臺灣博碩士論文加值系統

盲目等化器在數位通訊領域中的應用日趨重要，利用過度取樣( oversampled )後的通道輸出信號，設計盲目等化器，近年來已成為一熱門的研究範疇。在T. Kailath等人提出藉由將接收到的信號過度取樣或利用陣列天線來接收信號等方式獲得週期信穩定特性的信號並透過特徵值分解的方式，做盲目通道辨識與等化後，許多基於單一輸入多重輸出系統模型與通道輸出的二階統計特性發展出的盲目等化演算法相繼問世。
在這篇論文中，我們提出一個應用強制歸零條件與最小平方平均誤差法則的盲目等化演算法，藉由讓各個不同時間延遲的強制歸零等化器輸出間的平方平均誤差值之總合最小，進而將全部不同時間延遲的強制歸零等化器計算出。此方法的優點在於不受通道係數矩陣是否為方陣之限制，皆能夠將所有等化器同時求出，由於直接求取等化器，因而減少通道辨識誤差對於信號估測上所造成的影響；透過電腦的模擬與分析，可以明確得知此新方法有不錯的效能表現。

Blind channel identification and equalization become important and popular in digital communication system. Since T. Kailath et al have proposed the algorithms utilizing the cyclostationary signal via oversampling the received signals or receiving signals by antenna arrays. A number of blind equalization methods based on SIMO system model and second order statistics of channel output have been developed.
In this paper, we derive a new algorithm for blind equalization based on zero-forcing condition and minimum mean square error criterion. Minimizing the mean square error based on the different delay equalizers’ output . All possible delay zero-forcing equalizers can be computed simultaneously without channel coefficients matrix estimation so that the influence of the channel identification is reduced. Simulations are presented to demonstrate adequate performance of the new blind equalization algorithm.

Abstract………………………………………………………………………………… I
中文摘要…………………………………………………………………………………II
Chapter 1. Introduction………………………………………………………………1
Chapter 2. Blind Identification and Equalization Based on Second-Order Statistic: A Time Domain Approach…………………………………………………3
I. Problem Statement…………………………………………………………3
II. Time Domain Algorithm Derivation…………………………………… 5
III. Simulations……………………………………………………………… 12
Chapter 3. Subspace Methods for the Blind Identification of Multichannel FIR
Filter…………………………………………………………………… 16
I. Problem Statement……………………………………………………… 16
II. Subspace-Based Parameter Estimation Scheme………………………18
III. Simulations……………………………………………………………… 22
Chapter 4. Direct Blind Equalizers of Multiple FIR Channels: A Deterministic
Approach………………………………………………………………… 26
I. Problem Statement……………………………………………………… 26
II. Direct Blind Equalization Algorithm Development……………… 29
III. Simulations……………………………………………………………… 33
Chapter 5. Blind Zero-Forcing Equalization Based on MMSE Criterion
I. Introduction………………………………………………………………36
II. Problem Statement……………………………………………………… 38
III. ZF-MMSE Algorithm Development……………………………………… 40
A. Equalization Ability…………………………………………………… 40
B. Algorithm Implementation In Noisy Condition………………………46
C. Selection Of The Best Delay Equalizer………………………………47
D. Computation Complexity………………………………………………… 48
IV. Simulations……………………………………………………………… 50
V. Conclusion…………………………………………………………………55
VI. Appendixes…………………………………………………………………56
Chapter 6. Conclusion……………………………………………………………… 63
Reference……………………………………………………………………………… 64

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