林茂昭臺灣大學：電信工程學研究所王仲立Wang, Chung-LiChung-LiWang2007-11-272018-07-052007-11-272018-07-052006http://ntur.lib.ntu.edu.tw//handle/246246/58681Ashikhmin等人提出了在多輸入多輸出衰變通道中運作的低密度同位檢查編碼傳輸系統，在編碼長度大於十萬個位元時可以有貼近通道容量的效能。可是，這個系統在編碼長度小於一萬個位元時變的難以運用。在陳彥凱的碩士論文中密度同位檢查編碼傳送系統加上區碼記憶的系統在某些短碼時可以超越沒有區碼記憶的系統。在這篇論文中，我們在渦輪編碼多輸入多輸出傳輸架構上使用區碼記憶。首先，我們先簡單描述如何應用區碼記憶在渦輪編碼多輸入多輸出傳輸系統。重點擺在接收端的偵測方法。雖然外部訊息圖的分析在長碼時比較準確，但我們經由分析在外部訊息圖中，反映射器的轉移特徵曲線，依然可以解釋所提出架構的優點。最後，我們用各種天線數設定之下的模擬結果證實之前的推論。模擬結果顯示當編碼長度比較小時使用這個技術可以有很大的效能提升。In a paper authored by Ashikhmin, et. al., a low-density parity-check (LDPC) coded transmission scheme operated on multiple-input multiple-output (MIMO) fading channel was proposed, which can achieve capacity-approaching performance in case the code length is 100000 bits. Nevertheless, this scheme is difficult to use in case the code length is shorter than 10000 bits. According to Chen’s master thesis, LDPC coded MIMO using interblock memory outperform LDPC coded MIMO without interblock memory in some short code-length conditions. In this paper, we apply interblock memory to the turbo coded MIMO transmission system. First, a short description of applying interblock memory to turbo coded MIMO transmission system is given. We focus on the detection methods for the receiver scheme. Then we can explain the advantage of the proposed turbo coded MIMO by analyzing demapper transfer characteristics in Extrinsic Information Charts (EXIT charts), although EXIT charts usually works well only in the condition of long code length. Finally, our proposed schemes are verified by simulation results for various transmission antenna settings. The simulation results show that the proposed technique provides significant advantage in case that the code is short.1 Introduction 1 2 Preliminaries 4 2.1 MIMO Channel Model 4 2.2 Turbo Decoding 7 2.2.1 The MAP Decoding Algorithm 7 2.2.2 The Iterative Decoding Algorithm 14 2.3 Basics of Low-density Parity-check codes 20 2.3.1 Representations of LDPC codes 20 2.3.2 Iterative Decoding Algorithm: Sum-Product Algorithm (SPA) 22 2.3.3 Log-Domain SPA Decoding 24 2.4 Extrinsic Information Transfer (EXIT) Chart 27 2.4.1 Iterative Decoder for Parallel Concatenated Codes 27 2.4.2 Transfer Characteristics of Constituent Codes 29 3 Coded MIMO 32 3.1 Transmitter Side 33 3.2 Receiver Side 34 4 Coded MIMO Using Interblock Memory 37 4.1 Transmitter Side 38 4.2 Receiver Side 39 4.2.1 Restricted Iterative Detection 39 4.2.2 Complete Iterative Detection 40 4.2.3 Forward and Backward Detection 42 4.3 EXIT Chart Analysis 45 5 Simulations 52 5.1 Forward Detection 52 5.2 Forward and Backward Detection 58 5.3 Turbo and LDPC coded MIMO 63 6 Conclusions 65 Bibliography 66618097 bytesapplication/pdfen-US區碼記憶渦輪碼多輸入多輸出遞迴解碼interblock memoryturbo codesmultiple-input multiple-outputiterative decodingthesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/58681/1/ntu-95-R92942109-1.pdf