IEEE 802.16標準是一套新興的寬頻無線存取技術可以提供高速度網路存取及多媒體的服務。而且此標準可支援各種不同的服務類別等級來滿足QoS的需求。然而，規格書中並沒有規範要如何設計排程各種類型的服務資料流。在802.16 BWA系統中我們提出一個新穎的排程演算法，而這新穎的排程演算法稱作為最佳化公平頻寬配置演算法(Optimization of Fair Bandwidth Allocation, OFBA)。

在最佳化公平頻寬配置演算法中，對於IEEE 802.16 系統的每一個TDD frame可提供各種不同配額的流量。在每一個frame中會有配置的頻寬被稱為公用配額(Public Quota)，而所有的Service Class可以借用此公用配額。而且每一個Service Class所借用的額度要在Service Class所限定範圍內。若對於某一個Service Class的剩餘配額無法使用時，它會將這剩餘配額加至公用的配額中。若此回合中某一個Service Class須借用公用配額時，必須在下次回合時此Service Class還回之前所借的配額。

最後，比較OFBA與餘額公平性優先佇列(Deficit Fair Priority Queue, DFPQ)演算法，從模擬結果可得我們所提出演算法可觀測出系統Throughput較佳且可得平均的延遲時間及封包丟失率是減少的。

關鍵詞：最佳化公平頻寬配置演算法、公用配額量、餘額公平性優先佇列演算法、Throughput、平均延遲時間、封包丟失率

In the standard of IEEE 802.16, the specifications are for accessing Broadband Wireless Access (BWA) technology to provide high speed Internet access and multimedia service. Also, the standard supports different classes of services to meet the QoS requirements of different users. However, it is not defined about scheduling different types of service flow in the standard. Thus, in this paper, we propose a novel scheduling Algorithm for 802.16 BWA systems. This novel scheduling Algorithm is called Optimization of Fair Bandwidth Allocation (OFBA) Algorithm.

In OFBA Algorithm, different quota is provided to different class of traffic for each TDD frame (e.g. UGS, rtPS, nrtPS , BE ) for WiMax system. The allocated public bandwidth in one frame is called Public Quota which can be borrowed by all the classes. Each class cannot borrow a bandwidth over it is allowed. If part of the quota for one class is not used, it will be added to the public quota. If a class borrows from public quota in this round, it should return it to the public quota in the next round.

Eventually, Compare the OFBA with DFPQ Algorithm in 802.16 BWA systems. The simulation result can show that our proposed algorithm can achieve the system throughput is better and can observe system that average delay time and packet loss rate are reduced .

Key word：OFBA(Optimization of Fair Bandwidth Allocation)、Public Quota、DFPQ (Deficit Fair Priority Queue)、Throughput、Average delay time、Packet loss rate

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