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Multiuser detection is an important technology in wireless CDMA systems for improving both data rate as well as the user capacity. However, the computational complexity of this receiver prevents from the widespread use of this technique. Due to the high computational complexity, most of the CDMA systems today and in the near future will continue to use the conventional match filter with comparatively low user capacity and a slow data rate. However, if we could lower the computational complexity of multiuser detectors, most of the CDMA systems would likely to get advantage of this technique in terms of increased system capacity and a better data rate. The focus of our research is to reduce the computational complexity of multiuser receivers to improve the performance of multiuser detectors. Our research distinguishes itself in a number of ways. First, a new transformation matrix algorithm is used rather than the conventional linear transformation. Second, a mathematical model is proposed to produce consistent values of SNR for a wide range of users. Third, the performance measure adopted in this paper research is the achievable bit rate for a fixed probability of error (10-7).

Publications

  1. Syed S. Rizvi, Khaled M. Elleithy, Aasia Riasat, and Min Song.  A Low-Complexity Optimum Multiuser Receiver for DS-CDMA Wireless Systems. Journal of Communications, Vol. 5, No. 6, pp. 455 – 466, June 2010.[PDF]
  2. Syed S. Rizvi, Khaled M. Elleithy, and Aasia Riasat. Deterministic Formulization of SNR for Wireless Multiuser DS-CDMA Networks. International Journal of Computer Science and Information Security (IJCSIS). Vol. 3, No. 1, pp. 25-34, 2009.[PDF]
  3. Syed S. Rizvi, Aasia Riasat, and Khaled M. Elleithy. A Low-Complexity Algorithm for Improving Computing Power of Multiuser Receivers for Next Generation Wireless Systems. International Journal of Computer Science and Network Security (IJCSNS). Vol. 9  No. 6  pp. 1-10, 2009. [PDF]
  4. Syed S. Rizvi, Khaled Elleithy, and Aasia Riasat, “Analyzing SNR Performance of a Low-Complexity Wireless Multiuser Receiver for DS-CDMA Systems,” IEEE International Conference on Computer, Control & Communication (IEEE-IC4 2009), pp. 1 – 4, February 17-18, 2009, Karachi, Pakistan, 2009. [PDF]
  5. Syed S. Rizvi, Khaled Elleithy, and Aasia Riasat, “A Low Complexity Optimum Multi-user Receiver for Maximizing the BER Performance for DS-CDMA Systems,”IEEE International Conference on Computer, Control & Communication (IEEE-IC4 2009), pp. 1 – 6, February 17-18, 2009, Karachi, Pakistan, 2009. [PDF]
  6. Syed S. Rizvi, Khaled. M. Elleithy, and Aasia Riasat, Transformation Matrix Algorithm for Reducing the Computational Complexity of Multiuser Receivers for DS-CDMA Wireless Systems,” 8th IEEE Wireless Telecommunication Symposium (IEEE WTS 2007), Pomona, California, April 26-28 2007. [PDF]
  7. Gowrilakshmi Ponuratinam, Bhumika Patel, Syed S. Rizvi, and Khaled M. Elleithy, “Improvement in the Spread Spectrum System in DSSS, FHSS, AND CDMA, ”2009 ASEE Northeast Section Conference, University of Bridgeport, Connecticut(2009 NE ASEE), April 3-4, 2009. [PDF]
  8. Syed S. Rizvi, Aasia Riasat, and Khaled M. Elleithy, “A Closed Form Expression for BER of Synchronous DS-CDMA Multi-user Detector,” 9th IEEE Wireless Telecommunication Symposium (IEEE WTS 2008), Pomona, California, pp. 110-114,  April 24-26 2008. [PDF]
  9. Syed S. Rizvi, Khaled M. Elleithy, and Aasia Riasat, “Deterministic Formalization of the Processing Gain for Reducing MAI in Wireless Multiuser DS-CDMA Systems,” 5th Annual IEEE Consumer Communications and Networking Conference (IEEE CCNC’2008), pp. 859 – 860, January 10 – 12, 2008 in Las Vegas, Nevada. [PDF]
  10. Syed S. Rizvi and Aasia Riasat, “Bit Error Rate (BER) Analysis of Synchronous DS-CDMA Multiuser Receivers,” The 9th INFORMS Telecommunications Conference: Telecommunications Modeling, Policy, and Technology, March 27-29, 2008. Robert H. Smith School of Business, University of Maryland, College Park, MD [PDF]
  11. Syed S. Rizvi, Khaled M. Elleithy, and Aasia Riasat, “Transformation Matrix System for Reducing the Computational Complexity of Wireless Multi-user Receivers for DS-CDMA Systems,” 5th International Conference on Information Technology: New Generations ITNG 2008, April 7-9, 2008, Las Vegas, Nevada, USA. [PDF]
  12. Syed S. Rizvi, Khaled M. Elleithy, and Aasia Riasat, “The Impact of Reduced Computational Complexity of Multiuser Detectors on the Processing Gain in a Wireless DS-CDMA Multiuser System,” Proceedings of the 2007 International Conference on Wireless Networks (ICWN’07). Part of the 2007 World Congress in Computer Science, Computer Engineering, & Applied Computing (Worldcomp’07), pp. 70 – 76, Las Vegas, Nevada, USA, June 25-28, 2007.