Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/7265
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dc.contributor林宗男zh_TW
dc.contributor溫志煜zh_TW
dc.contributor.advisor廖俊睿zh_TW
dc.contributor.author吳哲彰zh_TW
dc.contributor.authorWu, Che-Changen_US
dc.contributor.other中興大學zh_TW
dc.date2008zh_TW
dc.date.accessioned2014-06-06T06:39:48Z-
dc.date.available2014-06-06T06:39:48Z-
dc.identifierU0005-0208200712411300zh_TW
dc.identifier.citation[1] IEEE 802.11 WG, “International Standard for Information Technology —Local and Metropolitan Area Networks-Specific Requirements — Part 11:Wireless LAN MAC and PHY specifications," 1999. [2] IEEE 802.11 WG, “Draft Supplement to Standard for Telecommunications and Information Exchange between Systems-LAN/MAN Specific Requirements— Part 11: Wireless MAC and PHY Specifications: MAC Enhancements for QoS," IEEE 802.11e, 2004. [3] Lamia Romdhani, Qiang Ni, and Thierry Turletti, “AEDCF: Enhanced Service Differentiation for IEEE 802.11 Wireless Ad-Hoc Networks”, IEEE WCNC'03 (Wireless Communications and Networking), vol.2, pp.1373-1378, 2003. [4] Q. Ni, L. Romdhani, and T. Turletti, “A survey of QoS Enhancements for IEEE 802.11 Wireless LAN”, Journal of Wireless Communications and Mobile Computing , vol.4, pp. 547-566, 2004. [5] Qiang Ni, Imad Aad, Chadi Barakat, and Thierry Turletti, “Modeling and Analysis of Slow CW Decrease for IEEE 802.11 WLAN”, IEEE 2003 International Symposium on Personal, Indoor and Mobile Radio Communication Proceedings , vol.2, pp.1717-1721, 2003. [6] Jong-Deok Kim and Chong-Kwon Kim, “Performance analysis and evaluation of IEEE 802.11e EDCF”, Wireless Communications and Mobile Computing, vol4, pp.55-74, 2004. [7] “The ns Manual”, http://www.isi.edu/nsnam/ns/doc/ns_doc.pdf. [8] “Network Simulator (ns), version 2”, http://www.isi.edu/nsnam/ns/. [9] “An IEEE 802.11e EDCA and CFB Simulation Model for ns-2”, http://www.tkn.tu-berlin.de/research/802.11e_ns2/. [10] Giuseppe Bianchi, “Performance Analysis of the IEEE 802.11 Distributed Coordination Function”, IEEE Journal on Selected Areas in Communications, vol.18, pp.535-547, 2000. [11] Kanghee Kim, Aftab Ahmad, and Kiseon Kim, “A Wireless Multimedia LAN Architecture Using DCF With Shortened Contention Window for QoS Provisioning”, IEEE Communications Letters, vol.7, pp.97-99, 2003. [12] Larry L. Peterson and Bruce S. Davie, “Computer Networks”, Morgan Kaufmann Publishers, 3nd Ed, 2003.zh_TW
dc.identifier.urihttp://hdl.handle.net/11455/7265-
dc.description.abstract隨著無線網路的發展,帶給我們很多的便利。為了在無線網路802.11上提供服務品質保證,因此802.11工作小組制訂了一個可以支援服務品質的新標準,名為802.11e,其中包含了一個以競爭視窗為基底增強分散式通道存取機制(EDCA)。在EDCA中,當工作站數目增多時,傳送封包的碰撞率增加,而且每個佇列在進入競爭週期時,產生的後退時間造成時間槽空閒之浪費。因此有學者提出適應性增強分散式協調機制(AEDCF),其目的是在工作站數目增加時,降低碰撞率。 在本論文中,我們提出一個新的方法,隨著網路狀態改變,我們利用韋伯機率分佈來找出相對應之網路狀態的最佳競爭視窗值,而且參數能隨著工作站數目以及平均碰撞率做動態調整。 最後,我們使用NS2模擬分析所提出的韋伯增強分散式通道存取(WEDCA),和增強分散式協調機制(EDCA)、適應性增強分散式協調機制(AEDCF)的效能差異比較。我們發現WEDCA能強化網路的公平性,所以公平性的表現比AEDCF好,而且使用動態參數的WEDCA,比使用固定參數的WEDCA和其他機制更能隨著網路狀態做適應的調整,而得到比較好的效能。zh_TW
dc.description.abstractThe development of 802.11 wireless local area networks makes our life more convenient. In order to provide Quality of Service (Qos), IEEE 802.11 working group has defined a new standard called IEEE 802.11e. It includes a contention-window based access control algorithm called enhanced distributed channel access (EDCA). In EDCA, the collision rate increases when the number of stations increases. In addition, backoff time results in the waste of the available transmission time. To reduce collision rate as the number of stations increases, adaptive EDCF (AEDCF) was proposed. In the thesis, we proposed a new solution called Weibull-based EDCA. In our algorithm, we use Weibull distribution probability to find the best contention window value corresponding to the current network state. The parameters in the distribution can be dynamically adjusted according to the number of stations and the average collision rate. Finally, we used Network Simulator Version 2 (NS2) to simulate our algorithms and compare them with EDCA and AEDCF. We found WEDCA provides better network fairness and adaptively adjust parameters of WEDCA was better than fixed parametersen_US
dc.description.tableofcontents壹、序論......................1 一、動機與目的................1 二、論文架構..................2 貳、802.11無線網路架構及分散式協調機制介紹.....3 一、IEEE 802.11基本架構.......3 二、IEEE 802.11 MAC...........5 (一) 碰撞偵測機制.............7 (二) 隱藏節點.................8 (三) 分散式協調機制...........10 (四) 集中式協調機制(PCF)......11 第三章802.11e介紹.............13 一、增強分散式通道存取(EDCA).............14 二、混合式控制通道存取(HCCA).............17 第四章IEEE 802.11效能改進之機制..........18 一、適應性EDCF(AEDCF)介紹.....18 (一) AEDCF演算法架構..........19 (二) 平均碰撞率的計算.........19 (三) 當資料傳送成功後競爭視窗值的設定.....20 (四) 當資料傳送失敗後競爭視窗值的設定.....20 伍、韋伯增強分散式通道存取................22 一、WEDCA介紹.................22 二、競爭視窗值的重設..........26 三、CW Adaptive WEDCA.........27 四、CW and Collision Rate Adaptive WEDCA......28 陸、模擬結果與分析............29 一、媒介存取機制比較..........29 二、模擬環境..................31 三、模擬效能分析..............33 (一) 傳輸頻寬.................34 (二) 平均延遲時間.............37 (三) 碰撞率...................39 (四) 公平性...................41 柒、結論與未來展望............42 參考文獻......................43zh_TW
dc.language.isoen_USzh_TW
dc.publisher電機工程學系所zh_TW
dc.relation.urihttp://www.airitilibrary.com/Publication/alDetailedMesh1?DocID=U0005-0208200712411300en_US
dc.subjectIEEE 802.11e Wireless LANen_US
dc.subject802.11e無線區域網路zh_TW
dc.subjectQuality of Serviceen_US
dc.subjectEnhanced Distributed Channel Accessen_US
dc.subjectWeibull probabilityen_US
dc.subject服務品質保證zh_TW
dc.subject增強分散式通道存取zh_TW
dc.subject韋伯機率zh_TW
dc.title802.11e無線網路之韋伯增強分散式通道存取zh_TW
dc.titleWeibull-Based Enhanced Distributed Channel Access in 802.11e Wireless LANen_US
dc.typeThesis and Dissertationzh_TW
item.grantfulltextnone-
item.openairetypeThesis and Dissertation-
item.languageiso639-1en_US-
item.fulltextno fulltext-
item.cerifentitytypePublications-
item.openairecristypehttp://purl.org/coar/resource_type/c_18cf-
Appears in Collections:電機工程學系所
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