計算法和ICI消除算法的準確性。 本文以此思路展開對多普勒頻移估計的研究,主要工作內容和創(chuàng)新點可以分為以下幾個方面： (1)現(xiàn)有OFDM系統(tǒng)多普勒頻移估計算法主要有時域自相關的估計思路和頻域功率譜估計思路。本文通過仿真分析表明三種估計算法在LTE系統(tǒng)中的估計性能。 (2)多普勒功率譜在多普勒頻域估計方法起到關鍵性作用。本文結合實際鐵路場景,分析了各個場景信道特征和場景對應的多普勒功率譜。 (3)LTE下行物理層以OFDM技術為基礎,具有自己規(guī)范的系統(tǒng)帶寬、幀結構、導頻圖案等參數。LTE測試協(xié)議給出了2種MIMO信道,以抽頭延遲線模型為基礎的EPA模型和以基于幾何圖形的隨機MIMO模型ITU模型。論文分析了MATLAB語言編寫的LTE物理層仿真器,并依照測試協(xié)議,檢測仿真器是否達到協(xié)議標準。 (4)使用合理的信道模型仿真實際信道,驗證了多普勒估計算法在高速移動鐵路場景中應用的可行性。 通過本文的研究,給出了三種基于TD-LTE標準、高速鐵路場景和多天線條件下能夠正確估計的多普勒頻移估計算法,并通過仿真分析為高速鐵路專用移動通信網絡設計及優(yōu)化提供一定的依據和參考。
[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.
【學位授予單位】：北京交通大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TN929.5

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本文編號：1493556