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Call Admission Control (call + admission_control)
Selected AbstractsNeural bandwidth allocation function (NBAF) control scheme at WiMAX MAC layer interfaceINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 9 2007Mario Marchese Abstract The paper proposes a bandwidth allocation scheme to be applied at the interface between upper layers (IP, in this paper) and Medium Access Control (MAC) layer over IEEE 802.16 protocol stack. The aim is to optimally tune the resource allocation to match objective QoS (Quality of Service) requirements. Traffic flows characterized by different performance requirements at the IP layer are conveyed to the IEEE 802.16 MAC layer. This process leads to the need for providing the necessary bandwidth at the MAC layer so that the traffic flow can receive the requested QoS. The proposed control algorithm is based on real measures processed by a neural network and it is studied within the framework of optimal bandwidth allocation and Call Admission Control in the presence of statistically heterogeneous flows. Specific implementation details are provided to match the application of the control algorithm by using the existing features of 802.16 request,grant protocol acting at MAC layer. The performance evaluation reported in the paper shows the quick reaction of the bandwidth allocation scheme to traffic variations and the advantage provided in the number of accepted calls. Copyright © 2006 John Wiley & Sons, Ltd. [source] CAC and routing for multi-service networks with blocked wide-band calls delayed, Part II: approximative link MDP frameworkEUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 1 2007Ernst Nordström In this paper, we study the call admission control (CAC) and routing issue in multi-service networks. Two categories of calls are considered: a narrow-band with blocked calls cleared and a wide-band with blocked calls delayed. The optimisation is subject to several quality of service (QoS) constraints, either on the packet or call level. The objective function is formulated as reward maximisation with penalty for delay. A suboptimal solution is achieved by applying Markov decision process (MDP) theory together with a three-level approximation. First, the network is decomposed into a set of links assumed to have independent Markov and reward processes respectively. Second, the dimensions of the link Markov and reward processes are reduced by aggregation of the call classes into call categories. Third, by applying decomposition of the link Markov process, the link MDP tasks are simplified considerably. The CAC and routing policy is computed by the policy iteration algorithm from MDP theory. The numerical results show that the proposed CAC and routing method, based on the approximate link MDP framework, is able to find an efficient trade-off between reward loss and average call set-up delay, outperforming conventional methods such as least loaded routing (LLR). Copyright © 2006 AEIT. [source] CAC and routing for multi-service networks with blocked wide-band calls delayed, part I: exact link MDP frameworkEUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 1 2006Ernst Nordström In this paper, we study the call admission control (CAC) and routing issue in multi-service networks. Two categories of calls are considered: a narrow-band (NB) with blocked calls cleared and a wide-band (WB) with blocked calls delayed. The objective function is formulated as reward maximisation with penalty for delay. The optimisation is subject to quality of service (QoS) constraints and, possibly, grade of service (GoS) constraints. A suboptimal solution is achieved by applying Markov decision process (MDP) theory together with a two-level approximation. First, the network is decomposed into a set of links assumed to have independent Markov and reward processes respectively. Second, the dimensions of the link Markov and reward processes are reduced by aggregation of the call classes into call categories. The CAC and routing policy is computed by the policy iteration algorithm from MDP theory. The numerical results show that the proposed CAC and routing method, based on the exact link MDP framework, is able to find an efficient trade-off between reward loss and average call set-up delay, outperforming conventional methods such as the least loaded routing (LLR). Copyright © 2005 AEIT. [source] Call admission control for voice over IPINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 4 2006Huseyin Uzunalioglu Abstract Voice over Internet protocol (VoIP) is a technology that enables the transmission of voice over an IP network. Recent years have witnessed heavy investment in this area in the commercial world. For VoIP to replace Public Switched Telephone Network (PSTN), it should provide voice quality comparable to circuit-switched PSTN networks. This paper addresses the mechanisms to guarantee VoIP quality of service (QoS). The focus is given to the call admission control, which blocks voice calls when the required resources are not available to guarantee the QoS for the call. We review call admission control approaches that can be applied to VoIP, and describe the advantages and disadvantages of each approach. In the second part of the paper, we present a measurement-based admission control scheme that achieves QoS in an efficient and scalable manner. The scheme uses voice traffic load measurements at each router link to compute link-level blocking policies for new call attempts. Then, these policies are translated into path-level blocking policies, which are applied to new call set-up requests. The performance of the scheme is presented for single and multiple-priority voice calls. Copyright © 2006 John Wiley & Sons, Ltd. [source] QoS guarantee in telecommunication networks: technologies and solutionsINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 10 2004Enzo Fortunato Abstract The aim of this paper is to show the effect of the presence of specific management functions within a network that offers quality of service (QoS). The objective is not privileging a particular technology but to highlight the importance to know which control functions a solution may use, which performance limits the functions have and what can be a realistic user expectation. The paper focuses on the meaning of QoS and on the applications requiring quality, then describes QoS solutions including transport technologies, QoS-oriented technologies, parameters and management functions. In more detail, the effect on QoS provision of the following issues is investigated and discussed concerning the possibility (or not) to aggregate and differentiate traffic, the implementation of call admission control and of traffic filtering to limit flows to their committed rates. Again, the conclusions should not be considered a merit mark about technology, but only an investigation about: what users and customers should expect by the technologies using specific control functions evidencing that the real limitations are not imposed by a specific technology, whose features may be changed and extended, but by the application of control functions that can guarantee requirements' matching. Copyright © 2004 John Wiley & Sons, Ltd. [source] Network dimensioning at the call level for the always-on networkINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 9 2004Soracha Nananukul Abstract It is becoming common for the network to provide always-on access services, where subscribers are guaranteed that their call requests will never be blocked. This paper studies the call-level link dimensioning for the always-on network with single-class traffic. The call-level QoS requirement is expressed in terms of the probability of a poor-quality call, which is the probability that a call experiences packet-level QoS violation at any time during its duration, as opposed to the probability of blocking in the network with call admission control (CAC). The system is modelled as the M/M/infinite system with finite population and an analytic expression for the probability of a poor-quality call is derived based on performability analysis. The effects of the call-level traffic characteristics on the required link resources are studied. It is also shown that the call-level link dimensioning for the always-on network needs more link resources than the network with CAC, and the call-level link dimensioning based on the analytic expression can be used to conservatively dimension the always-on network with arbitrarily distributed call holding time and inter-call time. The paper also studies the problem of estimating the call-level traffic characteristics when the knowledge of call boundaries is not available. Copyright © 2004 John Wiley & Sons, Ltd. [source] QOS and call admission control of multimedia traffic in a PCS networkINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 6 2004Duan-Shin Lee Abstract In this paper we study the quality of service of integrated voice and data services in a wireless network. The voice traffic is transmitted in circuit-switched mode and data traffic is transmitted in packet-switched mode. Voice traffic has high transmission priority and data packets are transmitted only when there are available channels not used by the voice traffic. Otherwise, the data packets wait in a data buffer. We consider two schemes to reduce the forced termination probability for the handoff voice calls. The two schemes are the reserved channel scheme and the queueing priority scheme. We apply a fluid analysis to study the performance of the data buffer under the two handoff schemes and the basic system in which there is no arrangement to reduce the forced termination probability of handoff calls. From this analysis, we derive admission controls for voice traffic as well as for data traffic. This analysis also enables us to conclude that the reserved channel scheme not only is more effective in reducing the forced termination probability of handoff calls, it is also more effective in providing the QOS guarantee for the data traffic. Another contribution of this paper is to develop a perturbation analysis to solve the fluid models efficiently and quickly. Copyright © 2004 John Wiley & Sons, Ltd. [source] Call admission control in cellular networks: A reinforcement learning solutionINTERNATIONAL JOURNAL OF NETWORK MANAGEMENT, Issue 2 2004Sidi-Mohammed Senouci In this paper, we address the call admission control (CAC) problem in a cellular network that handles several classes of traffic with different resource requirements. The problem is formulated as a semi-Markov decision process (SMDP) problem. We use a real-time reinforcement learning (RL) [neuro-dynamic programming (NDP)] algorithm to construct a dynamic call admission control policy. We show that the policies obtained using our TQ-CAC and NQ-CAC algorithms, which are two different implementations of the RL algorithm, provide a good solution and are able to earn significantly higher revenues than classical solutions such as guard channel. A large number of experiments illustrates the robustness of our policies and shows how they improve quality of service (QoS) and reduce call-blocking probabilities of handoff calls even with variable traffic conditions.,Copyright © 2004 John Wiley & Sons, Ltd. [source] Cross-layer design for call admission control of a high-capacity GEO satellite network with on-board cross-connectINTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS AND NETWORKING, Issue 6 2006Rose Qingyang Hu Abstract This paper addresses cross-layer design of end-to-end call admission control and beam-to-beam connectivity provisioning for a high-capacity multi-beam GEO satellite network with on-board cross-connectivity. On-board satellite switching is a technology designed to offer heterogeneous services, especially in demographically dispersed areas. Nevertheless, full on-board switching techniques are far from maturity. Their implementations have been proven expensive and difficult. There are also high risks involved in launching satellites for the stationary orbit surrounding the Earth. As a substitute, a satellite network with on-board cross-connect is devised in this paper. Connectivity provisioning and call admission control mechanisms associated with such a network are also presented. Simulation studies are conducted to show the effectiveness of the proposed mechanisms. Copyright © 2006 John Wiley & Sons, Ltd. [source] | ||||||||||