IEEE 802.11 分散式擷取協定系統效能分析

Abstract

IEEE 802.11 無線網路在最近幾年中成為了最受歡迎的無線區域網路技術(WLAN)，其中媒體存取控制協定(MAC)跟分散式擷取協定(DCF)已被明確規範為媒體存取技術，且廣泛的應用在新穎網路技術上；因此有效且深入的了解IEEE802.11 分散式擷取協定(DCF)技術為本篇論文主要探討重點，現存許多研究已經討論過這項議題，但這些研究都忽略許多實際上協定的細部行為規範。 本篇論文將細部討論現存模型在討論分散式擷取協定(DCF)上的問題，並針對此些問題提出一個新穎的分析模型，此模型考慮實際擷取通道協定狀況，並細部考慮各端點間的行為模式。根據此分析模型，我們可以簡易，但有效率且正確的分析無線區域網路效能。分析結果包含有效傳送機率(Transmission Probability) 、各端點吞吐量(Throughput) 、整體吞吐量(Aggregate Throughput)、傳送延遲(Delay Time)、及有效傳送時間間距(Interarrival Time)。最後藉由Qaulnet 模擬軟體模擬分析無線網路環境，與現存分析模型比較可有效證明我們模型正確性。

Recently, IEEE 802.11 protocol has been widely implemented in wireless local area networks (WLAN). The primary medium access control (MAC) technique, distributed coordination function (DCF), that specified contention-based medium access mechanism has been widely used to support applications in new regimes. Fully understanding IEEE 802.11 DCF is the focus of this article. This topic has already been discussed by several existing models, however most of them ignored some protocol details. This thesis is about the problems of existing models with DCF protocol and provides a new model that takes behaviors of the channel and more details into consideration. Based on the proposed model,we perform simple, but rigorously accurate analysis model of saturation extensive performance in WLAN to present our results in the transmitted probability, throughput, and interarrival time. All the findings are verified by Qualnet Simulation to ensure the accuracy and thoroughness of the proposed model.