• Journal of the Institute of Electronics Engineers of Korea TC
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• v.37 no.6
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• pp.361-361
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• 2000

In this paper, we propose a novel control signaling protocol that efficiently controls connection setup and increases the utilization of network resources. The proposed protocol, Separated Control Signaling Protocol(SCSP), separates bearer control from call control lot WDM optical networks. The main function of call control is to check the availability of network resources such as wavelengths and receivers at destination node. Bearer control is to reserve and assign wavelengths. The signaling architecture of this protocol consists of call controller and hearer controller The call controller handles call setup and release, activates the beater controller, and manages the status of call and bearer. The bearer controller reserves wavelengths, sets up bearer, tears down bearer. and notifies the status of beater to call controller. The state transition diagrams of each controller are designed. Using control messages and related primitives, the information flows for call setup and bearer setup, hearer teardown and call release, and reaction for setup failures are described to evaluate the performance. The simulation results show that the separated control signaling protocol is superior to conventional one in terms of call blocking probability and resource utilization.

• 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.

• Journal of Digital Contents Society
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• v.3 no.1
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• pp.89-99
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• 2002

Saturation routing algorithm is known to be an effective routing mechanism for tactical application and packet radio networks, since it minimizes the call set-up time and does not have to maintain routing tables. But, it is known that it has significant drawbacks with respect to the network efficiency, the overhead on the control messages [1]. We consider a tactical circuit-switched grid network with a maximum of tour links and two priority classes of voice traffic. Using the minimum first-derivative length (MFDL) path, we improve the blocking probability performance of a circuit-switched network without increasing the call set-up time and processor loading of the algorithm.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.10
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• pp.2586-2596
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• 1996

The handover area is the region where a call can be handled by the base stations in any of the adjacent cells, and handover duration time is viewed as the time an mobile station resides inthe handover area. In this paper, analytic model to estimate the distribution function(df) of the handover duration time is proposed. Based on the df of the handover duration time, the simulation and anlytic models for the First Come first Serve(FCFS) scheme are presented, and the simulation results for the Measurement Based Prioritization Scheme(MBPS) are compared with the analytic results of the FCFS handover scheme. Those results show that the MBPS scheme is seen to provide lower handover failures than FCFS queueing with slightly increasing the new call blocking probability.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.6
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• pp.1265-1270
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• 2011

Different wireless technologies have been developed for various mobile applications. To offer seamless service in next mobile communication systems, it needs handoff service between heterogeneous mobile access networks. A high data rate handoff call from WLAN to cellular mobile network can increase rapidly the blocking probability of BS of cellular mobile network. To solve this problem, this paper proposes a new handoff scheme based on user service profiles. The performances of the proposed scheme are evaluated using computer simulations.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.10
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• pp.2376-2394
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• 2013

In order to ensure both of the whole system capacity and users QoS requirements in heterogeneous wireless networks, admission control mechanism should be well designed. In this paper, Multi-agent Q-learning based Admission Control Mechanism (MQACM) is proposed to handle new and handoff call access problems appropriately. MQACM obtains the optimal decision policy by using an improved form of single-agent Q-learning method, Multi-agent Q-learning (MQ) method. MQ method is creatively introduced to solve the admission control problem in heterogeneous wireless networks in this paper. In addition, different priorities are allocated to multiple services aiming to make MQACM perform even well in congested network scenarios. It can be observed from both analysis and simulation results that our proposed method not only outperforms existing schemes with enhanced call blocking probability and handoff dropping probability performance, but also has better network universality and stability than other schemes.

• Journal of Information Processing Systems
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• v.2 no.2
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• pp.88-94
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• 2006

In wireless cellular networks, previous researches on admission control policies and resource allocation algorithm considered the QoS (Quality of Service) in terms of CDP (Call Dropping Probability) and CBP (Call Blocking Probability). However, since the QoS was considered only within a predetermined cell capacity, the results indicated a serious overload problem of systems not guaranteeing both CDP and CBP constraints, especially in the hotspot cell. That is why a close interrelationship between CDP, CBP and cell capacity exists. Thus, it is indispensable to consider optimal cell capacity guaranteeing multiple QoS (CDP and CBP) at the time of initial cell planning for networks deployment. In this paper, we will suggest a distributed determination scheme of optimal cell capacity guaranteeing both CDP and CBP from a long-term perspective for initial cell planning. The cell-provisioning scheme is performed by using both the two-dimensional continuous-time Markov chain and an iterative method called the Gauss-Seidel method. Finally, numerical and simulation results will demonstrate that our scheme successfully determines an optimal cell capacity guaranteeing both CDP and CBP constraints for initial cell planning.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.3A
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• pp.129-139
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• 2003

CAC is a very important issue in CDMA system in order to protect the required QoS(quality of service) and increase the system's capacity. In this paper, we proposed and analyzed a call admission control scheme using multiple thresholds, which can provide quick processing time and better performance. There are two effective thresholds used to decide call admission. One is the number of active users, and the other is the signal to interference ratio(SIR). If the threshold of active users are lower than the low number of users threshold, we accept the new call without any other conditions. Otherwise, we check the current SIR to guarantee the quality of our service. System then accepts the new call when the SIR satisfies system requirement. Otherwise, the call will be rejected. Multiple threshold schemes are investigated and their performance is compared with the number of user and power based CAC's. simulation results are provided to evaluate the performance.

• Journal of the Korean Society of Industry Convergence
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• v.6 no.4
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• pp.401-404
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• 2003

In most resource reservation strategies, which give higher priorities to handoff calls over new calls, new calls are often blocked even though there is plenty of available reserved resource. This causes inefficient resource utilization, especially when there are not so many handoff attempts. In this paper, we propose a new reservationstrategy called soft reservation in which new calls can be allocated to the reserved resource while maintaining the QoS of handoff acceptable. Using an M/M/c/c queuing model, we can see that the proposed strategy provides better performance than the conventional reservation strategy in terms of blocking probability of new call and dropping probability of handoff calls.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.471-472
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• 2007

At this paper, we use non reversible hierarchical scheme and fixed channel assignment scheme at the hierarchical cellular system with macrocell and microcell for the call process strategy Using this strategy, we analyze the system performance in accordance with the various dwell time at each cell. In this simulation result, the more the dwell time is small at microcell, the more the blocking probability and the handover failure probability is low.