跳到主要內容

臺灣博碩士論文加值系統

(44.220.255.141) 您好!臺灣時間:2024/11/15 02:05
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:鄭宏文
研究生(外文):Hung-Wung Cheng
論文名稱:解決寬頻分碼系統中正交可變展頻係數碼的內部碎裂問題
論文名稱(外文):Removing Internal Fragmentations of OVSF Codes in WCDMA Systems
指導教授:趙志民趙志民引用關係
指導教授(外文):Chih-Min Chao
學位類別:碩士
校院名稱:海洋大學
系所名稱:資訊工程學系
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:29
中文關鍵詞:寬頻多重分碼存取正交可變展頻因子內部碎裂
外文關鍵詞:Wideband Code Division Multiple AccessOrthogonal Variable Spreading Factorinternal fragmentation
相關次數:
  • 被引用被引用:0
  • 點閱點閱:144
  • 評分評分:
  • 下載下載:11
  • 收藏至我的研究室書目清單書目收藏:0
寬頻多重分碼存取為第三代行動通訊環境所使用的通訊技術。為了能提供使用者不同速率頻寬的服務,使用正交可變展頻因子碼為通道碼傳輸。而正交可變展頻因子碼在分配的過程中可能會產生碎裂問題,包含內部碎裂與外部碎裂;碎裂問題會造成系統使用效率下降及碼阻塞機率上升,所以本篇文章主要在處理內部碎裂的問題。當分配出去的傳輸率比使用者要求的速率還要高時,便產生了內部碎裂。為降低內部碎裂,一般是以多碼的方式解決,即同一時間分配較多的低速碼來達成使用者的要求。本篇採用單一碼的方式解決內部碎裂問題,將使用者要求的速率分割成數個二的指數次方之子要求,這些分割好的子要求,分別安排在不同的時間服務,並保證使用者都在最高期限內完成傳輸。模擬結果顯示本論文提出的方法與同樣以單一碼解決內部碎裂的最適分配法比較更能降低碼阻斷的機率,使用者等待系統服務時間也比較短。
WCDMA (Wideband Code Division Multiple Access) 3G mobile systems use OVSF (Orthogonal Variable Spreading Factor) code as canalization code. The use of OVSF codes has offered opportunities to provide variable data rates to flexibly support applications with different bandwidth requirements. When the OVSF code is assigned, it is sometimes inevitable that the tree may become fragmented. It is called the fragmentation problems. Fragmentations will increase code blocking probability and decrease system utilization. This thesis handles the internal fragmentation problem. Internal fragmentation occurs when the allocated data rate is larger than what is requested. Using multiple codes can reduce internal fragmentation. However, it requires higher hardware cost since a user needs to handle two or more codes at the same time. This thesis uses single code to save the internal fragmentation problem. Each request is divided into a lot of subrequests with bandwidth of power of two. We also introduce the concept of packet transmission deadlinto characterize real time traffic. The scheme we proposed can solve the internal fragmentation problem for real time traffic. Simulation results verify the effectiveness of our scheme.
摘要 i
Abstract ii
目錄 iii
圖目錄 iv
表目錄 v


第一章 序論 1
第二章 背景知識與相關研究 4
2.1 WCDMA系統架構 4
2.2 相關研究 10
第三章 動態搜尋法 14
3.1 速率切割策略 15
3.2 碼分配策略 17
第四章 系統模擬與分析 22
第五章 結論 26
參考文獻 27
[1] IMT-2000 homepage : http://www.itu.int/home/imt.html
[2] F. Adachi, M. Sawahashi, and H. Suda, “Wideband DS-CDMA for Next-Generation Mobile Communications Systems”, IEEE Comm. Magazine, vol. 36, pp. 56-69, Sept. 1998.
[3] F. Adachi, M. Sawahashi, and K. Okawa, “Tree-Structured Generation of Orthogonal Spreading Codes with Different Lengths for Forward Link of DS-CDMA Mobile Radio”, Electronic Letters, vol. 33, pp. 27-28, Jan. 1997
[4] R. Assarut, K. Kawanishi, U. Yamamoto, Y. Onozato, and M. Masahiko, “Region Division Assignment of Orthogonal Variable- Spreading-Factor Codes in W-CDMA”, Proc. IEEE Vehicular Technology Conf., pp. 1184-1898, 2001
[5] A. Baier et al., “Design Study for a CDMA-Based Third-Generation Mobile Radio System”, IEEE J. Selected Areas in Comm.,vol. 12, pp. 733-743, May 1994.
[6] C.-M. Chao, Y.-C. Tseng, and L.-C. Wang, ”Dynamic Bandwidth Allocation for Multimedia Traffic with Rate Guarantee and Fair Accessin WCDMA Systems”, IEEE Trans. on Mobile Computing, pp. 420–429, 2005
[7] C.-M. Chao, Y.-C. Tseng, and L.-C. Wang, ”Reducing internal and external fragmentations of OVSF codes in WCDMA systems with multiple codes”, IEEE Trans. on Wireless Communications, pp. 1516 – 1526, 2005
[8] W.-T. Chen, Y.-P. Wu, and H.-C. Hsiao, “A Novel Code Assignment Scheme for W-CDMA Systems”, Proc. IEEE Vehicular Technology Conf., pp. 1182-1186, 2001
[9] C.-M. Chao, S.-H. Wang, ” A Joint Code/Time Assignment Strategy with Minimal Fragmentations for CDMA Systems”, IEEE WCNC, pp. 1620- 1625, 2006
[10] E. Dahlman, B. Gudmundson, M. Nilsson, and J. Skold, “UMTS/MT-2000 Based on Wideband CDMA”, IEEE Comm. Magazine, pp. 70-80, Sept. 1998.
[11] V.K. Garg, IS-95 CDMA and cdma2000. Prentice Hall, 2000.
[12] Li, F.Y., Stol, N., “A priority-oriented call admission control paradigm with QoS renegotiation for multimedia services in UMTS”, VTC2001 Spring. IEEE VTS 53rd, pp. 2021-2025, 2000
[13] T. Minn, K.Y. Si, “Dynamic Assignment of Orthogonal Variable Spreading Factor Codes in W-CDMA”, IEEE Journal an Selected Areas in Communications, pp. 1429-1440, Aug. 2000
[14] J.G. Proakis, Digital Communications. McGraw-Hill, 1995
[15] Rao, Y.S., Kripalani, A., “cdma2000 mobile radio access for IMT 2000”, IEEE International Conference on Personal Wireless Communication, pp.17-19, Feb. 1999
[16] R. Steele, C.-C. Lee, and P. Gould, “GSM, cdmaOne and 3G Systems”, John Wiley & Sons, 2001
[17] Y.-C. Tseng and C.-M. Chao, ”Code Placement and Replacement Strategies for Wideband CDMA OVSF Code Tree Management”, IEEE Trans. on Mobile Computing, pp. 293–302, Oct. 2002
QRCODE
 
 
 
 
 
                                                                                                                                                                                                                                                                                                                                                                                                               
第一頁 上一頁 下一頁 最後一頁 top