隨著無線通訊技術的發展，不管是在LTE(Long Term Evolution)的第四代行動通訊，或著在未來5G行動通訊中，正交分頻多工(Orthogonal Frequency DivisionMultiplexing，OFDM)的技術還是十分重要的。本論文將會針對以分時雙工(Time Division Duplexing ，TDD)的正交分頻多工上行及下行鏈路系統，及調變原理做介紹。
而本論文將以軟體無線電方式，實現TDD OFDM上行及下行鏈路系統的發射機與接收機之間的溝通對傳(無人機與地面站對傳)。透過使用軟體無線電平台，可以即時的在單一頻率不同時間上，完成使用者與基地台的溝通，並可以觀察空中的訊號，經過空氣後發生的變化與不同大小增益帶來的影響，探討本論文系統的品質。

With the development of wireless communication technology, whether in the fourth generation of mobile communication of LTE (Long Term Evolution), or in the future 5G mobile communication, the technology of Orthogonal Frequency Division Multiplexing (OFDM) is still very important. This paper will introduce the TDD OFDM uplink and downlink systems and modulation principles.
In this paper, the communication between the transmitter and the receiver of the TDD OFDM uplink and downlink system is realized by software radio (the user and the base station are transmitting). Through the use of the software radio platform, users can communicate with the base station at a single frequency and at different times, and can observe the signals in the air, the changes after the air and the effects of different size gains to discussion on the quality of the signal and system, etc.

中文摘要 i
Abstarct ii
誌謝 iii
目錄 iv
圖目錄 vii
表目錄 xii
第一章 緒論 1
1-1 研究動機與背景 1
1-2 章節簡介 2
第二章 TDD OFDM上行與下行鏈路系統簡介 3
2-1 正交分頻多工簡介 3
2-2 正交分頻多工調變原理 3
2-3 保護區間(Guard Interval) 6
2-4 正交分頻多重存取系統 9
2-5 正交分頻多重存取系統 10
2-6 上下行鏈路TDD工作原理 11
第三章 無人機端與地面站端系統 12
3-1 地面站端發射機 15
3-1-1 星座圖映射器 15
3-1-2 參考訊號 16
3-1-3 快速傅立葉轉換 17
3-1-4 循環字首 19
3-2 地面站端接收機 20
3-2-1 符元時序同步(Symbol Timing Synchronization) 20
3-2-2 符元時序偏移討論 20
3-2-3 符元時序同步原理 21
3-2-4 載波頻率同步 22
3-2-5 載波頻率誤差之影響 22
3-2-6 載波頻率同步原理 25
3-2-7 訊框同步 26
3-2-8 通道估測 27
3-2-9 取樣後維持通道估測(Sample and Hold) 29
第四章 OFDM上下行鏈路硬體實現 30
4-1 無人機端下行鏈路發射機、上行鏈路接收機系統架構 30
4-2 下行鏈路發射機 31
4-2-1 星座圖映射器 31
4-2-2 參考訊號產生器 32
4-2-3 訊框架構產生器 33
4-2-4 子載波映射器 35
4-2-5 快速反傅立葉轉換器 37
4-2-5-1 FFT/IFFT 切換 39
4-2-5-2 蝶型運算器 39
4-2-5-3 FFT時序控制 42
4-2-5-4 位元反轉排序 43
4-2-6 循環前綴產生器 46
4-2-7 取樣率增加器 49
4-2-8 TDD 控制器 52
4-3 上行鏈路接射機 54
4-3-1 取樣率遞減器 54
4-3-2 符元時間同步與載波頻率同步模組 56
4-3-2-1 延遲相關器模組 57
4-3-2-2 峰值檢測器模組 58
4-3-2-3 訊框同步模組 60
4-3-2-4符碼同步 62
4-3-2-5載波頻率同步器 64
4-3-3 快速傅立葉轉換器 65
4-3-4 解子載波映射器 66
4-3-5 解訊框架構器 68
4-3-5 通道估測 70
4-3-5-1 參考訊號通道響應 71
4-3-5-2 線性內插法 72
4-3-6 通道等化 74
4-4 地面站端上行鏈路發射機、下行鏈路接收機系統架構 76
4-5 地面站端UL_Control 模組 77
第五章 軟體定義無線電平台與硬體實驗結果 80
5-1 軟體定義無線電 80
5-2 軟體定義無線電平台 80
5-3 FPGA (AC701) 82
5-4 RF Module(AD9361) 82
5-4 實驗結果 84
5-4-1 合成報告書 85
5-4-2 發射機硬體實現結果 86
5-4-3 接收機硬體實現結果 87
第六章 結論 92
參考文獻 93

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