Abstract
This paper presents efficient and convenient methods for computing the sum of large number of lognormal (LN) random variables (RVs) while utilizing the unexpanded form for the characteristic function of the sum obtained previously. These methods are (1) the application of appropriate quadrature rules to the integral involving the characteristic function for the sum after a proper change of variables, and (2) the application of the Epsilon algorithm to reduce the number of needed computations. The Epsilon algorithm is also used to compute the distribution for the sum of correlated LN RVs. Results indicate that while (1) presents a simple to evaluate sum in terms of the weights and nodes of the chosen quadrature rule, it may require 100 to 1,000s of terms to arrive at a reasonable approximation of the target cumulative distribution function. The second method reduces the needed evaluations to as little as 10 and improves the accuracy for both the lower end and higher end of the approximated cdf.
Similar content being viewed by others
References
Limpert E. et al.: Log-normal distributions across the sciences: keys and clues. BioScience, 51, 341–352 (2001)
Cox D.: Cochannel interference considerations in frequency reuse small-coverage-area radio systems. IEEE Trans. Commun. 30, 135–142 (1982)
Fenton L.: The sum of log-normal probability distributions in scatter transmission systems. IRE Trans. Commun. Syst. 8, 57–67 (1960)
Schwartz S.C., Yeh Y.S.: On the distribution function and moments of power sums with log-normal components. Bell Syst. Tech. J. 61, 1441–1462 (1982)
Safak A.: Statistical analysis of the power sum of multiple correlated log-normal components. IEEE Trans. Vehicular Technol. 42, 58–61 (1993)
Mehta N.B. et al.: Approximating a sum of random variables with a lognormal. IEEE Trans. Wirel. Commun. 6, 2690–2699 (2007)
Beaulieu N.C., Xie Q.: An optimal lognormal approximation to lognormal sum distributions. IEEE Trans. Vehicular Technol. 53, 479–489 (2004)
Szyszkowicz S.S., Yanikomeroglu H.: Limit theorem on the sum of identically distributed equally and positively correlated joint lognormals. IEEE Trans. Commun. 57, 3538–3542 (2009)
Beaulieu N.C.: An extended limit theorem for correlated lognormal sums. IEEE Trans. Commun. 60, 23–26 (2012)
Beaulieu N.C., Rajwani F.: Highly accurate simple closed-form approximations to lognormal sum distributions and densities. IEEE Commun. Lett. 8, 709–711 (2004)
Lam C.L.J., Le-Ngoc T.: Log-shifted gamma approximation to lognormal sum distributions. IEEE Trans. Vehicular Technol. 56, 2121–2129 (2007)
Liu Z. et al.: Approximating lognormal sum distributions with power lognormal distributions. IEEE Trans. Vehicular Technol. 57, 2611–2617 (2008)
Wu, Z.; et al.: A novel highly accurate log skew normal approximation method to lognormal sum distributions, In: IEEE Wireless Communications and Networking Conference, 2009 (WCNC 2009), Budapest, pp. 1–6 (2009)
Zhang Q., Song S.: A systematic procedure for accurately approximating lognormal-sum distributions. IEEE Trans. Vehicular Technol. 57, 663–666 (2008)
Di Renzo M. et al.: Approximating the linear combination of log-normal RVs via pearson type IV distribution for UWB performance analysis. IEEE Trans. Commun. 57, 388–403 (2009)
Di Renzo M. et al.: Further results on the approximation of log-normal power sum via pearson type IV distribution: a general formula for log-moments computation. IEEE Trans. Commun. 57, 893–898 (2009)
Di Renzo M. et al.: Smolyak’s algorithm: a simple and accurate framework for the analysis of correlated log-normal power-sums. IEEE Commun. Lett. 13, 673–675 (2009)
Di Renzo M. et al.: Distributed data fusion over correlated log-normal sensing and reporting channels: Application to cognitive radio networks. IEEE Trans. Wirel. Commun. 8, 5813–5821 (2009)
Di Renzo M. et al.: A comprehensive framework for performance analysis of cooperative multi-hop wireless systems over log-normal fading channels. IEEE Trans. Commun. 58, 531–544 (2010)
Zhao L., Ding J.: Least squares approximations to lognormal sum distributions. IEEE Trans. Vehicular Technol. 56, 991–997 (2007)
Szyszkowicz S.S. et al.: Aggregate interference distribution from large wireless networks with correlated shadowing: an analytical–numerical–simulation approach. IEEE Trans. Vehicular Technol. 60, 2752–2764 (2011)
Mahmoud A.S.H.: New Quadrature-based approximations for the characteristic function and the distribution function of sums of lognormal random variables. IEEE Trans. Vehicular Technol. 59, 3364–3372 (2010)
Gubner J.A.: A new formula for lognormal characteristic functions. IEEE Trans. Vehicular Technol. 55, 1668–1671 (2006)
Tellambura C., Senaratne D.: Accurate computation of the MGF of the lognormal distribution and its application to sum of lognormals. IEEE Trans. Commun. 58, 1568–1577 (2010)
Beaulieu N.C.: Fast convenient numerical computation of lognormal characteristic functions. IEEE Trans. Commun. 56, 331–333 (2008)
Abramowitz, M; Stegun, IA: Handbook of Mathematical Functions with Formulas, Graphs, and Mathematical Tables, NewYork: Dover, p. 890 (1972)
Burkardt, J.: Sandia Rules. (2011). Available: http://people.sc.fsu.edu/~jburkardt/m_src/sandia_rules/sandia_rules.html
Shanks D.: Non-linear trasnformations of divergent and slowly convergent sequences. J. Math. Phys. 34, 1–42 (1955)
Wynn P.: On a device for computing the (Sn) transformation. Math. Tables Other Aids Comput. 10, 91–96 (1956)
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Mahmoud, A.S.H., Rashed, A.H. Efficient Computation of Distribution Function for Sum of Large Number of Lognormal Random Variables. Arab J Sci Eng 39, 3953–3961 (2014). https://doi.org/10.1007/s13369-014-0993-y
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s13369-014-0993-y