在這篇論文中，我們提出一個改良式的多調-分碼多重接取系統，主要是利用接收端結合領航訊號的傳送多樣性來提高通道估測的準確性。文中除了闡述系統設計的原理和架構外，更依照兩種不同的資料配置方式，分別用數學分析出系統在慢速瑞雷衰減通道下的誤碼率，最後經由電腦模擬可以證明，當總傳送功率相同時，在接收端結合兩個通道的梳型領航訊號來做通道估測，確實能改善梳型領航訊號排列原本在頻率選擇性衰減表現不佳的現象。

In this thesis, we propose a modified MT-CDMA system, which can improve channel estimation accuracy by using transmit diversity of pilot signals. We not only expound the principles and structures of the system we proposed, but analyze its performance in slow Rayleigh fading channel environment. According to different ways to assign data symbols of transmitted signals, we have two different bit error rate results. At the same transmit power, the simulation results show that when we combine comb-type pilot signals of two parallel channels to estimate channel gains, we can recover the drawbacks of comb-type pilot arrangement, which can not perform well in frequency selective fading channel. Finally, the numerical results will be also shown.

中文摘要
Abstract
圖目錄
表目錄
第一章 緒論....................................................................................................1
1.1 研究動機.…………………………………………...............…………....1
1.2 論文章節介紹.…………………………………………..............……….1
第二章 多載波傳輸技術的基本原理與介紹................................................3
2.1 OFDM的特性與系統架構........................................................................3
2.1.1 傳統的OFDM架構...........................................................................4
2.1.2 基於離散傅立葉轉換的OFDM架構...............................................5
2.1.2.1 傳送和接收端的資料轉換................................................7
2.1.2.2 正交性................................................................................9
2.1.2.3 循環字首..........................................................................10
2.2 OFDM的優缺點......................................................................................11
2.3 單載波與OFDM之比較.........................................................................12
第三章 基於OFDM之分碼多重接取系統..................................................14
3.1 多載波-分碼多重接取系統.....................................................................14
3.2 多載波/直接序列-分碼多重接取系統...................................................20
3.3 多調-分碼多重接取系統.........................................................................21
3.4 系統比較..................................................................................................29

第四章 改良式多調-分碼多重接取系統...................................................31
4.1 通道估測..................................................................................................31
4.1.1 領航訊號排列..................................................................................32
4.1.2 領航訊號估測法..............................................................................34
4.1.3 內插法..............................................................................................38
4.2 改良式多調-分碼多重接取系統之原理與優點...................................39
4.3 系統效能分析..........................................................................................44
4.3.1 傳送端..............................................................................................44
4.3.2 通道模型..........................................................................................46
4.3.3 接收瑞..............................................................................................46
第五章 模擬結果之比較與分析..................................................................52
5.1 多重路徑干擾..........................................................................................52
5.1.1 頻率選擇性衰減的電腦模擬..........................................................54
5.1.2 Jake’s模型........................................................................................54
5.2 模擬結果..................................................................................................55
第六章 結論與未來展望..............................................................................65
附錄A MT-CDMA系統部分相關函數期望值之計算.................................66
附錄B 離散時間相關函數計算.....................................................................68
參考文獻............................................................................................................73

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