Journal of the Institute of Electronics Engineers of Korea TC (대한전자공학회논문지TC)

The Institute of Electronics and Information Engineers (대한전자공학회)
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A Study on the Performance Improvement with Subband Overlapping Variation for Overlapped Multicarrier DS-CDMA Systems

중복된 멀티캐리어 DS-CDMA 시스템의 서브밴드 중복율 변화에 따른 성능개선에 관한 연구

  • 오정헌 (국민대학교 전자공학부) ;
  • 박광철 (국민대학교 전자공학부) ;
  • 김기두 (국민대학교 전자공학부)
  • Published : 2000.09.01
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Abstract

Multicarrier DS-CDMA is an effective approach to realize wideband CDMA system in a multipath fading channel. In this paper, we propose a convolutionally-coded overlapped multicarrier DS-CDMA system, and analyze the performance with subband overlapping variation to determine the overlapping percentage showing best performance. Given a total number of subcarriers M*R, we will show that the BER variation is highly dependent on the rolloff factor P of raised-cosine chip wave-shaping filter irrespective of convolutional encoding rate I/M and repetition coding rate 1/R. We also analyze the possibility of reduction in total MUI by considering both variation of a rolloff factor (0 ($\beta$ :1) and variation of subband overlapping factor (0 ( A :2), and show that the proposed system may outperform the multicarrier DS-CDMA system in [1, 12].

멀티캐리어 DS-CDMA는 다중경로 페이딩 채널에서 광대역 시스템의 구현에 효과적인 방법이다. 본 논문에서는 콘볼루션 코딩을 적용한 중복된 멀티캐리어 DS-CDMA 시스템을 제안하고, 중복율 변화에 대한 성능을 분석하여 정해진 서브밴드 캐리어 수에 따라 최적의 성능을 제공하는 중복율을 제시한다. 특히 전체 서브캐리어 수에 따라 최적의 성능을 제공하는 중복율을 제시한다. 특히 전체 서브캐리어 수 M*R 값이 같다면 콘볼루션 코딩율 1/M과 반복 코딩율 1/R 값에 관계없이 칩 성형필터의 rolloff인자 β값이 같으면 중복율 변화에 따른 BET의 변화 형태가 거의 동일함을 보인다. 그리고 서브밴드의 중복인자 (0<β≤2) 변화와 rolloff인자(0<β≤1)의 변화에 따른 MUI를 분석하여 기존의 멀티태리어 시스템과 성능을 비교하고, 제안한 시스템의 중복율 변화에 따른 성능 개서 정도를 보인다.

Keywords

References

  1. D. N. Rowitch, Convolutional and Turbo Coded Multicarrier Direct Sequence CDMA, and Applications of Turbo Codes to Hybrid ARQ Communication Systems, Ph. D. Dissertation, Dept. of Electrical and Computer Engineering, University of California, San Diego, May 1998
  2. S. Hara, 'Overview of Multicarrier CDMA,' IEEE Communication Magazine, Dec. 1997 https://doi.org/10.1109/35.642841
  3. S. Kondo and L. B. Milstein, 'On the Performance of Multicarrier DS CDMA Systems,' IEEE Trans. Commun., Vol. 44, pp. 238-246, Feb. 1996 https://doi.org/10.1109/26.486616
  4. R. E. Ziemer and N. Nadgauda, 'Effect of Correlation between Subcarriers of an MCM/DSSS Communication System,' in Proc VTC'96, Atlanta, GA, April 1996 https://doi.org/10.1109/VETEC.1996.503425
  5. W. Xu and L. B. Milstein, 'Performance of multicarrier DS CDMA systems in the presence of correlated fading,' in Proc. VTC'97, Phoenix, Arizona, May 1997 https://doi.org/10.1109/VETEC.1997.605958
  6. K. D. Kim, J. H. Oh, L. B. Milstein, 'The Performance Improvement of a Multicarrier DS-CDMA System Using both Time-Diversity and Frequency Offset,' ETRI Journal, Vol. 21, No.4, pp. 29-40, Dec. 1999
  7. E. Sourour and M. Nakagawa, 'Performance of Orthogonal Multi-Carrier CDMA in a Multipath Fading Channel,' IEEE Trans. Commun., Vol. 44, pp. 356-367, Mar. 1996 https://doi.org/10.1109/26.486330
  8. N. Yee, J. P. Linnartz, and G. Fettweis, 'Multicarrier CDMA in Indoor Wireless Radio Network,' in Proc. 4th PIMRC'93, Yokohama, Japan, pp. D1.3.1-D1.3.5, 1993
  9. K. Fazel and L. Papke, 'On the Performance of Convolutionally-Coded CDMA/OFDM for Mobile Communication System,' in Proc. 4th PIMRC'93, Yokohama, Japan, pp. D3.2.1-D3.2.5, 1993
  10. A. Chouly, A. Barajal, and S. Jourdan, 'Orthogonal Multicarrier Technique Applied to Direct Sequence Spread Spectrum CDMA Systems,' in Proc. GLOBECOM'93, Houston, TX, pp. 1723-1728, Nov. 1993 https://doi.org/10.1109/GLOCOM.1993.318364
  11. L. Vandendorpe, 'Multitone Spread Spectrum Multiple Access Communications System in a Multipath Rician Fading Channel,' IEEE Trans. Veh Technol., Vol. 44, pp. 327-337, May 1995 https://doi.org/10.1109/25.385926
  12. 오정헌, 황용남, 염정원, 김기두, '다중경로 페이딩 채널에서 채널코딩을 적용한 중복된 멀티캐리어 DS-CDMA 시스템에 관한 연구,' 대한전자공학회 논문지, 제37권, 1호, 2000년 1월
  13. J. Proakis, Digital Communications, 3rd Edition, New York, McGraw-Hill, 1995
  14. S. Stein, 'Fading Channel Issues in System Engineering,' IEEE J. on Selected Areas in Commun., Vol. SAC-5, No.2, Feb. 1987
  15. W. C. Y. Lee, Mobile Communications Engineering, Theory and Applications, 2nd Edition, McGraw-Hill, New York, 1998
  16. A. J. Viterbi, 'Convolutional Codes and Their Performance in Communication Systems,' IEEE Trans. Commun., Vol. 19, pp. 751-772, Oct. 1971 https://doi.org/10.1109/TCOM.1971.1090700