Negative Binomial Approximation in Retrial Queue M/M/1 with Collisions and Impatient Calls

In the paper, the retrial queueing system of M/M/1 type with collisions and impatient calls is considered. The impatience of calls in the orbit is exponential distributed. The process of the number of calls in the orbit is analyzed. We propose the method of the negative binomial approximation using the first and the second moments of the distribution which were obtained asymptotically. The numerical analysis of comparison exact (obtained by simulation) and approximate distributions for different values of the system parameters are presented.