Blocking Probability Calculation Research Articles

Analytical Model of the Connection Handoff in 5G Mobile Networks with Call Admission Control Mechanisms.

Handoff mechanisms are very important in fifth-generation (5G) mobile networks because of the cellular architecture employed to maximize spectrum utilization. Together with call admission control (CAC) mechanisms, they enable better optimization of bandwidth use. The primary objective of the research presented in this article is to analyze traffic levels, aiming to optimize traffic management and handling. This article considers the two most popular CAC mechanisms: the resource reservation mechanism and the threshold mechanism. It presents an analytical approach to occupancy distribution and blocking probability calculation in 5G mobile networks, incorporating connection handoff and CAC mechanisms for managing multiple traffic streams generated by multi-service sources. Due to the fact that the developed analytical model is an approximate model, its accuracy was also examined. For this purpose, the results of analytical calculations of the blocking probability in a group of 5G cells are compared with the simulation data. This paper is an extended version of our paper published in 17th ConTEL 2023.

Limitation of Erlang B Traffic Model in Elastic Optical Network for Blocking Probability Estimation

Abstract In this paper, an algorithm for multipath connection provisioning in elastic optical network (EON) has been proposed. Initially, the algorithm prefers the single-path routing for service provisioning. But when single-path routing is not adequate to serve a dynamic connection, the algorithm switches to the connection request fragmentation. Its computation is based on the parameters such as capacity_constant and capacity_allowed to fragment the connection request on disjoint paths. Simulation results clearly state that the proposed algorithm performs well in service provisioning as compared to the traditional single-path routing algorithms and improves the average network throughput. Thereafter, we have investigated the limitation of Erlang B traffic model in EON for calculation of link blocking probability using routing and spectrum assignment (RSA) algorithm. It is verified by the following two ways: (i) effect on the blocking probability in case of constant load and (ii) effect of slot width on the blocking probability. Our simulation results indicate that in EON due to dynamic RSA, blocking probability is not constant in case of proportionate varying of call arrival and service rate giving constant load and blocking probability depends on the number of slots per link, but in Erlang B traffic model blocking probability is always constant in case of constant load and it considers wavelength per link instead of slots per link. This is attributed to the fact that Erlang B traffic model fails to calculate blocking probability accurately in EON. We have computed the carried traffic on 14 nodes, 21-link National Science Foundation Network (NSFNET) topology.

And Michał Dominik Stasiak Recurrent Method for Blocking Probability Calculation in Switching Networks with Overflow Links

and Michał Dominik Stasiak Recurrent Method for Blocking Probability Calculation in Switching Networks with Overflow Links

Internal Blocking Probability Calculation in Switching Networks with Additional Inter-Stage Links and Mixture of Erlang and Engset Traffic

Abstract In the article a new analytical approximate method for modeling multi-service switching networks with overflow links is proposed. The method can be used for blocking probability calculation in switching networks that are offered multi-service traffic generated by finite and infinite number of sources, i.e., in switching networks with multi-service Engset traffic, in switching networks with multiservice Erlang traffic, as well as in multi-service switching networks with Erlang and Engset traffic. The simulation study performed proves high accuracy of the method proposed and confirms the correctness and validity of all adopted theoretical assumptions.

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.

Blocking probability calculation in wavelength-routed all-optical networks

In this paper we have proposed a mathematical model to reduce the blocking probability of the WDM optical network. The mathematical model proposed has a closed-form expression and does not require simulated statistics, it has low implementation complexity and the computation is quite efficient. This model suggests us to choose the best path and appropriate number of free wavelengths in the network. We can go for the compromise between the path length and number of free wavelength. The model is also used to evaluate the blocking performance of NSFNet topology and hence used to improve its performance.

Quality of Service Aware Call Admission Control in Cell Based Multi-Service Photonic Network

The article tackles the problem of quality of service assurance in photonic networks. The idea of multi-servicephotonic network model with the coexistence of optical circuit and packet switching mechanisms and cell communication is used as a basis for service differentiation in the optical domain. Cell loss ratio as a key performance indicator determines the required optical switching mechanism. Service provisioning is performed using call admission control mechanism with real-time cell loss ratio estimation procedure. Service blocking probability calculation utilizes discrete event simulation of service provision and teardown requests applied to core network topology from COST 266 project. Three simulation scenarios are included in the analysis – pure optical packet switching network, and coexistence of optical packet and circuit switching with and without possibility of communication redirection between the switching mechanisms. Simulation scenarios are additionally altered with the cell loss ratio constraint and number of delay lines.

Blocking Probability Calculation for Cellular Systems with WCDMA Radio Interface Servicing PCT1 and PCT2 Multirate Traffic

This article proposes a method that can calculate the blocking probability of multi-service cellular systems with Wideband Code Division Multiple Access radio interface. The method considers a finite and an infinite source population and takes into account the interdependency of calls service processes in neighboring cells and in both the uplink and the downlink directions. The basis of the proposed method is the fixed-point methodology. A comparison of the results of analytical calculations to those of simulations confirms the accuracy of the proposed method. The proposed scheme can realize cost-effective radio resource management in 3G mobile networks and can be easily applied to network capacity calculations.

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.

Analysis of blocking probability in optical burst switched networks

In this article, we study the blocking probability in a wavelength division multiplexing (WDM) based asynchronous bufferless optical burst switched (OBS) network, equipped with a bank of wavelength converters. Our analysis encloses two wavelength reservation schemes JIT (just-in-time) and JET (just-enough-time), and two-class data rate. The contribution of our work includes: (i) derivation of an accurate model for blocking probability of lower priority bursts in case of a non-preempted model; (ii) provision of the analytical model for blocking probability calculation in the OBS network, which includes these variables: two signaling schemes, partial wavelength conversion, two-class data, traffic intensity, cross-connect speed, number of wavelengths in WDM fiber, number of fibers in the node, number of wavelength converters, and number of nodes in the path; (iii) simulation results, which show that partial wavelength conversion provide quite satisfactory quality of service. We compare performance in a single OBS node, under various sets of parameter values. The OBS network shows great flexibility in terms of used multiclass data, and there is no dependence on the used higher layer protocol.

Blocking Probability Calculation Using Traffic Equivalent Distributions in SIR-Based Power Controlled W-CDMA Cellular Systems

In W-CDMA systems, distributions of the interference power and the total transmit power both measured at base stations are respectively used for capacity analysis in the uplink and downlink. For accurate capacity analysis, these quantities must be in proportion to the traffic amount. However, these quantities are no longer in proportion to the traffic amount since the transmit power control maintains the signal to interference power ratio at a constant level. Although the relationship between these measurements and the traffic amount has been investigated, there are still challenges to calculate the statistics such as the blocking probability or the outage probability accurately. This paper proposes a method to calculate the blocking probability by transforming the distributions of these measurements into distributions that are referred to as traffic equivalent distributions, where the distributions are automatically adjusted according to the traffic amount. The calculated results show good agreement with the results obtained by dynamic computer simulations in the uplink, and show good agreement in the downlink as well when the traffic load is light. Accurate calculation of the blocking probability using a feedback loop and the observation of the traffic equivalents is also reported.

Point-to-point blocking probability in switching networks with reservation

In this paper reservation algorithms for multi-service switching networks are proposed. Two new approximate methods of the point-to-point blocking probability calculation in the multi-service switching networks are also presented in the paper. These methods can be used for blocking calculation in the switching networks with and without reservation. Special attention is paid to the method for determining the effective availability, which directly affects the accuracy of the final results. The results of analytical calculations are compared with the data of digital simulation of switching networks without and with reservation.

Point-to-group blocking in the switching networks with unicast and multicast switching

In this paper, a new approximate effective availability method of the point-to-group blocking probability calculation in switching networks carrying a mixture of different multi-rate unicast and multicast traffic streams is presented. Until recently, such methods have only been proposed for the single-services switching networks. To the best of our knowledge, methods of blocking probability calculation for multi-service switching network with multicast connection have not yet been considered. In this paper, four algorithms of setting-up multicast connections in multi-service switching networks are considered and discussed. Special attention is paid to the methods for determining the effective availability parameter in the case of multicast connections. The results of the analytical calculations are compared with the data of the digital simulations of the switching networks with unicast and multicast connections.

Deterministic algorithm for VP assignment in ATM networks

Virtual Path (VP) assignment is an important resource management activity in ATM networks. By using the VP concept, the logical layout of the network can be administered to minimize the total network cost to the provider. We formulate the VP assignment problem as a constrained optimization problem; the objective function to be minimized reflects processing/control costs at nodes and transmission costs between nodes. The blocking probability quality of service (QoS) requirements and overall throughput of the network are taken into consideration in the solution process as constraints. Since the solution space is complex, we develop a deterministic, iterative heuristic algorithm to reach a ‘near-optimal’ VP configuration for a given physical network and traffic demand. The Multi-Rate Loss Network model is used in the calculation of connection-level blocking probabilities. Results for static connection-routing are presented, for various forms of the objective function and constraints.

A stochastic system with MMPP input and an access function

AbstractIn classical studies of loss systems with restricted availability, the utilization was suggested of a probabilistic loss function, defining the conditional probability of an incoming call being rejected, as a function of the number of occupations in the destination group of servers. This paper gives an exact analysis of stochastic processes of practical relevance, associated with a system with MMPP (Markov Modulated Poisson Process) input, finite queueing capacity and a general loss function, assuming exponential service times. In addition to the process defining the state of the system at any instant, the analysis of the overflow point process (associated with the rejected arriving customers), the accepted point process (associated with the accepted arriving customers), and of the departure process will be presented. Together with the exact analysis of this system, based on the matrix analytical methodology of Neuts, (1981), we will derive expressions for calculating some key‐parameters of pertinent associated processes, which may also be used for their approximate modelling. Also, examples of applications and of blocking probability calculations in specific models of this class will be presented.

Analysis of Dependence Effects in Telephone Trunking Networks

Since theoretical and computational difficulties often preclude exact solution of telephone trunking network problems, approximate methods are naturally used. A typical approach is to determine link <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∗</sup> blocking probabilities and from them calculate point-to-point blocking probabilities by invoking independence assumptions. Although the link blocking probabilities may be quite accurate, the point-to-point blocking probability calculations will, in some cases, suffer from the independence assumptions. This paper presents a method of taking dependence into account for certain networks by approximating conditional probabilities which reflect the dependence. The approximations avoid the problems of dealing with the large sums associated with this problem.