臺灣博碩士論文加值系統

由於隨著使用者對於多媒體應用服務的需求逐日增加，第三代行動無線網路，像是UMTS，的一個重要目標則是希望能夠對於各種不同品質要求的應用服務提供有效的資料傳輸。因此，在無線電存取網路(RAN)中，無線電鏈結層(RLC)或是媒體存取(MAC)層藉由同時建立多個服務載體(bearers)來調和這些混合類型服務的需求。因此，一個重要的議題則是如何對於這些載體做適當的傳輸速率調整。此外，第三代無線電介面在比較低的協定層，例如實體層(PHY)、媒體存取層或是無線電鏈結層提供了一些傳輸速率調整的作法。在這篇論文中，我們則是著重在媒體存取層上速率調整作法與排程的研究與設計，並且根據優先權(priority)及緩衝器大小(buffer occupancy)提出了五個方法，分別是嚴格優先權方法、部分動態優先權調動方法、動態優先權調動方法、機率優先權方法及負載量測優先權方法。最後，從我們模擬的結果可以發現負載量測優先權方法比其他四個方法可以維持更好的公平性及達到更好的效能。而且負載優先權方法在這五個方法中有比較短的計算時間。

As the evolution of the end users' needs toward multimedia applications, an important feature of the third generation mobile networks like UMTS attempts to support efficiently multiple applications of different qualities of service. In the Radio Access Network, the RLC/MAC layer has also been designed to accommodate simultaneously mixed services through establishing multiple bearers. Thus, a major issue is the rate
adaptation of these bearers. Moreover, third generation radio interface provides procedures to the rate adaptation in the lower layers such as PHY, MAC or RLC layer. In the paper, we focus on MAC layer and propose five scheduling methods in terms of different considerations. The five methods are strict priority method, partially dynamic priority method, dynamic priority method, probability priority method and load measurement based priority method. Our simulations show that load measurement based priority method can maintain better fairness and achieve better performance than the other four methods. Furthermore, the computation time of the load measurement based priority method is one of the smallest of the five methods.

1. Introduction
2. Transport Format Combination Selection in the MAC Layer
3. Proposed Scheduling Methods
3.1 Strict Priority Method
3.2 Partially Dynamic Priority Method and Dynamic Priority
Method
3.3 Probability Priority Method
3.4 Load Measurement Based Priority Method
4. Simulation Results
5. Conclusions and Future Work

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