IEEE 802.11e標準是用來保障無線區域網路應用上的服務品質(QoS)。而其中的許可控制(Admission Control)是利用管理工作站來控制無線網路流量的機制。許可控制的判斷精準與否將會影響網路的服務品質甚巨。本篇論文主要提出一個估計存取類別(AC)和無線區域網路延遲的機制。在本機制中，要保證品質的是網路電話和網路影像。這兩種存取類別各有其上傳和下載的封包，而這兩種封包的延遲量正是本機制所估記的對象。本機制所採取的估計方法是將延遲量分為三個估計的部分。第一個部分是封包傳送所造成的延遲。第二個部分的是在隊列裡面的延遲時間。第三個部分是因為碰撞和錯誤造成的延遲。這三個部分相加之後就是估計的延遲量。其中由於現在大部分網路電話所採取的機制是採用固定時間進行的封包傳送，而在上傳和下載的封包中，每一個封包都必須要經過基地台，而每一個下載的封包都需要停留在基地台的隊伍裡，這樣一來，使得第二個部分的影響較為重要。故本篇論文主要的重點將會放在第二個部分的討論。實驗模擬的結果顯示對無線區域網路封包延遲量的估計有相當程度的準確性。

IEEE 802.11e standard is developed for QoS (quality of service) provisioning in WLANs (wireless local area networks). Admission Control is a mechanism that controls throughput of WLANs by managing stations. Evaluation of admission control is accurate ot not which plays aa important roll in QoS support. The motivation of this thesis is calculating WLANs delays with ACs (Access Categories). In this mechanism, we want to guarantee VoIP and video stream’s QoS. VoIP and video streams have uplink and downlink packets. We will calculate the delays of these packets are what. Our mechanism makes delays to three parts. One is propagation delay. Another is the delay that packets queue up in stations or APs (access points). The last is the delay which is wasted by collisions. Because of the most popular application of VoIP and video stream, the second delays are more important than the others. We will focus on the second type delays. Simulation results show that our method is accurate in calculating the delay of packets in WLANs.
Keywords: Admission Control, QoS, 802.11e, access category, EDCA

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