高速下行鏈路封包存取系統以有效的時間延遲控制支援即時性訊務之封包排程機制

Abstract

行動通訊技術的演進，隨著使用者對無線資料下載需求增加，朝著高速率的方向發展。在現有的第三代通訊系統下，提出了一種高速下行封包擷取技術（High Speed Downlink Packet Access, HSDPA）來提供更高速的下行鏈路資料封包傳送。近來，隨著高速率多樣化資料傳輸 的應用和需求與日俱增，為維持不同服務品質(QoS)的需求，無線資源的排程機制成為一個重要的問題。然而，現有架構在HSDPA 系統下的排程機制是以非即時性訊務為設計基礎，提供高速率的資料傳輸。 為能滿足即時性訊務在時間延遲的要求，在本論文中，我們提出一個排程機制演算法，其基本的設計思維是藉由控制時間延遲來滿足不同資料服務品質的要求。電腦模擬的結果指出，我們所提出的排程機制能夠將時間延遲控制在事先保證的範圍之內，且與現有的演算法做比較，將可提升系統吞吐量(Throughput)的效能，維持使用者公平性。

Originally, the design of High-speed downlink packet access (HSDPA) was for high bit rate non-real time services (interactive and background) and also for some extent real-time applications (e.g., streaming). Because of real-time applications have different Quality of Service (QoS) constraints more than non-real-time applications and usually Real Time (RT) service is considered to transfer the package with strict delay requirements on the end-to-end communication, thus the design of scheduling algorithms for real-time applications should be different from that for non-real-time applications. Usually, A QoS Aware Scheduler that prioritizes traffic based on its delay requirements is proposed in this paper. The proposed algorithm is designed to achieve a high throughput and a fair allocation of resources among users. Simulation results indicate that the proposed algorithm achieves a higher throughput and meet maximum queuing delay threshold by compared with existing HSDPA scheduling schemes.