本文選題：毫米波 + MIMO��； 參考：《電子科技大學(xué)》2017年碩士論文

【摘要】：未來的無線通信的目標(biāo)是提供更高的傳輸速率,更大的系統(tǒng)容量,滿足萬物互聯(lián)的通信需求。在傳統(tǒng)的低頻段頻譜上實(shí)現(xiàn)這一目標(biāo)并不現(xiàn)實(shí),通信必須向高頻段的毫米波擴(kuò)展。毫米波的物理性質(zhì)決定了其需要和MIMO技術(shù)聯(lián)合應(yīng)用,以提供良好的服務(wù)。在毫米波系統(tǒng)中使用大規(guī)模天線陣列,在提高性能的同時(shí),也帶來了經(jīng)濟(jì)成本和電路設(shè)計(jì)方面的問題。如果采用數(shù)字預(yù)編碼方案,需要配置和天線數(shù)相等的射頻鏈路,實(shí)現(xiàn)難度很大。采用混合架構(gòu)可以解決這一難題。在射頻域配置由移相器網(wǎng)絡(luò)組成的模擬預(yù)編碼器,在基帶配置傳統(tǒng)的數(shù)字預(yù)編碼器,可以大幅減少系統(tǒng)需要的射頻鏈路的數(shù)量�；旌霞軜�(gòu)的毫米波MIMO系統(tǒng)在信道估計(jì)和預(yù)編碼方面有很多值得研究的問題。第一,天線規(guī)模比較大,信道估計(jì)規(guī)模也同步上升,有必要研究新的信道估計(jì)方法。第二,信道估計(jì)準(zhǔn)確度的提升也是一個(gè)目標(biāo)。第三,模擬預(yù)編碼器由移相器組成,移相器只能調(diào)節(jié)相位,不能調(diào)節(jié)幅值,這種物理限制因素決定了必須研究適用于混合架構(gòu)系統(tǒng)的預(yù)編碼方法。針對這些問題,本文開展了一些研究。本文首先研究了毫米波在散射空間中的傳播特性,討論了毫米波信道的時(shí)域稀疏性和角域稀疏性。基于信道的稀疏性,本文使用群簇模型對毫米波窄帶信道進(jìn)行了建模分析。建立了混合架構(gòu)毫米波MIMO系統(tǒng)的數(shù)學(xué)表示模型。鑒于毫米波MIMO信道是稀疏的,本文對基于稀疏信號重構(gòu)的信道估計(jì)方法開展了研究。首先,介紹了壓縮感知和稀疏信號重構(gòu)的相關(guān)知識,討論了OMP和CoSaMP重構(gòu)算法。基于這兩種算法,本文設(shè)計(jì)了基于OMP和CoSaMP算法的信道估計(jì)方法,并進(jìn)行了仿真,分析了兩種方法的性能。在此基礎(chǔ)上提出一種改進(jìn)的稀疏信號重構(gòu)算法,該算法與OMP的不同之處在于每次匹配時(shí)選擇多個(gè)感知原子用于篩選。仿真結(jié)果表明,改進(jìn)的信道估計(jì)方法的性能優(yōu)于基于OMP的信道估計(jì)方法,且計(jì)算復(fù)雜度基本沒有增加。最后,本文對適用于混合架構(gòu)毫米波MIMO系統(tǒng)的預(yù)編碼方法進(jìn)行了研究。建立了混合預(yù)編碼問題的數(shù)學(xué)模型并討論了該問題的優(yōu)化目標(biāo)函數(shù)。在此基礎(chǔ)上研究了兩種基于交替優(yōu)化算法的混合預(yù)編碼矩陣計(jì)算方法。仿真結(jié)果表明,兩種方法都可以實(shí)現(xiàn)良好的性能,且實(shí)現(xiàn)復(fù)雜度較低。
[Abstract]:The goal of future wireless communication is to provide higher transmission rate and larger system capacity to meet the communication needs of interconnection. It is not realistic to achieve this goal in the traditional low frequency spectrum, so the communication must be extended to the millimeter wave in the high frequency band. The physical properties of millimeter wave make it necessary to combine with MIMO technology to provide good service. The use of large-scale antenna arrays in millimeter-wave systems not only improves performance, but also brings economic cost and circuit design problems. If the digital precoding scheme is adopted, it is difficult to configure the RF link with the same number of antennas. A hybrid architecture can solve this problem. The configuration of analog precoder composed of phase shifter network in RF domain and traditional digital precoder in baseband can greatly reduce the number of RF links required by the system. There are many problems in channel estimation and precoding for hybrid millimeter-wave MIMO systems. First, the antenna size is large and the channel estimation scale is rising simultaneously. It is necessary to study a new channel estimation method. Second, the improvement of channel estimation accuracy is also a goal. Thirdly, the analog precoder is composed of phase shifters, which can only adjust the phase, but not the amplitude. This kind of physical limitation determines that a precoding method suitable for hybrid architecture systems must be studied. In view of these problems, this paper carried out some research. In this paper, the propagation characteristics of millimeter-wave in scattering space are studied, and the time-domain sparsity and angular sparseness of millimeter-wave channel are discussed. Based on the sparsity of the channel, the cluster model is used to model the millimeter wave narrowband channel. A mathematical representation model of a hybrid millimeter-wave MIMO system is established. In view of the sparse millimeter-wave MIMO channel, the channel estimation method based on sparse signal reconstruction is studied in this paper. Firstly, the knowledge of compressed sensing and sparse signal reconstruction is introduced, and OMP and CoSaMP reconstruction algorithms are discussed. Based on these two algorithms, the channel estimation methods based on OMP and CoSaMP algorithms are designed and simulated, and the performance of the two methods is analyzed. On this basis, an improved sparse signal reconstruction algorithm is proposed. The difference between this algorithm and OMP is that multiple perceptual atoms are selected for filtering each match. Simulation results show that the performance of the improved channel estimation method is better than that of the channel estimation method based on OMP, and the computational complexity is not increased. Finally, a precoding method for hybrid millimeter-wave MIMO systems is studied in this paper. The mathematical model of hybrid precoding problem is established and the optimization objective function of the problem is discussed. On this basis, two hybrid precoding matrix calculation methods based on alternating optimization algorithm are studied. The simulation results show that both methods can achieve good performance and low implementation complexity.
【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TN919.3

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 Jonathan S. Lu;Daniel Steinbach;Patrick Cabrol;Philip Pietraski;;Modeling Human Blockers in Millimeter Wave Radio Links[J];ZTE Communications;2012年04期

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本文編號：1873987