本文關鍵詞： 信道測量 空間信道建模 雙站合成孔徑雷達 高鐵無線通信信道 多輸入多輸出　出處：《電子科技大學》2017年博士論文　論文類型：學位論文

【摘要】：20世紀90年代后期,多輸入多輸出(Multiple-Input Multiple-Output,MIMO)技術的興起為無線數字通信系統(tǒng)帶來了一場技術革新。與正交頻分復用技術相結合,MIMO已成為從IEEE802.11無線局域網到4G LTE(Long Term Evolution)系列通信技術的物理層標準,也是5G移動通信以及高速列車無線通信建議規(guī)范LTE-R(LTE for Railway)的關鍵核心技術。為了更好的評估、設計和優(yōu)化MIMO系統(tǒng),最有效和最直接的方法就是理解MIMO信道傳播機制的空間多樣性、定位信道傳播環(huán)境中的散射體,從而探測每個信道沖激響應分量的出發(fā)和達到方向,分析接收天線之間的衰落相關性和預測通信鏈路的可靠性和容量。目前,獲取MIMO信道空域特征的信道測量技術通常有兩類方法:機械轉動定向天線法和多天線系統(tǒng)測試法。其中,機械轉動定向天線的方法,除了耗時以外,只適用于靜態(tài)信道或者較低多普勒頻率信道的測量。隨著天線陣列的增大,多天線系統(tǒng)測試法需要對收集到的測試數據進行大量后處理,即使采用高性能的陣列方向估計算法,如MUSIC、SAGE、和ESPRIT,運算復雜度也很高,系統(tǒng)成本大。然而對于一些特殊的場景,如高速鐵路列車(High-Speed Railway,HSR)無線信道環(huán)境,除了高速移動性以外,極高的安全性要求也讓信道測量工作者難以在現有的HSR運行平臺上布局復雜的信道探測設備,使得傳統(tǒng)的信道測量方法難以實施。基于特定通信場景的空間信道模型是發(fā)展基于MIMO無線新技術標準的重要基礎,也是評定特定環(huán)境下MIMO技術性能的根本出發(fā)點。本文以高速鐵路列車無線通信系統(tǒng)為背景,探討高速運動場景下進行MIMO信道測量的有效新方法。本文的主要工作如下:1.提出一種基于雙站合成孔徑雷達(Bistatic Synthetic Aperture Radar,BiSAR)技術的新穎信道測量方法。本文將信道測量問題投影到BiSAR場景重構技術中,建立了一個固定發(fā)射機和勻速運動車載接收機信道傳播環(huán)境下的ST-BiSAR(Stationary Transmitter BiSAR)幾何模型。該模型很好地匹配了鐵路HSR無線通信的特定場景,通過BiSAR的場景重構技術定位信道中的散射體,從而提取信道特征,簡化信道測量。2.設計基于ST-BiSAR技術的信道仿真器。信道仿真器將具體的無線通信信道場景映射到ST-BiSAR的幾何模型中,分析成像空間的三維分辨率,設計合理的三維成像算法,重構出三維信道場景;基于信道散射體的三維分布地圖,提取出信道特征參數。根據成像的散射體圖像性能,對比信道特征參數的仿真結果和理論數值,評估出系統(tǒng)性能。本文利用信道仿真器對HSR信道的仿真分析結果,驗證了基于ST-BiSAR技術的信道測量方法是可行的。3.實現ST-BiSAR通信環(huán)境的三維場景重構。本文采用經典時域back-projection(BP)算法生成多層二維場景平面圖像,利用多普勒聚焦原理提取散射體的高度信息,構建出信道散射體的三維地圖。通過分析散射體的聚焦成像性能、散射體的成像地圖和信道的特征參數值,驗證了本文采用的三維信道成像技術是有效的。4.分析影響散射體成像或信道特征參數提取的因素。本文從散射體的位置分布、合成孔徑的時間、探測信道的帶寬和成像圖像的分辨率等方面,詳細討論了這些因素在不同參數設置下對散射體成像性能、信道特征參數提取的影響。從而為未來的研究工作提供參考。5.開展基于ST-BiSAR技術的信道測量現場試驗。在充分利用現有設備的基礎上,根據最大化性能、最小化成本的原則,本文設計了以通用軟件無線電平臺(Universal Software Radio Peripheral,USRP)為核心設備的信道探測發(fā)射端和接收端。通過平臺傳輸測試、靜止測距和位置定位能力對ST-BiSAR信道探測平臺的性能進行了驗證測試。開展了以固定的車載發(fā)射機和近乎勻速運行的車載接收機布局的ST-BiSAR無線通信場景的現場試驗。通過試驗的初步結果進一步驗證了基于ST-BiSAR技術信道測量方法的工程實踐性,并指出信道探測設備需要改進的地方。綜上所述,本文提出的基于BiSAR技術的信道測量方法的優(yōu)越性有三點:1).成本低、探測設備簡單,單通道足夠探測獲取MIMO空域特征;2).信道空域分辨率更高,尤其是較長距離的無線傳播信道;3).場景適應性強,特別是常規(guī)信道測量方法過于復雜、測量設備過于龐大和昂貴的信道場景,如高速鐵路無線通信信道。針對HSR信道場景,本文通過信道仿真和現場測試的初步結果驗證了基于BiSAR技術的信道測量方法滿足理論可行性和工程實踐性。
[Abstract]:In late 1990s, multiple input multiple output (Multiple-Input Multiple-Output MIMO) technology has brought a technological innovation to the wireless digital communication system. Combined with orthogonal frequency division multiplexing technology, MIMO has become the IEEE802.11 wireless LAN to 4G LTE (Long Term Evolution) physical layer standard series communication technology, mobile communication is 5G and the high-speed train wireless communication standard LTE-R (LTE for Railway proposal) key core technology. In order to better assess the design and optimization of MIMO system, the most effective and most direct method is to understand the MIMO channel propagation mechanism of space diversity, scattering body positioning channel propagation environment, so as to detect each channel impulse response component the departure and reach the receiving antenna direction, analysis between the fading correlation and prediction of communication link reliability and capacity. At present, access to MIMO channel space Channel measurement technology domain features there are two methods: mechanical rotation method of directional antenna and multi antenna system test method. The method of mechanical rotation directional antenna, in addition to time-consuming, measurement is only applicable to the static channel or low frequency Doppler channel. With the increase of the antenna array, multi antenna system test method to test the data collected are a lot of postprocessing, even with the array of high performance estimation algorithms, such as MUSIC, SAGE, and ESPRIT, the computational complexity is very high, the cost of the system. However, for some special scenes, such as high-speed trains (High-Speed Railway HSR) wireless channel environment, in addition to high mobility besides, high security requirements for workers to channel measurement in HSR platform on the existing layout of complex channel detection equipment, the traditional channel measurement method is difficult to implement. The spatial channel model based on scene specific communication is an important foundation for the development of new wireless technology based on MIMO standard, but also to assess the specific environment of basic performance of MIMO technology. Based on the background of wireless communication system for high-speed railway train, to explore a new effective method for MIMO channel measurement of high speed scenarios. The main work of this paper is as follows: 1. proposed a bistatic synthetic aperture radar (Bistatic Synthetic Aperture Radar, based on the novel BiSAR) channel measurement technology. This paper will channel measurement problem projected onto the BiSAR scene reconstruction technology, set up a fixed transmitter and receiver channel uniform motion vehicle communication environment ST-BiSAR (Stationary Transmitter BiSAR) of the geometric model. The model matches very well the specific scene of railway HSR wireless communication, by positioning the scene reconstruction technology of BiSAR channel in bulk Shoot the body, so as to extract the characteristics of the channel simplified.2. channel measurement design of channel simulator based on ST-BiSAR technology. The geometric model of channel simulator specific wireless communication channel is mapped to the ST-BiSAR scene in 3D imaging spatial resolution analysis, rational design of the three-dimensional image, reconstruct 3D scene 3D map of the distribution channel; channel scattering based on the extracted channel parameters. According to the image performance of scattering imaging, numerical simulation results of channel characters and theory, to evaluate the performance of the system. This paper uses the channel simulation of HSR channel is really like the results of the analysis, to verify the channel measurement method based on ST-BiSAR technology is the 3D reconstruction of ST-BiSAR communication environment the feasible.3.. This paper uses the classic back-projection domain (BP) algorithm to generate multi dimensional scene plane image, using Doppler poly The focal height information of scatterers extraction principle, construct the three-dimensional map of channel scatterers. By focusing on the analysis of imaging performance of scatterers, characteristic parameters of imaging map and channel scattering value, verified the technology of 3D imaging channel used in this paper is effective.4. analysis of factors affecting the scattering imaging or channel feature extraction this article from the position. The distribution of scatterers, synthetic aperture time, detecting channel bandwidth and image resolution and so on, these factors on the performance of imaging scatterers on different parameters was discussed in detail. The effect of extraction of channel characters. So as to provide reference to carry out.5. channel measurement experiment based on ST-BiSAR Technology for the research work in the future. Based on the full use of existing equipment, to maximize performance and minimize the cost principle, this paper designs the general software radio Electrical (Universal Software Radio Peripheral platform, USRP) is the core equipment of the detection channel transmitter and receiver. Through the platform transmission test, static ranging and positioning capability is tested and verified on the performance of ST-BiSAR channel detection platform. To carry out on-site ST-BiSAR wireless communication systems with fixed transmitter and receiver on-board vehicle near uniform layout run the test. The results further validate the engineering practice of ST-BiSAR technology based on channel measurement method, and pointed out the need to improve the local channel detection equipment. To sum up, the superiority of the channel measurement method based on BiSAR technology has three points: 1). The detection of simple equipment, low cost, single channel detection to obtain enough MIMO spatial feature; 2). Channel spatial resolution is higher, especially the long distance wireless communication channel; 3). The scene. Should be strong, especially the conventional channel measurement method is too complex, the channel scene is too large and expensive measurement equipment, such as high-speed railway wireless communication channel. According to the HSR channel scene, through the preliminary results of channel simulation and field test of the channel measurement method of BiSAR technology to meet the theoretical feasibility and engineering practice based on.

【學位授予單位】：電子科技大學
【學位級別】：博士
【學位授予年份】：2017
【分類號】：TN92

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本文編號：1498842