IEEE 802.11e無線區域網路的效能評估

Abstract

IEEE 802.11無線網路在最近這幾年因為價格降低和傳輸速度加快而發展迅速。現存的無線網路規格如IEEE 802.11a和IEEE 802.11b分別支援54和11 Mbps的傳輸速度，但是它們並不保證服務品質 (Quality of Service)。有鑑於此，IEEE 802.11標準制訂組織開始訂定IEEE 802.11e標準，以補強現有的規格來滿足服務品質保證之未來傳輸要求。 在本論文中，我們將探討IEEE 802.11e草稿中所提出的 Immediate Burst ACK Mechanism及Enhanced Distributed Coordination Function (EDCF) 的效能。我們將會模擬這些提議對系統產能 (Throughput)、佇列延遲 (Queuing Delay) 以及系統封包損失率的影響。此外，我們也將探討它們在 Ad Hoc 網路中的電源節省效率。我們最後將會根據所做的模擬結果提出適切的結論。

As cost decreases and data rate advances, IEEE 802.11 wireless local area networks (WLANs) become prevalent in recent years. The existing standards, such as IEEE 802.11a and IEEE 802.11b, even if they respectively support up to 54 and 11 Mbps data rates, do not support quality of services. Therefore, to enhance the current standards with the quality of service capability becomes the next focus of the IEEE 802.11 standard body. This results in the upcoming IEEE 802.11e extension. In this thesis, we will evaluate the performances of Immediate Burst Ack Mechanism and Enhanced Distributed Coordination Function (EDCF) that were proposed in the current draft of IEEE 802.11e. Specifically, we will simulate the resultant system throughput, queuing delay and system packet loss rate of these proposed mechanisms, and examine the pro-and-con of adopting them as part of the present IEEE 802.11 WLAN system. Their power-saving e±ciency over the ad hoc networks will also be investigated. Concluding remarks will be made based on our simulations.