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Capacity bounds for the CDMA system and a neural network: a moderate deviations approach

Published online by Cambridge University Press:  21 July 2009

Matthias Löwe
Affiliation:
Fachbereich Mathematik und Informatik, Universität Münster, Einsteinstrasse 62, 48149 Münster, Germany; maloewe@math.uni-muenster.de
Franck Vermet
Affiliation:
Laboratoire de Mathématiques, UMR CNRS 6205, Université de Bretagne Occidentale, 6 avenue Victor Le Gorgeu CS 93837, 29238 Brest Cedex 3, France; Franck.Vermet@univ-brest.fr
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Abstract

We study two systems that are based on sums of weakly dependent Bernoulli random variables that take values ± 1 with equal probabilities. We show that already one step of the so-called soft decision parallel interference cancellation, used in the third generation of mobile telecommunication CDMA, is able to considerably increase the number of users such a system can host. We also consider a variant of the well-known Hopfield model of neural networks. We show that this variant proposed by Amari and Yanai [CITE] has a larger storage capacity than the original model. Both situations lead to the question of the moderate deviations behavior of a sum of weakly dependent Bernoulli random variables. We prove a moderate deviations principle for such a sum on the appropriate scale.

Type
Research Article
Copyright
© EDP Sciences, SMAI, 2009

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