臺灣博碩士論文加值系統

在無線網路的傳輸上，利用網路編碼的技術可以獲得良好的傳輸效率。原因在於它能在中間節點對所收到的封包進行編碼處理，然後再廣播給其它鄰近的節點。相較於傳統的傳輸方式，使用網路編碼不僅可以增加傳輸的效率，傳輸的可靠度也大大地提升。
應用網路編碼之技術於無線傳輸上可分為兩種傳輸模式。第一種模式為解碼前送(Decode-and-Forward, DF)，它是利用XOR的運算方式對於所接收到的封包來進行編碼組合，然後再將經過編碼組合的封包廣播出去。第二種模式為放大前送(Amplify-and-Forward, AF)，它是利用多路存取通道(multiple access channel)的特性，直接同步接收由來源節點所傳送過來的類比訊號，不需透過解碼，直接將訊號放大後轉送給其它鄰近的節點，由鄰近的節點自行解碼。
在本論文中，我們將針對傳統、解碼前送與放大前送這三種傳輸模式做更進一步的分析與探討。我們結合錯誤更正碼的技術來改善傳輸的效率，而且不管在加成性白色高斯雜訊(Additive White Gaussian Noise, AWGN)通道或是Rayleigh衰減通道都能有效地提升傳輸效
率。除此之外，我們還使用了四種不同的調變方式來進行我們的模擬，並分析和比較在不同的訊雜比情況下，各通道與調變方式之性能表現。

In wireless transmission, the technique of network coding can be used to improve transmission throughput. With network coding, the intermediate nodes can encode the received packets before broadcasting them to other neighbors. Compared to the conventional relaying, it can greatly increase not only the throughput but also the reliability.
There are two kinds of transmission modes to apply the network coding techniques to wireless transmission. The first mode is called Decode-and-Forward (DF). In this mode, the intermediate node uses the XOR operation to encode the received packets, then broadcast them to neighbors. The second mode is called Amplify-and-Forward (AF), it uses the characteristic of multiple access channel to receive the analog signals simultaneously. The intermediate node does not decode the signals, it just amplifies and broadcasts the received signals. The neighbors should take the duty to decode the signals.
In this thesis, we focus on the performances of conventional relaying, DF and AF transmission modes. We combine the error correction coding techniques to improve throughput in Additive White Gaussian Noise (AWGN) channel and Rayleigh fading channel. Furthermore, we also use four different modulations to proceed our simulations, and compare the performances in different channels and different modulations.

摘要.............................................................................................................i
Abstract.....................................................................................................iii
誌謝...........................................................................................................iv
目錄.............................................................................................................v
圖目錄.......................................................................................................ix
表目錄.....................................................................................................xiii
1. 第一章 緒論.......................................................................................1
1.1 前言.....................................................................................1
1.2 網路編碼簡介.....................................................................1
1.3 研究動機與目的.................................................................3
1.4 論文各章節概述.................................................................4
2. 第二章 網路編碼原理簡介...............................................................6
2.1 網路編碼基本原理.............................................................6
2.2 場的定義與介紹.................................................................7
2.2.1 場..............................................................................8
2.3 網路編碼及線性網路編碼之定義.....................................9
2.3.1 網路編碼與線性網路編碼......................................9
2.3.2 網路編碼之定義....................................................11
2.3.3 線性網路編碼之定義............................................14
3. 第三章 雙向擴大傳輸於無線網路編碼之研究.............................17
3.1 簡介...................................................................................18
3.2 系統模組...........................................................................21
3.2.1 解碼前送之雙向擴大傳輸....................................21
3.2.2 放大前送之雙向擴大傳輸....................................22
3.3 雙向擴大傳輸之協定.......................................................23
3.3.1 解碼前送雙向擴大傳輸之協定............................25
3.3.2 放大前送雙向擴大傳輸之協定............................29
3.4 數值分析與模擬結果.......................................................31
4. 第四章 針對無線網路之雙向傳輸做更進一步的探討.................34
4.1 針對雙向傳輸做實際的模擬...........................................34
4.2 利用錯誤更正碼做進一步的改善...................................35
4.2.1 簡介........................................................................35
4.2.2 實驗模擬................................................................36
4.3 Rayleigh衰減通道..............................................................39
4.4 三種傳輸模式於不同調變方式之模擬...........................46
4.4.1 不同調變方式於AWGN通道之模擬....................46
4.4.2 不同調變方式於Rayleigh衰減通道之模擬..........55
5. 第五章 結論與未來展望.................................................................61
參考資料...................................................................................................62
作者簡介...................................................................................................64

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