本論文結合Dual Busy Tone及EDCF的部份技術來進行網路服務品質的改良。在無線網路裡，存在著兩種已經被討論很久的碰撞問題，第一種是隱藏節點的問題，第二種是暴露節點的問題。為了解決碰撞的問題，802.11使用了RTS/CTS的機制，但是這種機制並沒有辦法完全解決碰撞問題，反而會造成RTS/CTS封包的碰撞。為了解決碰撞問題，已經有很多論文提出相關解決機制。在DBTMA[19]裡，使用了兩種訊號分別稱為BTt(the transmit busy tone)和BTr(the receice busy tone)來保護RTS封包和資料封包的傳送。當傳送端傳送RTS的時候會啟動BTt(the transmit busy tone) ，而當接收端接收資料的時候會啟動BTr(the receice busy tone)。我們使用電腦模擬來評估我們所提出的方案。我們發現我們方案的效能可以勝過IEEE802.11e標準。

We propose a novel medium access control scheme which borrows ideas from the dual busy tone approach and the IEEE 802.11e standard for improving quality of services in wireless networks. In the field of medium access control in Wireless LAN, there are two notorious problems, which have been studied for a long time. They are the hidden terminal problem and the exposed terminal problem. To avoid the collisions caused by hidden terminals, the RTS/CTS approach is widely adopted. However, RTS and CTS frames themselves are still subject to collisions. The Transmit Busy Tone and the Receive Busy Tone were proposed to further mitigate the hidden terminal problem and the exposed terminal problem. The transmit busy tone provides protection for the RTS packets and thus, increase the probability of successful RTS reception at the intended receiver. The receive busy tone acknowledges the RTS packet and provide continuous protection for the subsequent data packets. We use computer simulations to justify the usage of our proposal. We show that the proposed scheme outperforms the IEEE 802.11e standard.

誌謝 I
中文摘要 II
Abstract III
目錄 IV
圖目錄 V
第一章 緒論 1
1.1 802.11簡介 1
1.1.1 RTS/CTS 2
1.1.2 分散式協調功能(DCF) 4
1.1.3 集中式協調功能(PCF) 6
1.1.4 EDCF簡介(802.11e) 7
1.1.5 Dual Busy Tone簡介 10
1.2 研究動機與文獻探討 13
1.3 文章導讀 14
第二章 方法和架構 15
2.1封包傳送時間模型架構 15
2.2有限狀態機 19
第三章 模擬結果與效能分析 23
3.1 模擬參數和模擬拓璞結構 23
3.2 模擬結果 27
第四章 結論 36
參考文獻 38

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