臺灣博碩士論文加值系統

在複雜干擾嚴重的無線傳輸環境中，為求降低資料在傳輸時受雜訊的干擾而產生之錯誤，結合錯誤更正碼於是被廣泛的應用在數位通訊領域中，例如：衛星通訊及行動通訊等。
互補碼調變(CCK, Complementary Code Keying)技術已使用於IEEE 802.11b規格中。其解碼方式目前有最大相似度(Maximum-Likelihood Algorithm)、大數解碼法(Majority Logic Algorithm)及晶格解碼法(Trellis Decoding)等。
本論文重新定義一種分解與結合的關係，將互補碼調變中每一個四進位的字元拆解成二個進位的位元資料，也就是由原來四進位的運算分解成二進位的運算(以降低接收端中解碼運算量)。隨後，經由渦輪編碼器編碼後，再組合成互補碼調變傳送出去。在接收端收到後，先由互補碼解調變再使用渦輪碼解碼，最後再依相關矩陣還原成原始信息。
吾人所定義之四進位與二進位符號之間的分解與組合關係，僅需要兩個二進位生成矩陣的運作及相對應關係便可產生四進位符號，此兩個二進位生成矩陣所對應的晶格結構複雜度(合計為128 個狀態點及172條分枝)遠低於一個四進位生成矩陣所對應的晶格結構複雜度(918 個狀態點及1108 條分枝)，因而有效減少解碼運算複雜度。

Under the complicated environment of wireless communication, the technology of error control coding is employed in the digital communication systems in order to reduce noise and interference errors in datum transmission. For example, satellite communications and mobile communications, etc.
Complementary Code Keying (CCK) is used in IEEE 802.11b standard. There are some decoding algorithms applied to CCK. It concludes maximum-Likelihood algorithm、majority logic algorithm and trellis decoding .
Besides, in this paper we define the relationship between decomposition and combination for each quaternary symbol.
It means to decompose a quaternary symbol into two binary bits. After the operation of turbo code encoding employed, a corresponding CCK is then formed by using the proposed combination .Consequently, the demodulation of CCK has been performed before turbo code decoding. Finally, we use the some matrix and combination to obtain the original information.
We propose the decomposition and combination between the quaternary and binary symbols, which only employ two binary generator matrices.
The complexity of two binary generator matrices is much less than a quaternary generator matrix.
Therefore, it will drastically reduce the complexity in the decoding process.

誌謝 ii
摘要 iii
ABSTRACT iv
目錄 v
表目錄 vii
圖目錄 ix
符號與中英辭彙對照 xii
1 緒論 1
1.1 研究動機 1
1.2 提出方案 2
1.3 內容大綱 3
2 IEEE 802.11 b無線區域網路簡介 4
2.1 無線通道環境簡介 4
2.2 IEEE 802.11b無線區域網路規格分析 6
2.3 IBSS與BSS無線網路架構介紹 8
3 互補碼調變(CCK)之探討 10
3.1 互補碼調變簡介 10
3.2 巴克碼(Barker Code) 10
3.3 互補碼調變技術 11
3.4 如何產生互補碼調變序列 13
3.5 互補碼調變傳/收器架構 17
3.6 RM4(1,3)碼架構之互補碼調變編解碼法則 18
4 渦輪碼之簡介 20
4.1 渦輪碼之基本原理 20
4.2 編解碼器架構 20
4.2.1 渦輪碼編碼原理 20
4.2.2 渦輪解碼原理 22
4.2.3 渦輪解碼演算法 23
4.2.4 另一類型的SISO解碼演算法 24
4.2.5 終止疊代(Iterative) 26
4.3 互補碼調變晶格編解碼法則 27
5 渦輪解碼法與互補碼調變整合之研究 34
5.1 互補碼調變之分解與組合 34
5.2 互補碼調變使用晶格編解碼法 38
5.3 互補碼調變方式與渦輪碼之結合 40
5.4 程式模擬效能比較分析 42
5.4.1 互補碼調變使用RM4(1,3)碼錯誤更正效果比較分析 42
5.4.2 巴克碼軟性及硬性判決解碼法錯誤更正效果比較分析 43
5.4.3 互補碼調變晶格解碼法錯誤更正效果比較分析 44
5.4.4 互補碼調變與渦輪碼結合之錯誤更正效果比較分析 44
5.5 圖形模擬比較分析 45
5.5.1 巴克碼解碼法 47
5.5.2 互補碼調變晶格解碼法 49
5.5.3 互補碼調變與渦輪碼結合(疊代一次) 50
5.5.4 互補碼調變與渦輪碼結合(疊代四次) 51
6 結論 52
參考文獻 53

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