為了迎接下世代行動通訊系統更高的資料率，混和預編碼有著較少的硬體花費和低功率消耗的特性讓它成為了熱門的研究議題。這個特性也使混和預編碼器非常適合巨量天線多重輸入多重輸出系統。在我的研究中，我提出了單射頻元件能量限制，因為我們發現總能量限制不符合實際情形，它會使射頻元件輸出的能量超出其上限。之後，我們提出了在射頻元件數大於資料束的數量情形下使用的混和預編碼器，多餘的射頻元件被拿來補償指向向量。由於編碼器的限制會造成所補償的向量偏移，這個偏移又會產生出多餘的干擾，而我們提出的混和預編碼器的優點是可以避免掉這個干擾。我們所提出的混和預編碼器的複雜度也很低。另外我們也探討了哪一種狀態的通道適合射頻元件數大於資料束的數量的情況。最後，模擬結果顯示我們提出方法頻譜效益優於過去傳統的方法。

To meet the higher data rate in the next generation mobile communication system, hybrid precoding has attracted a lot of attentions due to the low hardware cost and power consumption. That’s why hybrid precoder is suitable for millimeter-wave (mmWave) massive multiple-input multiple-output (MIMO) systems. In this work, we propose per RF chain power constraint because we find out total power constraint is not practical. Total power constraint may make RF chain power exceed its power limitation. Afterwards, we propose the hybrid precoder structure for the case that number of RF chains is greater than number of data streams. The extra RF chains is used for compensate the steering vector to obtain better performance. The advantage of our proposed hybrid precoder is that it has low computation complexity. We also explore which channel state is suitable for the case about number of data streams greater than number of RF chains. Finally, simulation results show the superiority of the proposed method in terms of achievable spectral efficiency over other previous solutions.

Abstract II
摘要 III
LIST OF FIGURES VI
LIST OF TABLES IX
Chapter 1 Introduction 1
1.1 General Background Information 1
1.2 Literature Review 2
Chapter 2 System Model 4
2.1 Conventional MIMO Systems 4
2.2 Hybrid Precoder Systems 6
2.3 Millimeter-Wave Channel Model 8
Chapter 3 Power Constraints and Problem Formulations 10
3.1 Power Constraint of Precoders 10
3.2 Problem Formulation 12
Chapter 4 Hybrid Precoder Design 15
4.1 The Method of Most Deviated Steering Vector Compensation with LS 15
4.2 The Most Deviated Steering Vector Compensation with EC 21
4.3 The Most Efficient Steering Vector Strengthening 23
4.4 The Comparison of The Beam Patterns and Computational Complexity 23
Chapter 5 Simulation Results 39
5.1 Power Usage Distribution of RF Chains 39
5.2 Spectral Efficiency Comparison versus SNR 53
5.3 The Spectral Efficiency Comparison versus Number of RF Chains 65
Chapter 6 Conclusion 70
References 71

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