Journal of Communications and Networks

  • 제7권3호
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  • Pages.243-247
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  • 2005
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  • 1229-2370(pISSN)
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  • 1976-5541(eISSN)
한국통신학회 (The Korean Institute of Commucations and Information Sciences)
권호 표지

A BLMS Adaptive Receiver for Direct-Sequence Code Division Multiple Access Systems

  • 발행 : 2005.09.01
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⟨ 이전 논문 다음 논문 ⟩

초록

We propose an efficient block least-mean-square (BLMS) adaptive algorithm, in conjunction with error control coding, for direct-sequence code division multiple access (DS-CDMA) systems. The proposed adaptive receiver incorporates decision feedback detection and channel encoding in order to improve the performance of the standard LMS algorithm in convolutionally coded systems. The BLMS algorithm involves two modes of operation: (i) The training mode where an uncoded training sequence is used for initial filter tap-weights adaptation, and (ii) the decision-directed where the filter weights are adapted, using the BLMS algorithm, after decoding/encoding operation. It is shown that the proposed adaptive receiver structure is able to compensate for the signal-to­noise ratio (SNR) loss incurred due to the switching from uncoded training mode to coded decision-directed mode. Our results show that by using the proposed adaptive receiver (with decision feed­back block adaptation) one can achieve a much better performance than both the coded LMS with no decision feedback employed. The convergence behavior of the proposed BLMS receiver is simulated and compared to the standard LMS with and without channel coding. We also examine the steady-state bit-error rate (BER) performance of the proposed adaptive BLMS and standard LMS, both with convolutional coding, where we show that the former is more superior than the latter especially at large SNRs ($SNR\;\geq\;9\;dB$).

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참고문헌

  1. S. Moshavi, 'Multi-user detection for DS-CDMA communications,' IEEE Commun. Mag., vol. 34, no. 10, pp. 124-137, Oct. 1996
  2. S. Buzzi, M. Lops, and A. Tulino, 'Partially blind adaptive MMSE interference rejection in asynchronous DS-CDMA networks over frequency-selective fading channels,' IEEE Trans. Commun., vol. 49, no. 1, pp. 94-108, Jan. 2001 https://doi.org/10.1109/26.898254
  3. M. Latva-aho and M. Juntti, 'MMSE detection of DS-CDMA systems in fading channels,' IEEE Trans. Commun., vol. 48, no. 2, pp. 194-199, Feb. 2000 https://doi.org/10.1109/26.823551
  4. W. Hamouda and P. McLane, 'A fast adaptive algorithm for MMSE receivers in DS-CDMA systems,' IEEE Signal Processing Lett., Feb. 2004
  5. S. Miller, 'An adaptive direct-sequence code-division multiple-access receiver for multi-user interference rejection,' IEEE Trans. Commun., vol. 43, no. 4, pp. 1746-1755, Apr. 1995 https://doi.org/10.1109/26.380225
  6. S. Miller, M. Honig, and L. Milstein, 'Performance analysis of MMSE receivers for DS-CDMA in frequency-selective fading channels,' IEEE Trans. Commun., vol. 48, no. 11, pp. 1919-1929, Nov. 2000 https://doi.org/10.1109/26.886493
  7. A. Barbosa and S. Miller, 'Adaptive detection of DS/CDMA signals in fading channels,' IEEE Trans. Commun., vol. 46, no. 1, pp. 115-124, Jan. 1998 https://doi.org/10.1109/26.655409
  8. G. Rajappan and M. Honig, 'Signature sequence adaptation for DS-CDMA with multipath,' IEEE J. Select. Areas Commun., vol. 20, no. 2, pp. 384-395, Feb. 2002 https://doi.org/10.1109/49.983359
  9. U. Madhow and M. Honing, 'MMSE interference suppression for direct-sequence spread-spectrum CDMA,' IEEE Trans. Commun., vol. 42, pp. 3178-3188, Dec. 1994 https://doi.org/10.1109/26.339839
  10. P. Rapajic and B. Vucetic, 'Adaptive receiver structures for asynchronous CDMA systems,' IEEE J. Select. Areas Commun., vol. 12, no. 4, pp. 685-697, May 1994 https://doi.org/10.1109/49.286675
  11. M. Honig, U. Madhow, and S. Verdu, 'Blind adaptive multiuser detection,' IEEE Trans. Inform. Theory, vol. 41, no. 4, pp. 944-960, July 1995 https://doi.org/10.1109/18.391241
  12. D. Das and M. Varanasi, 'Blind adaptive multiuser detection for cellular systems using stochastic approximation with averaging,' IEEE J. Select. Areas Commun., vol. 20, no. 2, pp. 310-319, Feb. 2002 https://doi.org/10.1109/49.983346
  13. S. Park and J. Doherty, 'Generalized projection algorithm for blind interference suppression in DS-CDMA communications,' IEEE Trans. Circuits Syst. II, vol. 44, pp. 453-460, June 1997 https://doi.org/10.1109/82.592574
  14. Z. Xu and M. Tsatsanis, 'Blind adaptive algorithms for minimum variance CDMA receivers,' IEEE Trans. Commun., vol. 49, no. 1, pp. 180-194, Jan. 2001 https://doi.org/10.1109/26.898261
  15. U. Madhow, 'Blind adaptive interference suppression for the near-far resistant acquisition and demodulation of direct-sequence CDMA signals,' IEEE Trans. Signal Processing, vol. 45, no. 1, pp. 124-136, Jan. 1997 https://doi.org/10.1109/78.552211
  16. Y. Li and K. Liu, 'On blind MIMO channel identification using second-order statistics,' in Proc. Inform. Science and Syst., Mar. 1996, pp. 1166-1171
  17. N. Mangalvedhe and J. Reed, 'Blind CDMA interference-rejection in multipath channels,' in Proc. IEEE VTC'97, Phoenix AZ, May 1997
  18. R. Gaudenzi, F. Giannetti, and M. Luise, 'Blind adaptive interference-rejection linear detectors for CDMA receivers,' in Proc. ISSSTA'96, Mainz, Germany, Sept. 1996
  19. S. Verdu, Multiuser Detection, Cambridge University Press, U.K., 1998
  20. H. V. Poor and X. Wang, 'Code-aided interference suppression for DS/CDMA communications-part I: Interference suppression capability,' IEEE Trans. Commun., vol. 45, pp. 1101-1111, Sept. 1997 https://doi.org/10.1109/26.623075
  21. M. J. Juntti, B. Aazhang, and J. O. Lilleberg, 'Iterative implementation of linear multiuser detection for dynamic asynchronous CDMA systems,' IEEE Trans. Commun., vol. 46, pp. 503-508, Apr. 1998 https://doi.org/10.1109/26.664306
  22. S. Haykin, Adaptive Filter Theory, 3rd ed., Englewood Cliffs, NJ: Prentice-Hall Inc. PTR, 1996
  23. B. Farhang-Boroujeny, Adaptive Filters Theory and Applications, U.K.: John Wiley & Sons, Inc., 1998