在這篇論文裡，我們提出了一個新的以資訊理論為基礎，在區域網路中去量測網路公平性的公式。當整體的網路負載為一個固定的值，則經由這個公式相對應所量測出來的值，會是一個介於0與1之間的數，公平性的數字若是越大，則表示網路越公平。這個公式可以廣泛的應用在許多不同的媒體存取控制層中，像是可以同時成功傳送多個封包的媒體存取控制層，或是不同長度的封包。為了要證明這個式子的正確性，我們模擬了在IEEE 802.11無線區域網路的環境，並且對於各種不同的節點加以量測，我們的結果指出，在長時間的情況之下，IEEE 802.11可以提供一個好的公平性，但是在短時間的IEEE 802.11則無法做到。

In this paper, we propose a novel information-theoretical fairness metric to evaluate the fairness of bandwidth allocation to distributed nodes in local area network. When the source traffic pattern is fixed, the proposed metric is a mapping from the set of all medium access control (MAC) protocols to the interval [0,1] in the real line such that a larger value corresponds to a MAC protocol that allocates bandwidth more fairly. The metric is applicable for a wide range of medium access control schemes including those in which the packet lengths are not identical and/or multipacket reception (MPR) capability is available. To verify the correctness of the novel metric, we use it to evaluate the fairness levels of an IEEE 802.11 wireless LAN composed of homogeneous or heterogeneous nodes. Our simulations indicate that for the IEEE 802.11 protocol, the short-term fairness level is low while the long-term fairness level is high. The information-theoretical fairness metric leads to a conclusion that is consistent to the previous finding in the lecture.

圖表目錄 3
第一章：簡介 4
1-1 無線區域網路介紹 4
1-2 無線區域網路之媒體存取控制層 5
1-3 公平性之介紹 6
第二章：以資訊理論為基礎的公平性方程式 8
2-1 資訊理論 8
2-2 以資訊理論為基礎來量測網路公平性的公式 9
2-3 評估不同時間尺度下網路的公平性 11
2-4 與其他公平性量測方式比較 13
2-5 範例說明 15
第三章：電腦模擬分析與結果 17
3-1 網路架構 17
3-2 網路環境 19
3-3 模擬結果 20
第四章：更廣泛的應用 25
4-1 不同比重節點的公平性量測 25
4-2 不同比重節點的公平性模擬結果 26
4-3 可以同時成功傳輸多個封包的公平性量測 31
第五章：結論 33
參考文獻 34

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