IEEE 802.16是一種無線寬頻網路標準，具有較高傳輸速率和較長通訊距離，以及能支援語音、影像多媒體服務等特點。在IEEE 802.16中定義了五種服務品質(Quality of Service; QoS)來滿足各種資料的需求。然而，在IEEE 802.16標準中並沒有將排程演算法作明確定義，所以這部分一直是開放給學者及通訊商來研究及探索。因此設計一個好的排程演算法來讓有限的頻寬資源能同時滿足即時性與非即時性服務的需求是相當重要的。
一個即時性的封包必須在其截止期限(deadline)內傳送出去，否則超過其截止期限，該封包就會被丟棄，而影響服務品質。本論文將會提出一個根據調變及編碼方式(Modulation and Coding Scheme; MCS)和即時性服務佇列中封包的截止期限，來安排其傳送優先順序的排程演算法，首先，我們會限制各服務類別的可用總頻寬，再根據調變與編碼方式，把所有的緊急封包先做排程。再把其他的封包根據調變與編碼方式做排程，讓較好的調變優先分配。模擬結果顯示透過此種方式可以在即時性服務類別中增加其傳輸量，並且保障每個務流都有基本的頻寬可使用，而且能讓即時性服務類別的封包丟失率有效的降低。

IEEE 802.16 is a standard for wireless communication network. It has the advantages of high transmission rate, long transmission distance and supporting various kinds of multimedia services such as voice and video. For these services, IEEE 802.16 defines five classes for quality of service (QoS) which will meet a variety of data service demands. Nevertheless, IEEE 802.16 does not define the scheduling algorithm for these classes. This is left for researchers and communication suppliers to explore. Therefore, it is important to design a good scheduling algorithm to satisfy the requirement of real time and non-real time service.
In this paper, we will propose a scheduling algorithm which will sort the priority of subscriber station (SS) according their modulation and coding scheme (MCS). Then, we will restrict the total available bandwidth for each class to ensure the scheduled bandwidth of each class. Then, the deadline will be used to decide the priority in ertPS and rtPS class when service flow uses the same MCS. The simulation result shows that the throughput of ertPS and rtPS can be increased for the same load with our algorithm and the loss rate will be decreased relatively.

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