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研究生:謝銘哲
研究生(外文):Ming-Je Hsieh
論文名稱:離散多載波傳收機之最佳通道傳輸率時域等化器
論文名稱(外文):Time-domain equalization for DMT transceivers to achieve channel capacity
指導教授:吳文榕
指導教授(外文):Wen-Rong Wu
學位類別:碩士
校院名稱:國立交通大學
系所名稱:電信工程系
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:2002
畢業學年度:90
語文別:中文
論文頁數:110
中文關鍵詞:離散多頻帶時域通道等化器通道傳輸率
外文關鍵詞:DMTTEQchannel capacity
相關次數:
  • 被引用被引用:0
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  • 下載下載:17
  • 收藏至我的研究室書目清單書目收藏:0
在離散多頻帶(Discrete Multi-tone,DMT)接收機中,使用一時域通道等化器(Time-domain equalizer,TEQ),藉此來縮短通道響應以達到降低符號間干擾(Intersymbol interference,ISI)的目的。近來有關TEQ之研究,不只在縮短通道以降低ISI,更以提升整體傳輸率為主要設計考量,其關鍵在於訊雜比(Signal-to-noise ration,SNR)的定義是否正確。要定義出正確的SNR,首先有關整體雜訊源的型態必須獲得確認。在DMT系統中,雜訊源主要分為兩個部分;一種為通道雜訊,另一種則為殘餘的ISI。近來,殘餘ISI的部份已獲得確認而提出了能達到最大傳輸率的TEQ設計。遺憾的是,此種方法並沒有考慮到通道雜訊的特殊影響。在本論文中,我們將要研究此一問題。首先將證明雜訊比預期的高,這部分可從雜訊不似傳送訊號具有前置週期(Cyclic Prefix,CP)的角度來解釋。如此一來,在TEQ之後各個頻帶上的SNR會被降低。我們所提出的方法將同時考慮殘餘ISI和通道雜訊的影響。經模擬之後可以看出,所提出的演算法確實優於現存所有的TEQ設計。

In a discrete multitone (DMT) receiver, a time-domain equalizer (TEQ) is used to shorten the channel impulse response. The general criterion for the TEQ design is to maximize bit loading. To do that, all noise sources have to be identified and taken into signal to noise ration (SNR) calculation. There are mainly two noise sources in a DMT system; one is the channel noise and the other is the residual intersymbol interference (ISI). Recently, the residual ISI has been identified as a noise source and a method to achieve maximum bit loading was proposed. Unfortunately, this method does not consider the special effect of channel noise. In this thesis, we intend to solve this problem. We first show that noise can be more damaging than it looks. This can be explained by the fact that the transmitted signal has a cyclic prefix (CP) while the noise signal does not. Thus, the SNR (for each tone) in the TEQ output is lower than that in its input. We then propose a TEQ design method that can simultaneously take the residual ISI and the channel noise into account. Simulations show that our method outperforms all existing TEQ design algorithms.

1. 簡介 1
2. 通道模擬 3
2.1. 原理介紹 3
2.1.1 傳輸線模型 4
2.1.2 傳輸線RLGC參數特性描述 5
2.1.3 混合式電路 8
2.2. 使用者介面 9
3. DMT介紹 17
3.1. 系統介紹 17
3.1.1 DMT Transmitter 18
3.1.2 DMT Receiver 20
3.2. 等化器架構 21
4. 現有演算法 26
4.1 MMSE最佳解 26
4.2 最佳通道響應縮減 29
4.3 最佳有限長度等化器(OPTIMUM FINITE-LENGTH EQUALIZATION,OFLE) 32
4.3.1 多重載波通道容量 32
4.3.2 最佳幾何訊雜比 33
4.4最佳位元率等化器(MAXIMIZE BIT RATE EQUALIZATION) 36
4.4.1 子通道之訊雜比模型 36
4.4.2 最佳位元率演算法 38
5. 新的演算法 43
5.1 TEQ對SNR的影響 43
5.1.1 通道雜訊干擾 44
5.1.2 ISI干擾 51
5.2 所提出的演算法 55
5.2.1 Channel Noise part 56
5.2.2 ISI part 57
5.2.3 The proposed algorithm 59
5.3 近似解與快速演算法 60
5.3.1 低複雜度之近似解法 60
5.3.2 快速之OCC演算法 63
6.計算機模擬 74
6.1模擬環境 74
6.2 模擬TEQ對SNR的影響 74
6.3 各種演算法的模擬與比較 76
7. 結論 107
參考文獻 109

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