隨著科技的日新月異，無線網路技術推陳出新，琳瑯滿目的應用程式與大幅提升的網路品質，造就現今社會人手一機的盛況。另外，又加上現代上網瀏覽影片的風氣日漸盛行，高解析度度的影音服務提供使用者更享受的體驗，卻使得行動網路數據流量呈現爆炸性的增加，網路使用率的成長造成無線行動網路已不堪負荷，頻譜資源短缺問題日益嚴重。
由於頻譜資源有限的情況下，致力於提供更好的網路品質、服務更廣大的使用者，許多技術架構被提出，例如：異質性網路(Heterogeneous Network，HetNet)、中繼(Relay)、車載網路(Vehicular Network，VANET)、裝置間通訊(Device to Device，D2D)…等等。這些技術的提出緩解了負載嚴重的問題，但急遽成長的網路使用率，仍然讓網路資源無法負荷，因此長期演進技術 (Long Term Evolution，LTE)開始尋求轉往免執照頻帶(Unlicensed Band)發展。
而在免執照頻帶中，有許多系統已經在使用，其中又以Wi-Fi系統使用率占最多數。LTE是3GPP所提出的技術標準，而Wi-Fi則是基於IEEE 802.11標準的技術，此兩種系統的運作模式有很大的差異，為了能有效的存取免執照頻帶，並且不影響到Wi-Fi系統，本篇論文所研究的目標便是在此情境下，提出LTE與Wi-Fi的共存方法。

With the rapid development of technology, wireless network technology innovation, a variety of applications and great improvement of the network quality, almost everyone carries a mobile phone nowadays. People usually watch video on the Internet and high-resolution of audio and video services provide users with more enjoyable experience, causing the explosive increase of the mobile network data traffic. The growth of network traffic has significantly increased the network loads, and the problem of spectrum resource shortages has become more serious.
Due to insufficient of spectrum resources, many technical architectures have been proposed to provide better network quality for numerous users, such as heterogeneous network (HetNet), vehicular network (VANET), Device to Device (D2D), and so on. Although these methods can alleviate the problem of serious loads, but the rapid growth of network traffic still lead to the shortage of network resources. Therefore, Long Term Evolution (LTE) has begun to develop the implementation on the unlicensed band.
In the unlicensed band, there have been many systems using it, Wi-Fi system is the largest among them. LTE is the technical standards proposed by 3GPP, and Wi-Fi technology is based on the IEEE 802.11 standard. The operating mode of this two systems are very different. In order to access the unlicensed band effectively without affecting the Wi-Fi system, the goal of this paper is to propose a method for the coexistence of LTE and Wi-Fi.

學位論文審訂書 i
論文公開授權書 ii
論文摘要 iii
Abstract iv
目錄 v
圖目錄 vii
表目錄 ix
第一章 導論 1
1.1 前言 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 Wi-Fi 5
2.1.1 Wi-Fi架構 5
2.1.2 Wi-Fi通道存取技術 8
2.1.3 Wi-Fi標準技術演進 12
2.2 長期演進技術(LTE) 15
2.2.1架構簡介 15
2.2.2無線存取技術 18
2.2.3資源區塊(Physical Resource Block，PRB) 19
2.3 LTE與Wi-Fi共存機制 20
2.3.1 載波聚合(Carrier Aggregation，CA) 20
2.3.2 共存機制概述 23
2.3.3 授權輔助存取(LAA)共存機制規範標準 25
2.3.4 基於載波感測自適應傳輸之LTE-U共存技術 27
2.4相關文獻 29
第三章 研究方法 30
3.1 系統架構 30
3.2 LTE與Wi-Fi共存機制 33
3.2.1 共存流程 33
3.2.2 最佳時間比例(δ)計算流程 35
3.3 效能函數(Utility Function) 36
3.3.1定義效能函數 36
3.3.2 Wi-Fi封包成功傳輸機率計算 38
3.4 最佳免競爭週期之時間比例(δ) 41
3.4.1時間比例(δ)候選區間 41
3.4.2 LTE使用者篩選機制 45
3.4.3 最大化整體吞吐量之最佳時間比例(δ) 48
3.5 時間複雜度分析 49
第四章 效能與分析 50
4.1 模擬環境與參數設定 50
4.2 模擬結果與效能分析 53
第五章 結論 68
參考文獻 69

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