時槽式無線網路下之路徑頻寬評估

Abstract

了解端對端路徑頻寬對於網路管理及應用程式管理來說，是很重要的。 雖然在有線與無線網路上路徑頻寬評估已被廣泛地研究，但在時槽式無線網路上一個路徑頻寬的有效評估依舊是缺乏的。 隨著時槽式無線網路技術(如：藍芽、ZigBee、WiMAX)日益受歡迎，但由於它們在資料連結層上的特別特性而使得對所有的無線應用上的無線頻道之有效使用率仍保持著挑戰性。 在這篇論文中，我們建議一種新的頻寬評估技術(TSProbe)去評估在時槽式無線系統中的端對端路徑頻寬。 TSProbe是由AdHoc Probe所衍生的，它基於時槽式連結中之間不同的連結層特性之固有關係而採用一種可適應且可重複的探測方法。 對應著分析，我們發現有效的連結頻寬是被取決於已使用的封包大小。再來，我們為TSProbe呈現一個理論依據且建議出一個方法，並在多種的模擬場景中評估它的效能。 最後，我們更進一步對於評估一個路徑頻寬而在測試環境及網際網路的實驗場景中來評估它的穩定性，結果呈現出TSProbe在所有的例子中是同樣地精確、有效且穩定的。

Knowing the end-to-end path capacity is important for network and applications management. Although path capacity estimation in wired and wireless networks have been extensively investigated, but an effective estimate of path capacity in time-slotted wireless networks is still lacking. With the increasing popularity of time-slotted wireless technologies (e.g. Bluetooth, ZigBee, WiMAX), the effective utilization of the wireless channel remain challenging for all wireless applications due to special property of them in the data link layer. In this thesis, we propose a new capacity estimation technique, TSProbe, to estimate end-to-end path capacity in time-slotted wireless systems. TSProbe is inspired by AdHoc Probe, and it deploys an adaptive and iterative probing scheme based on the intrinsic relationships between various link layer properties for time-slotted connections. With analysis, we found the effective link capacity is dependent on the employed packet size. Moreover, we exhibit a theoretical basis and propose an efficient approach for TSProbe, and evaluated its performance in a variety of simulation scenarios. Finally, we further evaluated its reliability in testbed and Internet experiment scenarios for estimating a path capacity. The results present that TSProbe is consistently accurate, effective and reliable in all cases.