Abstract
A dual rate synchronous DS/CDMA system provides service to low bit rate and high bit rate users. In a fixed duration interval, a low rate user transmits one bit while a high rate user transmits M bits. The differences in the bit transmission rates result in different processing gains for each class of user. In this paper, we propose a decision feedback decorrelator for the dual rate synchronous DS/CDMA system which uses modified correlators and initiates the bit decision process at the end of the high rate bit interval. Each step of the decision process is executed by utilizing the decisions of all previously decoded users. This dual rate decision feedback receiver (evaluated by simulation) is found to outperform two types of decorrelators for dual rate CDMA systems. It is also observed that as the interferers grow stronger relative to the desired user, the performance of the decision feedback receiver for decoding the desired user approaches the single user bound.
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References
D.G. Brennan, Linear diversity combining techniques, Proceedings of IRE 47 (June 1959) 1075–1102.
J. Chen and U. Mitra, Further results for multi-rate decorrelators for synchronous DS/CDMA systems, in: Proceedings of 34th Annual Allerton Conference on Communication, Control and Computing, Monticello, IL (October 26, 1996).
D.S. Chen and S. Roy, An adaptive multiuser receiver for CDMA systems, IEEE Journal on Selected Areas in Communications 12(5) (June 1994) 808–816.
A. Duel-Hallen, Decision-feedback multiuser detector synchronous for code-division multiple access channel, IEEE Transactions on Communications 41 (February 1993) 285–290.
A. Duel-Hallen, A family of multiuser decision-feedback detectors for asynchronous for code-division multiple access channels, IEEE Transactions on Communications 43(2/3/4) (February/March/April 1995) 421–434.
M.L. Honig and S. Roy, Multi-user communication with multiple symbol rates, in: Proceedings of the IEEE Symposium on Information Theory, Whistler, BC, Canada (September 1995) p. 381.
A. Hottinen, H. Holma and A. Toskala, Multiuser detection for multirate CDMA communications, in: Proceedings of IEEE International Conference on Communications (1996).
C.-L. I and R.D. Gitlin, Multi-code CDMA wireless personal communications networks, in: Proceedings of IEEE International Conference on Communications, Vol. 2, Seattle, WA (June 18- 22, 1995) pp. 1060–1064.
A. Johansson and A. Svensson, Successive interference cancellation schemes in multi-rate DS/CDMA systems, in: Proceedings of 45th IEEE Vehicular Technology Conference, Vol. 2, Chicago, USA (July 25- 28, 1995) pp. 704–708.
W.C.Y. Lee, Mobile Communications Engineering (McGraw-Hill, 1993).
R. Lupas and S. Verdú , Linear multiuser detectors for synchronous code-division multiple-access channels, IEEE Transactions on Information Theory 35(1) (January 1989) 123–136.
R. Lupas and S. Verdú , Near-far resistance of multiuser detectors in asynchronous channels, IEEE Transactions on Communications 38(4) (April 1990) 496–508.
U. Madhow and M.L. Honig, MMSE interference suppression for direct-sequence spread-spectrum CDMA, IEEE Transactions on Communications 42(12) (December 1994) 3178–3188.
T. Ottosson and A. Svensson, Multi-rate schemes in DS/CDMA systems, in: Proceedings of 45th IEEE Vehicular Technology Conference, Vol. 2, Chicago, USA (July 1995) pp. 1006–1010. Accepted for publication in Wireless Personal Communications.
P. Patel and J. Holtzman, Analysis of a simple successive interference cancellation scheme in a DS/CDMA, IEEE Journal on Selected Areas in Communications 12(5) (June 1994) 796–807.
M. Saquib, R. Yates and N. Mandayam, Decorrelating detectors for a dual rate synchronous DS/CDMA system, in: Proceedings of 46th IEEE Vehicular Technology Conference, Vol. 1, Atlanta, USA (April 28- May 1, 1996) pp. 377–381.
M. Saquib, R. Yates and N. Mandayam, Decorrelating detectors for a dual rate synchronous DS/CDMA system, Wireless Personal Communications, accepted.
Z. Siveski, Y. Bar-Ness and D.W. Chen, Error performance of synchronous multiuser code division multiple access detector with multidimensional adaptive canceler, European Transactions on Telecommunications and Related Technologies 5(6) (November- December 1994) 719–724.
M.K. Varanasi and B. Aazhang, Multistage detection in asynchronous code-division multiple-access communications, IEEE Transactions on Communications 38(4) (April 1990) 509–519.
M.K. Varanasi and B. Aazhang, Near-optimum detection in synchronous code-division multiple-access systems, IEEE Transactions on Communications (May 1991) 725–736.
S. Verdú , Optimum multi-user signal detection, Ph.D. thesis, University of Illinois at Urbana-Champaign (1984).
T.-H. Wu and E. Geraniotis, CDMA with multiple chip rates for multi-media communications, in: Proceedings of the 28th Annual Conference on Information Sciences and Systems, Princeton University (March 1994) pp. 992–997.
R. Wyrwas, M.J. Miller, R. Anjaria and W. Zhang, Multiple access options for multi-media wireless systems, in: Proceedings of the 3rd Workshop on Third Generation Wireless Information Networks, WINLAB, Rutgers University (April 1992) pp. 289–294.
Z. Xie, R.T. Short and Rushforth, A family of sub-optimum detectors for coherent multiuser communications, IEEE Journal on Selected Areas in Communications 8(4) (March 1990) 683–690.
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Saquib, M., Yates, R. & Mandayam, N. A decision feedback decorrelator for a dual rate synchronous DS/CDMA system. Wireless Networks 4, 497–506 (1998). https://doi.org/10.1023/A:1019153717568
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DOI: https://doi.org/10.1023/A:1019153717568