跳到主要內容

臺灣博碩士論文加值系統

(3.236.110.106) 您好!臺灣時間:2021/07/25 23:53
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:高柏庭
研究生(外文):Po-Ting Kao
論文名稱:直序展頻CDMA超寬頻無線通訊系統之適應性部分平行干擾消除技術
論文名稱(外文):Adaptive Partial Parallel Interference Cancellation Techniques for DS-CDMA Ultra-Wideband Wireless Communications
指導教授:王晉良
指導教授(外文):Chin-Liang Wang
學位類別:碩士
校院名稱:國立清華大學
系所名稱:通訊工程研究所
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:2004
畢業學年度:92
語文別:中文
論文頁數:56
中文關鍵詞:超寬頻無線通訊系統
外文關鍵詞:PPICLMSmultiuser detectionUWB
相關次數:
  • 被引用被引用:0
  • 點閱點閱:166
  • 評分評分:
  • 下載下載:14
  • 收藏至我的研究室書目清單書目收藏:0
超寬頻(UWB)無線通訊技術的特點為具有極寬的頻帶以及極低的傳輸功率,故可用來提升傳輸速率並且降低和其他無線通訊系統的干擾,而直序展頻分碼多工(DS-CDMA)技術則可以提供這個高傳輸速率的需求,除了以脈衝(pulse)形式傳輸資料以外,DS-CDMA UWB系統的基本概念與傳統的DS-CDMA是相似的,而DS-CDMA技術的一個主要問題在於系統的容量(capacity)受限於多用戶存取干擾(MAI)的多寡,這個情形同樣也出現在DS-CDMA UWB系統之中,因此我們必須使用多用戶偵測技術來解決這個問題。
和其他無線通訊系統不同的是,UWB系統所面臨的通道是一個短距離的室內環境同時具有嚴重的多重路徑干擾。在本論文中,我們將介紹幾種傳統的多用戶偵測技術,例如平行干擾消除(PIC)、部份平行干擾消除(PPIC)、以及簡化的部份平行干擾消除(SPPIC),然後針對UWB系統的通道模型修改這些多用戶偵測技術。
為了進一步改善PPIC的效能,我們將討論一些調整PPIC權值(partial weight)的方法,其中一種較普遍的方法為適應性多級平行干擾消除(adaptive multistage PIC)。但是對於像DS-CDMA UWB這樣高速傳輸的系統來說,過高的資料傳輸速率使得這種方法難以實現。為了解決這個問題,我們提出了一種新的適應性部份平行干擾消除技術,稱之為位元層級適應性加權部份平行干擾消除(bit-level adaptive weighted PPIC),目的在於將原本操作在片碼速率(chip-rate)的運算速度降低到位元速率(bit-rate)。
最後,我們將以電腦軟體模擬比較本論文提出的演算法以及幾種傳統多用戶偵測技術的不同。由模擬的結果我們可以看出,我們所提出的演算法確實可以用較少的運算複雜度來提升DS-CDMA UWB系統的效能。
i
The significant features of ultra-wideband (UWB) technology are broader spectrum
and lower power transmission, which can be applied to improve data rate and reduces
interference in wireless communications. In order to meet the demand for high data
rates, the direct-sequence code-division multiple access (DS-CDMA) technology is
applied to UWB systems. The basic operations of a DS-CDMA UWB system are
similar to the conventional DS-CDMA system except that the pulses are transmitted
rather than carriers. One major problem associated with DS-CDMA is that its capacity
is seriously limited by multiple access interference (MAI), and this is the same issue
for DS-CDMA UWB systems. To overcome this problem, we have to employ some
multiuser detection techniques to deal with the MAI problems for DS-CDMA UWB
systems.
Unlike other wireless communication systems, a UWB system faces a short
range indoor environment and serious multipath channels. In this thesis, we first
introduce several conventional multiuser detection techniques, such as parallel
interference cancellation (PIC), partial parallel interference cancellation (PPIC), and
simplified partial parallel interference cancellation (SPPIC). Then we modify the
conventional multiuser detection techniques by re-defining the channel model for
UWB systems.
To further improve the performance of PPIC, some approaches that adjust the
partial weights of PPIC are discussed. One common approach of weight selection is
adaptive multistage PIC, but this approach has to be operating at the chip rate and is
difficult to implement for an ultra-high rate situation such as DS-CDMA UWB
systems. To solve this problem, we propose a new adaptive weighted PPIC by
simplifying the adaptive frequency from the chip rate to the bit rate, called bit-level
adaptive weighted PPIC. Similar to the original multiuser detection technique, we
derive this new adaptive weighted PPIC for UWB channels.
Finally, we show some computer simulation results of proposed algorithm and
different multiuser detection techniques. The results indicate that this proposed
algorithm can actually improve the system performance of DS-CDMA UWB with
lower computational complexity.
Abstract i
Contents iii
List of Figures vi
List of Tables viii

Chapter 1 Introduction 1
1.1 The FCC Rules of UWB…...…...…………………………………………….... 2
1.2 UWB System Realization….…………………................................................... 2
1.3 Direct-Sequence CDMA System......................................................................... 4
1.4 The Advantages of DS-CDMA System............................................................... 5
1.5 Thesis Outline…………………………............................................................... 5

Chapter 2 System Model of DS-CDMA UWB 7
2.1 Modulation of DS-CDMA UWB System…………………................................ 7
2.1.1 The Pulse Shaping of UWB……................................................................ 7
2.1.2 System Model in AWGN…………………….......................................... 9
2.2 UWB Channel Model ………………………………........................................ 10
2.3 The Conventional Multiuser Detection in AWGN Channel………….....…..... 12
2.3.1 The Conventional Total PIC…………………………....………............. 13
2.3.2 The Conventional PPIC…………………………………..…................... 14
2.3.3 The Simplified PPIC…………..…………………….……...................... 14
2.4 The Modified Multiuser Detection in UWB Channel........................................ 15
2.4.1 Channel Model for Multiuser Detection................................................... 15
2.4.2 The Modified Total PIC……………….................................................... 17
2.4.3 The Modified PPIC…………………………........................................... 18
2.4.4 The Modified SPPIC………………......................................................... 18

Chapter 3 Adaptive Multiuser Detection for DS-CDMA UWB System 24
3.1 Imperfect RAKE Receiver…………………………………….………….….... 24
3.1.1 All-RAKE Receiver………..……............................................................ 24
3.1.2 Selective-RAKE Receiver………..……................................................... 25
3.1.3 Partial-RAKE Receiver………..……....................................................... 25
3.2 Adaptive Weighted Partial PIC…………………………………….……..….... 26
3.2.1 Adaptive Multistage PIC…….………..……............................................ 26
3.3 DS-CDMA UWB with Imperfect RAKE Receiver……………...……………. 28
3.4 A New Bit-Level Adaptive Weighted Partial PIC for UWB Channel............... 29
3.4.1 The AWGN Scheme…………..……....................................................... 30
3.4.2 The Multipath Scheme…….…..……....................................................... 31
3.5 Summary……………………………………………………………................ 33

Chapter 4 Simulation Result 37
4.1 Performance Comparison of Different Multiuser Detection............................. 38
4.2 Performance Comparison of Different RAKE Receivers……......................... 39
4.3 Performance Comparison of Different RAKE Finger Numbers....................... 40
4.4 Performance Comparison of Different Cancellation Stages.............................. 41
4.5 Summary……………...……………………………………………………..... 41

Chapter 5 Conclusions 52

Bibliography 54
[1] D. Porcino and W. Hirt, “Ultra-wideband radio technology: potential and challenges ahead,” IEEE Commun. Mag., vol. 41, pp. 66 - 74, July 2003.
[2] G. R. Aiello and G. D. Rogerson, “Ultra-wideband wireless systems,” IEEE Microwave Mag., vol. 4, pp. 36 - 47, June 2003.
[3] Federal Communication Commission, “In the matter of revision of the commission’s rule regarding ultra-wideband transmission systems, first report and order,” adopted: Feb. 14, 2002; released: Apr. 22, 2002.
[4] P. Runkle, J. McCorkle, T. Miller, and M. Welborn, “DS-CDMA: the modulation technology of choice for UWB communications,” IEEE Conf. Ultra Wideband Systems and Technologies, Nov. 2003, pp. 364 - 368.
[5] M. Z. Win and R. A. Scholtz, “Impulse radio: how it works,” IEEE Commun. Lett., vol. 2, pp. 36 - 38, Feb. 1998.
[6] M. Z. Win and R. A. Scholtz, “Ultra-wide bandwidth time-hopping spread-spectrum impulse radio for wireless multiple-access communications,” IEEE Trans. Commun., vol. 48, pp. 679 - 689, Apr. 2000.
[7] D. C. Laney, G. M. Maggio, F. Lehmann, and L. Larson, “Multiple access for UWB impulse radio with pseudochaotic time hopping,” IEEE J. Select. Areas Commun., vol. 20, pp. 1692 - 1700, Dec. 2002.
[8] R. van Nee and R. Prasad, OFDM for Wireless Multimedia Communications. Boston/London: Artech House, 1999.
[9] “Multi-band OFDM physical layer proposal for IEEE 802.15 task group 3a,” IEEE document # P802.15-03/268r3, http://www.multibandofdm.org/papers/ 15-03-0268-03-003a-Multi-band-CFP-Document.pdf.
[10] T. Pjanpera and R. Prasad, Wideband CDMA for Third Generation Mobile Communications. Boston/London: Artech House, 1998.
[11] “XtremeSpectrum CFP Document,” IEEE document # P802.15-03/334r3, ftp://ftp.802wirelessworld.com/15/03/15-03-0334-03-003a-xtremespectrum-cfp-presentation.pdf
[12] Y. P. Nakache and A. F. Molisch, “Spectral shape of UWB signals influence of modulation format, multiple access scheme and pulse shape,” in Proc. IEEE Veh. Technol. Conf. (VTC ’03), vol. 4, Apr. 2003, pp. 2510 - 2514.
[13] M. K. Varanasi and B. Aazhang, “Multistage detection in asynchronous code-division multiple-access communications,” IEEE Trans. Commun., vol. 38, pp. 509-519, Apr. 1990.
[14] D. Divsalar, M. K. Simon, and D. Raphaeli, “Improved parallel interference cancellation for CDMA,” IEEE Trans. Commun., vol. 46, pp. 259-268, Feb. 1998.
[15] N. S. Correal, R. M. Buehrer, and B. D. Woerner, “A DSP-based DS-CDMA multiuser receiver employing partial parallel interference cancellation,” IEEE J. Select. Areas Commun., vol. 17, pp. 613-630, April 1999.
[16] M. Welborn and J. McCorkle, “The importance of fractional bandwidth in ultra-wideband pulse design,” in Proc. IEEE Int. Conf. Commun. (ICC ’02), vol. 2, Apr. 2002, pp. 753 - 757.
[17] J. Foerster and Qinghua Li, “UWB channel modeling contribution from Intel,” IEEE document #02279r0p802_15_SG3a, http://grouper.ieee.org/groups/802/15/ pub/2002/Jul02/02279r0P802-15_SG3a-Channel-Model-Cont-Intel.doc.
[18] A. Saleh and R. Valenzuela, “A Statistical Model for Indoor Multipath Propagation,” IEEE J. Select. Areas Commun., vol 5, pp. 128 - 137, Feb. 1987.
[19] G. L. Stüber, Principles of Mobile Communications. Norwell, MA: Kluwer, 1996.
[20] Huaning Niu, J. A. Ritcey, and Hui Liu, “Performance of UWB RAKE receivers with imperfect tap weights,” in Proc. IEEE Int. Conf. Acoustics, Speech, and Signal Processing, (ICASSP '03), vol. 4 , Apr. 2003, pp. IV - 125-128.
[21] Guoqiang Xue, Jianfeng Weng, L. N. Tho, and S. Tahar, “Adaptive multistage parallel interference cancellation for CDMA,” IEEE J. Select. Areas Commun., vol. 17, pp. 1815 - 1827, Oct. 1999.
[22] P. M. Clarkson, Optimal and Adaptive Signal Processing. Boca Raton, FL: CRC, 1993.
[23] S. Haykin, Adaptive Filter Theory. 4th ed., Upper Saddle River, NJ: Prentice-Hall, 2002.
[24] D. Cassioli, M. Z. Win, F. Vatalaro, and A. F. Molisch, “Performance of low-complexity RAKE reception in a realistic UWB channel,” in Proc. IEEE Int. Conf. Commun. (ICC ’02), vol. 2, Apr. 2002, pp. 763 - 767.
[25] K.-M. Wu, Interference Suppression Techniques for DS-CDMA Wireless Communications. Ph.D. Dissertation, Department of Electrical Engineering, National Tsing Hua University, Hsinchu, Taiwan, July 2002.
QRCODE
 
 
 
 
 
                                                                                                                                                                                                                                                                                                                                                                                                               
第一頁 上一頁 下一頁 最後一頁 top