多載波系統中，傳送訊號的峰均值功率比 (Peak-to-Average Power Ratio, PAPR) 過高是個急須解決的問題。在本論文中，針對等間隔4安插訊號的正交分頻多重進接 (Orthogonal Frequency Division Multiple Access, OFDMA) 系統的上傳端，提出一個全新的低複雜度選擇性映射 (Selective Mapping, SLM) 架構來降低PAPR。新架構提出一系列轉換向量 (Conversion Vectors)，運用時域上訊號與不同轉換向量做環形摺積 (Circular Convolution) 來產生候選訊號 (Candidate Signals)，運算量極低，更減少反快速傅立葉轉換 (Inverse Fast Fourier Transform, IFFT) 的需要量。此外論文中提出一系列低運算量的特殊轉換向量，適用於等間隔4安插訊號之 OFDMA系統上傳端，依不同使用者做適當的載波配置，選取適當的轉換向量，使其相對於頻域上只是有訊號的載波位置做相位旋轉，不僅使轉換向量做最有效的運用，降低運算複雜度，更能有效降低PAPR。此新低複雜度SLM架構，為OFDMA系統上傳端，提供一個實際可行的低複雜度方式，有效降低PAPR，且維持與傳統SLM相同之錯誤率 (Bit Error Rate, BER) 效能。

One of the major drawbacks of multi-carrier systems is the high peak-to-average power ratio (PAPR) of the transmitted signals. In this paper, the proposed novel low-complexity selective mapping (SLM) schemes are applicable to interleaved-4 orthogonal frequency division multiple access (OFDMA) uplink systems for PAPR reduction. The novel scheme just needs one inverse fast Fourier transform (IFFT) block because that the phases of the transmitted signals in frequency domain are rotated by circular convolution with conversion vectors in time domain. Moreover, a special set of conversion vectors are proposed in novel scheme, which are not only computed with low complexity but also reduce the PAPR effectively. In proposed scheme, different conversion vectors and appropriate subcarriers mapping are picked up for different users. The scheme supplies a practicable low-complexity method for PAPR reduction in interleaved-4 OFDMA uplink systems. Besides, the bit error rate (BER) performance is as good as the SLM scheme.

第一章　導論........................................................................1
1.1研究背景......................................................................1
1.2 研究動機.....................................................................3
1.3論文架構......................................................................4
第二章 系統架構...........................................................5
2.1 OFDMA系統................................................................5
2.2 PAPR...........................................................................7
2.3 SLM..............................................................................8
2.4 低複雜度SLM架構......................................................9
第三章 新低複雜度SLM架構.....................................12
3.1轉換向量....................................................12
3.2 新低複雜度SLM架構I..............................14
3.2.1 載波配置...............................................................16
3.2.2 候選訊號產生器...................................................18
3.3新低複雜度SLM架構II..............................28
第四章 複雜度分析......................................................30
第五章 系統模擬..........................................................34
5.1載波配置模擬.............................................................34
5.2候選訊號產生器.........................................................36
5.3 PAPR降低效能比較.................................................38
第六章 結論.................................................................44
附錄......................................................................................45
附錄A 中英對照表...........................................................45
附錄B 英文縮寫對照表...................................................48
參考文獻...............................................................................51

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