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IEEE Transactions on Wireless Communications
Volume 1 Number 1, January 2002

Table of Contents for this issue

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Successive Interference Cancellation Algorithms for Downlink W-CDMA Communications

Mohamed F. Madkour, Member, IEEE Someshwar C. Gupta, Fellow, IEEE and Yi-Pin Eric Wang

Page 169.

Abstract:

In this paper, successive intracell interference cancellation (IIC) of the wideband-code division multiple access (W-CDMA) signal at the mobile unit is considered. Three new interference cancellation techniques suitable for the downlink of any CDMA system with orthogonal spreading are proposed. No prior knowledge of users' spreading codes or even their spreading factors are required for interference cancellation. A new term, effective spreading code, has been introduced in this paper which is defined as the interfering user physical code as seen by the desired user within the desired user symbol duration. The mobile receiver estimates the effective spreading codes of the interfering users regardless of their spreading factors using fast Walsh transform (FWT) correlators (instead of the regular correlators) and uses this information to suppress the intracell multiuser interference. Three different interference-suppressing techniques are studied:subtraction; combined interfering signal projection; and separate interfering signal subspace projection. The complexity of the proposed techniques is low compared to conventional interference cancellation techniques. For a W-CDMA system and the IMT-2000 vehicular channel model, a capacity increase of up to 150% of the original (without IIC) system capacity is shown.

References

  1. T. Ojanpera and R. Prasad, Wideband CDMA for Third Generation Mobile Communications, Boston, MA: Artech House, 1998.
  2. "Specifications of Air-Interface for 3G Mobile System Version 1.0", Association of Radio Industries and Business (ARIB), 1999 .
  3. J. Proakis, Digital Communications, 3rd ed.   New York: McGraw-Hill, Inc, 1995.
  4. T. Ottoson and A. Svensson, "Multi-rate schemes in DS/CDMA systems", in Proc. IEEE VTC'95, Chicago, IL, July 26-28 1995, pp.  1006-1010. 
  5. A. Klein, "Data detection algorithms specially designed for the downlink of CDMA mobile radio systems", in Proc. IEEE VTC'97, Phoenix, AZ, May 1997, pp.  203- 207. 
  6. A. Hottinen, H. Holma and A. Toskala, "Multi-user detection for multi-rate CDMA communications", in Proc. IEEE Int. Conf. Commun., Dallas, TX, June 24-28 1996.
  7. M. J. Juntti, "System concept comparisons for multi-rate CDMA with multi-user detection", in Proc. IEEE VTC'98, Ottawa, Canada,May 1998, pp.  36- 40. 
  8. M. F. Madkour and S. C. Gupta, "Performance analysis of a wireless multirate direct-sequence CDMA using fast Walsh transform and decorrelating detection", IEEE Trans. Commun., vol. 48, pp.  1405-1412, Aug.  2000 .
  9. A. Johansson and A. Svensson, "Successive interference cancellation in multiple data rate DS/CDMA systems", in Proc. IEEE VTC'95, Chicago, IL, July 26-28 1995.
  10. P. Teder, G. Larsson, B. Gudmundson and M. Ewerbring, "CDMA with interference cancellation: A technique for high capacity wireless systems", in Proc. IEEE Int. Conf. Commun., Geneva, Switzerland, 1993.
  11. P. Patel and J. Holtzman, "Analysis of a simple successive interference cancellation scheme in DS/CDMA system", IEEE J. Select. Areas Commun., vol. 12, pp.  796-807, June  1994.
  12. X. Wang and H. V. Poor, "Blind multi-user detection: A subspace approach", IEEE Trans. Inform. Theory, vol. 44, pp.  677 -690, Mar.  1998.
  13. M. Golanbari and G. E. Ford, "Signal monitoring on the downlink of cellular CDMA communications with interference cancellation", in Proc. IEEE Wireless Communications and Networking Conf., WCNC'99, New Orleans, LA, Sept. 21-25 1999.
  14. K. Hooli, M. Latva-aho and M. Juntti, "Multiple access interference suppression with linear chip equalizers in WCDMA downlink receivers", in Proc. IEEE Global Telecommunications Conf. 1999, GLOBCOM'99, vol. 1A, pp.  467-471. 
  15. R. Kohno, H. Imai, M. Hatori and S. Pasupathy, "Combination of an adaptive array antenna and a canceller of interference for direct-sequence spread-spectrum multiple access system", IEEE J. Select. Areas Commun., vol. 8, pp.  675-681,  May  1990.
  16. M. F. Madkour, S. C. Gupta and Y.-P. E. Wang, "A novel downlink blind interference cancellation in a W-CDMA mobile communications system", in Proc. IEEE Wireless Communications and Networking Conf., WCNC'99, New Orleans, LA, Sept. 21-25 1999 .
  17. M. F. Madkour, S. C. Gupta and Y.-P. E. Wang, "A novel downlink W-CDMA blind interference cancellation using the subspace approach", in Proc. 33rd Asilomar Conf., Pacific Grove, CA, Oct. 24-27 1999.
  18. G. E. Bottomley, "Improved successive cancellation of DS-CDMA signals using signal orthogonalization", in Proc. IEEE Int. Conf. Universal Personal Communications, ICUPC'96, Cambridge, MA, Sept.-Oct. 29-2 1996, pp.  141-144. 
  19. W. L. Brogan, Modern Control Theory, Englewood Cliffs, NJ: Prentice-Hall, 1982.