將多輸入多輸出系統 (Multiple-Input Multiple-Output, MIMO) 技術應用到稀疏編碼多重接取系統 (Sparse Code Multiple Access, SCMA) 對於第五代行動通訊將會是一項重要的技術。透過結合MIMO與SCMA可以使頻譜效益更大，然而在現今的MIMO-SCMA系統中，並沒有考慮如何設計碼簿 (Codebook)。
首先，我們先提出新型的MIMO-SCMA系統，這種系統需要同時決定傳送天線的碼字 (Codeword)，與傳統的空間多工不同，我們希望透過空間多樣性來取得優勢。
在設計碼簿方面，我們利用經典的正交振幅調變(Quadrature Amplitude Modulation, QAM) 先做設計，把用戶所使用的碼字間的最短距離最大化當作目標，同時也要考慮其他用戶的干擾情況，利用稀疏矩陣在空間資源上的看法，則可以獲得良好的多樣性增益 (Diversity Gain)。
除了16-QAM星座點以外，我們也透過搜尋其他星座點，嘗試建立比16-QAM所建立的碼簿還要更好的碼簿，而也確實使得母碼簿的最短距離更大了一些，但整體效能並不只由母碼簿 (Mother Codebook) 所決定，在這樣的資源下，依舊有我們缺乏考慮的地方。
由模擬結果顯示，不論我們如何設計其他星座點，只要有妥善的將數個空間資源以空間多樣性的角度同時使用，則至少一定會在高訊雜比 (Signal to Noise Power Ratio) 的情況下得到多樣性增益，進而使得表現的斜率變大；如果有妥善設計，則將會在可通訊的訊雜比範圍勝過傳統的系統架構。

Sparse code multiple access (SCMA) is a non-orthogonal multiple access scheme for future fifth generation wireless networks. This scheme is considered as a promising way to support massive connectivity and increase the spectral efficiency of the next generation communication systems. Additionally, multiple-input multiple-output (MIMO) has been identified as a crucial technology for improving spectral efficiency. However, traditional MIMO-SCMA system only apply SCMA codebook to MIMO system by spatial multiplexing.
In this paper, we propose a novel downlink MIMO-SCMA system with the novel SCMA codebook. In order to increase channel capacity, the codebook will be designed not only at the time or frequency resources but also at the space resources simultaneously. Besides, this paper also provide a simple and complete method which using a kind of complex constellation and specific angle combination to construct codebooks for each users.
The simulation result shows that the proposed system with the proposed codebooks have a better performance compared to traditional scheme at the feasible signal to noise ratio range in terms of bit error rate. This phenomenon reveals our proposed scheme takes advantage of diversity gain.

論文審定書 i
誌謝 ii
中文摘要 iii
ABSTRACT iv
CONTENTS v
LIST OF FIGURES vii
Chapter 1 導論 1
1.1 研究動機 6
1.2 論文架構 7
Chapter 2 系統介紹 8
2.1 多輸入多輸出無線通訊系統之基本架構 8
2.1.1 空間多工 8
2.1.2 空間多樣性 8
2.2 稀疏編碼多重接取系統之基本架構 10
Chapter 3 系統架構 12
3.1 傳統MIMO-SCMA系統架構 12
3.2 提出的新型系統架構 15
Chapter 4 碼簿設計 18
4.1 SCMA碼簿設計 18
4.1.1 稀疏矩陣 19
4.1.2 母碼簿 21
4.1.3 旋轉矩陣 23
4.2 提出的多天線SCMA碼簿設計 25
4.2.1 基於星座點之母碼簿設計方式 26
4.2.2 基於星座點之旋轉矩陣搜尋方法 29
4.3 星座點設計 31
4.3.1 基於12-PSK與QPSK組成星座點 31
4.3.2 基於8-PSK與8-PSK組成星座點 32
Chapter 5 模擬結果與討論 34
5.1 新型碼簿的討論與錯誤率 34
5.2 傳統系統與提出的系統錯誤率比較 37
5.3 不同星座點的比較 39
Chapter 6 結論 41
附錄 42
REFERENCE 45
中英對照表 51
縮寫對照表 56

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