李學智臺灣大學：電信工程學研究所游宗樺You, Zong-HuaZong-HuaYou2007-11-272018-07-052007-11-272018-07-052005http://ntur.lib.ntu.edu.tw//handle/246246/58798在本論文，我們提出了一個可應用於多天線系統的室內向量寬頻通道模型。本通道模型是根據Saleh-Valenzuela的通道模型而來並且由 、 及 這三個參數來描述。 是直接波與線性廻歸線(斜率為 )截點的差值、 為線性廻歸線的斜率、 為射線的平均抵達頻率。我們同時提出並驗證一個萃取這些通道參數的方法。然後我們利用此一通道模型來探討當多天線系統使用切換式波束形成(switch beamforming)或空間多工 (spatial multiplexing) 技術時，對於不同的通道參數所表現出的通道特性及傳輸效能。 　　切換式波束形成技術可以降低最小所需的訊號雜訊比(minimum required SNR)，即使直接波被完全阻擋。我們發現當 越大、線性廻歸線的斜率越陡或射線的平均抵達頻率越小時，最小所需的訊號雜訊比將越小。然而，使用空間多工技術則會有相反的結果－環境的多路徑波成份越多，所需的訊號雜訊比越小。此外，當環境的多路徑波成份貧乏時，使用空間多工技術系統的傳輸效能可能會比單一輸出單一輸入(SISO)的系統差。In this thesis we propose a vector wideband indoor channel model which can be employed by systems with closely spaced multiple antenna elements. This channel model is based on the single cluster Saleh-Valenzuela (S-V) model and described by the parameter set { , , } which are respectively the amplitude difference of the direct path and the start point of the multipath regression line, the slope of the regression line, and the mean arrival rate. The procedure to extract the channel parameters is also proposed and verified. Then, we use this channel model to discuss the channel characteristics and transmission performance of multi-antenna systems employing switch beamforming or spatial multiplexing for different channel parameters. The switch beamforming technique can reduce the minimum required signal to noise ratio (SNR) even though the direct path is almost blocked. We found that the minimum required SNR is smaller when the is getting greater, the slope of the regression line is getting larger, and the mean arrival rate is getting smaller. However, the spatial multiplexing technique has the opposite result, i.e. the richer the multipath components, the smaller the SNR. In addition, when the environment has poor multipath components, the transmission performance of systems employing spatial multiplexing may be worse than that of single-input single-output (SISO) systems.Contents Abstract Ⅰ Contents Ⅲ List of Figures Ⅴ List of Tables IX Chapter1 Introduction 1 1.1 Motivation 1 1.2 Organization of the Thesis 3 Chapter2 Wireless Indoor Channel Model 5 2.1 The Saleh-Valenzuela Channel Model 5 2.2 The Method to Extract , γ and λ 9 2.2.1 Our Procedure 10 2.2.2 Verify Our Procedure 13 2.3 Parameter Sets of Different Size Rooms 17 2.4 The Modified S-V Model for Systems Employing Directional Antennas or Multiple Antennas 18 2.3.1 Systems Employing Directional Antennas 18 2.3.2 Systems Employing Multiple Antenna Elements 19 Chapter3 Channel Characteristics of OFDM Systems with Multiple Antenna Elements 21 3.1 Array Beamforming Theory 21 3.1.1 Linear Array Pattern 22 3.1.2 Effective Channel Responses of Array Beamforming 23 3.1.3 Switched Beam Array 24 3.2 Spatial Multiplexing 24 3.2.1 Channel Unknown to the Transmitter 25 3.2.2 Channel Known to the Transmitter 28 3.3 Simulation 29 3.3.1 Effective Channel Responses for Switched Beam Array 29 3.3.2 Singular Values and Condition Numbers of Channel Matrices 33 3.3.3 Capacity 38 Chapter4 Performance Analysis of OFDM Systems in Indoor Environments 41 4.1 The Architecture of the Transceiver Employing Array Beamforming 42 4.2 The Architecture of the Transceiver Employing Spatial Multiplexing 45 4.2.1 Channel Unknown to the Transmitter 46 4.2.2 Channel Known to the Transmitter 47 4.3 Procedure of Generating Multipath Channels and Defining SNR 48 4.4 Simulation Result (I) 49 4.5 Simulation Result (II) 59 Chapter5 Conclusion 65 Reference 671053208 bytesapplication/pdfen-US室內通道模型多輸入多輪出波束型成空間多工indoor channel modelMIMObeamformingspatial multiplexingthesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/58798/1/ntu-94-R92942007-1.pdf