以Wi-Fi無線網路瀏覽網際網路網頁已經成為許多消費性電子裝置(如智慧型手機、PDA、Apple iPad等)的基本功能，但其電力消耗卻也是這類裝置待機時間的最大瓶頸之一。IEEE 802.11a/b/g MAC層網路協定中只有名為PSM的省電機制。而PSM並沒有針對無線上網進行最佳化。因此，在這篇論文中，我們針對使用IEEE 802.11無線區域網路技術瀏覽網際網路網頁的環境，提出一個考慮人類使用習慣的省電機制。在發出HTTP request之後，我們利用TCP header的Timestamp來計算下一個封包的RTT，依此調整listening period的大小。當所有下載連線都已經結束之後，我們讓行動裝置進入長時間睡眠模式，此時listening interval可拉大成1秒以上。由於此時是使用者閱讀網頁的時間，增加listening period不但可以達到顯著的省電效果，也不會降低使用者所感受到的網路服務品質。等到使用者點擊了下一個超連結，無線網路裝置可以將listening period縮減為預設。

Web browsing via Wi-Fi wireless access networks has become a basic function on a variety of consumer mobile electronic devices, such as smart phones, PDAs, and the Apple iPad. It has been found that in terms of energy consumption, wireless communications/networking plays an important role in mobile devices. Since the power-saving mode (PSM) of the IEEE 802.11 a/b/g standard is not tailored for the HTTP protocol, we propose a novel power saving scheme that exploits the characteristics of web applications. After sending HTTP requests, the proposed power saving scheme updates the estimated value of RTT based on the information contained in the TCP timestamp header field. Next, the proposed scheme adjusts the value of the listening period based on the estimated value of RTT. When all TCP connections have been closed, the wireless network card could enter the deep-sleeping mode. In this case, the value of the listening period could be larger than one second, since the user is reading the webpage and is unlikely to send another HTTP request within one second. The usage of the deep-sleeping mode can significantly reduce the power consumption of mobile devices.

致謝 I
中文摘要 II
Abstract III
目錄 IV
圖目錄 V
表目錄 VI
第一章 緒論 1
1.1 IEEE 802.11無線區域網路簡介 1
1.2 IEEE 802.11 電源管理 5
1.3 Web Traffic 行為模式 6
1.4 研究動機與文獻探討 7
1.5 文章導讀 11
第二章 系統架構 12
2.1 無線區域網路架構 12
2.2 Web Traffic Model 13
第三章 The Web Browsing model PSM 17
3.1 RTT的估算法 19
3.2 Listen Interval的計算法 19
3.3 修改IEEE 802.11 Protocol 20
第四章 模擬結果與效能分析 21
4.1 比較的演算法 21
4.2 模擬環境與參數 24
4.3 模擬結果與分析 27
第五章 結論 39
參考文獻 40

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