臺灣博碩士論文加值系統

PN碼同步在CDMA通信系統中有著非常重要的地位，在文獻裡頭，多重路徑衰減與多使用者干擾對PN碼追蹤的影響，
已個別地被討論。多重路徑衰減的影響，可以使得DLL結合rake接收器與通道估測器來解決這樣的問題；而多使用
者的干擾，則DLL可以結合資料估測器來降低這個的干擾。
在下傳的展頻碼同步，可能會遭受到多重路徑的影響；然而在上傳的展頻碼同步，干擾的因素不僅有多重路
徑衰減，還包括多使用者的干擾，可惜的是上述的方法的使用，並不能夠同時解決這兩種的問題。
本論文裡頭，兩種新的同調直接決定延遲鎖定迴路(CDD-DLL)的PN碼追蹤架構被發展出來，而且能夠克服這
兩種干擾因素的影響。首先所提的架構為rake 接收之DLL，並結合一個通道與一個資料的估測器，這種新的架構能
適合在多重衰減路徑與多使用者干擾的環境下被使用。第二種新的設計為原來的CDD-DLL架構再結合多重路
徑干擾消除器(MPI canceller)來消除多重路徑衰減的影響，這架構稱之為MPI-CDD DLL。這兩種設計在多重路徑
衰減與多使用者干擾的環境下的數值分析結果顯示，傳統的DLL架構所遭受到這兩種干擾因素的影響，已被這兩種
新的設計所改善，而且MPI-CDD DLL對於抑制干擾的能力更勝於首先提出的CDD-DLL，其原因是MPI-CDD DLL可以完
全消除多重路徑衰減的影響。

PN code tracking plays a very important role in CDMA communication systems.
In literature, the influences of multipath fading and of multiuser interference
on PN code tracking are studied separately. The multipath fading influence is
mitigated by combining a rake receiver and a channel estimator in
the Delay-Locked Loop (DLL). The multiuser interference is overcome by
incorporating a data estimator into the DLL. In the downlink, PN code tracking
may suffer from the multipath fading influence. However, the multipath fading
and the multiuser interference influences exist in the uplink. Unfortunately,
sole use of the aforementioned methods cannot solve out both influences simultaneously.
In this thesis, two new Coherent Decision-Directed Delay-Locked Loop (CDD-DLL)
PN-Code tracking schemes are developed and either can overcome both influences.
First, a channel and a data estimators are incorporated into the DLL inherent
with a rake receiver. This new scheme works properly in an environment with
multipath fading and multiuser interference. Second, the original CDD-DLL is
combined with a multipath interference canceller (MPI) to reduce both influences.
Analytical results are derived for the two schemes proposed and are validated
with numerical simulations. Simulation results show that the conventional DLLs
working in a multipath fading and multiuser interference environment can be
significantly improved using the new schemes. Moreover, the latter outperforms
the former because the multipath interference is cancelled completely.

感謝辭……………………………………………………………… i
中文摘要…………………………………………………………… ii
英文摘要………………………………………………….……… iii
目錄………………………………………………………………… iv
圖表目錄………………………………………………………… vii
第一章 緒言……………………………………………………… 1
1.1 論文探討………………………………………………… 1
1.2 研究動機………………………………………………… 3
第二章 PN碼的同步迴路在展頻通訊系統的分析與介紹……. 5
2.1 PN碼的同步模型與效能測量…………………………. 6
2.2 PN碼的追蹤迴路分析…………………………………. 10
2.2.1 同調DLL系統介紹………………………………… 10
2.2.2 非同調DLL系統介紹………………………………… 17
2.3 同調DLL IC設計………………………………………… 25
2.3.1 架構介紹…………………………………………. 26
2.3.2 動作說明………………………………………… 27
2.3.3 模擬結果………………………………………… 27
第三章 多重路徑影響與多使用者干擾對DLL的影響分析… 41
3.1 多重路徑衰減通道對非同調DLL的影響分析…….. 42
3.1.1 系統與通道模型的描述…………………………… 42
3.1.2 非同調DLL的效能分析…………………………… 44
3.2 多使用者干擾對非同調DLL的影響分析………….. 48
3.2.1 系統與通道模型的描述…………………………… 48
3.2.2 非同調DLL的系統分析…………………………… 49
3.2.3 效能分析……………………………………………51
3.3 電腦的模擬與分析………………………………… 54
3.3.1 多重路徑衰減通道對非同調DLL之影響的電腦
模擬與分析………………………………………… 54
3.3.2 多使用者對非同調DLL之干擾的電腦模擬與分析.58
第四章 在多重路徑衰減與多使用者干擾下CDD-DLL的同步效能
分析…………………………………………………. 71
4.1 在多重路徑衰減與多使用者干擾環境下的系統描述 71
4.1.1 通道模型與訊號模型的描述……………………….72
4.1.2 原系統所遭遇的問題………………………………73
4.1.3 CDD-DLL的系統描述……………………………… 75
4.1.4 在理想通道估測下的迴路效能分析………………77
4.2 電腦模擬與分析…………………………………. 80
第五章 在多重路徑衰減與多使用者干擾下MPI-CDD DLL的同步效能
分析………………………………………… 89
5.1 MPI-CDD DLL系統描述………………………... 90
5.1.1 在多重路徑衰減與多使用者干擾環境下的系統描述 90
5.1.2 理想迴路的線性分析…………………………….. 96
5.2 電腦模擬與分析………………………………… 98
第六章 討論與建議………………………………………. 106
縮寫……………………………………………………….. 108
參考文獻………………………………………………….. 109
Appendix A………………………………………………... 113
Appendix B………………………………………………... 119

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