On the Distribution of the Sum of Independent Random Variables and Its Application

An approximate analytical method for the evaluation of the cumulative distribution function (CDF) of the sum of L independent random variables (RVs) is presented. The proposed method is based on the convergent infinite series approach، which makes it possible to describe the CDF in the form of an in...

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Main Authors: Hossein Samimi, Paeiz Azmi
Format: Article
Language:English
Published: Iran Telecom Research Center 2009-03-01
Series:International Journal of Information and Communication Technology Research
Subjects:
Online Access:http://ijict.itrc.ac.ir/article-1-295-en.html
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author Hossein Samimi
Paeiz Azmi
author_facet Hossein Samimi
Paeiz Azmi
author_sort Hossein Samimi
collection DOAJ
description An approximate analytical method for the evaluation of the cumulative distribution function (CDF) of the sum of L independent random variables (RVs) is presented. The proposed method is based on the convergent infinite series approach، which makes it possible to describe the CDF in the form of an infinite series. The computation of the coefficients of this series needs complicated integrations over the RV’s probability density function (PDF). In some cases، the required integrations have closed-form in terms of confluent hypergeometric function and in other cases، the required integrations can not be analytically solved and have not a closed-form solution. In this paper، an approximation method for computation of the coefficients of the CDF series is presented that only needs the mean and the variance of the RV، so it has low computational complexity; it eliminates the need for calculation of complex functions and can be used as a unified tool for determining CDF of a sum of statistically independent RVs. To present an application for the developed approximation method، it is used to find the distribution of the sum of generalized Gamma (GG) RVs. The derived approximate expressions are used in the performance analysis of equal-gain combining (EGC) receivers operating over GG fading channels. The accuracy of the developed approximation method is verified by performing comparisons between exact existing results in the literature and computer simulations results.
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spelling doaj.art-e4b6e93b5c1849528ec081346575c1102023-02-08T07:28:48ZengIran Telecom Research CenterInternational Journal of Information and Communication Technology Research2251-61072783-44252009-03-0111312On the Distribution of the Sum of Independent Random Variables and Its ApplicationHossein Samimi0Paeiz Azmi1 Iran Telecommunications Research Center(ITRC) Tehran, Iran Tarbiat Modares University Tehran, Iran An approximate analytical method for the evaluation of the cumulative distribution function (CDF) of the sum of L independent random variables (RVs) is presented. The proposed method is based on the convergent infinite series approach، which makes it possible to describe the CDF in the form of an infinite series. The computation of the coefficients of this series needs complicated integrations over the RV’s probability density function (PDF). In some cases، the required integrations have closed-form in terms of confluent hypergeometric function and in other cases، the required integrations can not be analytically solved and have not a closed-form solution. In this paper، an approximation method for computation of the coefficients of the CDF series is presented that only needs the mean and the variance of the RV، so it has low computational complexity; it eliminates the need for calculation of complex functions and can be used as a unified tool for determining CDF of a sum of statistically independent RVs. To present an application for the developed approximation method، it is used to find the distribution of the sum of generalized Gamma (GG) RVs. The derived approximate expressions are used in the performance analysis of equal-gain combining (EGC) receivers operating over GG fading channels. The accuracy of the developed approximation method is verified by performing comparisons between exact existing results in the literature and computer simulations results.http://ijict.itrc.ac.ir/article-1-295-en.htmlcumulative distribution functiongeneralized gamma fadingconvergent infinite seriesequal-gain combining
spellingShingle Hossein Samimi
Paeiz Azmi
On the Distribution of the Sum of Independent Random Variables and Its Application
International Journal of Information and Communication Technology Research
cumulative distribution function
generalized gamma fading
convergent infinite series
equal-gain combining
title On the Distribution of the Sum of Independent Random Variables and Its Application
title_full On the Distribution of the Sum of Independent Random Variables and Its Application
title_fullStr On the Distribution of the Sum of Independent Random Variables and Its Application
title_full_unstemmed On the Distribution of the Sum of Independent Random Variables and Its Application
title_short On the Distribution of the Sum of Independent Random Variables and Its Application
title_sort on the distribution of the sum of independent random variables and its application
topic cumulative distribution function
generalized gamma fading
convergent infinite series
equal-gain combining
url http://ijict.itrc.ac.ir/article-1-295-en.html
work_keys_str_mv AT hosseinsamimi onthedistributionofthesumofindependentrandomvariablesanditsapplication
AT paeizazmi onthedistributionofthesumofindependentrandomvariablesanditsapplication