單精度量化大規(guī)模MIMO系統(tǒng)上行信道估計與導(dǎo)頻設(shè)計
發(fā)布時間：2018-10-15 19:55
【摘要】：隨著移動通信的迅猛發(fā)展,第五代移動通信系統(tǒng)需要支持更高的數(shù)據(jù)傳輸速率。而由于無線資源的日漸緊張,大規(guī)模多輸入輸出(Multiple-Input Multiple-Output,MIMO)技術(shù)可以充分利用空間資源,因而可以大幅度提高能量效率和頻譜利用率,成為了5G的關(guān)鍵技術(shù)之一。同時大規(guī)模MIMO系統(tǒng)存在著海量數(shù)據(jù)處理、系統(tǒng)總消耗功率巨大、硬件成本昂貴等問題。對于解決上述問題一種有效的技術(shù)是在基站的接收機中使用低精度的模數(shù)轉(zhuǎn)換器(Analog to Digital Converter,ADC),以此來降低大規(guī)模MIMO系統(tǒng)部署的成本與功耗。要使系統(tǒng)在低精度量化的基礎(chǔ)上進行可靠且高速的通信,則必須獲取更加準確的信道狀態(tài)信息(Channel-State Information,CSI)。由于小區(qū)內(nèi)所有用戶同時同頻工作,為避免小區(qū)內(nèi)干擾,所以單個小區(qū)內(nèi)的用戶需發(fā)送相互正交的導(dǎo)頻序列�；谝陨蠈SI和導(dǎo)頻的要求,本文將重點研究單精度量化大規(guī)模多輸入輸出(One-Bit Massive MIMO)系統(tǒng)的上行信道估計和導(dǎo)頻設(shè)計問題。首先,介紹了單用戶SIMO系統(tǒng)和大規(guī)模多用戶MIMO系統(tǒng)模型以及相應(yīng)的信道模型,并分析了在TDD通信方式下系統(tǒng)上行導(dǎo)頻傳輸及上下行數(shù)據(jù)傳輸過程。其次,介紹了單用戶SIMO系統(tǒng)的上行信道估計。首先闡述了不同類型CSI對系統(tǒng)信道容量的影響。接著介紹了基于導(dǎo)頻的信道估計算法,進而分析了在線性接收下的數(shù)據(jù)檢測。最后在此基礎(chǔ)上推導(dǎo)了系統(tǒng)的可達速率。隨后,基于單精度量化單用戶SIMO系統(tǒng)上行信道估計,研究了單精度量化大規(guī)模多用戶MIMO系統(tǒng)中的最小二乘(Least Square,LS)估計和最小均方誤差(Minimum Mean Square Error,MMSE)估計。但由于上述兩種算法均是基于信道輸入和量化輸出之間的互信息量,因而不能直觀地體現(xiàn)量化噪聲對信道估計性能及可達速率的影響。接下來通過基于Bussgang分解理論的線性分解來表示單精度量化輸入輸出之間的關(guān)系,進而推導(dǎo)出了線性最小均方誤差(Linear Minimum Mean Square Error,LMMSE)估計。最后分析了三種算法的復(fù)雜度、均方誤差(Mean Square Error,MSE)以及系統(tǒng)的可達速率。仿真結(jié)果表明,LS估計的性能最差,但計算復(fù)雜度更低,也更適合大規(guī)模MIMO系統(tǒng)。最后,本文提出了一種新的基于循環(huán)移位Zadoff-Chu(ZC)序列的正交導(dǎo)頻生成方案。首先對常用的參考信號基序列的特性進行了分析,進而深入研究了現(xiàn)有文獻中正交導(dǎo)頻的生成方式,即控制小區(qū)內(nèi)所有用戶在不同的時隙段發(fā)送各自的導(dǎo)頻(時間導(dǎo)頻)。然后針對時間導(dǎo)頻的數(shù)據(jù)傳輸效率較低這一缺陷,本文提出了一種新的正交導(dǎo)頻生成方案,即通過ZC序列在時域循環(huán)移位生成不同用戶的導(dǎo)頻(ZC導(dǎo)頻),進而以最大化可達速率為目標對導(dǎo)頻長度進行優(yōu)化。仿真結(jié)果表明,與現(xiàn)有文獻中的導(dǎo)頻生成方案相比,采用本文所提方案可以將信道估計的MSE降低約12%,由于對導(dǎo)頻長度進行了優(yōu)化,系統(tǒng)可達速率提高了約10%。
[Abstract]:With the rapid development of mobile communication, the fifth generation mobile communication system needs to support higher data transmission rate. However, due to the increasing shortage of wireless resources, large-scale multi-input output (Multiple-Input Multiple-Output,MIMO) technology can make full use of space resources, so it can greatly improve energy efficiency and spectral efficiency, which has become one of the key technologies of 5G. At the same time, there are some problems in large scale MIMO system, such as massive data processing, huge power consumption and high hardware cost. An effective technique to solve the above problem is to use a low-precision ADC (Analog to Digital Converter,ADC in the receiver of the base station to reduce the cost and power consumption of large-scale MIMO system deployment. In order to achieve reliable and high-speed communication on the basis of low precision quantization, more accurate channel state information (Channel-State Information,CSI) must be obtained. Since all users in the cell work at the same time, in order to avoid interference within the cell, users in a single cell need to transmit orthogonal pilot sequences. Based on the above requirements for CSI and pilot, this paper will focus on the uplink channel estimation and pilot design of single-precision quantized large scale multiple-output (One-Bit Massive MIMO) systems. Firstly, the single-user SIMO system, the large-scale multi-user MIMO system model and the corresponding channel model are introduced, and the uplink pilot transmission and uplink data transmission process of the system under the TDD communication mode are analyzed. Secondly, the uplink channel estimation of single user SIMO system is introduced. Firstly, the influence of different CSI on the channel capacity of the system is discussed. Then the channel estimation algorithm based on pilot is introduced, and the data detection under linear reception is analyzed. Finally, the reachability rate of the system is deduced. Then, based on the uplink channel estimation of single-precision quantized single-user SIMO systems, the least square (Least Square,LS) estimation and the least mean square error (Minimum Mean Square Error,MMSE) estimation of single-precision quantized large-scale multi-user MIMO systems are studied. However, the above two algorithms are based on the mutual information between channel input and quantization output, so the influence of quantization noise on channel estimation performance and reachable rate can not be intuitively reflected. Then the linear decomposition based on Bussgang decomposition theory is used to express the relationship between the input and output of single precision quantization, and then the linear minimum mean square error (Linear Minimum Mean Square Error,LMMSE) estimation is derived. Finally, the complexity of the three algorithms, mean square error (Mean Square Error,MSE) and the reachable rate of the system are analyzed. Simulation results show that the performance of LS estimation is the worst, but the computational complexity is lower, and it is more suitable for large-scale MIMO systems. Finally, a new orthogonal pilot generation scheme based on cyclic shift Zadoff-Chu (ZC) sequences is proposed. Firstly, the characteristics of common reference signal base sequences are analyzed, and then the generation method of orthogonal pilot frequency in the existing literature is deeply studied, that is, all users in the cell are controlled to transmit their own pilot (time pilot) in different time slots. Then a new orthogonal pilot generation scheme is proposed to solve the problem of low data transmission efficiency of time pilot. The pilot frequency (ZC) of different users is generated by cyclic shift of the ZC sequence in time domain, and the pilot length is optimized with the aim of maximizing the reachable rate. The simulation results show that the proposed scheme can reduce the MSE of channel estimation by about 12 points compared with the pilot generation scheme in the existing literature. Because of the optimization of pilot length, the reachable rate of the system can be increased by about 10%.
【學(xué)位授予單位】：廣東工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TN919.3
本文編號：2273670
[Abstract]:With the rapid development of mobile communication, the fifth generation mobile communication system needs to support higher data transmission rate. However, due to the increasing shortage of wireless resources, large-scale multi-input output (Multiple-Input Multiple-Output,MIMO) technology can make full use of space resources, so it can greatly improve energy efficiency and spectral efficiency, which has become one of the key technologies of 5G. At the same time, there are some problems in large scale MIMO system, such as massive data processing, huge power consumption and high hardware cost. An effective technique to solve the above problem is to use a low-precision ADC (Analog to Digital Converter,ADC in the receiver of the base station to reduce the cost and power consumption of large-scale MIMO system deployment. In order to achieve reliable and high-speed communication on the basis of low precision quantization, more accurate channel state information (Channel-State Information,CSI) must be obtained. Since all users in the cell work at the same time, in order to avoid interference within the cell, users in a single cell need to transmit orthogonal pilot sequences. Based on the above requirements for CSI and pilot, this paper will focus on the uplink channel estimation and pilot design of single-precision quantized large scale multiple-output (One-Bit Massive MIMO) systems. Firstly, the single-user SIMO system, the large-scale multi-user MIMO system model and the corresponding channel model are introduced, and the uplink pilot transmission and uplink data transmission process of the system under the TDD communication mode are analyzed. Secondly, the uplink channel estimation of single user SIMO system is introduced. Firstly, the influence of different CSI on the channel capacity of the system is discussed. Then the channel estimation algorithm based on pilot is introduced, and the data detection under linear reception is analyzed. Finally, the reachability rate of the system is deduced. Then, based on the uplink channel estimation of single-precision quantized single-user SIMO systems, the least square (Least Square,LS) estimation and the least mean square error (Minimum Mean Square Error,MMSE) estimation of single-precision quantized large-scale multi-user MIMO systems are studied. However, the above two algorithms are based on the mutual information between channel input and quantization output, so the influence of quantization noise on channel estimation performance and reachable rate can not be intuitively reflected. Then the linear decomposition based on Bussgang decomposition theory is used to express the relationship between the input and output of single precision quantization, and then the linear minimum mean square error (Linear Minimum Mean Square Error,LMMSE) estimation is derived. Finally, the complexity of the three algorithms, mean square error (Mean Square Error,MSE) and the reachable rate of the system are analyzed. Simulation results show that the performance of LS estimation is the worst, but the computational complexity is lower, and it is more suitable for large-scale MIMO systems. Finally, a new orthogonal pilot generation scheme based on cyclic shift Zadoff-Chu (ZC) sequences is proposed. Firstly, the characteristics of common reference signal base sequences are analyzed, and then the generation method of orthogonal pilot frequency in the existing literature is deeply studied, that is, all users in the cell are controlled to transmit their own pilot (time pilot) in different time slots. Then a new orthogonal pilot generation scheme is proposed to solve the problem of low data transmission efficiency of time pilot. The pilot frequency (ZC) of different users is generated by cyclic shift of the ZC sequence in time domain, and the pilot length is optimized with the aim of maximizing the reachable rate. The simulation results show that the proposed scheme can reduce the MSE of channel estimation by about 12 points compared with the pilot generation scheme in the existing literature. Because of the optimization of pilot length, the reachable rate of the system can be increased by about 10%.
【學(xué)位授予單位】：廣東工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TN919.3
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