正交分頻多工(OFDM)的主要缺點之一在於在傳送OFDM訊號過程中會產生高的峰值對均值功率比，以致於訊號經過功率放大器之後會造成非線性失真。部份傳輸序列法(PTS-partial transmit sequence)可以有效改善OFDM訊號的PAPR。但傳統的PTS調變技術必須搜尋相位因子的所有可能組合，其搜尋複雜度會隨著子區間的數量和相位因子的種類呈現指數形式增加。本論文中，我們提出新的PTS技術僅需要些微效能的降低卻能有效減少大量傳統PTS的高計算複雜度的缺點。

One of the main drawbacks of orthogonal frequency division multiplexing (OFDM) is the high peak-to-average power ratio (PAPR) of the transmitted OFDM signal. Partial transmit sequence (PTS) technique can improve the PAPR statistics of an OFDM signal. As ordinary PTS technique requires an exhaustive search over all combinations of allowed phase factors, the search complexity increases exponentially with the number of sub-blocks. In this paper, we propose a novel PTS technique with reduced complexity that achieves significant reduction in search complexity with little performance degradation.

目錄

第一章  概論 P.1

第二章  正交分頻多工系統介紹 P.6

第三章  正交分頻多工系統的峰值對平均值功率比 P.14
3.1  峰值對平均值功率比 P.14
3.2  降低PAPR的方法 P.18

第四章  部分傳輸序列法 P.24
4.1  原始的部分傳輸序列法 P.24
4.2  反覆翻轉運算法 P.27
4.3  漸進倍增反相法 P.28
4.4  結論 P.33
第五章  模擬與分析 P.41
5.1  數值分析結果P.41
5.2  結論 P.43
第六章  結論 P.51
圖目錄

圖1.1  多載波系統圖 P.5
圖2.1  ASK, FSK及PSK三種基本調變波形 P.10
圖2.2  次載波完全正交 P.11
圖2.3  OFDM通訊系統的方塊圖 P.12
圖2.4  OFDM傳輸示意圖 P.13
圖3.1  載波疊加及PAPR的產生 P.21
圖3.2  4個次載波利用BPSK調變訊號振幅分布的情形 P.22
圖3.3  PAPR依N大小不同所呈現的CDF分布圖形 P.23
圖4.1  PTS技術的方塊圖 P.35
圖4.2  QPSK調變情形 P.36
圖4.3  反覆翻轉運算法流程圖 P.37
圖4.4  反覆翻轉運算法N = 64 P.38
圖4.5  反覆翻轉運算法N = 128 P.39
圖4.6  漸進倍增反相法流程圖 P.40
圖5.1  N = 64，M = 4時各種PAPR調降方法的CCDF P.45
圖5.2  N = 128，M = 4時各種PAPR調降方法的CCDF P.46
圖5.3  N = 64，M = 8時各種PAPR調降方法的CCDF P.47
圖5.4  N = 128，M = 8時各種PAPR調降方法的CCDF P.48
圖5.5  N = 64，M = 4, 8, 16之CCDF P.49
圖5.6  N = 128，M = 4, 8, 16 CCDF P.50

表目錄

表1  各方法計算量的比較 P.35

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