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研究生： 賴勇利
Yung-Li Lai
論文名稱： 以共同載波頻率偏移修正於交錯分配正交分頻多重存取系統
A Common Carrier Frequency Offset Correction Scheme in Interleaved OFDMA Systems
指導教授： 張大中
Dah-Chung Chang
口試委員:
學位類別： 碩士
Master
系所名稱： 資訊電機學院 - 通訊工程學系
Department of Communication Engineering
畢業學年度： 96
語文別： 中文
論文頁數： 79
中文關鍵詞： 正交分頻多重存取 、載波頻率偏移
外文關鍵詞： OFDMA, carrier frequency offset
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    • 以共同載波頻率偏移修正於交錯分配正交分頻多重存取系統在本篇論文被提出與探討。雖然在過去的方法中，由多使用者之載波頻率偏移所造成的多重存取干擾可以被有效的消除，特定使用者子載波間的干擾卻不能完全被移除。在我們的方法中，發現在交錯分配正交分頻多重存取系統中可以完全移除特定使用者子載波間的干擾。模擬結果顯示以最佳共同載波頻率偏移修正可達到最小均方誤差效能

    An interleaved OFDMA system with a common carrier frequency offset correction scheme is studied in the thesis. Although the multiple access interference (MAI) effect due to the carrier frequency offsets (CFOs) among multiusers can be mitigated in past works, the intercarrier interference (ICI) effect was not removed. In our work, we explore and remove the ICI effect in an interleaved OFDMA system with CFOs. Simulation results show that the new scheme with optimal common CFO correction can achieve the minimum mean square error performance.

    第一章:序論 1 1.1 前言 1 1.2 章節架構介紹 3 第二章：OFDM及OFDMA系統介紹 4 2.1 OFDM 4 2.1.1 OFDM系統簡介 4 2.1.2 OFDM與FDM的比較 5 2.1.3 循環字首 5 2.1.4 訓練符元 6 2.1.5 領航訊號 7 2.2 OFDMA系統簡介 7 第三章: OFDMA 之上行系統 9 3.1 OFDMA 上行傳送端架構 9 3.2 OFDMA子載波配置方式 10 3.2.1子頻帶(sub-band)系統 11 3.2.2交錯分配( Interleaved )系統 11 3.3 OFDMA 上行接收端解調法 12 3.3.1 直序解調(Direct Method) 12 3.3.2 CLJL解調法 13 3.3.3 HL 解調法 16 3.4 接收端解調法的討論 18 3.4.1 CLJL與HL解調法的缺點 18 3.4.2直序解調與CLJL解調效能的比較 19 3.5 交錯分配系統下消除CLJL與HL不能解決的ICI影響 21 3.6 適應性方法尋找交錯分配系統HL輸出第一項之常數 22 3.7 基於Modified CLJL 和 Modified HL 解調法之共同載波頻率偏移補償 27 3.7.1 加入共同載波頻率偏移補償後的數學推導 27 3.7.1.1 Modified CLJL 解調法 28 3.7.1.2 Modified HL 解調法 31 3.7.2使得Modified CLJL達到MMSE之CCFO估計方式 33 3.7.3 使得Modified HL達到MMSE之CCFO估計方式 35 3.7.4錯誤訊號取得方式 36 3.7.5 CCFO初使值如何設定 37 第四章:系統模擬及結果比較 38 4.1 系統模擬架構圖與參數設定 38 4.2 CFO與通道頻率響應之估計方法 39 4.3 模擬與結果 41 4.3.1 CLJL與HL之缺點模擬圖 41 4.3.2直序解調 與 CLJL 之性能比較模擬圖 43 4.3.3適應性方法尋找交錯分配系統HL輸出第一項之常數 45 4.3.4 HL與 Modified HL 多次疊代效能比較 47 4.3.5 CCFO 初使值偵測 49 4.3.6真實MSE與近似MSE的比較 50 4.3.7 CCFO收歛曲線圖 52 4.3.8 BER曲線圖 56 第五章:結論 60 參考文獻 61 附錄1 63 附錄2 68

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