The distribution function of a sum of lognormal random variables (RVs) appe
ars in several communication problems. Approximations are usually used for
such distribution as no closed form nor bounds exist, Bounds can be very us
eful in assessing the performance of any given system. In this letter, we d
erive upper and lower bounds on the distribution function of a sum of indep
endent lognormal RVs, These bounds are given in a closed form and can be us
ed in studying the performance of cellular radio and broadcasting systems.