本篇論文在同步與非同步DS-CDMA系統環境下探討基因演算法對於多使用者偵測器。雖然崁入的基因演算法和多時期偵測器可以改進傳統基因演算法對於多使用者偵測，但是當使用者個數增加時，多時期偵測器會招致計算的消耗。為了在每一代中消除多時期偵測器的動作，擁有可調整的父母大小及擴大的取樣空間的改良式基因演算法被發展，所提出的基因演算法有較少的複雜度可以實現幾乎和崁入多時期偵測器進入基因演算法一樣，有相同位元錯誤率的效能。模擬的結果證明所提出的基因演算法逼近最佳偵測器的效能。
此外，在同步的CDMA系統中，透過無相關的頻率非選擇性的瑞立衰減通道，我們將應用改良式基因演算法於一個空間分集接收助益的多使用者偵測器。電腦模擬的結果也將顯示出所提出的基因演算法在多使用者的偵測上可以比傳統的基因演算法實現較低的位元錯誤率的效能。

In this thesis, an improved genetic algorithm (GA) for multi-user detectors is investigated in synchronous and asynchronous DS-CDMA systems. Although the embedded GA and multistage detector (E-GA/MSD) can also improve the conventional GA performance for multiuser detection, the MSD incurs high computational consumption when the users are growing. To eliminate the MSD operation at each generation, an improved GA with adjustable parent size and enlarged sampling space is developed. The proposed GA with much less complexity can achieve almost the same BER performance as the E-GA/MSD. Simulation results demonstrate that the proposed GA is near to an optimum detector.
Additionally, we apply the proposed GA to a spatial diversity reception assisted multiuser detector over uncorrelated flat Rayleigh fading channels in synchronous CDMA systems. As expected, computer simulations also show that the proposed GA can achieve the lower BER performance than conventional GA.

感謝詞 i
中文摘要 ii
英文摘要 iii
目錄 iv
圖表目錄 vi
第一章 序論1
1.1 文獻探討1
1.2 研究動機3
第二章 DS-CDMA系統中多使用者偵測器5
2.1 直接序列分碼多重接取系統5
2.1.1 DS-CDMA 系統下的基頻帶訊號模型5
2.2 DS-CDMA之多使用者偵測器 7
2.2.1 傳統偵測器7
2.2.2 最佳多使用者偵測器8
2.2.3 解相關偵測器 9
2.2.4 最小均方誤差偵測器10
2.3 非線性之次佳多使用者偵測器12
2.3.1 多時期偵測器12
2.4 電腦模擬與分析13
第三章 在DS-CDMA系統中根據基因演算法之多使用者偵測器21
3.1 傳統基因演算法之多使用者偵測器21
3.1.1 基本的基因演算法21
3.1.2 根據傳統基因演算法之多使用者偵測器22
3.2 一些修改的基因演算法之多使用者偵測器25
3.2.1 Yen所提修改的基因演算法之多使用者偵測器25
3.2.2 Shayesteh所提修改的基因演算法之多使用者偵測器26
3.3電腦模擬與分析28
第四章 非同步直接序列分碼多重接取系統38
4.1 研究動機38
4.2 改良式基因演算法之多使用者偵測39
4.2.1 崁入MSD進入傳統基因演算法39
4.2.2 改良式基因演算法之多使用者偵測 41
4.3 天線分集的助益的基因演算法之多使用者偵測46
4.3.1 系統的架構及描述46
4.3.2 改良式基因演算法應用在天線分集助益的多使用者偵測器49
4.4 電腦模擬與分析52
第五章 討論與建議65
參考文獻67
縮寫71

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