• ETRI Journal
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• v.39 no.3
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• pp.345-352
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• 2017

Traffic management is a highly beneficial mechanism for satisfying quality-of-service requirements and overcoming the resource scarcity problems in networks. This paper introduces an optimal connection admission control mechanism to decrease the packet loss ratio and end-to-end delay in cognitive radio sensor networks (CRSNs). This mechanism admits data flows based on the value of information sent by the sensor nodes, the network state, and the estimated required resources of the data flows. The number of required channels of each data flow is estimated using a proposed formula that is inspired by a graph coloring approach. The proposed admission control mechanism is formulated as a semi-Markov decision process and a linear programming problem is derived to obtain the optimal admission control policy for obtaining the maximum reward. Simulation results demonstrate that the proposed mechanism outperforms a recently proposed admission control mechanism in CRSNs.

• Journal of the Korea Society of Computer and Information
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• v.6 no.3
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• pp.72-77
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• 2001

The method of connection admission control is presented by using the equations related with traffic classes for real-time connection admission control. without assuming the cell arrival processes in the multi-level structure of ATM traffic control. The equations related with traffic classes are obtained by 3 or 4 of first order inequalities from the admissible ranges of connection considering the expected total instantaneous demand to guarantee the required quality of services of each class.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.20 no.41
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• pp.51-60
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• 1997

In this paper, A Connection Admission Control(CAC) algorithm by Dynamic Bandwidth Allocation is proposed. The B-ISDN will be required to carry traffic generated by a various traffic sources. These source will have all traffic flow characteristics and quality of services requirements. When a connectionless message with burstiness arrives at a node during a renewal period, CAC will be dynamically determined connection request by using the predetermined connection admission bounds in estimating the number of input arriving cells. The proposed algorithm estimates the available bandwidth by observing cell streams of the aggregate traffic. A connection request is accepted if the available bandwidth is larger than declared peak rate, and otherwise rejected. The proposed CAC scheme is shown to be promising and practically feasible in obtaining efficient transmission of burst traffic with guaranteed quality of services.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.3
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• pp.593-603
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• 1997

Connection admission decision in ATM networks requires decision made in real time using fast algorithm. It is difficult to construct a model of the multiplexed traffic and thus, approximation of the traffic load is necessary. In this paper, we propose a measurement-based dynamic CAC(Connection admission Control) in ATM(Asynchronous Transfer Mode) networks, which observes current traffic by the moving window and set the window size to the value which is computed from the measured cell loss amount. It is based on the measurements of the traffic load over an admission period that is load enough to reflect the current traffic behavior instead of analytic modeling. And, the dynamic reallocation of bandwidth for each class leads to effective bandwidth utilization. The performance of proposed method is analyzed through computer simulation. The performance of proposed method is analyzed by using SIMAN simulation package and FORTRAN language. As can be seen in the simulation result, cell loss performance and bandwidth utilization have been increased.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.4B
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• pp.338-344
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• 2002

This paper proposes a transient (predictive) connection admission control (CAC) scheme using the transient quality of service (QoS) measure for CDMA cellular systems with bursts On-Off sources. We need an approximate and bounded approach for real-time CAC applications. We derive the transient outage probability as the QoS measure using the Chernoff bound and the refuted large deviation approximation. Numerical results show that the predictive CAC is a promising approach for the multicell CDMA systems.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.6A
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• pp.927-934
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• 2000

In this paper, we propose a predictive(transient) connection admission control(CAC) scheme for satellite systems that supports on-board packet switching of multimedia traffic with predefined quality of service(QoS) requirements. The CAC scheme incorporates the unique characteristics of satellite systems, e.g. large propagation delays, no onboard buffer, and low computational requirement. The CAC scheme requires the estimation of the On-Off traffic characteristics ($\lambda$, $\mu$) of the traffic sources. These estimated values are used to predict the transient cell loss ratio at each downlink. In case the QoS requirements are not met the proposed CAC scheme rejects the new connection. The numerical results obtained suggest that the proposed scheme is an excellent candidate for real time burst and cell level connection prediction and control in broadband on-board satellite networks.

• Journal of KIISE:Information Networking
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• v.29 no.2
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• pp.181-187
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• 2002

Connection admission control(CAC), which decides whether or not to accept a new call request, is one of the most Important preventive congestion control techniques in asynchronous transfer mode(ATM) networks. To develop a practical CAC scheme, first we propose a "Modified Cell Loss Probability MP${\nu}"$, which is based on "Virtual Cell Loss Probability P${\nu}"$, taking into account mean burst duration of input traffic source and buffer size in ATM networks. MP${\nu}"$ computes more accurate cell loss probability than P${\nu}"$ without increasing computational complexity, since P${\nu}"$ is formulated simply form the maximum and the average cell rate of input traffic. P${\nu}"$ is overestimated as compared to the real cell loss probability when the mean burst duration is relatively small to the buffer capacity. Then, we Propose a CAC scheme, based on "Modified Virtual Bandwidth(MVB)" method, which may individualize the cell loss probabilities in heterogeneous traffic environments. For the proposed approach, we define the interference intensity to identify interferences between heterogeneous traffic sources and use it as well as MP${\nu}"$ to compute MVB. Our approach is well suitable for ATM networks since it provides high bandwidth utilization and guarantees simple and real time CAC computation for heterogeneous traffic environments.heterogeneous traffic environments.

• ETRI Journal
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• v.22 no.4
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• pp.40-50
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• 2000

We apply a "sliding-window" Maximum Likelihood(ML) estimator to estimate traffic parameters On-Off source and develop a method for estimating stochastic predicted individual cell arrival rates. Based on these results, we propose a simple Connection Admission Control(CAC)scheme for delay sensitive services in broadband onboard packet switching satellite systems. The algorithms are motivated by the limited onboard satellite buffer, the large propagation delay, and low computational capabilities inherent in satellite communication systems. We develop an algorithm using the predicted individual cell loss ratio instead of using steady state cell loss ratios. We demonstrate the CAC benefits of this approach over using steady state cell loss ratios as well as predicted total cell loss ratios. We also derive the predictive saturation probability and the predictive cell loss ratio and use them to control the total number of connections. Predictive congestion control mechanisms allow a satellite network to operate in the optimum region of low delay and high throughput. This is different from the traditional reactive congestion control mechanism that allows the network to recover from the congested state. Numerical and simulation results obtained suggest that the proposed predictive scheme is a promising approach for real time CAC.

• The Transactions of the Korea Information Processing Society
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• v.4 no.7
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• pp.1788-1796
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• 1997

In this paper, we propose a new connection admission control(CAC) algorithm for traffic control in ATM network in which traffic estimation is performed based on user-specified parameters at every moment of connection request or connection release by recursive formula which makes real-time calculation possible. And traffic estimation using cell flow measurement is carried out when the number of connectioned calls does not change during a measurement reflection period. Performance analysis of the proposed method is carried out using several aspects for homogeneous and heterogeneous bursty traffic. The results showed that the proposed CAC method revealed better performance, than conventional CAC method for burst model in both utilization and QoS point of view.

• ETRI Journal
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• v.28 no.5
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• pp.593-606
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• 2006

Thanks to the great possibilities of providing different types of telecommunication traffic to a large geographical area, satellite networks are expected to be an essential component of the next-generation internet. As a result, issues concerning the designing and testing of efficient connection-admission-control (CAC) strategies in order to increase the quality of service (QoS) for multimedia traffic sources, are attractive and at the cutting edge of research. This paper investigates the potential strengths of a generic digital-video-broadcasting return-channel-via-satellite (DVB-RCS) system architecture, proposing a new CAC algorithm with the aim of efficiently managing real-time multimedia video sources, both with constant and high variable data rate transmission; moreover, the proposed admission strategy is compared with a well-known iterative CAC mainly designed for the managing of real-time bursty traffic sources in order to demonstrate that the new algorithm is also well suited for those traffic sources. Performance analysis shows that, both algorithms guarantee the agreed QoS to real-time bursty connections that are more sensitive to delay jitter; however, our proposed algorithm can also manage interactive real-time multimedia traffic sources in high load and mixed traffic conditions.