Call Admission Control Scheme Research Articles

Adaptive call admission and bandwidth control in DVB-RCS systems

The paper presents a control architecture aimed at implementing bandwidth optimization combined with call admission control (CAC) over a digital video broadcasting (DVB) return channel satellite terminal (RCST) under quality of service (QoS) constraints. The approach can be applied in all cases where traffic flows, coming from a terrestrial portion of the network, are merged together within a single DVB flow, which is then forwarded over the satellite channel. The paper introduces the architecture of data and control plane of the RCST at layer 2. The data plane is composed of a set of traffic buffers served with a given bandwidth. The control plane proposed in this paper includes a layer 2 resource manager (L2RM), which is structured into decision makers (DM), one for each traffic buffer of the data plane. Each DM contains a virtual queue, which exactly duplicates the corresponding traffic buffer and performs the actions to compute the minimum bandwidth need to assure the QoS constraints. After computing the minimum bandwidth through a given algorithm (in this view the paper reports some schemes taken in the literature which may be applied), each DM communicates this bandwidth value to the L2RM, which allocates bandwidth to traffic buffers at the data plane. Real bandwidth allocations are driven by the information provided by the DMs. Bandwidth control is linked to a CAC scheme, which uses current bandwidth allocations and peak bandwidth of the call entering the network to decide admission. The performance evaluation is dedicated to show the efficiency of the proposed combined bandwidth allocation and CAC.

On delay constrained CAC scheme and scheduling policy for CBR traffic in IEEE 802.11e wireless LANs

AbstractCBR (constant bit rate) traffic is expected to be an important traffic source in wireless networks. Such sources usually have stringent jitter or delay requirements and in many cases they should be delivered exactly as they were generated. In this paper, we propose a strictly guaranteed QoS (quality‐of‐service) provisioning CAC (call admission control) scheme with a polling‐based scheduling policy for CBR traffic in IEEE 802.11e wireless LANs. Under such a scheme, the proposed transmit‐permission policy for HCCA (HCF controlled channel access) method can forecast the maximum suffered delay for each packet and derive sufficient conditions so that all the CBR sources satisfy their time constraints to provide deterministic QoS guarantees. A simple analytical model is carried out to estimate the average queueing delay of the proposed scheme. In addition to theoretical analysis, simulations are conducted to validate its promising performance. Our simulation results show that the proposed scheme maintains a high throughput with respect to the whole range of system load. Copyright © 2009 John Wiley & Sons, Ltd.

Call Admission Control Strategy for System Throughput Maximization Using DOVE

Tanzilah Noor Shabnam, Md. Imdadul Islam, M. R. Amin 1, First Department of Electronics and Communications Engineering,East West University, 43 Mohakhali, Dhaka 1212, Bangladesh, tanzilah_nsu031@yahoo.com Department of Computer Science and Engineering, Jahangirnagar University, Savar, Dhaka 1342, Banglades, imdad@juniv.edu *3,Corresponding Department of Electronics and Communications Engineering,East West University, 43 Mohakhali, Dhaka 1212, Bangladesh, ramin@ewubd.edu doi: 10.4156/jcit.vol5.issue8.14

A distributed-request-based CDMA CAC for DiffServ multimedia services in wireless cellular mobile networks

In this paper, a distributed-request-based CDMA DiffServ (differentiated service) call admission control (CAC) scheme is proposed to provide various multimedia services seamlessly in wireless mobile Internet. Conventional CDMA CAC schemes cannot fully support DiffServ QoS (Quality of Service) and seamless handoff due to lack of consideration on service priority and seamless mobility. Therefore, in order to achieve QoS guarantee for each service class, seamless fast-handoff, and high utilization of the scarce wireless resource, we define a code assignment policy and an adaptive access permission scheme taking each user’s service priority and mobility into consideration. For that purpose, in the proposed scheme, the DQRUMA/CDMA is combined with the new code assignment scheme and the adaptive access permission probability (APP). Numerical examples show that the forced termination ratio of handoff calls is guaranteed to be much less than the blocking ratio of new calls for a seamless fast-handoff while proposed scheme provides QoS guarantee for each service class efficiently.

A New Call Admission Control Scheme for Heterogeneous Wireless Networks

Call Admission Control (CAC) between heterogeneous networks, such as an integrated 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) network and a Wireless Local Area Network (WLAN), plays an important role to utilize the system resources in a more efficient way. In this paper, we propose that the preference to the WLAN is determined based on the traffic load in the WLAN and the location of the cellular users. Our analysis relies on a previous study that divides the 3G cellular coverage area into zones based on the amount of resources that are required to support a connection to a mobile user. Using this model, we derive new call blocking and handoff failure probabilities as well as new call and handoff attempt failure probabilities. Through simulations, we investigate proper preference settings by changing the WLAN load in a 3 ring-based sector with a WLAN hotspot.

Uplink Cross-Layer Scheduling with Differential QoS Requirements in OFDMA Systems

Fair and efficient scheduling is a key issue in cross-layer design for wireless communication systems, such as 3GPP LTE and WiMAX. However, few works have considered the multiaccess of the traffic with differential QoS requirements in wireless systems. In this paper, we will consider an OFDMA-based wireless system with four types of traffic associated with differential QoS requirements, namely, minimum reserved rate, maximum sustainable rate, maximum latency, and tolerant jitter. Given these QoS requirements, the traffic scheduling will be formulated into a cross-layer optimization problem, which is convex fortunately. By separating the power allocation through the waterfilling algorithm in each user, this problem will further reduce to a kind of continuous quadratic knapsack problem in the base station which yields low complexity. It is then demonstrated that the proposed cross-layer method cannot only guarantee the application layer QoS requirements, but also minimizes the integrated residual workload in the MAC layer. To further enhance the ability of QoS assurance in heavily loaded scenario, a call admission control scheme will also be proposed. The simulation results show that the QoS requirements for the four types of traffic are guaranteed effectively by the proposed algorithms.

Fair admission control scheme based on conditional preemption in traffic-groomed optical networks

In optical-grooming networks, the capacity fairness issue can be resolved by utilizing a call admission control mechanism. Existing call admission control schemes are generally based on one of the four different techniques, namely static bandwidth reservation (SBR), static threshold setting (STS), mathematical statistics (MS), and Markov decision processing without buffer implementation (NB). However, irrespective of the technique used, a tradeoff exists between the network fairness and the network throughput. Accordingly, this article presents a conditional-preemption call admission control (CP-CAC) scheme designed to increase the network throughput while simultaneously maintaining the fairness. The CP-CAC method is based on a dynamic threshold setting concept and is implemented using a single connection buffer (C-Buf) and a set of virtual buffers (V-Bufs). In general CAC mechanisms, if the residual bandwidth is sufficient to satisfy a new request but some requests are already buffered, the new request can be treated in two different modes, i.e. with-preemption (WP) or without-preemption (NP). In contrast, in the CP-CAC scheme proposed in this study, a conditional-preemption (CP) mode is proposed in which statistical information about the blocking probability is used to determine the preempt (or not) decision. The simulation results show that compared to the NB call admission control mechanism, the proposed CP-CAC scheme improves the network throughput without sacrificing the fairness. In addition, the average waiting time induced by the buffer implementation is just 0.25 time units. Finally, it is shown that the proposed method ensures fairness in a variety of common network topologies, including 6 × 6 mesh-torus, NSF, and Cost 239.

Performance analysis of a cell‐based call admission control scheme for QoS support in multimedia wireless networks

AbstractNext generation wireless communication systems, including 3G and 4G technologies, are envisaged to support more mobile users and a variety of high‐bandwidth multimedia services. Different multimedia services have diverse bandwidth and quality of service (QoS) requirements from their users that need to be guaranteed by wireless cellular systems. Furthermore, these systems will use micro/pico cellular architecture to provide a higher capacity. As a result of the smaller coverage area of this architecture, handoff events will occur at a much higher rate compared with the present macrocellular systems. In this paper, a multiple‐threshold bandwidth reservation scheme combined with a call admission control algorithm is proposed and analyzed. The objective of our work is to achieve better QoS provisioning for mobile users while achieving efficient utilization of the available limited bandwidth. The proposed scheme is modeled as M/M/C/C queueing system and the performance measures, call blocking probability (CBP), and call dropping probability (CDP) are computed. The performance of our scheme is compared with the Complete Sharing (CS) policy. Simulation results show that our scheme surpasses the CS policy in terms of CBP, CDP, and bandwidth utilization. Copyright © 2010 John Wiley & Sons, Ltd.

Wireless Heterogeneous Networks and Next Generation Internet

The recent advances in wireless access technologies as well as the increasing number of mobile applications have made Wireless Internet a reality. A wide variety of bandwidth demanding services including high speed data delivery and multimedia communication have been materialized through the convergence of the next generation Internet and heterogeneous wireless networks. However, providing even higher bandwidth and richer applications necessitates a fundamental understanding of wireless Internet architecture and the interactions between heterogeneous users. Consequently, fundamental advances in many concepts of the wireless Internet are required for the ultimate goal of communication anytime anywhere. This special issue of the ACM Mobile Networks and Applications Journal is dedicated to the recent advances in the area of Wireless Internet. We accepted 10 papers out of 59 submissions from all over the world with a 17% acceptance rate. Papers describing management schemes, protocols, models, evaluation methods, and experimental studies of Wireless Internet are included in this special issue to provide a broad view of recent advances in this field. In the first paper, R. Yu, Y. Zhang, M. Huang, and S. Xie address the call admission control (CAC) problem in cognitive radio networks in their work titled “Cross-Layer Optimized Call Admission Control in Cognitive Radio Networks.” In addition to traditional CAC challenges, they also consider the presence of sensing errors that may mislead the CAC strategy to make an inefficient or even incorrect decision. To this end, the parameters of CAC strategy and spectrum sensing scheme are simultaneously tuned to minimize the dropping rate while satisfying the requirements of both blocking rate and interference threshold by the developed optimization framework. The crosslayer optimization is modeled as a non-linear programming problem after introducing a multiple-stair Markov model to approximate the non-memoryless state transitions. Accordingly, the dropping rate is shown to be reduced while still meeting the blocking rate and the interference probability constraints. In their paper titled “Joint Dynamic Resource Allocation for QoS Provisioning in Multi-Access and Multi-Service Wireless Systems,” D. Calabuig, J. F. Monserrat, D. Martin-Sacristan and N. Cardona analyze the resource allocation problem in multi-access wireless systems. The joint dynamic resource allocation (JDRA) algorithm simultaneously allocates the best-suited Radio Access Technology (RAT) and the amount of resources to all the users active in a multi-access wireless system. The Quality of Service (QoS) requirements of different users in terms of delay and bit rate are guaranteed through an optimization formalization based on a Hopfield Neural Network (HNN) formulation. The analysis and simulations highlight the advantages of joint decision approach compared to a twostep procedure and show that JDRA can address different levels of congestion and load distribution among RATs compared to the state-of-the-art. In the paper titled “LAMA/CA: A Load-Adaptive MAC Protocol for Short Packets”, Z. Noar develops a load adaptive medium access control protocol with collision avoidance. The protocol design is based on the fact that very often the Internet access messages, such as HTTP E. Ekici Ohio State University, Columbus, OH, USA e-mail: ekici@ece.osu.edu

A novel CAC scheme for homogeneous 802.11 networks

This paper proposes a new call admission control (CAC) scheme for one-hop homogeneous 802.11 DCF networks. Using the proposed scheme, we can perform admission control quickly and easily without the need for network performance measurements and complex calculations. The CAC rule is derived under asymptotic conditions, but our extensive numerical examples show that it works well for practical-sized networks with a finite retransmission limit and realistic nonsaturated traffic.

DDCA in Cellular Network using Fuzzy rule based Multi-agent System

Present mobile networks have different Quality of Service (QoS) requirements to support increasing need with major objectives such as better admission control, effective bandwidth utilization, and fault tolerance. So the network aims at satisfying their demands without much degradation of quality in terms of call dropping and call blocking. It is possible by admission control algorithms and by optimizing the sharing and utilization of existing resources in an effective way. It improves the overall p erformance of the network system. This paper addresses different Quality of Service (QoS) requirements of the users of a cellular network with a focus on fuzzy based Call Admission Control Scheme (CAC) and optimized bandwidth allocation using M ulti Agent System M odel. We propose combined framework to address resource allocation problem. This problem can be dealt with the help of two issues in Admission control and Transmission control. The admission control – the decision to admit or reject the calls based on fuzzy logic control. Transmission control is provided thru Distributed Dynamic Channel allocation(DDCA) using co-operative negotiation of M ulti-Agent System. We demonstrate the efficiency of the proposed framework model by determining call dropping probability and call blocking probability.

Probabilistic framework and performance evaluation for prioritized call admission control in next generation networks

Next generation networks (NGN) are designed to support a wide range of applications with various service classes (SCs) guaranteeing the respective quality of service (QoS) levels. Since such networks are resource constrained, call admission control (CAC) is imperative to achieve the required QoS levels. In this paper, a new probabilistic framework for CAC schemes is proposed based on controlling each SC independently by admitting low priority SC calls with a variable imposed probability. The incorporation of such a probabilistic framework is considered under a bandwidth-centric approach named probabilistic bandwidth reservation scheme (PBRS). Though equal service times are usually assumed in the literature, the present analysis considers SCs of different service times. By employing Markov chain analysis to treat the independent SCs that correspond to different call specifications, analytical expressions for the call blocking probabilities (CBPs) are derived. The performance of the proposed CAC scheme is studied not only with regard to CBP but, also, taking into account the priorities assigned to different SCs as well as fairness among various SCs and total network throughput. The proposed probabilistic framework allows the dynamic control of network resources considering also priority assignment, fairness and throughput. Analytical results concerning delay tolerant (DT) and delay-non-tolerant (DNT) traffic have been obtained applying the proposed scheme. Moreover, the relevant simulations have verified the accuracy of the proposed analysis.

Power-based multi-cell call admission control scheme for wideband-CDMA systems

Wideband code division multiple access (WCDMA) systems are interference-limited. When a WCDMA system operates at nearly full capacity, admitting a new user may affect the stability of the system. Therefore, the proper call admission control (CAC) is crucial and should balance between quality of service (QoS) requirements for the new user as well as for the existing users and the required high capacity. In this paper, we investigate this trade-off in the uplink direction using a power-based multi-cell admission control (MC-AC) algorithm. Multimedia services are considered with different QoS requirements in this algorithm. Different traffic scenarios are also considered. Simulation results reveal that the proposed MC-AC algorithm has many advantages over single-cell admission control (SC-AC) in terms of the overall stability of the system and the total system throughput.

Investigation of capacity and call admission control schemes in TD-SCDMA uplink systems employing smart antenna techniques

Due to the TDMA (time division multiple access)-time division duplex (TDD) specialization in the uplink (UL) of code division multiplex access (CDMA) systems, some advanced techniques, such as smar...

A novel dynamic call admission control policy for wireless network

To address the issue of resource scarcity in wireless communication, a novel dynamic call admission control scheme for wireless mobile network was proposed. The scheme established a reward computing model of call admission of wireless cell based on Markov decision process, dynamically optimized call admission process according to the principle of maximizing the average system rewards. Extensive simulations were conducted to examine the performance of the model by comparing with other policies in terms of new call blocking probability, handoff call dropping probability and resource utilization rate. Experimental results show that the proposed scheme can achieve better adaptability to changes in traffic conditions than existing protocols. Under high call traffic load, handoff call dropping probability and new call blocking probability can be reduced by about 8%, and resource utilization rate can be improved by 2%–6%. The proposed scheme can achieve high source utilization rate of about 85%.

Design and analysis of an adaptive guard channel based CAC scheme in a 3G-WLAN integrated network

In wireless networks, guard channel based Call Admission Control(CAC) schemes are widely used to protect handoff calls for seamlesswireless services. However, the introduction of guard channelsin wireless networks results in the increase in the new callblocking probability. This general situation also occurs in a3G-WLAN integrated network. To solve this problem in a 3G-WLANintegrated network for QoS support, we propose an adaptive guardchannel based CAC scheme in this paper. Themain objective of our guard channel based CAC scheme is to alleviatethe increase in the new call blocking probability due to guardchannels while it can still protect handoff calls. For thedesign of our adaptive guard channel based CAC scheme, we firstdevelop and analyze a performance model for a general guard channelbased CAC scheme based on a level-dependent quasi birth and deathmodel. The analytic results are used to design our adaptive guard channelbased CAC scheme. Numerical studies show that our adaptiveguard channel based CAC scheme can achieve its objective and its performance is near optimal.

Voice Communications over 802.11 Ad Hoc Networks: Modeling, Optimization and Call Admission Control

Supporting quality-of-service (QoS) of multimedia communications over IEEE 802.11 based ad hoc networks is a challenging task. This paper develops a simple 3-D Markov chain model for queuing analysis of IEEE 802.11 MAC layer. The model is applied for performance analysis of voice communications over IEEE 802.11 single-hop ad hoc networks. By using the model, we finish the performance optimization of IEEE MAC layer and obtain the maximum number of voice calls in IEEE 802.11 ad hoc networks as well as the statistical performance bounds. Furthermore, we design a fully distributed call admission control (CAC) algorithm which can provide strict statistical QoS guarantee for voice communications over IEEE 802.11 ad hoc networks. Extensive simulations indicate the accuracy of the analytical model and the CAC scheme.

Performance Analysis of Multi-Parametric Call Admission Control Strategies in Un-Buffered Multi-Service Cellular Wireless Networks

In this paper model of integrated voice/data cellular wireless networks (CWN) are investigated. The unified approximate approach to calculate the desired Quality of Service (QoS) metrics in an isolated cell of such networks under two multi-parametric call admission control (CAC) strategies is developed. One of them is based on the guard channels scheme while the second is based on a threshold scheme. Results of the numerical experiments are given and a comparison of QoS metrics under different CAC strategies is carried out.

Admission control scheme of extended rtPS algorithm for VoIP service in IEEE 802.16e with adaptive modulation and coding

The extended real time polling service (ertPS) algorithm is added toIEEE 802.16e-2005 standards so that voice over internet protocol(VoIP) service could use resources efficiently by considering on/offcharacteristic of voice source. The IEEE 802.16e standard employsadaptive modulation and coding (AMC) to maximize transmission rateby assigning variable rate in accordance with the user'stime-varying channel conditions determined mainly by distance frombase station (BS) to mobile subscriber station (MSS). In order toapply AMC, we divide a cell into two zones with different averagesignal-to-noise ratio (SNR) where each zone uses its own onetransmission mode. In this paper, we construct 3-dimensional Markovprocess of M/G/1 type whose steady state probability is obtainedby the matrix analytic method. By using the steady state probabilityof Markov process, we obtain the probability distribution ofqueueing delay and find the admissible region of VoIP users with therequired constraint on delay bound. Next, we propose a calladmission control (CAC) scheme by considering two admissible regionsfor handoff calls and new calls satisfying constraints on delaybound and dropping probability of handoff call. In order to finddropping probability of handoff call and blocking probability of newcall, we construct Markov chain model of proposed CAC scheme atcall-level. By the mathematical results of packet-level andcall-level, we obtain admissible region to admit new call andadmissible region to admit handoff call satisfying the requiredconstraints on delay bound and dropping probability of handoff call.

Call Admission Control with Load-Balancing Capability in Integrated Cellular/WLAN Networks

We propose a call admission control scheme in cellular and wireless local area networks (WLANs) integration: integrated service-based admission control with load-balancing capability (ISACL). The novel aspects of the ISACL scheme include that load transfer in the cellular/WLAN overlapping areas is allowed for the admission of originating data calls from the area with cellular access only and vertical handoff requests to the cellular network. Packet-level quality of service (QoS) constraints in the WLANs and other-cell interference in the code division multiple access (CDMA) cellular network are taken into account to derive the WLANs and cellular capacity. We model the integrated networks using a multi-dimensional Markov chain and the important performance measures are derived for effective optimization of the admission parameters. The analytical model is validated by a computer simulation. The variation of admission parameters with traffic load and the dependence of resource utilization on admission parameters are investigated. It is shown that optimal balancing of the traffic load between the cellular network and WLANs results in the maximum resource utilization. Numerical results demonstrate that substantial performance improvements can be achieved by applying the proposed ISACL scheme.