跳到主要內容

臺灣博碩士論文加值系統

(44.211.239.1) 您好!臺灣時間:2023/01/31 06:35
字體大小: 字級放大   字級縮小   預設字形  
回查詢結果 :::

詳目顯示

: 
twitterline
研究生:鄧逸雯
研究生(外文):I-Weng Teng
論文名稱:2D-OVSF碼於OFDMA行動通訊系統效能之評估
論文名稱(外文):Performance Evaluation of 2D-OVSF Codes over OFDMA Mobile Communication Systems
指導教授:譚旦旭譚旦旭引用關係黃永發黃永發引用關係
口試委員:林仁勇簡福榮
口試日期:2008-07-31
學位類別:碩士
校院名稱:國立臺北科技大學
系所名稱:電機工程系所
學門:工程學門
學類:電資工程學類
論文種類:學術論文
論文出版年:2008
畢業學年度:96
語文別:中文
論文頁數:62
中文關鍵詞:OFDMA正交分頻2D-OVSF碼上鏈頻率選擇性衰減都普勒效應
外文關鍵詞:OFDMAOFDM2D-OVSF CodeUplinkFrequency Selective FadingDoppler Effect
相關次數:
  • 被引用被引用:0
  • 點閱點閱:593
  • 評分評分:
  • 下載下載:0
  • 收藏至我的研究室書目清單書目收藏:0
本論文探討二維正交可變展頻因子(Two-Dimensional Orthogonal Variable Spreading Factors, 2D-OVSF)碼於正交分頻多工存取(Orthogonal Frequency Division Multiple Access, OFDMA)行動通訊系統之上鏈(Uplink)效能。當無線通道具有頻率選擇性衰減(Frequency Selective Fading)及都普勒效應(Doppler Effect)時,其分集性效益(Diversity Gain)可提升系統效能,但在多用戶(Multiuser)系統中,正交展頻碼會失去正交性,而導致多重存取干擾(Multiple Access Interference, MAI),並使OFDMA行動通訊系統之多用戶效能惡化。因此本文針對分集性效益與多重進接干擾對系統效能之影響進行理論分析,並進一步以電腦模擬驗證之。模擬結果顯示,應用2D-OVSF碼在OFDMA上鏈系統中,針對不同頻率選擇性衰減及都普勒效應之通道環境,適當地選用頻域與時域之展頻因子,可提升多用戶系統效能。
This study evaluates the performance of two-dimensional orthogonal variable spreading factors (2D-OVSF) codes on uplink of orthogonal frequency division multiple access (OFDMA) mobile communication systems. For wireless channel with frequency selective fading and Doppler frequency shift, the diversity gain can enhance system performance. However, in the multiuser environment the performance is degraded due to multiple access interference (MAI) resulting from the loss of orthogonality between users. Therefore, firstly, this thesis analyzes the effect of diversity gain and MAI on bit error rate (BER) and then verifies the derived results via simulations. Simulation results indicate that appropriate selection of time and frequency spreading factors of 2D-OVSF codes for OFDMA uplink can improve performance of multiuser systems.
中文摘要 i
英文摘要 ii
誌謝 iii
目錄 iv
表目錄 vii
圖目錄 viii
第一章 緒論 1
1.1 研究動機與目的 1
1.2 研究方法 2
1.3 各章節內容摘要 2
第二章 正交分頻多工系統簡介 3
2.1系統演進 3
2.2正交分頻多工系統 3
2.2.1正交分頻多工系統架構 5
2.2.2正交性 6
2.2.3離散傅立葉轉換 7
2.2.4保護區間 7
2.3正交分頻多工在頻率選擇性衰減通道之效能 11
2.4正交分頻多工優缺點 12
2.5耙式接收器 12
2.5.1全部接收型耙式接收器 14
2.5.2局部接收型耙式接收器 14
2.5.3選擇型耙式接收器 14
2.5.4限制選擇型耙式接收器 14
第三章 無線通訊系統通道模型 16
3.1通道模型簡介 16
3.2多重路徑傳播效應 17
3.3瑞利分布 18
3.4頻率選擇性衰減 18
3.5都普勒效應 19
3.5.1緩慢衰減 22
3.5.2快速衰減 22
3.6頻率選擇性衰減通道模型 23
第四章 二維OVSF碼 24
4.1 OVSF碼和2D-OVSF碼簡介 24
4.2碼樹 25
4.2.1 OVSF碼樹 25
4.2.2時域分散和頻域展頻長度相等的2D-OVSF+碼樹 26
4.2.3時域分散和頻域展頻長度不同的2D-OVSF+碼樹 28
4.3 2D-OVSF‾碼 30
4.4 2D-OVSF碼間的正交性 31
4.4.1 M等於N時2D-OVSF+碼的正交性 32
4.4.2 M不等於N時2D-OVSF+碼的正交性 33
4.4.3 2D-OVSF‾碼的正交性 35
4.5通道效應對OVSF碼及2D-OVSF的影響 36
4.5.1選擇性衰減在上傳通道對OVSF碼的影響 36
4.5.2選擇性衰減在上傳通道對2D-OVSF+碼的影響 39
4.5.3選擇性衰減在上傳通道對2D-OVSF—碼的影響 42
第五章實驗結果 45
5.1模擬架構 45
5.1.1系統參數 45
5.1.2通道設定 45
5.1.3效能評估 46
5.2通道效應對正交分頻多工的影響 46
5.2.1通道延遲小於保護區間 47
5.2.2通道延遲大於保護區間 50
5.3用戶數I=1之模擬 53
5.4用戶數I=2之模擬 55
第六章 結論與未來展望 57
參考文獻 58
縮寫中英對照 61
[1] J. A. C. Bingham, “Multicarrier Modulation for Data Transmission: an Idea Whose Time Has Come,” IEEE Commun. Magazine, May 1990, pp. 5-14.
[2] A. S. Bahai and B. R. Saltzberg, Multi-Carrier Digital Communications Theory and Applications of OFDMs, New York, Kluwer Academic/Plenum Publishers, 1999.
[3] A. J. Viterbi, CDMA: Principles of Spread Spectrum Communication, Addison-Wesley Wireless Communications June 1995.
[4] J. G. Proakis, Digital Communication, Fourth Edition, McGraw-Hill, 2001.
[5] J. S. Lee and L.E. Miller, CDMA System Engineering handbook, Artech House, 1998.
[6] J. K. Cavers, Mobile Channel Characteristics, Boston Kluwer, 2000.
[7] W. Zou and Y. Wu, “COFDM: an Overview,” IEEE Trans. On Broadcasting, Mar. 1995, pp.1 - 8.
[8] L. Hanzo, M. Munster, B. Choi and T. Keller, OFDM and MC-CDMA for Broadband Multi-User Communications, WLANs and Broadcasting, New York, John Wiley & Sons, March 2004.
[9] R. D. Gitlin, “Multi-code CDMA Wireless Personal Communications Networks,” IEEE International Conference on Communications, June 1995, pp. 1060-1064.
[10] J. K. Kim, et al., “Design of Binary Multi-code CDMA System with Constant Amplitude,” Third International Conference on Information Technology and Application, July 2005, pp. 259-264.
[11] L. Lee. and F. Adachi, “Chip-interleaved Multi-rate CDMA with 2-dimensional OVSF Spreading,” IEEE International Conference on Vehicular Technology, May 2006, pp. 1767-1771.
[12] C. P. Liu, et al., “A Multiple Rate Multicarrier Direct Sequence CDMA System with 2D OVSF Codes in Fading Channels,” IEEE Trans. On Wireless Communications, June. 2007, pp. 2162-2171.
[13] Y. F. Hung, C. P. Tsai and K. H. Liu, “Performance of Multiuser Detection for 2-D Spreading Coded OFCDM Communication Systems over Frequency and Time Selective Fading Channels,” IEEE Proceedings of Asia-Pacific Conference on Communications, Oct. 2007, pp.271-274.
[14] S. Hara, “Overview of Multicarrier CDMA,” IEEE Communications Magazine, Dec. 1997, pp. 126-113.
[15] W. Y. Zou and Y. Wu, “COFDM: An Overview,” IEEE Trans. On Broadcasting, Mar. 1995, pp.1-8.
[16] R. V. Nee and R. Prasad, OFDM Communications, Published by Artech House, 2000.
[17] S. Haykin, Communication Systems, 4th ed., Published by John Wiley & Sons, 2001.
[18] S. Hara and R. Prasad, Multicarrier Techniques for 4G Mobile Communications, Published by Artech House, 2003.
[19] A. V. Oppenheim and R. W. Schafer, Discrete-Time Signal Processing, Published, by Prentice Hall, 1999.
[20] Q. Li and L.A. Rusch, “Multiuser Detection for DS-CDMA UWB in the Home Environment.”, IEEE Journal on Selected Areas in Communications, 2002, pp. 1701-1711.
[21] D. Cassioli, M. Z. Win, F. Vatalaro and A. F. Molisch, “Performance of Low-complexity RAKE Reception in a Realistic UWB Channel,” IEEE International Conference on Communications, 2002, pp. 763-767.
[22] A. Rajeswaran, V. S. Somayazulu, and J. R. Foerster, ” RAKE Performance for a Pulse Based UWB System in a Realistic UWB Indoor Channel” IEEE International Conference on Communications, 2003, pp. 1879-2883.
[23] K. Takizawa and R. Kohno “Low-complexity Rake Reception and Equalization for MBOK DS-UWB Systems,” IEEE International Conference on Telecommunications, 2004, pp. 1249-1253.
[24] G. Short, et al. “A Proposal for a Selection of Indoor UWB Path Loss Model” IEEE P802.15 June 2002.
[25] V. K. Garg and J. E. Wilkes, Wireless and Personal Communications Systems, Prentice Hall Inc., 1996.
[26] T. Minn and K. Y. Siu, “Dynamic Assignment of Orthogonal Variable-Spreading-Factor Codes in W-CDMA,” IEEE Journal on Selected Areas in Communications, Aug. 2000, pp.1429-1440.
[27] C. M. Yang, P. H. Lin, G. C. Yang and W. C. Kwong, “2D Orthogonal Spreading Codes for Multicarrier DS-CDMA Systems,” IEEE Conference on Digital Object Identifier, May 2005, pp. 3277-3281.
[28] W. C. Jakes, Microwave Mobile Communications, Prentice John Wiley & Sons, 1975.
[29] Y. R. Zheng and C. Xiao, “Improved Models for the Generation of Multiple Uncorrelated Rayleigh Fading Waveforms,” IEEE Communications Letters, June 2002, pp. 256-258.
[30] N. Kostov, “Mobile Radio Channels Modeling in MATLAB,” Radio Engineering, Dec. 2003, pp. 12-16.
QRCODE
 
 
 
 
 
                                                                                                                                                                                                                                                                                                                                                                                                               
第一頁 上一頁 下一頁 最後一頁 top
無相關期刊