We consider in this paper the stability of retrial queues with a versatile retrial policy. We obtain sufficient conditions for the stability by the strong coupling convergence to a stationary ergodic regime for various models of retrial queues including a model with two types of customers, a model with breakdowns of the server, a model with negative customers, and a model with batch arrivals. F...

We study the stability of single server retrial queues under general distribution for retrial times and stationary ergodic service times, for three main retrial policies studied in the literature: classical linear, constant and control policies. The approach used is the renovating events approach to obtain sufficient stability conditions by strong coupling convergence of the process modeling th...

We consider basic M/M/c/c (c ≥ 1) retrial queues where the number of busy servers and that of customers in the orbit form a level-dependent quasi-birth-and-death (QBD) process with a special structure. Based on this structure and a matrix continued fraction approach, we develop an efficient algorithm to compute the joint stationary distribution of the numbers of busy servers and retrial custome...

Retrial queues are frequently observed in a real world system likewise call center or internet service industries. In this paper, a retrial queue system in which the number of retrials of each customer is limited by a finite number, say m is considered. That is, if a customer fails to enter the service facility at mth retrial, then the customer leaves the system without service. The effects of ...

The use of a Markovian inventory system is critical part management. purpose this study to examine the demand for two commodities in system, one which designated as major item (Commodity-I) and other complimentary (Commodity-II). Demand arrives according Poisson process, service time exponential at queue-dependent rate. We investigate strategy (s,Q) type control commodity-I with random lead but...

We describe main models and results of a new branch of the queueing theory, theory of retrial queues, which is characterized by the following basic assumption: a customer who cannot get service (due to finite capacity of the system, balking, impatience, etc.) leaves the service area, but after some random delay returns to the system again. Emphasis is done on comparison with standard queues wit...

⎯We consider a single server retrial queue with batch arrivals, two phases of heterogeneous service and multiple vacations with Npolicy. The primary arrivals find the server busy or doing secondary job (vacation) will join orbit (group of repeated calls). If the number of repeated calls in orbit is less than N, the server does the secondary job repeatedly until the retrial group size reaches N....

We consider a discrete-time Geo/G/1 retrial queue in which the retrial time has a general distribution and the server, after each service completion, begins a process of search in order to find the following customer to be served. We study the Markov chain underlying the considered queueing system and its ergodicity condition. We find the generating function of the number of customers in the or...

We consider a retrial queueing system with a finite number of homogeneous sources of calls and a single server. Each source generates a request after an exponentially distributed time. An arriving customer finding the server idle enters into service immediately; otherwise the customer enters into an orbit. The service times are supposed to be exponentially distributed random variables. An orbit...

This paper analyses the steady state behaviour of an M/G/1 retrial queue with impatient subscribers, two phases of essential service, general retrial time and general vacation time. If the primary call, on arrival finds the server busy, becomes impatient and leaves the system with probability (1 ) and with probability , it enters into an orbit. The server provides preliminary first essential se...