臺灣博碩士論文加值系統

正交分頻技術已被廣泛地運用在現今的寬頻通訊系統中，例如在許多無線個人區域網路提供高速傳輸應用。
正交分頻多工系統有許多優點，是其被廣泛應用的主要原因，然而在正交分頻多工系統裡，有一主要的缺點就是在傳送的訊號中有較高的峰值對均值功率比，它會增加類比至數位轉換器和數位至類比轉換器複雜度，並降低傳送端功率放大器的效能。
在這篇論文中，我們將重點著重於探討部分傳輸序列演算法中的演算搜尋複雜度，在傳統的窮盡式搜尋法中，我們需要去計算所有可能產生的相位組合，然而窮盡式搜尋法的搜尋複雜度會隨著系統的子區塊數目的增加而呈指數成長，在先前學習研究當中，我們在部分傳輸序列為基礎之正交分頻多工系統中發現了一些有用的特性，窮盡式搜尋法中有幾組相位組合其所產生的峰值對均值功率比值是一樣的。在這群相同峰值對均值功率比值的相位組合有著完美的關係，幫助我們於日後的演算。利用這些特性，窮盡式搜尋演算法僅需要去找尋具有相同峰值對均值功率比值的相位組合中的一組即可，因此可以明顯地降低搜尋複雜度。
在這文獻中，我們應用部分傳輸序列的完美特性於先前所提及的幾種理想搜尋演算法中，去降低演算法的搜尋複雜度，由電腦模擬發現，在具有相同的峰值對均值功率比值表現中，這幾種理想搜尋演算法的搜尋複雜度已有明顯的降低。

OFDM technology has been widely used in many wideband communication systems, for example, it has been applied in high speed personal area networks.
OFDM system has many advantages, however, it has one major drawback at the transmitter, the high peak-to-average power ratio (PAPR). High PAPR increases the complexity of the ADC and DAC converters, and reduces the complexity of the transmitter power amplifier.
We focus on exploring algorithm complexity of PTS system in this thesis. To fine the optimal solution of PTS algorithm, we need to perform exhaustive search with all combinations of rotation phases. However, the search complexity increases exponentially with the number of sub-blocks. In previous study, we have found some useful features of PTS-based OFDM systems. Several combinations of rotation phases can yield to the same PAPR output. Elegant relationships among these combinations help us to calculate them in advance. With these properties, the exhaustive search algorithm just needs to perform once for the set with same PAPR output combinations, and hence, dramatically reduces the search complexity.
In this thesis, we apply the elegant features of PTS-bases OFDM systems to several sub-optimal search algorithms to reduce their search complexities. With computer simulations, we find that the search complexity for all these sub-optimal search algorithms has been significantly reduced under the same PAPR performance.

致謝……………………………………………………………………………..……..I
中文摘要………………………………………………………………….……… .…II
Abstract…………………………………………………………………………........III
目錄………………………………………………………………………………..….V
圖目錄……………………………………………………………………………....VII
表目錄………………………………………………………………………………..IX
第一章 正交分頻多工系統峰值對均值功率比…………………………......………1
1.1正交分頻多工技術簡介……………………………………………………..1
1.2 峰值對均值功率比……………………………………….…………………3
1.3 各種降低峰值對均值功率比方法介紹………………….…………………7
1.3.1削減法…………………………………………..…………………….…7
1.3.2 編碼………………………………………………..……………………8
1.4 選擇映射技術………………………………………………….……….… ..9
1.5 部份傳輸序列技術………………………………………………………11
第二章 部份傳輸序列窮盡式搜尋法探討…………………………………………18
2.1窮盡式搜尋法簡介…………………………………….…………………...18
2.2鄰近分割法中相同PAPR值的旋轉因子組合探討……………………….19
2.3交錯分割法中相同PAPR值的旋轉因子組合探討…………………….…24
2.4 結論………………………………………………………….…….……….29
第三章 次佳化部份傳輸序列之相位選擇搜尋演算法應用於簡易窮盡式搜尋法
…………………………………30
3.1次佳化部份傳輸序列之相位選擇搜尋演算法……………….…….……..30
3.2次佳化演算法應用於簡易窮盡式搜尋法………….….…………………..34
3.3 結論…………………………………….…………………...………….…..40
第四章 Cross-Entropy演算法應用於簡易窮盡式搜尋法…………………...41
4.1 Cross-Entropy演算法………………………….…………………….41
4.2 New-Cross-Entropy演算法………………………………….……….45
4.3結論………………………………………………………………….……...54
第五章 Cross-Entropy次佳化部份傳輸序列之相位選擇搜尋演法應用於簡易窮盡式搜尋法…………………………………………..………………..55
5.1 Cross-Entropy次佳化部份傳輸序列之相位選擇搜尋演算法……...55
5.2 New-Cross-Entropy次佳化搜尋法………..………………………………64
5.3 結論………………………………………………..……………………….71
第六章 總結……………………………………………….………………………...72
參考資料......................................................................................................................73

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