臺灣博碩士論文加值系統

目前人們已經可以說是無法離開網路而生活，為了要讓人們可以無時無刻都可以取存網路，IEEE就提出了IEEE 802.11系統的無線網路技術，希望可以使網路的存取更為便利，但是現在人們需要無線網路所來提供的服務不再侷限在單純的文字或圖片的傳輸，取而代之的是大量的影音多媒體資料，並且IEEE 802.11系統的技術除了頻寬不足以滿足大量的影音多媒體服務之外，依然無法使得地處偏遠或是在網路不易佈建的地方能以較經濟及便利的方式來存取無線網路，所以IEEE又提出了IEEE 802.16系統的無線寬頻網路技術─也就是WiMAX。
本論文的主旨是在探討如何在WiMAX的架構下，要如何利用有限的頻寬來滿足多媒體資料的傳輸需求，並且又不會過份的排擠到優先權較低的其他服務(如FTP、HTTP等)。我們提出了一個可以應用在WiMAX上的上下行頻寬分配及封包排程機制，利用各種服務對服務品質需求的不同特性來做不同的頻寬配置及封包排程，希望可以藉由這個機制使的網路上各種不同的服務都可以獲得所需要的資源，並且可以使得珍貴的頻寬可以做最大效率的使用。

Nowadays, the convenient of the network has changed the human’s life. To make people access the network easier, IEEE developed IEEE 802.11, so called Wi-Fi, wireless network technology. But with the limit of Wi-Fi to bandwidth, transmission range and mobility speed, people can’t really access internet at any where, any time. To satisfy the need of human, IEEE develops a new wireless technology, the IEEE 802.16, so called WiMAX, to provide an access of wideband, large transmission range and high mobility speed.
WiMAX classifies network services into four classes according to the different requirement of the quality-of-service (QoS) to the network. In order to meet various QoS requirements, we proposed a bandwidth allocation mechanism in conjunction with packet scheduling to efficiently allocate the bandwidth to both uplink and downlink traffic simultaneously. The mechanism is based on the priority and available time that packets must be sent out. The main objective is to lower the packet drop rate of real-time high priority traffic, such as Unsolicited Grant Services (UGS) and Real Time Protocol Services (rtPS) while keeps the high utilization of radio resource of a base station. In addition, the average packet delay under various loading conditions and the fairness of bandwidth allocation among subscriber stations will also be examined.

摘要.....................................................i
ABSTRACT................................................ii
誌謝……………………………………………………………………iii
目錄……………………………………………………………………iv
表目錄…………………………………………………………………vi
圖目錄…………………………………………………………………vii
第一章緒論 1
1.1 簡介 1
1.2 研究動機與目的 1
1.3 論文架構 2
第二章WiMAX相關背景及規格 3
2.1 背景介紹 3
2.2 技術背景總論 5
2.3 WiMAX協定家族介紹 7
2.4 WiMAX規格介紹 8
2.4.1 服務類別 8
2.4.2 服務品質架構介紹 10
2.4.2.1 各種服務品質的子系統 11
2.4.2.2 媒體存取控制協定資料單位格式 12
2.4.2.3 媒體存取控制標頭 13
2.4.3 WiMAX訊框架構 15
2.4.3.1 分時多工 15
2.4.3.2 下行子訊框架構 17
2.4.3.3 上行子訊框架構 18
2.5 其他演算法的討論 21
第三章WiMAX QoS架構之演算法之設計 24
3.1 QoS的基本問題 24
3.1.1規格上的頻寬配置法會遇到的問題 24
3.2.1碰撞解釋 26
3.2 QoS系統架構 27
3.2.1系統模型 27
3.2.1.1封包分類器 29
3.2.1.2封包排程器 31
3.2.1.3頻寬請求器 31
3.2.1.4頻寬請求資料庫 34
3.2.1.5上/下行頻寬請求器 35
3.2.2基地端運作流程 36
3.2.3用戶端運作流程 38
3.3 封包分類介紹 38
3.3.1及時性封包 39
3.3.1.1緊急性封包 40
3.3.1.2非緊急性封包 40
3.3.2非及時性封包 41
3.3.3用戶滿足度 41
3.4 頻寬配置流程 42
3.4.1及時性封包頻寬配置 42
3.4.1.1虛擬佇列的建立 43
3.4.1.2利用虛擬佇列配置頻寬 45
3.4.2非及時性封包頻寬配置 46
3.5 封包排程演算法 48
第四章演算法的效能評估 49
4.1 文獻演算法說明 49
4.2 模擬環境及相關參數設定 50
4.3 模擬數據及說明 53
4.3.1封包丟棄率 54
4.3.2平均封包延遲時間 56
4.3.3頻寬使用率 58
4.4 頻寬配置公平性 60
第五章 系統調整及測 65
5.1 具自我相似性封包流量之模擬 65
5.2 上/下行流量比例調整 68
5.3上/下行頻寬配置上限對封包丟棄率的影響 69
第六章結論 72
6.1 結論 72
6.2 Future Work 72
參考文獻 74

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