Approximations of retrial queue with limited number of retrials

We consider the retrial queues in which the number of retrials of each customer is limited by a finite number, say mm. If a customer fails to enter the service facility at the mmth retrial, then the customer leaves the system forever without service. Approximation formulae for the distributions of queue length process, waiting time and the number of retrials made by a customer during his waiting time are derived by the approach in Fredericks and Reisner [10]. Some monotonicity properties are also presented.