在IEEE 802.11無線區域網路傳輸中因CSMA/CA演算法導致效能低落，在個人的論文中提出了分散式動態效能改進演算法，該演算法分析通道傳輸密度推測活躍無線節點的數目，並透過動態控制MAC傳輸協定中的競爭視窗大小，各節點可有效提升系統傳輸產出，另外針對無線節點間的公平性議題，包含無線節點間因調變編碼產生的效能異常及無線基地台與節點間上下行傳輸非對稱現象，在本論文中透過數學模型與模擬探討，提出修改無線基地台的傳輸佇列，達到各無線節點間的傳輸公平性，本論文所提出的DBM(Density Based Method)演算法，由實驗結果可以看出有效地改善傳統IEEE 802.11 DCF的傳輸效能，並且避免無線錯誤對傳輸效能的干擾。配合針對公平性所提出的SA-CW (Self-Adjusting Contention Window scheme)無線通道存取方法，從數據及分析上，可以發現各無線節點間可以避免多速率傳輸異常現象，及無線基地台上下行瓶頸議題，在吞吐量、公平性指標、時間延遲上都有大幅度地改善。

The performance of the Distributed Coordination Function (DCF) (i.e. the basic access method of the IEEE 802.11 protocol) is far from optimum due to use of the binary exponential backoff (BEB) scheme as its collision avoidance mechanism. The literatures contained considerable enhancements of DCF issues and its performance analysis. However, most schemes assume data rate and traffic load are the same among wireless devices, which are opposite to realistic wireless environments and arise fairness issues. The fairness issue includes the performance anomaly and links asymmetry may occur among wireless devices in deployed Wireless Local Area Networks (WLANs). Previous studies proposed solutions that addressed either performance anomaly (throughput) or asymmetric links (fairness) issue. In this dissertation, we emphasize the necessity to consider both issues concurrently. A self-adjusting contention window scheme (SA-CW) is proposed to improve system fairness and efficiency by solving concurrently performance anomaly and asymmetric links issues in IEEE 802.11 WLANs with multi-rate transmissions. Moreover, we present a simple yet pragmatic distributed algorithm, designated the density based access method (DBM), which allows stations to dynamically optimize the network throughput based on run-time measurements of channel status.

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