Full-availability Group Research Articles

Analytical model of the multi-service cellular network servicing multicast connections

In this paper, a new analytical method of blocking probability calculation in multi-service cellular systems with multicast connections is proposed. The new analytical method considers the influence of both WCDMA and Iub interfaces on multicast traffic streams characteristics. The basis for the discussed method is a model of the full-availability group with traffic compression and the fixed-point methodology. The results of the analytical calculations of the cellular system with multicast connections are compared with the results of the simulation experiments, which confirms the accuracy of the proposed method. The proposed scheme can be applicable for a cost-effective resource management in UMTS/HSPA/LTE mobile networks and can be easily applied in proper network dimensioning.

Analytical Modeling of the WCDMA Interface with Packet Scheduling

The article presents the application of a new analytical model of the full-availability group carrying a mixture of different multi-rate traffic classes with compression property for modeling the WCDMA radio interface with packet scheduling. The proposed model can be directly used for modeling of theWCDMA interface in the UMTS network servicing different traffic classes. The described model can be applied for a validation of the efficiency of the WCDMA interface measured by the blocking probability and the average carried traffic for particular traffic classes.

Modelling of state-dependent multirate systems carrying BPP traffic

This paper presents a simple approximate calculation methodology of the occupancy distribution and the blocking probability in state-dependent systems with multirate Binomial–Poisson–Pascal traffic. The particular traffic streams are generated by an infinite, as well as by a finite, population of traffic sources. The proposed methodology is based on the generalized Kaufman–Roberts recursion. The model enables calculations to be carried out for the systems in which accepting a new call depends on an admission control algorithm (e.g., a model of a full-availability group with bandwidth reservation) as well as for those systems in which accepting a new call depends on the structure of a system (e.g., a model of a limited-availability group). The results of the analytical calculations have been compared with the simulation results of exemplary state-dependent systems.

Modeling of systems with overflow multi-rate traffic

The article proposes an analytical method for determining occupancy distribution and blocking probability in systems which are offered overflow traffic composed of multi-service traffic streams. The described analytical model enables determination of parameters of traffic overflowed from primary groups in hierarchically constructed telecommunication networks. The proposed method is based on an appropriate modification of the Kaufman-Roberts recursion for the full-availability group with multi-rate traffic and uses the modified Fredericks & Hayward's approximation. Additionally, an approximate method for dimensioning systems with multi-service overflow traffic is also presented. The analytical results of the blocking probability and the results obtained in the dimensioning processes calculated using the presented methodology are compared with the data obtained from the system simulation process.

Asymmetric convolution algorithm for blocking probability calculation in full-availability group with bandwidth reservation

The paper proposes a new approximate calculation method of occupancy distribution and blocking probability in the full-availability group (FAG) with multi-rate traffic streams and bandwidth reservation. The algorithm involves calculation of system state probabilities by a convolution operation. In the paper, an effective method of calculating state probabilities in a reservation space of the system is derived. The analytical results of blocking probabilities in the FAG with bandwidth reservation, obtained on the basis of the proposed analytical method, are compared with the data obtained on the basis of other known analytical methods and with the simulation results. The accuracy of the proposed method is evaluated for different multi-rate Bernoulli (Erlang), Poisson (Engset), Pascal traffic streams. The method proposed is characterised by lower complexity than the convolution algorithm for the FAG with bandwidth reservation devised earlier.

A simple approximation of the link model with reservation by a one-dimensional Markov chain

This paper presents a new approximate calculation algorithm of the blocking probability in the full-availability group with reservation carrying a mixture of different multi-rate traffic streams. The algorithm is based on transforming multi-dimensional service processes in the system into a one-dimensional discrete Markov chain, which is characterised by a product form solution. Special attention is paid to the method for determining reverse transition rates and state probabilities in this Markov chain. The results of analytical calculations of the blocking probability are compared with the results of digital simulation of systems with bandwidth reservation. This research has shown a better accuracy of the proposed method as compared to the accuracy of other known solutions. The derived formulae can be useful for the analysis of ISDN and B-ISDN switching systems.

A New Method for Computing the Last Trunk Occupancy for High-Usage Telephone Routes

In this paper, a new formula is derived for the last trunk occupancy of a full-availability group of trunks, assuming sequential hunting, which is an important performance measure for high-usage telephone routes. The formula can be easily programmed on the computer, and it avoids the occurrence of arithmetic overflow during computation, allowing the evaluation of the last-trunk occupancy for large groups of trunks.

A new method for computing Erlang-B formula

In this paper, a new form of Erlang-B formula is derived, so that it can be easily programmed on the computer, and so that it can be computed for any lost-call system with full-availability group of trunks, with no restriction on its size or on the volume of traffic offered.

The Probability of Loss of Calls in Heavy Traffic

The full availability group of trunks with an arbitrary distribution of the inter-arrival times and a negative exponential holding time distribution is considered. The possibility of evaluating the probability of loss of calls by Erlang’s formula, as a first approximation, is established under very general conditions on streams with high intensity, when not very strict requirements on the quality of service are made.