隨著現今科技的快速發展，行動裝置的能力也越來越強大。從以往僅能夠撥打電話，到現在除了能夠做即時的文字訊息傳輸外，多媒體串流的傳輸以及休閒娛樂的提供也越來越強大。而這些服務都與行動網路息息相關，因此提供順暢的網路體驗變成為電信商積極的目標。

在傳統的3G（3rd Generation）網路時代，其速度和頻寬已經足以讓使用者能夠保持順暢的連接。而後推出的4G（4th Generation）行動網路更大幅提升所支援的終端速度以及頻寬的上限，讓使用的網路體驗更能大幅的提升，特別是在近期也相當興盛的高速鐵路上。

本論文的情境為高速鐵路上列車內之使用者與基地台之間進行資料傳輸，提出的機制是透過在列車車頂架設多個傳輸介面/天線，並充分利用多天線之優勢，依照使用者所要傳輸的封包類型以及各傳輸介面的訊號品質及採用的MCS（Modulation Coding Scheme），來進行分配並同步傳輸，改善整體效能。

本實驗由LTE-Sim網路模擬器來分析效能，此方法透過多傳輸介面獲取較多的傳輸資源，並透過將封包分配至適當的傳輸介面進行傳輸，能讓整體網路效能更好。模擬結果亦證明此方法在行動網路中具有可行性。

With the rapid development of the technology, the mobile communication device become more and more powerful. At the beginning, the mobile phone can just make a simple voice call. But now, the smart phone can not only send a text message but also play the real-time online streaming and play online game. All of these service are associate with the mobile network. Hence, providing a better network experience becomes an important topic for ISP（Internet Service Provider）.

In 3G mobile network period, the network speed and bandwidth can provide user with stable connections. In 4G mobile network period, with higher speed and more bandwidth, the network user experience become well, especially in the high speed railway scenario.

This thesis focuses on the transmission between the user in the train and base station in High Speed Railway scenario. The proposed scheme can enhance the overall performance by full using the multi-antenna on the train to transmission and selecting a suitable interface for each packet type in transmission.

The experiment was conducted by LTE-Sim network simulator to analyze the performance of this method to grab more transmission resource and send packet via suitable interface, allowing better overall network performance. The simulation results also show that this method is feasible in mobile network in HSR.

第一章 1
1.1 簡介 1
1.2 研究動機 3
1.3 論文架構 4
第二章 相關背景與研究 5
2.1 長期演進技術（LTE）簡介 5
2.2 換手機制（Handover）簡介 19
第三章 研究方法 25
3.1 情境假設 26
3.2 機制流程 27
3.3 無縫換手機制（Seamless Handover Scheme） 28
3.4 CQI預測機制 32
3.4.1 利用線性回歸模型的RSRP預測機制 33
3.4.2 SNR值之計算 36
3.4.3 SNR值轉換CQI 37
3.4.4 CQI對應之調變技術 39
3.5 封包排程機制 40
3.5.1 第一次排程 42
3.5.2 第二次排程 43
第四章 模擬效能與分析 45
4.1 模擬環境與參數設定 45
4.2 模擬效能評測與分析 47
第五章 結論 55
參考文獻 56

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