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| DC 欄位 | 值 | 語言 |
|---|---|---|
| dc.contributor.advisor | 張進福 | |
| dc.contributor.author | Hsu Chih-Hua | en |
| dc.contributor.author | 徐志華 | zh_TW |
| dc.date.accessioned | 2021-06-12T18:29:38Z | - |
| dc.date.available | 2007-08-28 | |
| dc.date.copyright | 2007-08-28 | |
| dc.date.issued | 2007 | |
| dc.date.submitted | 2007-08-02 | |
| dc.identifier.citation | [1] Theodore S. Rappaport, Wireless Communication: Principle and Practices, Prentice Hall, 2nd edition, 2002.
[2] J. K. Cavers, Mobile Channel Characteristics, Kluwer Academic Publisher, 2000. [3] “11-03-0940-04-000n-tgn-channel-models,” from 802.11 TGn, May 10, 2004. [4] J. Irvine, J. -P. Couvy, F.Graziosi, J. Laurila, G. Mossakowski, and P Robin, “System Architecture for the MOSTRANI Project ( mobile services for high speed trains),” Vehicular Technology Conference, IEEE 47th Volume 3, pp. 1917-1921 vol.3, 1997. [5] http://www.hsr.gov.tw/ [6] Clive Tang and Victor Stolpman,”An Adaptive learning Approach to Adaptive OFDM”,IEEE Communications Society,2004 [7] T. Keller and L. Hanzo, “Adaptive Modulation Techniques for Duplex OFDM Transmission”, IEEE Trans. on Vehicular Technology, Vol. 49, No. 5, Sept 2000, pp. 1893-1906 [8] R. van Nee and R. Prasad, “OFDM for Wireless Multimedia Communications”, Artech House, Boston, Jan 2000. [9] R. Steele and W. Webb, “Variable rate QAM for data transmission over Rayleigh fading channels,” in Wireless. Calgary, Alberta, Canada: IEEE, 1991, pp. 1–14. [10] H. Matsuoka, S. Sampei, N. Morinaga, and Y. Kamio, “Adaptive modulation system with variable coding rate concatenated code for high quality multi-media communications systems,” in 46th Vehicular Technology Conf.. Piscataway, NJ: IEEE, 1996, pp. 478–491. [11] A. Czylwik, “Adaptive OFDM for wideband radio channels,” in Proc. Globecom. London, U.K.: IEEE, 1996, pp. 713–718. [12] J. K. Cavers, “An analysis of pilot symbol assisted modulation for Rayleigh fading channels,” IEEE Trans. Veh. Technol., vol. 40, no. 4, pp. 686–693, 1991. [13] ETSI TR 125 943 v5.1.0 | |
| dc.identifier.uri | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/27949 | - |
| dc.description.abstract | 可適性調變(Adaptive Modulation)的技術主要是提高資料的傳輸量，其做法是利用目前的通道條件好壞，做為調整下一次要傳送的調變位階依據。換句話說，當通道好時，使用高位階的調變技術，例如16-QAM，當通道不好時，使用低階的調變技術，例如QPSK或是更低階的BPSK。
OFDM(Orthogonal Frequency Division Multiplexing：正交頻率多工)可以在有限的頻寬內增加資料的傳輸量，其利用多個相互正交的子載波在有限的頻寬內傳送資料。OFDM具備有抵抗多重路徑、符號之間的干擾(ISI)等優點。於是乎，將可適性調變與OFDM相互結合使用，更可以提高無線通訊的傳輸量。 傳統的可適性調變應用於正交頻率多工上，只具有單方向性的傳送方式，而且還有諸多的假設性條件存在，例如接收端告知發送端訊息時的通道為一個完美通道，另一假設為包含在調變資料中的調變位階訊息不可以受到通道的影響，換句話說，接收端一定可以將調變位階訊息解調還原成正確訊息。這些假設都與現實環境有所差距。本篇論文提出一個新的方法可以讓雙方面都傳送資料，而不是局限於單方向性的傳輸。 本篇論文使用的方法為利用領航字元(Pilot)的錯誤率改變下一次要傳送出去的調變位階。而且調變資料當中不需要包含調變位階的訊息，使用的方法為接收端將領航字元取出後用不同的解調器解調，再計算該錯誤率，取最低的錯誤率的調變方式就是整個OFDM的調變位階。另外也將OFDM劃分成不同的區塊，每一個區塊用不同位階的調變方式調變，這樣可以使得整體的產出量達到最大。 | zh_TW |
| dc.description.abstract | The fundamental technology of adaptive modulation is to advance data throughput。The principle is receiver adjusts modulation level for next transmission depend on channel condition，i.e. when the channel condition is appropriate，it use high modulation level； when the channel is unfavorable，it use low modulation level，For example QPSK or BPSK。
OFDM (Orthogonal Frequency Division Multiplexing) can improve data throughput in the limited bandwidth。It transmits orthogonal sub-carriers in the limited bandwidth。OFDM can resist multi-path，ISI etc.. If we combine adaptive modulation and OFDM technology，we can get higher data throughput than single technology. Traditional adaptive modulation with OFDM have single transmission direction only and many assumptive conditions。For example，there is a perfect channel between transmitter and receiver。Another is modulation level in the modulated frame mustn't affect by channel，i.e. the receiver can demodulate the level of modulation accurately. However these assumptive conditions were not true in the real world。 We propose a new algorithm for adaptive modulation with OFDM。We calculate pilot's BER to adjust modulation level for next transmission，and decide which modulation level we use to demodulate it。 Other topic is to separate many blocks in a OFDM symbol。Each block has different modulation level then we can get maximum data throughput。 | en |
| dc.description.provenance | Made available in DSpace on 2021-06-12T18:29:38Z (GMT). No. of bitstreams: 1 ntu-96-P94942006-1.pdf: 2081775 bytes, checksum: 4f69f588a6e8c21f1236940d1129223e (MD5) Previous issue date: 2007 | en |
| dc.description.tableofcontents | 誌謝....................................................iii
中文摘要..................................................v 英文摘要................................................vii 第一章 緒論...............................................1 1.1 前言...............................................1 1.2研究動機...........................................1 1.3研究環境...........................................2 1.4模擬通道...........................................2 1.5論文架構...........................................3 第二章 高速移動通道與OFDM系統............................5 2.1 正交多頻分工系統簡介...............................5 2.2 正交多頻分工系統優缺點.............................7 2.3 正交多頻分工系統的應用實例.........................8 2.4 模擬通道模型.......................................9 第三章 雙向性OFDM可適性調變.............................21 3.1 傳統式OFDM可適性調變架構.........................21 3.2 傳統式OFDM可適性調變切換機制.....................22 3.3 雙向性OFDM可適性調變.............................24 3.4 結論..............................................33 第四章 區塊式雙向性可適性調變............................35 4.1 研究動機..........................................35 4.2 區塊式雙向性可適性調變............................36 4.3 結論..............................................42 第五章 部份通道已知OFDM可適性調變.......................43 5.1 研究動機..........................................43 5.2 部份通道已知之區塊雙向性OFDM可適性調變...........43 5.3 結論..............................................48 第六章 結論與未來研究方向................................49 6.1 結論..............................................49 6.2 未來研究方向......................................50 參考文獻.................................................53 圖目錄 圖1-1 基地台與列車的架構圖........................................3 圖2-1 OFDM系統方塊圖.............................................5 圖2-2(a) 分頻多工頻譜圖............................................6 圖2-2(b) OFDM頻譜圖................................................6 圖2-3 Cyclic Prefix圖.............................................7 圖2-4 都卜勒效應示意圖...........................................10 圖2-5 都卜勒位移示意圖...........................................10 圖2-6 Ricean通道場景示意圖......................................11 圖2-7 Rayleigh通道場景示意圖....................................13 圖2-8 U型圖.....................................................15 圖2-9 聚集通道的都卜勒位移效應...................................15 圖2-10 小規模衰減性質比較圖.......................................17 圖3-1 傳統式OFDM可適性調變架構..................................21 圖3-2 傳統式OFDM可適性調變方塊圖................................22 圖3-3 傳統式OFDM可適性調變位元錯誤率切換圖......................23 圖3-4 傳統式OFDM可適性調變切換機制流程圖........................24 圖3-5(a) 雙向性OFDM可適性調變發射端架構圖.........................25 圖3-5(b) 雙向性OFDM可適性調變接收端架構圖.........................25 圖3-6 領航字元擺放樣態圖.........................................26 圖3-7 領航字元為QPSK時的位元錯誤率圖............................27 圖3-8 領航字元為8PSK時的位元錯誤率圖............................27 圖3-9 領航字元為16QAM時的位元錯誤率圖...........................28 圖3-10 雙向性OFDM可適性調變方塊圖................................28 圖3-11 雙向性OFDM可適性調變切換機制流程圖........................29 圖3-12 雙向性OFDM可適性調變領航字元與資料配置圖..................30 圖3-13 雙向性OFDM可適性調變產出圖................................31 圖3-14 雙向性OFDM可適性調變位元錯誤率圖..........................32 圖3-15 雙向性OFDM可適性調變的頻譜效率圖..........................33 圖4-1(a) 區塊式雙向性OFDM可適性調變領航字元區塊圖.................35 圖4-1(b) 區塊式雙向性OFDM可適性調變資料區塊圖.....................35 圖4-2 區塊式雙向性OFDM可適性調變架構圖..........................36 圖4-3 區塊式雙向性OFDM可適性調變領航字元與資料配置圖(FFT=1024)..37 圖4-4 區塊式雙向性OFDM可適性調變流程圖..........................37 圖4-5 區塊式雙向性OFDM可適性調變方塊圖..........................38 圖4-6 區塊式雙向性OFDM可適性調變產出圖(FFT=1024)................38 圖4-7 區塊式雙向性OFDM可適性調變位元錯誤率圖(FFT=1024)..........39 圖4-8 區塊式雙向性OFDM可適性調變封包錯誤率圖(FFT=1024)..........40 圖4-9 區塊式雙向性OFDM可適性調變領航字元與資料配置圖(FFT=512)...40 圖4-10 區塊式雙向性OFDM可適性調變產出圖(FFT=512).................41 圖4-11 區塊式雙向性OFDM可適性調變位元錯誤率圖(FFT=512)...........41 圖5-1 部份通道已知領航字元與資料配置圖(FFT=1024).................44 圖5-2 部份通道已知區塊式雙向性OFDM可適性調變產出圖(FFT=1024)....44 圖5-3 部份通道已知區塊式雙向性OFDM可適性調變位元錯誤率圖(FFT=1024).........................................................45 圖5-4 部份通道已知區塊式雙向性OFDM可適性調變封包錯誤率圖(FFT=1024).........................................................46 圖5-5 部份通道已知領航字元與資料配置圖(FFT=512)..................46 圖5-6 部份通道已知區塊式雙向性OFDM可適性調變產出圖(FFT=512).....47 圖5-7 部份通道已知區塊式雙向性OFDM可適性調變位元錯誤率圖(FFT=512)..........................................................47 表目錄 表2-1 不同速度下最大都卜勒位移表.................................10 表2-2 Ricean通道模擬步驟........................................12 表2-3 Rayleigh通道模擬步驟......................................14 表2-4 同調時間與不同速度的關係...................................16 表2-5(a) COST 259 RA 通道模型.....................................18 表2-5(b) COST 259 TU 通道模型.....................................18 表2-5(c) COST 259 HT 通道模型.....................................19 表3-1 雙向性OFDM可適性調變模擬條件..............................30 表4-1 區塊式雙向性OFDM可適性調變模擬條件........................36 表5-1 部份通道已知模擬條件表.....................................43 | |
| dc.language.iso | zh-TW | |
| dc.subject | 正交頻率多工 | zh_TW |
| dc.subject | 可適性調變 | zh_TW |
| dc.subject | 調變位階 | zh_TW |
| dc.subject | 抵抗多重路徑 | zh_TW |
| dc.subject | 產出量 | zh_TW |
| dc.subject | OFDM | en |
| dc.subject | throughput | en |
| dc.subject | resist multi-path | en |
| dc.subject | adaptive modulation | en |
| dc.subject | modulation level | en |
| dc.title | OFDM可適性調變在高速移動環境之研究 | zh_TW |
| dc.title | A Study of Adaptive Modulation with OFDM In High Mobility Environment | en |
| dc.type | Thesis | |
| dc.date.schoolyear | 95-2 | |
| dc.description.degree | 碩士 | |
| dc.contributor.oralexamcommittee | 鐘嘉德,黃政吉,魏學文 | |
| dc.subject.keyword | 可適性調變,調變位階,正交頻率多工,抵抗多重路徑,產出量, | zh_TW |
| dc.subject.keyword | adaptive modulation,modulation level,OFDM,resist multi-path,throughput, | en |
| dc.relation.page | 54 | |
| dc.rights.note | 有償授權 | |
| dc.date.accepted | 2007-08-03 | |
| dc.contributor.author-college | 電機資訊學院 | zh_TW |
| dc.contributor.author-dept | 電信工程學研究所 | zh_TW |
| 顯示於系所單位： | 電信工程學研究所 | |
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