Performance of mobile prepaid and priority call services

In this letter, we conduct simulation experiments to study a mobile phone system that provides priority and prepaid call services using service nodes. An analytical model for the nonprepaid and prepaid services has been developed to verify the computer simulations. We observe that there exists a threshold point such that beyond this point, increasing the number of mobile switching center ports (service node ports or the radio channels) does not improve the system performance. Furthermore, our results show that priority assignment schemes may significantly affect the operator's revenue.