多輸入多輸出(multi-input multi-output, MIMO)的通訊系統係於發射端及接收端運用多根天線的方式來有效提升系統容量，對於多收發天線的MIMO系統來說，主要關心的是這硬體複雜性和計算成本上的需求。其有效的解決辦法是在接收端應用天線子集的選擇，其中被選擇的天線使通道容量達到最大。
本篇論文運用三個演算法，減少天線演算法(Decremental selection algorithms, DSA)以及加入天線演算法(Incremental selection algorithms, ISA)，是以遞迴方式在每一次的步驟中盡可能減少損失下減少或加入一根天線，使通道容量達到最大，因此在接收端需要使用的射頻電路(RF chains)數量可藉著天線選擇來減少硬體上的複雜度，同時降低成本上的需求。
這兩個演算法需要高運算複雜度的反矩陣運算，因此為了降低運算複雜度我們運用豪斯霍德 (Householder) 轉換來減少系統的運算複雜度，最後則利用電腦來模擬這些天線選擇演算法並比較其效能和運算複雜度。

Multi-input multi-output (MIMO) communication systems that employ more than one antenna element at both transmitter and receiver are showed to be an efficient method to increase channel capacity. For MIMO communication systems, the major concern is the hardware complexity and computational cost. A promising solution way is to employ the antenna subset selection at the receiver and the antennas are selected to maximize channel capacity. In order to reduce capacity loss and maximize channel capacity, the thesis uses two antenna selection schemes, decremental selection algorithm (DSA) and incremental selection algorithm (ISA), which recursively drop or select one more antenna element in the pre step. However, there are high computational complexity of matrix inversion in these algorithms. In order to reduce computational complexity, the Householder transformation is utilized to alleviate the overall computational complexity of the system. Finally, simulations are conducted to compare these antenna selection algorithms in terms of computational complexity and performance.

摘要……………………………………………………………………………………Ⅰ
Abstract………………………………………………………………………………Ⅱ
目錄……………………………………………………………………………………Ⅲ
圖目錄…………………………………………………………………………………Ⅴ
表目錄…………………………………………………………………………………Ⅶ

第一章 導論
1.1 前言………………………………………………………………………1
1.2 研究動機…………………………………………………………………3
1.3 論文架構…………………………………………………………………3

第二章 MIMO多天線技術…………………………………………………………4
2.1 MIMO 多天線技術之簡介……………………………………………… 4
2.2 MIMO多天線技術之原理…………………………………………………6
2.3 天線分集技術……………………………………………………………8
2.4 MIMO技術的應用…………………………………………………………11
2.5 系統模型…………………………………………………………………12

第三章 天線選擇…………………………………………………………………15
3.1 天線選擇之簡介…………………………………………………………15
3.2 天線選擇演算法…………………………………………………………18
3.2.1 刪減天線演算法(Decremental Selection Algorithm)……… 21
3.2.2 加入天線演算法(Incremental Selection Algorithm)……… 22

第四章 豪斯霍德(Householder)轉換下的天線選擇………………………… 24
4.1 豪斯霍德(Householder)轉換之簡介………………………………… 24
4.2 使用豪斯霍德(Householder)轉換的天線選擇……………………… 29

第五章 運算複雜度分析…………………………………………………………35
5.1 刪減天線演算法(Decremental Selection Algorithm)…………… 35
5.2 加入天線演算法(Incremental Selection Algorithm)…………… 36
5.3 使用豪斯霍德(Householder)轉換的天線選擇……………………… 37
5.4 複雜度整理………………………………………………………………38

第六章 電腦模擬與分析…………………………………………………………39

第七章 結論與未來展望…………………………………………………………46

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