為了因應行動通訊傳輸量的迅速增長，光學毫米波(MMW)是5G高速接取網路的一項關鍵技術。許多無線網路運營商著重於行動網路前段的網絡架構，其優點是具有集中的控制管理以及優化的服務品質。在行動網路前段中，如何以成本效益高的方式將新佈放的天線端與現有的中央機房做緊密的結合，並用於無線-光纖整合網路，是一項重要的課題。然而，目前在5G行動網路前段上行所提出的MMW產生與接收方式，都是以高頻元件為主。但是高頻元件會帶來許多本質上的問題，例如較高的熱雜訊、及昂貴的價格等。
為了解決這個問題，本論文以5G行動網路前段上行為基底，提出了以低頻寬元件來產生與接收MMW的解決方案。第一，設計一個於中央機房的接收端架構，利用光學降頻的方式，以低於12GHz頻寬的元件來接收30GHz的MMW信號。第二，在傳輸端利用10GHz半導體雷射的兩個不同的非線性動態模態 : 週期一(Period 1)和穩定鎖定(Stable Locking)來產生MMW信號，取代傳統的直接調變。利用以上兩種方式，以低頻寬元件完成MMW信號的產生與接收，將有效的降低建置及營運成本，並且減輕系統複雜度。
在本篇論文中，MMW信號形式以OFDM為主，將不同調變模式的MMW信號經由單模光纖傳輸B2B和25公里，無線傳輸0.3公尺、1公尺和1.5公尺的情況下進行量測與探討，以驗證提出架構之可行性。

To cope with the surging growth of internet mobile traffic and wireless services, optical millimeter wave (MMW) is a key technology to promote radio-frequency-over-fiber (RFoF) to become a promising solution for the next generation 5G high-speed access networks. Thus most wireless operators focus on mobile fronthaul (MFH) network architecture featuring a centralized controlling and managing with optimized service quality. In such MFH networks one major challenge is to seamlessly integrate the abundant newly deployed remote radio head (RRH) with the existing central offices (COs) for hybrid optical-wireless MMW service in a cost-effective manner. However, devices with high bandwidth seem to be the only approach to transmit and receive the optical MMW signal at MFH uplink in 5G hybrid fiber-wireless systems. Unfortunately, many sticky problems arise from high bandwidth devices in receivers, such as limited noise preventions and huge construction expenditure.
To resolve this dilemma, we propose a novel solution to appropriately transmit and receive MMW signals featuring with low bandwidth components in this work. We firstly design a receiver architecture to receive 30 GHz MMW uplink in COs but with beneath 12 GHz bandwidth devices mainly based on an optical frequency conversion, and secondly we utilize two different nonlinear dynamic patterns of a 10 GHz semiconductor laser, period-1 and stable locking, to generate uplink MMW signals instead of direct modulation via high bandwidth modulator. Hence, the employed components are all with a bandwidth requirement below 12 GHz, which leads to an effective cost reduction and relieve system complexity. In this work, a back-to-back and a 25-km single mode fiber transmission with 0.3-m, 1-m and 1.5-m wireless transmission scenarios are experimentally demonstrated with various modulation formats.

目錄
第1章 諸論 1
1.1 前言 1
1.2 研究背景 2
1.2.1 第五代行動通訊簡介 2
1.2.2 集中式無線電接取網路 3
1.2.3 毫米波 5
1.3 研究動機 8
1.4 論文編排 9
第2章 系統原理 10
2.1 OFDM系統編碼與解碼 10
2.2 OFDM系統的電-光轉換 13
2.3 OFDM系統的光-電轉換 15
2.4 光學移頻技術 17
2.5 天線原理 18
2.6 半導體雷射注入鎖模原理 19
第3章 行動網路前段之30GHz毫米波系統 22
3.1 實驗架構 22
3.1.1 行動網路前段下行架構 22
3.1.2 行動網路前段上行架構 23
3.2 實驗流程 25
3.2.1 下行實驗 25
3.2.2 上行實驗 29
3.3 實驗數據 31
3.3.1 上行光學移頻架構 32
3.3.2 上行光學移頻與電學移頻之比較 33
第4章 以穩定鎖模技術調變之30GHz毫米波系統 36
4.1 實驗架構 36
4.2 實驗流程 38
4.3 實驗數據 43
第5章 以P1技術調變25.7GHz毫米波之上行系統 46
5.1 實驗架構 47
5.2 實驗流程 48
5.3 實驗數據 51
第6章 結論 56

圖目錄

圖 1‑1分散式無線網路與集中式無線網路之概念比較 4
圖 1‑2 基地台架構演進圖 (a) 傳統分散式無線網路大型細胞(macro cell)基地台; (b) 概念式BBU與RRH分離之基地台; (c) 集中式無線網路與BBU叢集 4
圖 1‑3 毫米波及其他常用頻段之示意圖 5
圖 1‑4 蜂巢式網路覆蓋密度與行動通訊演進之比較表 7
圖 1‑5 蜂巢式網路之分類 (a) 大型覆蓋面積macro cell ; (b) 小型覆蓋面積micro cell ; (c) 微型覆蓋面積femto cell 7
圖 1‑6 水分子與氧氣於電磁波各頻段所造成的衰減 8
圖 2‑1單載波與直載波之關係示意圖 10
圖 2‑2 OFDM系統(左)與FDM系統(右)頻譜示意圖 11
圖 2‑3 OFDM系統傳送端調變器示意圖 11
圖 2‑4 OFDM系統接收端解調器示意圖 12
圖 2‑5 Mach-Zehnder 調變器架構圖 13
圖 2‑6 Mach-Zehnder 調變器轉換調變曲線 15
圖 2‑7 OFDM直接檢測系統中各項拍頻示意圖 16
圖 2‑8 光學移頻概念示意圖 17
圖 2‑9 天線之waveguide結構圖 19
圖 2‑10 半導體雷射注入鎖模之非線性動態機制示意圖 21
圖 3‑1 行動網路前段之系統概念圖 22
圖 3‑2 行動網路前段下行架構與信號頻譜示意圖 23
圖 3‑3 行動網路前段上行架構與信號頻譜示意圖 24
圖 3‑4 Optical Carrier Suppression 頻譜圖 26
圖 3‑5 數位OFDM之波形與頻譜圖 27
圖 3‑6 調變後之光學OFDM系統頻譜圖 27
圖 3‑7 OFDM相互拍頻後之電頻譜圖 28
圖 3‑8 角型天線頻率響應圖(量測範圍:15-40GHz) 29
圖 3‑9 上行30GHz毫米波OFDM頻譜圖 30
圖 3‑10 光學移頻後之OFDM頻譜圖 31
圖 3‑11 Received power vs. BER: 光學移頻上行系統 32
圖 3‑12 光學移頻與傳統電學移頻架構比較圖 33
圖 3‑13 Received power vs. BER: 光學移頻與傳統電學移頻 34
圖 4‑1 40GHz MZM調變與Stable Locking調變系統之傳輸端 37
圖 4‑2 Stable Locking調變系統示意圖 38
圖 4‑3 Stable Locking調變系統之上行接收端 38
圖 4‑4 ML與free-running SL之頻譜圖 39
圖 4‑5 Stable Locking頻譜圖 40
圖 4‑6 Stable Locking單頻帶調變30GHz毫米波OFDM之頻譜圖 41
圖 4‑7 光學移頻之Stable Locking OFDM頻譜圖 42
圖 4‑8 放大後之光學移頻Stable Locking OFDM頻譜圖 43
圖 4‑9 Received power vs. BER: 以Stable Locking調變30GHz OFDM 44
圖 4‑10 Received power vs. BER: Stable Locking調變與40GHz MZM調變 45
圖 5‑1 以P1調變毫米波信號於行動網路前段上行之概念圖 46
圖 5‑2 P1調變毫米波信號實驗架構圖 47
圖 5‑3 數位OFDM之波形與頻譜圖 49
圖 5‑4 P1-OFDM、free-running ML、ML之光頻譜圖 50
圖 5‑5 RF電頻譜圖 51
圖 5‑6 無天線傳輸之P1毫米波上行系統 52
圖 5‑7 Received spectrum and constellation: 無天線傳輸、光纖傳輸B2B 52
圖 5‑8 Received spectrum and constellation: 無天線傳輸、光纖傳輸25km 53
圖 5‑9 含天線傳輸之P1毫米波上行系統 53
圖 5‑10 Received spectrum and constellation: 天線傳輸1m、光纖傳輸25km 54
圖 5‑11 Received spectrum and constellation: 天線傳輸1.5m、光纖傳輸25km 54
圖 5‑12 含天線傳輸之free-running毫米波上行系統 54
圖 5‑13 Received spectrum and constellation: 天線傳輸1.5m、光纖傳輸25km 55

表格目錄

表格 3‑1 OFDM 參數表 25
表格 5‑1 P1-OFDM 參數表 48

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