本文選題：噴泉碼　切入點：LT碼　出處：《中國礦業(yè)大學》2017年碩士論文　論文類型：學位論文

【摘要】：隨著無線通信系統(tǒng)的快速發(fā)展,用戶對信息傳輸的可靠性提出了更高的要求。噴泉碼作為一種基于刪除信道的信道編碼技術,被廣泛應用于可靠廣播傳輸場景中。其采用了隨機編碼的思想,具有無固定碼率、魯棒性、高效性、較低的編譯碼復雜度、無需反饋信道來確保傳輸的可靠性和適應實時變化的信道等優(yōu)點。然而噴泉碼作為一種依據某種啟發(fā)思想設計出來的信道編碼技術,其度分布函數和編譯碼算法仍然具有很大的改進空間。本文以噴泉碼技術為主體,針對噴泉碼的譯碼效率低、編碼矩陣不滿秩以及應用場景問題,研究了噴泉碼的度分布算法、編譯碼算法及可靠傳輸方案。主要研究工作如下:第一,針對噴泉碼較低的譯碼效率問題,MBRSD度分布算法通過控制度為1編碼包的連接方式優(yōu)化了平均可譯集大小從而減少了譯碼時間。由于該算法中缺少度為1的編碼包且其分布不均勻,通過把增加度為1的編碼包的插值算法與MBRSD度分布算法相結合,本文提出了IMBRSD度分布算法。改進的算法減少了成功譯碼需要的編碼包數,并且降低了系統(tǒng)的誤碼率。第二,針對噴泉碼編碼矩陣存在的不滿秩情況會導致接收端無法正確譯碼的問題,本文在發(fā)送端對編碼矩陣進行了滿秩矩陣預處理。其通過對編碼矩陣進行增廣矩陣處理,選出少量列向量補充到原編碼矩陣中來構成滿秩矩陣。本文提出的編碼矩陣滿秩優(yōu)化算法降低了噴泉碼譯碼失敗概率。第三,針對固定碼率無法匹配實時變化的信道容量問題,本文將滿秩優(yōu)化后的噴泉碼應用在廣播傳輸方案中從而解決了不可靠傳輸問題。發(fā)送端依據接收端反饋的正確譯碼包的數目計算實際信道的刪除概率,然后根據實際信道條件調整編碼包輸出個數。該傳輸方案可以減少反饋信道帶來的能量消耗并且能夠自適應地實現碼率與時變信道容量的匹配,增加了廣播的可靠性。
[Abstract]:With the rapid development of wireless communication system, users put forward higher requirements for the reliability of information transmission. Fountain code is a channel coding technology based on deleted channel. It is widely used in reliable broadcast transmission scenarios. It adopts the idea of random coding and has no fixed code rate, robustness, high efficiency, low encoding and decoding complexity. There is no need for feedback channels to ensure the reliability of transmission and the advantages of adapting to real-time changing channels. However, fountain code is a channel coding technique designed according to some heuristic idea. The degree distribution function and the encoding and decoding algorithm still have a great improvement space. In this paper, the fountain code is used as the main body. In view of the low decoding efficiency of the fountain code, the rank of the coding matrix and the application scene, the degree distribution algorithm of the fountain code is studied. Coding and decoding algorithms and reliable transmission schemes. The main research work is as follows: first, In order to solve the problem of low decoding efficiency of fountain codes, the MBRSD distribution algorithm optimizes the average translatable set size by controlling the connection of coding packets with a degree of 1, thus reducing the decoding time. Due to the lack of coded packets with degree 1 in the algorithm, the decoding time is reduced. And its distribution is uneven, By combining the interpolation algorithm with the MBRSD degree distribution algorithm, an improved IMBRSD degree distribution algorithm is proposed. The improved algorithm reduces the number of coding packets required for successful decoding and reduces the bit error rate (BER) of the system. In view of the problem that the incomplete rank of the fountain code coding matrix will cause the receiver to be unable to decode correctly, this paper preprocesses the full rank matrix of the code matrix at the sending end. A small number of column vectors are selected to add to the original coding matrix to form the full rank matrix. In this paper, the full rank optimization algorithm of the coding matrix reduces the decoding failure probability of fountain code. Thirdly, for the channel capacity problem in which the fixed code rate can not match the real-time variation, In this paper, the full rank optimized fountain code is applied to the broadcast transmission scheme to solve the unreliable transmission problem. The sender calculates the deletion probability of the actual channel according to the number of correct decoding packets feedback from the receiver. Then the output number of coding packets is adjusted according to the actual channel conditions. The proposed scheme can reduce the energy consumption brought by the feedback channel and adaptively match the code rate with the time-varying channel capacity and increase the broadcast reliability.
【學位授予單位】：中國礦業(yè)大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TN911.22

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本文編號：1631687