Reviewed were the mathematical methods that are used to investigate the polling systems which found wide application in modeling and design of various transport and industrial processes. Emphasis was made on the models of polling systems used to investigate the wireless broadband networks. The polling systems were classified; presented were stochastic models and methods of investigating discrete-time and continuous-time systems, systems with cyclic, periodic, and random queue polling, as well as the methods of their optimization.

The paper presents a review of papers on stochastic polling systems published in 2007–2020. Due to the applicability of stochastic polling models, the researchers face new and more complicated polling models. Stochastic polling models are effectively used for performance evaluation, design and optimization of telecommunication systems and networks, transport systems and road management systems, traffic, production systems and inventory management systems. In the review, we separately discuss the results for two-queue systems as a special case of polling systems. Then we discuss new and already known methods for polling system analysis including the mean value analysis and its application to systems with heavy load to approximate the performance characteristics. We also present the results concerning the specifics in polling models: a polling order, service disciplines, methods to queue or to group arriving customers, and a feedback in polling systems. The new direction in the polling system models is an investigation of how the customer service order within a queue affects the performance characteristics. The results on polling systems with correlated arrivals (MAP, BMAP, and the group Poisson arrivals simultaneously to all queues) are also considered. We briefly discuss the results on multi-server, non-discrete polling systems and application of polling models in various fields.

This paper investigates the characteristics of the MAP/M/1/N queuing system in the transient mode. The matrix method for solving the Kolmogorov equations is proposed. This method makes it possible, in general, to obtain the main characteristics of the considered queuing system in a non-stationary mode: the probability of losses, the time of the transient mode, the throughput, and the number of customers in the system at time t. The developed method is illustrated by numerical calculations of the characteristics of the $MAP/M/1/3$ system in the transient mode.

An M/M/1 queueing system with an unreliable device is considered in the study. The device fails in an exponentially distributed time during which it is in the working condition and serves a demand. The device recovers during an exponentially distributed time according to the threshold policy specified by threshold level q ≥ 1. After a successive failure, the device does not recover until the number of demands exceeds level q. In the study, the system operating in the stationary regime is analyzed and the problem of optimal recovery control aimed at the minimization of the mean cost for a given penalty structure is solved.

We consider a two-channel queuing system with unreliable servers which fail alternately for modeling of hybrid communication systems, which have a millimeter-wave (71-76 GHz, 81-86 GHz) radio channel as a backup communication channel. The stationary distribution of the system states and the most important performance characteristics were obtained.