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Performance Analysis of Multi-Carrier DS-CDMA Wireless Systems Using Frequency-Time Spreading Codes in Fading Channels
|關鍵字:||3G;第三代行動通訊;2-D spreading codes;MC/DS-CDMA;二維展頻碼;多載波直接序列展頻分碼多工系統||出版社:||電機工程學系所||引用:|| S. Kondo and L.B. Milstein, “Performance of multicarrier DS CDMA systems,” IEEE Trans. Commun., vol. 44, pp. 238-246, Feb. 1996.  S.-M. Tseng and M.R. Bell, “Asynchronous multicarrier DS-CDMA using mutually orthogonal complementary sets of sequences,” IEEE Trans. Commun., vol. 48, pp. 53-59, Jan. 2000.  N. Yee and J.-P. Linnartz, “Controlled equalization of multi-carrier CDMA in an indoor Rician fading channel,”Proc. of IEEE VTC'94, Jan. 1994, vol. 3, pp. 1665-1669.  A. Clouly, A. Brajal and S. Jourdan, “Orthogonal multicarrier techniques applied to direct sequence spread spectrum CDMA system,” Proc. of IEEE GLOBECOM'93, Nov. 1993, pp. 1723-1728.  E. Sourour and M. Nakagawa, “Performance of orthogonal MC CDMA in a multipath fading channel,” IEEE Trans. Veh. Technol., vol. 44, no. 3, pp. 356-367, Mar. 1996.  S. Hara and R. Prased, “Overview of multicarrier CDMA,” IEEE Commun. Mag., vol. 35, no. 12, pp. 126-133, Dec. 1997.  S. Kondo and L. B. Milstein, “Performance of multicarrier DS-CDMA systems,” IEEE Trans. Commun., vol. 44, no. 2, pp. 238-246, Feb. 1996.  S. M. Tseng and M. R. Bell, “Asynchronous multicarrier DS-CDMA using mutually orthogonal complementary sets of sequences,” IEEE Trans. Commun., vol. 48, no. 1, pp. 53-59, Jan. 2000.  C.-M. Yang, G.-C. Yang, P.-H. Lin and W. C. Kwong, “2-D orthogonal spreading codes for multi-carrier DS- CDMA systems,” Proc. of IEEE ICC'03, May 2003, vol. 5, pp. 3277- 3281.  W.C. Kwong, G.-C. Yang, and C.-Y. Chang, “Wavelength-hopping time-spreading optical CDMA with bipolar codes” J. Lightwave Technol., vol. 22, no. 9, pp. 1640-1647, Nov. 2004.  C.-P. Hsieh, C.-Y. Chang, G.-C. Yang and W.C. Kwong, “A bipolar-bipolar code for asynchronous wavelength-time optical CDMA,” to appear in IEEE Trans. Commun.  A. W. Lam and S. Tantaratana, Theory and Application of Spread Spectrum Systems. Piscataway, NJ: IEEE, 1994.  G.-C. Yang and W. C. Kwong, Prime Codes with Applications to CDMA Optical and Wireless Networks, Boston, MA: Artech House, 2002.  M.-S. Alouini and M.K. Simon, “Performance analysis of coherent equal gain combining over NaKagami-m fading channels,” IEEE Trans. Vehicular Technol., vol. 50, pp. 1449-1463, Nov. 2001.  M. Pureley, “Performance evaluation for phase-coded spread-spectrum multiple-access communication-Part I: System Analysis,” IEEE Trans. Commun., vol. 25, pp. 795-799, Aug. 1977.  M. Pursley and D. Sarwate, “Performance evaluation for phase-coded spread-spectrum multiple-access communication--Part II: Code Sequence Analysis,” IEEE Trans. Commun., vol. 25, pp. 800-803, Aug. 1977.  M.-S. Alouini, S.-W. Kim and A. Goldsmith, ”RAKE reception with maximal-ratio and equal-gain combining for DS-CDMA systems in Nakagami fading,” Universal Personal Communications Record, 1997. Conference Record., 1997 IEEE 6th International Conference on , vol. 2, pp. 708-712, Oct. 1997.  T. Rappaport, “Characterization of UHF multipath radio channels in factory buildings,” Antennas and Propagation, IEEE Transactions on, vol. 37, pp. 1058-1069, Aug. 1989.  J.-G. Proakis, Digital Communication, 4th edition, McGraw-Hill, 2001.  K. Pahlavan and A.-H. Levesque, Wireless Information Networks, Weily-Interscience, 1995.  C.-C. Chai, R.C.H. Ho, and Y.H. Chew, “Diversity Order Optimization of Multiuser Multicarrier Wireless Systems in Nakagami Fading Channel,” IEEE Trans. Vehicular Technol., vol. 2, pp.1297-1301, June. 2005.  R.-L. Peterson, R.-E. Ziemer, and D.-E. Borth, Introduction to Spread-Spectrum Communication, 1995.||摘要:||
近年來的無線通訊領域當中，不斷推出引起消費者熱烈迴響的新系統，從第一代行動通訊的AMPS，第二代行動通訊的GSM，和當今市場上最火紅的第三代行動通訊3G (W-CDMA)，都使得世界上各個角落的通訊和溝通有著不一樣的新思維，然而下一世代目前稱為B3G的眾多技術當中，多載波調變技術則受到各界的矚目。在各種編碼技術當中，二維正交可變長度展頻碼2D OVSF code 已經被應用在多載波直接序列展頻分碼多工的系統上但有人數上的限制。在本篇論文中，我們將改善一個之前提出的非正交的二維展頻碼 2-D frequency-time spreading code在此我們稱為改善的二維展頻碼在同樣的效能下，可以供給相同的使用者人數且利用此展頻碼的正交性質，在犧牲部分系統效能的情形下，讓使用者人數可以大幅的提升。
In this thesis, we focus on the improvement of the coding schemes in multicarrier direct-sequence code-division multiple-access (MC/DS-CDMA) systems. While two-dimensional (2-D) orthogonal variable spreading factor (OVSF) codes with good auto- and cross-correlation properties were proposed for the MC/DS-CDMA systems in order to eliminate multiple-access interference, the number of orthogonal code sequence is restricted by the code length. Therefore, 2-D frequency-time spreading (FTS) code was proposed to increase the number of orthogonal code sequences by sacrificing some performance. To further improve the code cardinality and system performance, we here propose a modified 2-D FTS code. The new coding scheme uses Walsh code for frequency hopping, but a modified Barker code for time spreading. The new code is obtained by special permutations of Walsh code onto the time slots of the modified Barker code. To keep the cross-correlation functions as low as possible, the permutation is algebraic controlled by prime sequences over Galois field of a prime number. Finally, we evaluate the performance of the modified 2-D FTS code in the MC/DS-CDMA system over a non-fading AWGN, Rayleigh fading, and Rician fading channel, and compare with those of the 2-D OVSF and original FTS codes.
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