Wyniki wyszukiwania - BazTech

1

Queuing models for wireless mesh networks

Hanczewski S., Sobieraj M., Stasiak M. D, Weissenberg J.

Image Processing & Communications

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2013

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Vol. 18, no. 4

21--31

EN

In this paper we discuss a proposition of various applications of new queueing models that have been developed within the CARMNET project in nodes of the mesh network. These models allow characteristics of systems that service multi-rate traffic to be determined, e.g., the average queue length or the average waiting time for calls of a given class. The proposed models can be used to design, analyse and optimize multiservice networks.

2

A New Analytical Model of UMTS Cell

Stasiak M., Hanczewski S.

Image Processing & Communications

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2012

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Vol. 17, no. 1-2

81--89

EN

This paper discusses a new analytical model of the WCDMA radio interface. The proposed model is based on Erlang’s Ideal Grading with multi-rate traffic and different availability characteristics. Thanks to the application this model, it is possible in the proposed model to take into consideration not only the influence of interference from different cells, but also different traffic management mechanisms. The operation of the new model is presented with the example of the WCDMA interface in which selected classes of calls have introduced traffic constraint. The proposed model is characterized by its simplicity, while the results obtained with its application are characterized by accuracy that is acceptable for the model to be used in engineering calculations.

3

Algorithm for queueing networks with multi-rate traffic

Iversen V. B., King-Tim K.

Advances in Electronics and Telecommunications

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2011

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Vol. 2, no. 3

3--7

EN

In this paper we present a new algorithm for evaluating queueing networks with multi-rate traffic. The detailed state space of a node is evaluated by explicit formulæ. We consider reversible nodes with multi-rate traffic and find the state probabilities by taking advantage of local balance. Theory of queueing networks in general, presumes that we have product form between the nodes. Otherwise, we have the state space explosion. Even so, the detailed state space of each node may become very large because there is no product form between chains inside a node. A prerequisite for product form is reversibility which implies that the arrival process and departure process are identical processes, for example state-dependent Poisson processes. This property is equivalent to reversibility. Due to product form, an open network with multi-rate traffic is easy to evaluate by convolution algorithms because the nodes behave as independent nodes. For closed queueing networks with multiple servers in every node and multi-rate services we may apply multidimensional convolution algorithm to aggregate the nodes so that we end up with two nodes, the aggregated node and a single node, for which we can calculate the detailed performance measures.

4

Multi-rate overflow traffic modeling

Głąbowski M., Kubasik K., Stasiak M.

Poznan University of Technology Academic Journals. Electrical Engineering

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2007

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No 54

49-56

EN

The article proposes an analytical method for determining basic traffic characteristics of systems which are offered overflow traffic composed of multi-rate traffic streams. The described analytical model enables determination of parameters of traffic overflowed from primary groups for systems servicing single and multi-service switching networks with overflow traffic on the basis of Ka u f man-Roberts model for full-availability group with a Poisson requests distribution stream. Additionally, a method for determining a channel occupancy distribution in the alternative group with traffic overflowed from primary groups in their occupation state has been also presented. Analytical calculation results of blocking probability calculated using the presented methodology have been compared with the data obtained from the system simulation process.

5

Modelling of the influence of connection handoff on UMTS traffic characteristics

Głąbowski M., Sobieraj M., Stasiak M.

Poznan University of Technology Academic Journals. Electrical Engineering

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2007

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No 54

57-64

EN

The paper presents a model of a group of cells, exploiting the effects of connection handoff between cells, aimed at increasing the traffic capacity of a system. The analytical model proposed is based on the model of limited-availability group, which makes it possible to determine basic traffic characteristics in the system under consideration. In the paper it is applied the generalized model of the limited-availability group, i.e. the group which consists of separated transmission links of various capacities. The results of analytical calculations of blocking probability in a group of UMTS cells were compared with simulation data, which confirmed high accuracy of the proposed method.