多載波分碼多工系統(Multi-Carrier Code Division Multiple Access, MC-CDMA)是一種高速率多重存取的無線傳輸系統，其在頻率選擇性衰減通道(Frequency Selecting Fading Channel)環境下，具有頻率多樣性(Frequency Diversity)。然而當此系統應用在上鏈(Uplink)傳輸時，展頻碼(Spreading Code)會因為不同使用者的訊號通過不同的頻率選擇性衰減通道，使其展頻碼間之正交性失去，造成嚴重的多重存取干擾(Multiple Access Interference, MAI)。在本論文中，我們利用稀疏高斯整數序列(Sparse Gaussian Integer Sequence, SGIS)來建構我們的轉換矩陣，此轉換矩陣是將展頻碼矩陣與反快速傅立葉轉換(Inverse Fast Fourier Transform, IFFT)形成一低複雜度的矩陣。SGIS與其對偶序列具有的優良特性，可以有效降低MAI，且稀疏的特性也會使得此系統的峰均值功率比(Peak-to-Average Power Ratio, PAPR)有效降低，在傳送端的複雜度也可以大幅度地降低。由於轉換矩陣為一循環矩陣且又為么正矩陣(Unitary Matrix)，當系統為半載的情況時，我們可以將MAI完全消除。多載波分碼多工系統相較於單載波分碼多工系統(Single-Carrier Code Division Multiple Access, SC-FDMA)擁有完整的頻率多樣性，SC-FDMA的頻率多樣性取決於其快速傅立葉轉換(Fast Fourier Transform, FFT)的大小，所以當多樣性提高，其運算複雜度亦會大幅度的上升。而擁有完整的頻率多樣性，可以有效地降低在頻率選擇性衰減通道之中的錯誤率。

Multi-Carrier Code Division Multiple Access (MC-CDMA) Systems provides a high data rate multiple access wireless communications, which retain frequency diversity under a frequency selective fading channel. However, when MC-CDMA system is applied in uplink transmission, because of spreading codes for different user’s frequency selective fading channel, the orthogonality between the spreading code will lost, which cause server Multiple Access Interference (MAI) problem. In this paper, the sparse Gaussian integer sequence (SGIS) are used to construct the low complexity transform matrix, which is the combination of spreading matrix and inverse fast fourier transform (IFFT) matrix. SGIS and its dual sequence have some great property that mitigates MAI, and the feature of sparse also effectively reduce the PAPR, the computational complexity at transmitter will also be reduced. Moreover, the transform matrix are a circular matrix and unitary matrix, we can eliminate MAI when the system is half-loading. MC-CDMA compared to Single-Carrier Code Division Multiple Access (SC-FDMA) has full frequency diversity, unlike SC-FDMA that its frequency diversity depends on FFT size, so when enhance the diversity, the computational complexity will increase significantly.

論文審定書 i
誌謝 ii
中文摘要 iii
Abstract iv
目錄 v
圖次 vii
第一章 導論 1
1.1 研究動機 3
1.2 論文架構 3
第二章 系統介紹 4
2.1 正交分頻多工系統 4
2.2 多載波分碼多工系統 8
第三章 轉換矩陣之設計 11
3.1 展頻碼矩陣與轉換矩陣 11
3.2 使用稀疏高斯序列之轉換矩陣產生方式 12
第四章 新多載波分碼多工上鏈系統 15
4.1 傳送端架構 15
4.2 接收端架構 16
4.3 多用戶間的干擾消除 20
4.4 錯誤率推導 22
第五章 模擬結果 28
5.1 選擇性架構 28
5.2 錯誤率比較 29
5.2.1 調變方式相同 30
5.2.2 OFDM Symbol總位元數同 34
5.2.3 峰均值功率比 38
第六章 結論 40
參考文獻 41
中英對照表 49
縮寫對照表 55

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