隨著智慧型手機以及平板電腦等手持式裝置的廣泛使用，無線通訊網路的發展此更加迅速，而即時性影音服務的需求量日益提昇，以至於現有的無線網路資源無法滿足所有使用者的需求，因此如何有效率的使用頻寬資源則成為現在無線通訊網路發展的一大重點。
目前長期演進技術中基地台的封包排程機制仍然沒有一個真正公平且有效率的演算法，因此本論文在長期演進技術的無線網路環境下，提出一個適用於即時影音串流的封包排程機制，希望能夠提昇排程效率，減少使用者因超過時效(Out-of-Date)而產生的封包丟棄問題，以達到更高的基地有效吞吐量(Goodput)。
本篇論文使用封包延遲作為考量，並以封包預測機制(Packet Prediction Mechanism, PPM)，改進的長期演進技術下行封包排程機制，藉由觀察使用者佇列中的封包時戳(Time Stamp)以及該應用服務所能容忍的延遲預算(Delay Budget)，計算出封包延遲時間，預估使用者未來有可能的封包過期情況，以利於基地台提高使用者的傳輸優先權，達到減少過期封包的效果。另外在每個傳輸時間間隔時，考量到使用者移動性(User Mobility)的不同，在資源分配時使用不同的分配機制，以達到提昇頻譜的使用效率。
模擬結果顯示我們所提出的排程機制相較於其他現有常見的排程演算法更能夠提昇基地台的有效吞吐量，以及減少封包遺失率，降低封包延遲時間，在公平性也能達到不錯的效果。

The growing demand of real-time services, such as Video streaming, VoIP , with high constraints on delays and bandwidth brings new challenges in the design of wireless communication system. So how to use radio resource efficiently becomes an important point for the LTE system.

In our paper, we proposed a new LTE downlink packet scheduler, which chooses packet delay to prioritize user, and uses Packet Prediction Mechanism to solve the burst transmission situation. We also used the Channel Quality Indicator that users send feedback to the eNodeB to classify user mobility, and then in every transmission time interval, we utilized different resource allocation schemes for the high mobility users.

The simulations are conducted by LTE-Sim R5 to analyze the performance of proposed method. And the simulation results show that the proposed method outperforms other packet scheduling schemes, no matter in Goodput, Packet Delay, or Packet loss rate. It shows that the proposed method can improve the spectrum efficiency and satisfy the QoS requirements of real-time traffic.

學位論文審定書 i
論文摘要 ii
Abstract iii
目錄 iv
圖目錄 vi
表目錄 viii
第一章 導論 1
1.1 前言 1
1.2 研究動機 3
1.3 論文架構 6
第二章 相關背景 7
2.1 3GPP長期演進技術(LTE)簡介 7
2.1.1 LTE基本系統架構 8
2.1.2 LTE無線存取技術 10
2.1.3 無線電資源管理(Radio Resource Management) 16
2.2 相關論文 17
2.2.1 封包排程 17
2.2.2 使用者移動性 21
第三章 LTE排程 24
3.1 使用者移動性之劃分 28
3.2 基本封包排程機制 30
3.3 佇列管理以及封包過期預測 33
3.4 封包插隊機制 46
3.5 資源分配機制 48
第四章 模擬與分析 52
4.1 模擬環境與參數設定 52
4.2 模擬結果與效能分析 55
第五章 結論 67
參考文獻 68

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