Constrained adaptive algorithm for multiple access interference suppression in DS/CDMA communication systems

Sang C. Park, John F. Doherty

Research output: Contribution to conferencePaper

Abstract

This paper presents a new adaptive algorithm for interference suppression in DS/CDMA communication systems. A constrained SGD algorithm is proposed to adaptively adjust the filter parameter by minimizing a properly chosen cost function while satisfying a set of constraints. The algorithm incorporates some a priori knowledge of the desired signal for filter adaptation instead of a training sequence. The algorithm improves the steady state performance by jointly estimating the reference parameter as well as the filter parameters. An iterative maximum likelihood absolute mean estimation algorithm is devised to estimate the reference parameter. The sequential EM algorithm is used to monotonically decrease the cost function. For each input, the algorithm updates the parameters by iterating between estimating the cost function (E step), and minimizing the cost function with respect to each unknown parameter (M step). In the M step of the filter update algorithm, a set of constraints is applied to guarantee convergence. Thus, the algorithm asymptotically converges to the constrained optimum solution. The proposed algorithm is tested by computer simulations and is shown to significantly improve the steady state performance compared to the existing adaptive algorithm.

Original languageEnglish (US)
Pages592-596
Number of pages5
StatePublished - Dec 1 1996
EventProceedings of the 1996 15th Annual Military Communications Conference, MILCOM 96. Part 3 (of 3) - Washington, DC, USA
Duration: Oct 21 1996Oct 24 1996

Other

OtherProceedings of the 1996 15th Annual Military Communications Conference, MILCOM 96. Part 3 (of 3)
CityWashington, DC, USA
Period10/21/9610/24/96

Fingerprint

Interference suppression
Multiple access interference
Adaptive algorithms
Code division multiple access
Communication systems
Cost functions
Maximum likelihood

All Science Journal Classification (ASJC) codes

  • Electrical and Electronic Engineering

Cite this

Park, S. C., & Doherty, J. F. (1996). Constrained adaptive algorithm for multiple access interference suppression in DS/CDMA communication systems. 592-596. Paper presented at Proceedings of the 1996 15th Annual Military Communications Conference, MILCOM 96. Part 3 (of 3), Washington, DC, USA, .
Park, Sang C. ; Doherty, John F. / Constrained adaptive algorithm for multiple access interference suppression in DS/CDMA communication systems. Paper presented at Proceedings of the 1996 15th Annual Military Communications Conference, MILCOM 96. Part 3 (of 3), Washington, DC, USA, .5 p.
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abstract = "This paper presents a new adaptive algorithm for interference suppression in DS/CDMA communication systems. A constrained SGD algorithm is proposed to adaptively adjust the filter parameter by minimizing a properly chosen cost function while satisfying a set of constraints. The algorithm incorporates some a priori knowledge of the desired signal for filter adaptation instead of a training sequence. The algorithm improves the steady state performance by jointly estimating the reference parameter as well as the filter parameters. An iterative maximum likelihood absolute mean estimation algorithm is devised to estimate the reference parameter. The sequential EM algorithm is used to monotonically decrease the cost function. For each input, the algorithm updates the parameters by iterating between estimating the cost function (E step), and minimizing the cost function with respect to each unknown parameter (M step). In the M step of the filter update algorithm, a set of constraints is applied to guarantee convergence. Thus, the algorithm asymptotically converges to the constrained optimum solution. The proposed algorithm is tested by computer simulations and is shown to significantly improve the steady state performance compared to the existing adaptive algorithm.",
author = "Park, {Sang C.} and Doherty, {John F.}",
year = "1996",
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Park, SC & Doherty, JF 1996, 'Constrained adaptive algorithm for multiple access interference suppression in DS/CDMA communication systems', Paper presented at Proceedings of the 1996 15th Annual Military Communications Conference, MILCOM 96. Part 3 (of 3), Washington, DC, USA, 10/21/96 - 10/24/96 pp. 592-596.

Constrained adaptive algorithm for multiple access interference suppression in DS/CDMA communication systems. / Park, Sang C.; Doherty, John F.

1996. 592-596 Paper presented at Proceedings of the 1996 15th Annual Military Communications Conference, MILCOM 96. Part 3 (of 3), Washington, DC, USA, .

Research output: Contribution to conferencePaper

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N2 - This paper presents a new adaptive algorithm for interference suppression in DS/CDMA communication systems. A constrained SGD algorithm is proposed to adaptively adjust the filter parameter by minimizing a properly chosen cost function while satisfying a set of constraints. The algorithm incorporates some a priori knowledge of the desired signal for filter adaptation instead of a training sequence. The algorithm improves the steady state performance by jointly estimating the reference parameter as well as the filter parameters. An iterative maximum likelihood absolute mean estimation algorithm is devised to estimate the reference parameter. The sequential EM algorithm is used to monotonically decrease the cost function. For each input, the algorithm updates the parameters by iterating between estimating the cost function (E step), and minimizing the cost function with respect to each unknown parameter (M step). In the M step of the filter update algorithm, a set of constraints is applied to guarantee convergence. Thus, the algorithm asymptotically converges to the constrained optimum solution. The proposed algorithm is tested by computer simulations and is shown to significantly improve the steady state performance compared to the existing adaptive algorithm.

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Park SC, Doherty JF. Constrained adaptive algorithm for multiple access interference suppression in DS/CDMA communication systems. 1996. Paper presented at Proceedings of the 1996 15th Annual Military Communications Conference, MILCOM 96. Part 3 (of 3), Washington, DC, USA, .