In this paper, we analyze and synthesize a multi-server loss system with repeated customers, arising out of NTT DoCoMo-developed telecommunication networks. We first provide the numerical solution for a Markovian model with exponential retrial intervals. Applying Little’s formula, we derive the main system performance measures (blocking probability and mean waiting time) for general non-Markovi...

As a model for streaming multimedia applications, we study an unreliable retrial queue with infinite-capacity orbit and normal queue for which the retrial rate and the server repair rate are controllable. Customers join the retrial orbit if and only if their service is interrupted by a server failure. Interrupted customers do not rejoin the normal queue but repeatedly attempt to access the serv...

A repairable 1 M G / / retrial queue with general retrial times, Bernoulli vacation, setup times and two-phase service is investigated in this paper. Customers are allowed to balk and renege at particular times. We assume that the customers who find the server busy or down are queued in the orbit in accordance with a first-come-first-served (FCFS) discipline. All customers demand the first “ess...

This paper is motivated by an open problem posed by Senthil Kumar and Arumuganathan in their paper published in June 2009 [10]. We study the steady state behavior of an M/G/1 retrial queue with non-persistent customers, two phases of heterogeneous service and different vacation policies. We consider the case where the customer after obtaining the first essential service may or may not opt for a...

This paper considers a single-server retrial queue with constant retrial rate and batch arrivals, where an unreliable server may take an additional optional vacation after the first essential vacation. Customers arrive at the system according to a compound Poisson process, and they are served immediately if the server is available; otherwise, they will enter a retrial orbit and form a single wa...

Motivated by the need for performance models suitable for modeling and evaluation of wireless sensor networks, we introduce a retrial queueing system with a finite number of homogeneous sources, unreliable servers, orbital search, and unreliable orbit. All random variables involved in model construction are assumed to be independent and exponentially distributed. Providing a generalized stochas...

We consider Markovian multiserver retrial queues where a blocked customer has two opportunities for abandonment: at the moment of blocking or at the departure epoch from the orbit. In this queueing system, the number of customers in the system (servers and buffer) and that in the orbit form a level-dependent quasi-birth-and-death (QBD) process whose stationary distribution is expressed in terms...

In this paper, we analyze a retrial queueing system with Batch Markovian Arrival Processes and two types of customers. The rate of individual repeated attempts from the orbit is modulated according to a Markov Modulated Poisson Process. Using the theory of multi-dimensional asymptotically quasi-Toeplitz Markov chain, we obtain the stability condition and the algorithm for calculating the statio...

Abstract: The present investigation deals with M/G/1 retrial queue with unreliable server and general retrial times. The server is subject to breakdowns and takes some setup time before starting the repair. The server renders first essential phase of service (FES) to all the arriving customers whereas second optional phase services (SOS) are provided after FES to only those customers who opt fo...

A new approach is suggested to study transient and stable regimes in overloading retrial queueing systems. This approach is based on limit theorems of averaging principle and diffusion approximation types for so-called switching processes. Two models of retrial queueing systems of the types h?/G/i/w.r (multidimensional Poisson input flow, one server with general service times, retrial system) a...