臺灣博碩士論文加值系統

在IEEE 802.16d可為無線都會型網路支援高頻寬傳輸，但系統標準並未對頻寬管理提出有效的方法，因此，一個適合可行的頻寬分配演算法，將是非常重要的。
本篇論文提出一套新的頻寬分配機制，與Leaky Bucket演算法搭配，並且操作在WiMAX系統。在PMP(Point-to-Multipoint)模式環境中，對於下載與上傳的訊框(frame)分配，以基地台(Base Station)與用戶端(Subscriber Station)內部的佇列長度為依據，來給予symbols數量，不過只以佇列長度為依據是不恰當的，需加上Leaky Bucket的演算，限制住SS頻寬要求，達到下載與上傳合理的分配。
另外，動態分配頻寬，經由模擬可以得知，讓系統在支援下載與上傳傳送時，當某一方需要較多頻寬時，即時的調整比例，對於頻寬的使用上，比起固定式分配，還來的有效益。

The IEEE 802.16d claims to support high bandwidth for the wireless metropolitan area network. However, the standard does not propose including the method for bandwidth management. Therefore, a feasible bandwidth allocation algorithm will be very important.
The thesis proposes a Leaky Bucket based admission control algorithm and dynamic bandwidth algorithm for a WiMAX BS. For a new services flow, the admission control algorithm (CAC) will calculate the required bandwidth according to the Leaky Bucket parameters of the flow. Only if the total required bandwidth of all flows is smaller than the system capacity, the new flow can admitted. In the run time, the BS needs to allocate symbols to DL/UL subframes for every frame. In addition to the queue length, we also use the required bandwidth calculated by CAC as a parameter to allocate the bandwidth dynamically.
The proposed algorithm are implemented in the NS-2 simulator and verified by simulation. Compared to the fixed allocation scheme, our algorithm can provide quality of service and uses the bandwidth efficiency.

中文摘要 I
英文摘要 II
目錄 III
表目錄 V
圖目錄 VI
第一章 緒論 1
1.1 前言 . . . . . . . . . . . . . . . . . . . . . . . . . . .1
1.2 研究動機與目的 . . . . . . . . . . . . . . . . . . . . . . 2
1.3 預計成果與目標 . . . . . . . . . . . . . . . . . . . . . . 2
1.4 論文簡述 . . . . . . . . . . . . . . . . . . . . . . . . .2
第二章 WiMAX媒體存取控制層 4
2.1 前言 . . . . . . . . . . . . . . . . . . . . . . . . . . .4
2.2 WiMAX寬頻無線存取簡介 . . . . . . . . . . . . . . . . . . .5
2.2.1 TDD subframe與FDD subframe . . . . . . . . . . . . . . 5
2.2.2 WiMAX節點進入網路程序與初始化 . . . . . . . . . . . . . . 6
2.3 WiMAX品質保證技術 . . . . . . . . . . . . . . . . . . . . 8
2.3.1 WiMAX排程服務 . . . . . . . . . . . . . . . . . . . . .8
2.3.2 Service Flow簡介與建立方式 . . . . . . . . . . . . . . .9
2.3.3 Service Flow所代表Quality of Service參數簡介 . . . . . 11
2.4 Frame分配簡介 . . . . . . . . . . . . . . . . . . . . . 13
2.4.1 Frame詳細結構 . . . . . . . . . . . . . . . . . . . . 14
2.4.1.1 DL-MAP與UL-MAP介紹 . . . . . . . . . . . . . . . . .16
2.4.1.2 MAC管理訊息簡介 . . . . . . . . . . . . . . . . . . .18
2.5 WiMAX模組(WiMAX module)簡介. . . . . . . . . . . . . . .19
第三章 Leaky Bucket與動態頻寬分配演算法 23
3.1 前言 . . . . . . . . . . . . . . . . . . . . . . . . . .23
3.2 系統設計 . . . . . . . . . . . . . . . . . . . . . . . .24
3.3 程式架構 . . . . . . . . . . . . . . . . . . . . . . . .25
3.4 Leaky Bucket演算法與Admission Control . . . . . . . . . 26
3.4.1 MDQ數值計算 . . . . . . . . . . . . . . . . . . . . . 27
3.5 動態頻寬分配演算法 . . . . . . . . . . . . . . . . . . . 28
3.5.1 下載與上傳分配符元數量 . . . . . . . . . . . . . . . . .29
3.6 舉例 . . . . . . . . . . . . . . . . . . . . . . . . . .30
第四章 模擬結果與討論 32
4.1 網路模擬器第二版(Network Simulator - 2，簡稱NS-2)簡介 . . 32
4.2 模擬環境參數 . . . . . . . . . . . . . . . . . . . . . .32
4.3 模擬分析 . . . . . . . . . . . . . . . . . . . . . . . .33
4.3.1 Bucket Size (σ數值)計算方式. . . . . . . . . . . . . .34
4.3.2 動態頻寬分配(Dynamic Bandwidth Allocation)效果分析 . . 35
4.3.3 系統吞吐量(Throughput)效能分析 . . . . . . . . . . . . 37
4.3.4 封包延遲(Packet Delay)分析. . . . . . . . . . . . . . 39
4.3.5 Best Effort Traffic吞吐量分析. . . . . . . . . . . . .40
第五章 結論與未來研究 42
參考文獻 43

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