WiMAX提供了高速度網路存取和多媒體的服務，而且可支援多種不同類型的QoS。因此，在頻寬有限的情況下，有效的分配頻寬給多種的服務類型，確保即時性資料的流量和延遲時間，達到最有效的資源分配的目標，這方面的相關議題可加以探討。論文中將對於RED-based DFPQ(Random Early Dection based Deficit Fair Priority Queue)進行改良，提出ERBS，在RED-based DFPQ演算法中，以計算封包數量來當作佇列長度，但只適用於每個封包的長度為相同的，當封包長度為不同時，封包數量不等於佇列長度，另外，當同一等級數個連線封包數量超過第二門檻時，都固定為同一Deficit Counter(DC)值，可能分配相同的DC值給不同負載的各個連線，使得負載較重的連線會有較大的延遲時間。因此，在本論文中，我們以佇列的位元組長度來決定是否超過門檻來決定是否改變DC值。以各個佇列的長度來決定其權重(weight)值來分配其原有的總DC值，如此，這些連線分配到的總DC值不變，而各連線分配到的DC值將與佇列長度成正比。

The WiMAX network provides high speed internet multimedia service and supports a variety of types of Qos.Thus, it is important to allocate bandwidth to different class of traffic effectively in this network. The resource must be allocated effectively to guarantee the delay of real-time traffic.
An algorithm named Enhance RED-based Scheduling is proposed in this paper to improve the performance of RED-based Scheduling algorithm. In RED-based Scheduling algorithm, the packet number of each queue is found to decide the scheduled bandwidth. In this way, a queue with smaller packets tends to have larger scheduled bandwidth than it needs. It is only applicable to queues with the same packet size. Also, when the number of packets exceeds the second threshold, the deficit counter (DC) is fixed in RED-based Scheduling algorithm. Then, the connection with heavier load will have larger delay time than that with smaller load although they may be the same class. Thus, we byte length of each queue is used to decide the DC value in this paper. Also, the DC will depend on the length of queue if one queue exceeds the second threshold.

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