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研究生:陳達宏
研究生(外文):Chen, Da-Hon
論文名稱:直序式展頻多工通訊之非同調混合式PN碼擷取
論文名稱(外文):Noncoherent Hybrid PN code Acquisition for Multiple Access Direct-Sequence Spread-Spectrum Communications
指導教授:吳傳嘉
指導教授(外文):Chwan-Chia Wu
學位類別:博士
校院名稱:國立台灣工業技術學院
系所名稱:電機工程技術研究所
學門:工程學門
學類:電資工程學類
論文種類:學術論文
論文出版年:1997
畢業學年度:85
語文別:中文
論文頁數:1
中文關鍵詞:直序式展頻通訊分碼多工擷取匹配濾波器虛擬亂碼追蹤範圍
外文關鍵詞:direct-sequence spread spectrumcode-division multiple-accessacquisitionmatched filterpseudonoise codetracking range
相關次數:
  • 被引用被引用:3
  • 點閱點閱:211
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  • 下載下載:0
  • 收藏至我的研究室書目清單書目收藏:0
在直序式展頻多工非同調通訊中﹐有多種方法可以完成PN碼之同步﹐
用以回復接收訊號。通常符碼的同步過程可分為PN碼擷取及追蹤兩個步驟
。所以設計一個有效的擷取系統﹐是成本效應上重要的參數﹐另外一個重
要的考量是追蹤迴圈的設計﹐其功能在符碼同步之後繼續追蹤符碼的相位
﹐以保持通訊的持續。此一追蹤系統操作的範圍是取決於追蹤迴圈對追蹤
範圍的需求。
本論文首先討論一個基於串並列架構的混合式數位濾波器(HDMF)﹐本濾波
器是將接收的PN碼和當地的PN碼﹐進行單次﹑完整PN碼的關連值計算。對
於一個長的PN碼而言﹐由於並列之架構可以大幅的縮短關連值的計算時間
﹐使其適用於高速PN碼碼率之傳輸﹐以提升資料傳輸時的效益。另外﹐本
文中亦提出一個新的搜尋方式稱為 HSED (Hybrid Searchby
Eliminating Data symbol)﹐其類似於並行搜尋﹐利用多個混合式數位關
連器同時計算不同相位之關連值﹐亦採用串列搜尋的方式掃瞄PN碼﹐搜尋
正確的相位。此一混合式的的搜尋方式能有效的使用於自動頻率控制迴圈
中﹐並經由分析得知其追蹤範圍會隨著使用的關連器數量增加而增加。
最後分析上述兩種架構在多工通訊環境下的效能﹐係針對Rayleigh及
Rician分佈時之干擾通道﹐分析PN碼偵測及誤判機率及平均擷取時間﹐用
以評估擷取系統的效能。
PN code synchronization plays a vital role of data recovery at
the receiving end of a direct-sequence spread-spectrum (DS/SS)
multiple access system. The code synchronization is usually
achieved in two steps, i.e., acquisition and tracking. It is
desired to design an efficient acquisition system that is cost-
effective to some design parameters. In the mean time, it is
also important to design a cost-effective tracking loop for code
tracking process so that code synchronization can be maintained
as long as the communication link is connected. This requires
that the tracking range of the tracking loop is as large as
possible to allows the system to be operated in a robust
environment.This dissertation first proposes a digital matched
filter design based on a hybrid serial-parallel architecture.
The proposed hybrid digital matched filter (HDMF) adopts single-
dwell serial search approach to evaluate full correlation of the
incoming PN code and the locally generated code. The serial-
parallel structure suggests that, when the PN code length is
large, the correlation evaluation time can be greatly reduced
compared to that of a digital matched filter of a parallel
architecture. This implies that a faster (PN code) chip rate can
be applied and thus yields a wider bandwidth for data
transmission. A new search scheme is also proposed in this
dissertation. The scheme proposed adopts a hybrid structure that
performs correlation evaluation for different code phases
simultaneously and thus is similar to that performed by parallel
search. However, it also performs serial search to scan all the
possible code phases if the tests conducted by a given parallel
search is not adequate to locate the correct code phase. This
proposed hybrid search scheme, called Hybrid Search by
Eliminating Data symbol(HSED), is also useful for tracking
process if the tracking loop is constructed by an automatic
frequency control (AFC) loop. Through an algebraic analysis, it
can be shown that the tracking range is proportionally increased
by the increase of parallel correlators in use in the HSED
scheme.Performance of both schemes are analyzed through which
the effect of multiple access interference (MAI) on the code
acquisition performancefor Rayleigh and Rician fading channels
is studied. The closed-formexpressions of the detection and
false alarm probabilities and mean acquisition time are derived.
Cover
Abstract
Contents
List of Figures
List of Tables
1 Introduction
2 A Hybrid Digital Matched Filter for Direct Sequence Spread Spectrum Systems
2.1 Hybrid Serial-Parallel Architecture
2.2 Segment Switching Scheme
2.3 Implementation
2.4 Discussions
3 A Hybrid Search Scheme for Rapid Acquisition and Wide Code Tracking Range
3.1 Fundamentals
3.2 The HSED Scheme
3.3 Mean Acquisition Time
3.4 Tracking Range Improvement
3.5 Discussions
4 Code Acquisition Performance
4.1 Effect of Multiple Access Interference in Fading Channels
4.2 Acquisition via Serial-Parallel Correlator
4.3 Acquisition via HSED Scheme
4.4 Numerical Results
5 Conclusions
Appendices
References
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