Discrete gamma approximation in retrial queue MMPP/M/1 based on moments calculation

In the paper, the retrial queueing system of MMPP/M/1 type is considered. The process of the number of calls in the system is analyzed. The method for the approximate calculation of the first and the second moments is suggested. We propose the method of the discrete gamma approximation based on obtained moments. The numerical analysis of the obtained results for different values of the system parameters is provided. Comparison of the distributions obtained by simulation and the approximate ones is presented. © 2017, Springer International Publishing AG.