IEEE 802.16標準是一種無線都會型網路(Wireless Metropolitan Access Network; WM AN)，具有低成本、高速率與較大的傳輸距離等特點。為了保障各種多媒體服務品(Quality of Service; QoS) ，服務流被分為五種類別。然而，在IEEE 802.16標準中並未提供上下載頻寬的排程方法。因此，如何設計一個排程演算法來滿足所有服務品質類別的需求，是一個值得探討的議題。
在全球互通微波存取(Worldwide Interoperability for Microwave Access; WiMAX) 網路中，用戶端工作站(Subscriber Station; SS)在傳送資料前必需向基地台(Base Station; BS)傳送頻寬需求，待分配到頻寬之後才能上傳資料。本論文我們提出了一個稱作依頻寬需求調變的輪詢法(polling according to the bandwidth request; PBW)。在此一上行的排程演算法中，當用戶端工作站被輪詢(Polling)，且此時有資料要做傳送，用戶端工作站會傳送頻寬要求給基地台。當基地台收到頻寬要求時，根據頻寬需求來調整輪詢間隔(Polling Interval)。模擬結果顯示出，藉由調整輪詢間隔可以使傳送機會增加。

IEEE 802.16 is a standard for Wireless Metropolitan Area Network (WMAN). It has the advantages of low cost, high speed and long distance communication. To ensure the Quality of Service (QoS) for different multimedia applications, the service flows are classified into five classes. Nevertheless, IEEE802.16 does not provide standard for uplink and downlink bandwidth scheduling of this network. Therefore, it is a good issue for exploring to design a scheduling algorithm to meet the QoS requirement of all classes.
In worldwide interoperability for microwave access (WiMAX), Subscriber Station (SS) has to send bandwidth request to Base Station (BS) before sending data. After SS receives the bandwidth assignment from BS, it can begin to send its data. This thesis proposes an uplink scheduling algorithm named polling according to the bandwidth request (PBW). When SS is polled and has data to send, it will send bandwidth request to BS. Then, BS will adjust polling interval according to this bandwidth request. The simulation result shows that can increase transmission opportunity by adjust polling interval . The result is as good as predicted.

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