Abstract
A random variable X is a generalized gamma random variable with parameters α, β, and γ. The difference D of two sums of independent generalized gamma random variables is considered. Of particular interest is the value of F D (0) which could be used to derive the error probability and outage probability of a communication system. In the special cases that the beta parameters are equal, the expressions for the PDF and the CDF could be simplified and expressed in terms of Laguerre polynomials.