近年來隨著無線網路利用率增加，使得無線網路的供應商必頇提共更好的傳輸品質、更大的傳輸範圍與多樣化的網路應用下Quality-of-Service (QoS)成為支援無線網路服務的重要條件之一。隨著網路服務的發達與無線通訊技術漸趨成熟，語音、數據通訊與各種行動服務需求日益增加，現階段的無線與行動通訊系統卻得面臨費率昂貴、使用便利性不足、或傳輸速率不足的瓶頸，使用者對於新技術的期待也愈來愈強烈。為了支援現今頻寬無線存取網路的目的及應用，IEEE逐提出了IEEE 802.16[1]標準或稱為WiMAX(Worldwide Interoperability for Microwave Access)。IEEE 802.16標準有許多優聯的特性，如傳輸距離遠、高傳輸率、支援高速移動環境、提供服務品質等等，特別是高傳輸率，現今的網路應用需要越來越高的頻寬，並且也存在”最後一哩”(Last mile)的問題，因此對於有效的分配網路資源到多個subscriber stations(SSs)且確保QoS作用於每條連線到各個SS上成為一項重要的探討問題。目前IEEE 802.16標準對於各種QoS連線尚未明確制定一個排程演算法來分配上傳與下載頻寬，卻也提供一個完整的QoS參數集，應用於不同的服務連線使用提供不同的服務。本研究提出了在point-to-multipoint (PMP)模式下設計一個有效率的QoS排程演算法，利用參數的調整提供更具有彈性的服務品質以公平的對待各種不同性質的資料，以利於rtPS服務連線傳送來支援目前日新月異的多媒體傳輸。並且利用標準中所提供的QoS參數來排程各種不同類型的服務連線，與分配連線的上傳頻寬，進而達到有效率的使用所有網路資源。

Multimedia applications in wireless communication have shown notable increases over recent years. Specifically, Quality of Service (QoS) has become an important support mechanism in the context of a variety of applications which utilize network resources. The IEEE 802.16 standard for Wireless Metropolitan Area Networks (WirelessMAN) provides a complete QoS control structure designed to enable flow isolation and service differentiation over the common wireless interface. Although the media access control (MAC) mechanisms defined in this standard can offer predefined QoS provisioning on a pre-connection basis (additionally, many algorithms have been addressed to support QoS guarantees for various kinds of applications), the design for a stable, efficient and flexible MAC scheduling algorithm for such QoS provisioning still remains to be discovered. In this paper, we propose a QoS control scheme, Efficient Bandwidth Allocation (EBA), for the WirelessMAN system. Notably, this schedule enables predefined service parameters to control the service provided for each uplink connection and it provides each connection with different service opportunities such that the BS could allocate the most suitable bandwidth constantly for each connection with the various QoS parameters. Moreover, through MAC layer resource allocation, the proposed algorithm is capable of providing QoS guarantee for the SSs under different distance.

中文摘要...................................................................................................................... I
英文摘要...................................................................................................................... II
目錄.............................................................................................................................. III
圖目錄..........................................................................................................................V
表格目錄.....................................................................................................................VI
字母縮寫對照表........................................................................................................VII
第一章導論 .......................................................................................................... 01
1.1 簡介.......................................................................................................... 01
1.2 研究動機….................................................................................................. 02
1.3 論文架構...................................................................................................... 3
第二章相關背景研究.............................................................................................. 5
2.1 802.16 無線網路基本介紹......................................................................... 5
2.1.1 802.16 基本運作…........................................................................... 9
2.1.2 802.16 網路運作程序.......................................................................10
2.2 802.16 QoS................................................................................................... 12
2.2.1 802.16 排程服務..................................................................................12
2.2.2 Service Flow 介紹及其運作方式......................................................13
2.2.3 IEEE 802.16 QoS 架構........................................................................17
2.3 802.16 排程機制................................................................................ 18
2.3.1 Weight Fair Queue/Priority Queue......................................................18
2.3.2 DFPQ (Distributed Fair Priority Queuing)..........................................19
2.4 佇列中排程機制.......................................................................................... 21
2.4.1 EDF......................................................................................................21
2.4.2 GPS......................................................................................................21
2.4.3 WFQ.................................................................................................... 24
第三章頻寬分配的機制......................................................................................... 26
IV
3.1 動機與目的.................................................................................................. 26
3.2 佇列排程機制.............................................................................................. 29
3.2.1 rtPS Queue.......................................................................................... 29
3.2.2 nrtPS Queue........................................................................................ 30
3.2.3 BE Queue........................................................................................... 32
3.3 有效頻寬分配............................................................................................. 32
第四章模擬結果與討論.......................................................................................... 35
4.1 模擬工具介紹.............................................................................................. 35
4.1.1 NS2 語法..................................................................................................... 38
4.1.2 NS2 圖形分析工具介紹...............................................................................40
4.1.3 NS2 產生的trace file....................................................................................41
4.2 模擬環境參數設定...................................................................................... 43
4.3 模擬結果分析與討論.................................................................................. 43
第五章結論 .......................................................................................................... 50
參考文獻...................................................................................................................... 51

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