We investigate a polling model for a radio-cell of the broadband wireless IEEE 802.11 DCF network. Polling system consists of N M/M/1-type queues with impatient customers. The switch-over times are assumed to be non-z...
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(纸本)9781424439676
We investigate a polling model for a radio-cell of the broadband wireless IEEE 802.11 DCF network. Polling system consists of N M/M/1-type queues with impatient customers. The switch-over times are assumed to be non-zero. A customer has limited random waiting time and after the time expires the customer leaves the system unless its service has not been started. The computation scheme of the power-series algorithm for the evaluation of the joint queue length distributions for the model under consideration is presented. Having the joint queue length distributions calculated, we obtain the performance characteristics.
A frequent observation in service systems with queues in parallel is that customers in other queues tend to be served faster than those in one's own queue. This paper quantifies the probability that one's serv...
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A frequent observation in service systems with queues in parallel is that customers in other queues tend to be served faster than those in one's own queue. This paper quantifies the probability that one's service would have started earlier if one had joined another queue than the queue that was actually chosen, for exponential multiserver systems with queues in parallel in which customers join one of the shortest queues upon arrival and in which jockeying is not possible. (c) 2008 Elsevier B.V. All rights reserved.
We consider a polling model with multiple servers, each of which visits the queues according to its own service order table. In general, such a model is not tractable by means of analytical techniques. In this paper, ...
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The IEEE 802.4 and FDDI (Fibre Distributed Data Interface) standards are high speed MAC (Medium Access Control) protocols for LAN/MANs employing a timer-controlled token passing mechanism, the so-called Timed Token Pr...
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The IEEE 802.4 and FDDI (Fibre Distributed Data Interface) standards are high speed MAC (Medium Access Control) protocols for LAN/MANs employing a timer-controlled token passing mechanism, the so-called Timed Token Protocol, to control station access to the shared media. MAC protocols belonging to the class of timed token protocols support synchronous and real-time (i.e., time-critical) applications, and provide priority among asynchronous (i.e., non time-critical) applications. During the last few years, a lot of research has focused on the study of timed token protocols to obtain performance measures such as throughputs or mean waiting times. The recent development of the power-series algorithm (PSA) has opened new perspectives in the analysis of this class of protocols. This paper shows the versatility of the PSA technique to evaluate the station buffer occupancy and delay distributions of a very general model which can be used to represent the behavior of several LAN/MANs MAC protocols, among which the timed token MAC protocols. Specifically, the focus of the paper is on the solution of an almost exact model of the IEEE 802.4 MAC protocol. Since the model we propose and solve numerically by exploiting the PSA technique is an approximate model of the FDDI MAC protocol, the paper also reports on a comparison between performance measures obtained for this model and simulation results for the corresponding (exact) model of FDDI.
Many computer-communication networks in which the transmission right is circulated among the nodes have been modeled as polling systems. This paper concerns optimization of cyclic polling systems with respect to the s...
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Many computer-communication networks in which the transmission right is circulated among the nodes have been modeled as polling systems. This paper concerns optimization of cyclic polling systems with respect to the service disciplines at the nodes. The service disciplines are chosen to be Bernoulli schedules. Because the optimization problem is not analytically tractable, a numerical approach to determine the optimal schedule, based on the power-series algorithm, is discussed. Light- and heavy-traffic asymptotes of the optimal schedule are presented;they are based on light-traffic asymptotes of the mean waiting times and the stability condition, respectively. A partial solution of the optimization problem is given;this follows directly from the mu c-rule for priority systems. The influence of system parameters on the optimal Bernoulli schedule is examined. Finally, a fast approach to approximate the optimal schedule is presented and tested.
An iterative numerical technique for the evaluation of queue length distributions is applied to multi-queue systems with one server and cyclic service discipline with Bernoulli schedules. The technique is based on pow...
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