臺灣博碩士論文加值系統

為了要以較低的投資成本來擴大基地台(BS)的服務範圍，以及維持良好的訊號雜訊比，使用中繼站(RS; relay station)的技術逐漸成為重要的研究範疇。此外，在現今多媒體通訊的環境下，傳輸服務品質(QoS; Quality of Service)的保證是一個很重要的課題。因此，一個能夠有效使用系統資源，同時能保證QoS的無線資源排程演算法是必要的。
在本篇論文中，我們提出了一個在有中繼型態WiMAX網路系統中，提供下行鏈路服務品質保證及系統效能提升之QoS_GTE排程法演算法。QoS_GTE 由傳送時間基準(TT_based)路徑選擇演算法、服務排序基準(SO_based)資源分配演算法，以及同時傳送(TC; transmission concurrency)判別演算法所組成。TT_based路徑選擇演算法選擇傳送時間最短的路徑為傳輸路徑；SO_based資源分配演算法給予較高緊迫性的使用者較高的優先權，使不同層級的使用者可以滿足各自的QoS。在QoS 滿足的同時，又能提高系統的傳輸量。同時傳送判斷演算法則是使系統資源作有效的重複使用。由模擬結果得知，我們所提出的路徑選擇演算法確實比過去文獻中所提出的方法好，不僅系統傳輸量為最高，各層級使用者的服務品質也是最好的；資源分配演算法也在大部分的時候都能達到品質保證；同時傳送判別演算法亦可增加系統之服務量。同時，中繼站的擺放位置對系統的表現也有很大的影響，在我們設定的模擬情境中，中繼站的擺放位置以基地台服務半徑的四分之三為最佳。

Mandarin Abstract i
English Abstract ii
Acknowledgements iii
Contents iv
List of Figures vi
List of Tables vii
Chapter 1 Introduction 1
Chapter 2 System Model 6
2.1 Environment 6
2.2 WiMAX Technology 7
2.3 Services 9
2.4 Channel Model 13
2.5 Available Data Rate 14
Chapter 3 QoS_GTE Scheduling Scheme 17
3.1 TT_based Path Selection Algorithm 18
3.2 SO_based Resource Allocation Algorithm 20
3.2.1 Definition of 21
3.2.2 Resource Allocation 24
3.3 TC Decision Algorithm 25
Chapter 4 Simulation Results and Discussions 30
4.1 Manhattan Street Like Environment 31
4.2 Traffic Models and QoS Requirements 33
4.3 Performance Evaluation 35
4.3.1 Performance Evaluation on Relay schemes 36
4.3.2 Station Performance Evaluation on Location of Relay 45
Chapter 5 Conclusions 51
Bibliography 53
Vita 55

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