臺灣博碩士論文加值系統

在這篇論文中，我們首先探討因為無線多媒體應用的快速發展，而產生目前在無線網路上的品質服務保證問題，進而討論目前最廣為使用的無線網路媒介使用機制—IEEE 802.11在品質服務保證問題上的不足之處。我們進一步探討一些目前在已經提出來IEEE 802.11無線網路上的品質服務保證加強機制，包括官方解決方案IEEE 802.11e，並且分析並瞭解這些方法的優缺點。接下來我們在IEEE 802.11e架構上提出一個新的以滿意度為基準的媒介使用機制，叫做SEDCF，這個新的機制的目標是(1)提供以傳輸速率為基準的服務區別，(2)達到對於所有連線之間的剩餘頻寬使用的公平性，以及(3)同時保持較高的網路傳輸量。透過ns-2網路模擬器的模擬，我們評估了SEDCF和其他品質服務保證加強機制的效能。最後，我們將提出結論和未來可供努力的方向。

Abstract……………………………………………………………………………….I
摘要…………………………………………………………………………………...II
致謝………………………………………………………………………………….III
Contents…..…………………………………………………………………………IV
List of Figures……………………………………………………………………….VI
List of Tables……………………………………………………………………….VII

Chapter 1 Introduction……..…...…………..……………………………………….1
1.1 Current IEEE 802.11 Medium Access Control Scheme..........................…...1
1.2 Motivation………………………..…………………………………………2
1.3 Organization……………………..………………………………………….3

Chapter 2 Related Work……………………………………………………………..4
2.1 Enhanced DCF of IEEE 802.11e (EDCF)……..……………………………4
2.2 Adaptive Enhanced DCF (AEDCF) – CW-Based QoS Enhancement..…….7
2.3 Adaptive Fair Enhanced DCF (AFEDCF) – Backoff-Based QoS Enhancement……………………………………………………………………..9
2.4 Ifs-Based Distributed Fair Queuing (IDFQ) – Ifs-Based QoS Enhancement……………………………………………………………………11
2.5 Discussion…………………………………………………………………13



Chapter 3 Satisfaction-Based Medium Access Control Scheme…………………15
3.1 Characteristic and Assumption………..…………………………………...15
3.2 Parameters………..………………………………………………………..16
3.3 Algorithm………………………………………………………………….18
3.3.1 Phase 1 – Contention Window Adjustment Procedure………….18
3.3.2 Phase 2 – Backoff Timer Decreasing Procedure………………..20

Chapter 4 Performance Evaluation………………………………………………..21
4.1 Simulation Environment…………………………………………………..21
4.2 Performance Metrics………………………………………………………23
4.3 Simulation Result………………………………………………………….25
4.3.1 Baseline Comparison of Related Works….……………………..25
4.3.2 SEDCF Phase 1 vs. AEDCF…………………………………….27
4.3.3 SEDCF Phase 1 vs. SEDCF Phase 1+2…………………………31
4.3.4 SEDCF phase 1 vs. AFEDCF…………………………………..34
4.3.3 Mean delay of AEDCF vs. AFEDCF vs. SEDCF phase 1 vs. SEDCF phase 1+2……………………………………………………..…..37
4.3.3 SEDCF Phase 1 vs. SEDCF Phase 1+2 Vs. AEDCF…………...38

Chapter 5 Conclusion and Future Work…………………………………………..41

Reference…………………………………………………………………………….43

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[8] Gannoune, L. Robert, S., “Dynamic tuning of the contention window minimum (CW/sub min/) for enhanced service differentiation in IEEE 802.11 wireless ad-hoc networks”, Personal, Indoor and Mobile Radio Communications, 2004. PIMRC 2004, 5-8 Sept. 2004, page(s): 311- 317 Vol.1
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