臺灣博碩士論文加值系統

在本篇論文中，為了兼顧實用與理論，在實驗室中產生了相關性複數中上衰落通道並且分析相關性通道上分集結合之二階統計特性-水平跨越比例和平均衰落區間。在最大-比率結合的推導中 [20]，利用了匹配濾波器的概念並且假設接收到的信號彼此間是獨立的。而在先前的研究中[45], [46], [49]，他們也是直接利用傳統的最大-比率結合定義-封包平方和。但當接收到的信號間有相關性時，最大-比率結合的傳統定義是錯誤的並且失去了最大訊雜比的優勢。在相關性通道中，最大-比率結合是依照KL 展開式推導獲得 [28]，所以在做最大比率結合前，需要消除信號間的相關性，才能使訊號擁有最大訊雜比。

In practice and in theory, correlated complex Nakagami-m fading channels are generated in a laboratory environment, level crossing rate and average fade duration of diversity
combining over correlated Nakagami-m fading channels are analyzed in this paper. In the derivation of maximal-ratio combining [20], it uses the concept about matched filter and assumes that received signals are independent. The maximal-ratio combining method that was conventionally employed in the previous studied [45], [46], [49] directly sums envelope squares across all branches. If the fading channels are correlated, this method is definitely incorrectly performed and undoubtedly loses its predominance. By definition, when the fading channels are correlated, the MRC should be derived in accordance with the KL expansion theorem for random processes [28]. As a result, a whitening process has to be conducted prior to the power accumulation process for the maximum SNR.

Contents…... ............................................................................. iii
List of Figures ............................................................................ v
List of Tables ........................................................................... vii
Chapter 1 Introduction .......................................................... 1
Chapter 2 Review of Nakagami-m Channel Models ........... 4
2.1 Channel Models ................................................................................ 4
2.2 Nakagami-m Fading Channels........................................................ 12
2.3 First-Order Statistics ....................................................................... 15
2.3.1 Outage Probability ............................................................. 15
2.3.2 Average Bit Error Probability ............................................ 15
2.3.3 Channel Capacity ............................................................... 16
2.4 Second-Order Statistics .................................................................. 19
2.4.1 Level Crossing Rate........................................................... 19
2.4.2 Average Fade Duration ...................................................... 20
2.5 Diversity Combining ...................................................................... 20
2.5.1 Diversity Methods ............................................................. 21
2.5.2 Combining Techniques ...................................................... 22
Chapter 3 Fading Simulators .............................................. 24
3.1 Clarke‘s Fading Channel ................................................................ 25
3.2 The Nakagami-m Simulator Based on Sum-of-Sinusoids .............. 27
3.3 Correlated Fading Branches ........................................................... 29
3.3.1 Cholesky Decomposition ................................................... 29
3.3.2 Q.T. Zhang‘ Method .......................................................... 33
3.4 Complex Simulator ......................................................................... 39
Chapter 4 Second-Order Statistics of Diversity Combining
over Correlated Nakagami-m Fading Channels42
4.1 On Nakagami-m Fading Channels .................................................. 42
4.2 On Equal-Gain Combining over Correlated Nakagami-m Fading
Channels ........................................................................................ 46
4.2.1 Non-identical Case ............................................................ 46
4.2.2 Identical Case .................................................................... 50
4.3 On Selection Combining over Correlated Nakagami-m Fading
Channels ........................................................................................ 53
4.3.1 Non-identical Case ............................................................ 53
4.3.2 Identical Case .................................................................... 57
4.4 On Maximal-Ratio Combining over Correlated Nakagami-m
Fading Channels ............................................................................ 59
4.4.1 Identical Case .................................................................... 60
4.4.2 Non-identical Case ............................................................ 63
Chapter 5 Second-Order Statistics of Maximal-Ratio
Combining over Whitened Nakagami-m
Fading Channels ................................................ 66
5.1 On Maximal-Ratio Combining over L- Branch Correlated
Nakagami-m Fading Channels....................................................... 66
5.1.1 Identical Case .................................................................... 67
5.1.2 Non-identical Case ............................................................ 69
5.2 Correlation of Complex Signals ..................................................... 71
5.3 Whitening Method .......................................................................... 74
5.3.1 Eigen Decomposition ........................................................ 74
5.3.2 Cholesky Decomposition ................................................... 75
5.4 Simulation Results ............................................................................ 76
5.4.1 Parameter Settings ............................................................. 76
5.4.2 Simulated and Theoretical Covariance Matrix .................. 77
5.4.3 Simulated and Theoretical PDF, LCR and AFD ................ 78
Chapter 6 Conclusions ......................................................... 82
Bibliography ............................................................................. 83

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