• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.6
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• pp.1522-1545
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• 2012

Call admission control (CAC) plays an important role in mobile cellular network to guarantee the quality of service (QoS). In this paper, a dynamic hybrid CAC scheme with integrated cutoff priority and handoff queue for mobile cellular network is proposed and some performance metrics are derived. The unique characteristic of the proposed CAC scheme is that it can support any number of service types and that the cutoff thresholds for handoff calls are dynamically adjusted according to the number of service types and service priority index. Moreover, timeouts of handoff calls in queues are also considered in our scheme. By modeling the proposed CAC scheme with a one-dimensional Markov chain (1DMC), some performance metrics are derived, which include new call blocking probability ($P_{nb}$), forced termination probability (PF), average queue length, average waiting time in queue, offered traffic utilization, wireless channel utilization and system performance which is defined as the ratio of channel utilization to Grade of Service (GoS) cost function. In order to validate the correctness of the derived analytical performance metrics, simulation is performed. It is shown that simulation results match closely with the derived analytic results in terms of $P_{nb}$ and PF. And then, to show the advantage of 1DMC modeling for the performance analysis of our proposed CAC scheme, the computing complexity of multi-dimensional Markov chain (MDMC) modeling in performance analysis is analyzed in detail. It is indicated that state-space cardinality, which reflects the computing complexity of MDMC, increases exponentially with the number of service types and total channels in a cell. However, the state-space cardinality of our 1DMC model for performance analysis is unrelated to the number of service types and is determined by total number of channels and queue capacity of the highest priority service in a cell. At last, the performance comparison between our CAC scheme and Mahmoud ASH's scheme is carried out. The results show that our CAC scheme performs well to some extend.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.12
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• pp.529-538
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• 2002

Conventional method to reduce the handoff call blocking probability(PBH) in mobile communication system is to reserve a predetermined number of channels only for handoff calls. To determine the number of reserved channels, an optimization problem, which is generally computationally heavily involved, must be solved. In this Paper, we propose a call admission control (CAC) scheme that can be used to reduce the PBH without reserving channels in advance. For this, we define a new measure, gain, which depends on the state of the system upon the arrival of a new call. The proposed CAC decision rule relies on the gain computed when a new call arrives. SRN, an extended stochastic Petri nets, provides compact modeling facilities for system analysis can be calculated performance index by appropriate reward to the model. In this Paper, we develop SRN models which can perform the CAC with gain. The SRN models are 2 level hierarchical models. The upper layer models are the structure state model representing the CAC and channel allocation methods considering QoS with multimedia traffic The lower layer model Is to compute the gain under the state of the upper layer models.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.9A
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• pp.1013-1021
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• 2004

In the WCDMA mobile multimedia communication system, the adaptive array antenna IS adopted to improve the performance of the system by reducing inter-user interference using antenna beam control. Usually, the interference resulted from the higher data rate users is much more significant to the lower data rate users than the other way around, so the overall performance can be enhanced by reducing the interference from higher data rate users. In order to maximize the efficiency of adaptive antenna operation, an optimal call admission control, especially during handoff, adaptive to the data rates is a critical problem. In this paper, We propose a call admission control algorithm based on the Soft QoS concept for the efficient processing of the handoff of higher data rate calls, and an adaptive handoff control mechanism according to the data rates. The proposed algorithm has been evaluated by computer simulation that it accommodates high data rate users among many lower data rate users much better, and the average call blocking probability for lower rate users becomes much lower than the conventional call admission control algorithm.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.6
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• pp.205-212
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• 2003

Because a wireless ad hoc network does not have fixed infrastructure, a call admission control approach researched in a wireless network is not feasible to this network. In this paper, we propose call admission control scheme to support this problem and the burst handoff traffic due to group mobility in a wireless ad hoc network. This scheme is an adaptive guard channel scheme which adapt the number of guard channels in each MBS(mobile base station) according to the current estimate of the potential handoff call rate derived from the number of ongoing calls within the coverage area of an MBS that initiate group handoff in a wireless ad hoc network. Our simulation studies are performed for comparisons of the proposed scheme with the other channel allocation schemes. Simulation results show that the proposed scheme efficiently reduces handoff call blocking probability in wireless ad hoc networks.

• Proceedings of the IEEK Conference
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• summer
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• pp.185-188
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• 2004

Sufficient bandwidth that can support multimedia service has to be provided in the next generation wireless communication system. In this paper, the effective handoff scheme considering the position of mobile terminal is proposed. In addition, the dynamic channel allocation scheme is proposed. The shared channel in this algorithm can reduce more the blocking probability and the dropping probability. The proposed algorithms are simulated by SMPL library in C language. The simulation results show that the blocking probability and the dropping probability of the call can be reduced up to $60\%\;and\;10\%$ using the proposed algorithms, respectively.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.469-470
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• 2007

We used the non-reversible hierarchical scheme and the fixed channel assignment scheme for the strategy of call processing at hierarchical cellular system. We analyzed the performance of system according to the number of channel assigned at macrocell out of the usable channel at global system. Microcell is assigned the channel excepted the channel assigned at macrocell. The more the channel was aigned at macrocell, the more decreased the blocking probability became. The blocking probability of microcell had similar trend.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.30B no.10
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• pp.86-94
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• 1993

This paper presents the two-stage neural network method for efficient channel assignment of cellular mobile radio network. The first stage decomposes the region into non-adjacent groups of cells and the second stage assigns channels to the decomposed groups. The neural network model is tested with an experimental system of eighteen channels dedicated for nineteen hexagonal-cell region. When radom call requests of average density of 2 Erl/Cell to 8 Erl/Cell are presented, the real-time channel assignment method reduces the call-blocking rate up to 16% against the existing SCA(Static Channel Assignment) method.

• Journal of KIISE:Computer Systems and Theory
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• v.26 no.2
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• pp.223-231
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• 1999

본 논문은 두 개의게이트웨이를 사용한 격자구저망에서 최적의 게이트웨이 위치 설정을 위한 알고리즘을 제안하고 원리를 유도하였다. 최적의 게이트웨이 위치란 격자구조망내 각 노드에서 게이트웨이까지의 평균 최소 링크 수를 가지는 위치로 정의한다. 두 개의 게이트웨이르 사용함으로써 망내의 신뢰도 향상 효과를 가져오며, 우회 경로로 인한 호차단 확률(call blocking probability)과 호설정시간(call setup time)을 최소화한다. 따라서 본 논문에서는 망의 성능을 향상시키기 위하여 두 개의 게이트웨이의 최적의 위치를 결정하는 Grid-Traverse 알고리즘을 제안하고 설정원리들을 유도하여 , 수학적 귀납법으로 이 원리들을 증명하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1999.05a
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• pp.295-300
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• 1999

In Wireless ATM Networks, the mobility management of that is used currently have been studying variously. In this paper, we show the properties of location registration, update, and handoff control mechanism of these first. And then, for frequent handoff occurring condition under minimized cellular environment by degrees, we did comparison and analysis focucing on handoff delay, call-blocking rate and call-dropping rate with communication break-time and velocity variation.

• 전자공학회논문지 IE
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• v.48 no.4
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• pp.47-52
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• 2011

In this paper, we analyse the performance of cellular system for call admission method considering to various service types. The call admission control method using the effective bandwidth concept is employed in this paper. In addition, the bandwidth for a new calls and a handover calls is allocated by taking account of the blocking rate of new calls and the dropping rate of handover calls. We reserved wireless resource and used waiting buffer for hanover calls. We simulated using computer for the performance analysis of system.