在第四代行動通訊(4G)中，正交分頻多工 (Orthogonal Frequency Division Multiplexing, OFDM)是被廣泛使用的調變系統，但其每個子載波之間因為通道和環境因素，而產生非常大的旁帶(Side lobe)，與OFDM 技術相比，通用濾波正交分頻多工[1][2](Universal Filtered - Orthogonal Frequency Division Multiplexing, UF-OFDM) 技術在結合其優點的同時避免了一些缺陷，UF-OFDM 不需要循環前綴，並且具有良好的帶外抑制和極高的頻譜利用率,因此其更適合作為第五代行動通訊(5G)通信系統的物理層波形技術。
本論文的主要目的，是在UF-OFDM系統之中，提出一個新的時間同步檢驗方法，並在此方法下，提升同步精準度，以改善傳統時間同步方法的缺點，在ODFM系統中，傳統的時間同步方法主要是由 Schmidl [3]所提出，但此方法應用在UF-ODFM系統上會產生平台效應(Plateau effect)導致其同步精準度降低，因此本文提出了一種基於摺積特性的改良時間同步方法，相比傳統方法，所提方法利用同步前導碼(Preamble)與濾波器摺積後的特性，前後部份前導碼疊加等於中間部分前導碼，在雙重檢驗下縮短了平台效應，使同步精確度和系統表現提升。
本論文除了模擬亦結合了實驗，並應用於光纖無線系統(Radio over Fiber, RoF)，展示UF-OFDM在單子帶與多子帶傳輸中，不同時間同步方法與接收光功率(Receive Optical Power, ROP)的表現，以及探討多子帶傳輸系統中，解調訊號時濾波器長度對於子帶間的串音干擾(Cross talk)和非同步傳輸環境時不同時間同步方法精準度，找出最合適的濾波器長度，並提供未來UF-OFDM眾多服務與應用。

In the fourth generation mobile communication (4G), orthogonal frequency division multiplexing (OFDM) is a widely used modulation system, but each subcarrier produces a very large side lobe due to channel and environmental factors. Compared with OFDM technology, general filter orthogonal frequency division multiplexing [1] Universal filtered - orthogonal frequency division multiplexing (UF-OFDM) technology combines its advantages and avoids some defects. UF-OFDM does not need cyclic prefix, and has good out of band suppression and high spectrum utilization. Therefore, it is more suitable for the physical layer waveform technology of the fifth generation mobile communication (5g) communication system.
The main target of this paper is to propose a new time synchronization test method in UF-OFDM system, and under this method, improve the synchronization accuracy to improve the shortcomings of traditional time synchronization methods. In ODFM system, the traditional time synchronization method is mainly proposed by Schmidl [?], but when this method is applied to UF-OFDM system, it will produce plateau effect As a result, the synchronization accuracy is reduced. Therefore, this paper proposes an improved time synchronization method based on the convolution characteristics. Compared with the traditional method, the proposed method uses the characteristics of the convolution of the synchronous preamble and the filter. The superposition of the front and rear preamble is equal to the middle preamble, which shortens the platform effect under the double test and improves the synchronization accuracy and system performance.
In addition to simulation, this paper also combines experiments and applied it to the radio over fiber (RoF) system to show the performance of received optical power (ROP) of UF-OFDM with different time synchronization method in single subband and multi subband transmission, and to explore the cross talk between subbands when demodulating signals in multi subband transmission system and asynchronous transmission environment, find out the most appropriate filter length, and provide many services and applications for UF-OFDM in the future.

摘要 i
ABSTRACT ii
致謝 iv
目錄 v
圖目錄 vii
表目錄 x
第一章 緒論 1
1.1 前言 1
1.2 研究動機與目的 4
1.3 論文架構 6
第二章 訊號介紹與實驗元件原理 7
2.1 正交分頻多工 7
2.2 通用濾波正交分頻多工 11
2.2.1 傳送端架構 11
2.2.2 接收端架構 13
2.3 濾波器的選擇與參數設計 15
2.3.1 濾波器介紹 15
2.3.2 Dolph-Chebyshev 濾波器特性 17
2.4 光載射頻 19
2.3.1 光電調變器 20
2.3.2 天線 23
2.3.3 光感測器 25
2.3.4 光學訊號的直接接收機制 29
第三章 同步介紹與傳統方法 32
3.1 同步的基本概念 32
3.2 同步系統介紹 33
3.3 Schmidl’s 方法 34
3.3.1 OFDM應用Schmidl’s方法 35
3.3.2 UF-OFDM應用Schmidl’s方法 36
第四章 UF-OFDM新的同步方法與比較 39
4.1 Cho’s 方法 39
4.2 提出新的方法 41
4.3 時間同步方法性能比較 45
第五章 實驗設置與結果 48
5.1 光纖無線通訊整合系統 48
5.2 實驗架構與參數 52
5.3 實驗結果 57
第六章 結論 64
參考文獻 65

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