在WiMAX網路中定義了不同優先權的服務資料型態。即時性資料優先權較高，非即時性資料優先權較低。當資料透過WiMAX傳輸時，在頻寬有限的情況下，確保在有限的頻寬下更加有效率的保證即時性資料的延遲時間，避免當資源漸趨不足時不能做有效的資源分配，並且預防突然資料量的增加而無法做出反應機制，這些問題值得好好研究。
在本論文中，我們提出一個調適性頻寬借用機制，由傳統的頻寬分配方式去做改變；即時性資料在當前的訊框分配資源不足時，則後續的訊框必須將及時性資料的頻寬增加，同時非即時性資料的頻寬同步減少。若借用頻寬之後分配的資源足夠，則下個訊框必須歸還借來的頻寬，符合有借有還的道理。總體而言能有效降低即時性資料的延遲時間，對於頻寬資源更有效率的分配。

In WiMAX network, service flows with different priorities are defined. The priority of real time traffic is higher than that of non real time traffic. As bandwidth is limited, the resource must be allocated effectively to guarantee the delay time of real time traffic in WiMAX. .Besides this, the proposed algorithm must be able response quickly to prevent the sudden shortage of resource. These problems are worth studying well.
In this paper, we propose an Adaptive Bandwidth-Borrowing (ABB) algorithm. This algorithm is upgraded from the traditional bandwidth allocation protocol. When the resource assigned to the real time traffic in the current frame is insufficient, it must be increased in following frames. For this, the bandwidth allocated to the non real time traffic must be reduced simultaneously. After the allocated resource to the real time traffic is enough, the borrowed bandwidth must be returned in the next frame. The reasoning for this is “The borrowed ones must be returned sooner or later”. As a whole, the delay time in the real time traffic is reduced effectively with the mechanism. Also, the bandwidth can be allocated more effectively.

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