摘 要

由於無線傳輸可使用的頻寬有限，因此如何在有限的頻寬資源下，使系統達到較高的流通量(Throughput)以支援最多的使用者是一個重要的研究的課題。本論文提出一個同時考量媒體存取控制(MAC)與通道實體(PHY)的跨層級(Cross-Layer)訊框傳送排程法則。針對即時性資料流，我們提出 具通道感知最早截止優先(Channel-Aware Earliest Deadline First, CAEDF)服務法則。CAEDF同時考慮用戶的通道狀況與即時性資料所能容忍最大傳送延遲時間(Maximum Latency)，使資料得以在用戶通道狀況良好情況下，透過較高速的調變技術傳送出去。針對非即時性資料流，我們提出具通道感知餘額輪流法則(Channel-Aware Deficit Round, Robin CADRR)服務法則來調整可傳送之封包數量，進而達到使用頻寬量的補償效果，如此，除可增加整體流通量，亦兼顧用戶使用頻寬量之長程公平性(Long-term Fairness)。
我們所提出的法則可在提升系統流通量的情況下，同時兼具滿足即時資料流的服務品質(Quality of Service)需求以及非即時資料流的長程公平性。模擬結果顯示在IEEE 802.16e網路中，使用CAEDF和CADRR法則傳送資料時，整體系統流通量比使用傳統EDF和DRR與Priority FCFS法則的整體系統流通量分別增加19%，使用者數量也分別增加了12.5%與53%。CAEDF法滿足了即時資料流之延遲要求，因此能夠大量減少封包的丟棄率，有效提升即時資料流用戶收訊的品質。而CADRR對於非即時資料流的用戶，無論用戶使用那種調變技術，透過額度的調整，可以達到長程公平性。

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