• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.1
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• pp.67-74
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• 2009

This paper presents a method of improving the service availability by distributing the traffic of voice/data calls over the multi-layer cells in a mobile communication network. The traffic model is described and the call handling performance is analyzed. In our method, a fast moving call is moved to and serviced in the upper layer cell. A call is also moved upward when an overflow occurs. But unlike other methods, the call that is moved upward in the overflow case is the one which has the longest sojourn time in the cell. Moreover, when the call that was moved upward due to overflow condition stays longer than a certain period of time in the upper layer cell, the system moves the call back to the lower layer in order to save the more expensive resources of the upper layer cell. Call handling performance of this method evaluated from M/M/C/K models shows clear improvement with respect to call blocking probability and forced termination probability.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.2 no.1
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• pp.59-70
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• 1998

In the wireless mobile exchange communication system, the proper handling of originating call(OC) and handover call(HC) is important. Specially, when it's viewed from the user side, mobile users feel more weighting soul disappointment with the handover blocking probability moving from current cell to adacent cell than with originating call blocking probability happening new call in current cell. Accordingly,this paper is proposed and analyzed the timeout buffer system and guard channel for decreasing handover blocking probability. In analytic result, The more guard channel increase,t he more originating call blocking probability increase and handover blocking probability decrease. Also, the more timeout duration increase, the more handover blocking probability decrease.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.12B
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• pp.1112-1122
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• 2008

This paper reviews the Parlay X and proposes SIP multimedia session control mechanism which is able to be implemented over IMS using Extended Call Control APIs of Parlay X. Parlay X is one of the industrial standards of Open API in the telecommunication to open network resources and capabilities to third party service providers. In this paper, SIP session control mechanism is described by depicting call flows of basic and essential session handling methods including session initiation, transfer, restoration, and termination. We also show how easy Parlay X Extended Call Control APIs can be used for the purpose of complicated calls handling in the IT applications. To verify feasibility of the blended services based on convergence of telecommunication and internet with regard to performance, we accomplish experimental performance of Extended Call Control APIs from IT application through open service gateway. We show Open API could be applied to next generation network based on IMS without serious degradation of the network performance.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.12
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• pp.145-154
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• 2003

In this paper we propose service schemes for the control message of voice and data connections served by a Softswitch in NGN (next generation networks). After that we propose a method of evaluating the performance of a Softswitch that provides a limited delay to voice connections. Via numerical experiments, we verify the implication of the proposition in the design of a Softswitch, which simultaneously incorporates voice and data services in the NGN framework.

• International Journal of Contents
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• v.1 no.2
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• pp.13-17
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• 2005

Base Station Controller which belongs to IMT-2000(International Mobile Telecommunication - 2000) network has several types of structure for efficient control protocol. This difference of structure occurs two different protocols for call handling. Recently the need of IMT-2000 is highly increasing, so it is important to analyze the performance of processors and IPC(Inter-Processor Communication) module with structure of BSC and protocol difference. This paper presents the performance comparison of different types of BSC in view of processor utilization, waiting time, queue length and QoS(Quality of Service) through the simulation model.

• Korean Management Science Review
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• v.10 no.1
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• pp.107-125
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• 1993

Modern telecommunication switching systems are SPC(Stored Program Control) machines handling voice, data and other kinds of traffic, in an environment which tends to be fully digital switching and transmission. The throughput of such systems is determined by the real time capacity of its centralized or distributed control processors and by the traffic capacity of the switching network. Designers must verify the traffic and call processing capacity of the switching system and check its performance under traffic load before it is put into service. Verification of traffic and call processing capacity of switching systems is one of the problems treated by teletraffic studies ; teletraffic studies are based on stochastic process, queueing theory, simulations and other quantitative methods of decision making. This study suggests the general methodology to evaluate the throughput and performance of the ISDN switching system. TDX-10 ISDN switching system are employed to give illustrative examples of the methodologies discussed in this study.

• Journal of Korean Institute of Industrial Engineers
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• v.13 no.2
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• pp.17-34
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• 1987

Modern telecommunication switching systems are SPC (Stored Program Control) machines handling voice, data and other kinds of traffic, in an environment which tends to be fully digital switching and transmission. The throughput of such systems is determined by the real time capacity of its centralized or distributed control processors and by the traffic capacity of the switching network. Designers must verify the traffic and call processing capacity of the switching system and check its performance under traffic load before it is put into service. Verification of traffic and call processing capacity of switching systems is one of the problems treated by teletraffic studies; teletraffic studies are based on stochastic process, queueing theory, simulations and other quantitative methods of decision making. This paper reviews the general methodologies to evaluate the throughput and performance of the digital switching system. TDX-10, which is a fully digital switching system under development in ETRI, is employed to give illustrative examples of the methodologies discussed in this paper.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.12A
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• pp.1868-1875
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• 1999

The design of LAI(Local Area Identifier), the first paging area for searching the mobile terminal has a close relation with the performance of paging channel in CDMA cellular network. This paper discussed the performance of the forward channel of IS-95 CDMA standard, known as the paging through the related messages such as call control message, channel assignment message, etc. Modeling and simulation work were conducted to quantify the performance of paging channel in terms of traffic handling capacity and blocking levels. The results shown are based on a specific system call model based on the operating system of cell cite. This serves as illustrative guidelines for the proper engineering of common control channel, which has a major impact on the overall performance of cellular network.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.7
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• pp.1321-1334
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• 1994

This paper presents the service handling schemes of an intelligent peripheral(IP) which provides the service function as a physical entity in the intelligent network. Four service request handling scheme are compared for and IP which can handle both ordinary requests and prioritized requests on the blocked-call-delayed basis. Delayed requests are assumed to be stored in a finite storage buffer. Scheme-I exclusively allows prioritized requests be stored and to use a fixed number of reserved servers. The other three schemes without reserved servers(Scheme-II.III,and IV) allow both types of requests to be stored and prioritized requests pushout ordinary requests if the buffer is full. For these four schemes, the blocking probabilities and delay distributions of both types of requests are numerically obtained. From the numericall results, the schemes without reserved servers reduce the blocking probability of ordinary requists without a severe penalty on proritized requests. For three schemes without reserved servers, it is noted that prioritized requests should br served on the first-in, first-out basis, and ordinary requests should be served on the last-in, first-out basis.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.4
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• pp.449-459
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• 2015

A lot of people were trapped in elevators without power supply when BLACK-OUT situation occurred in 2011. The telephone network of control room connected to the elevators had problem operating poorly. In this paper we propose an ICT based elevator emergency call device prototype system and evaluate the performance of the system. The proposed system quickly responds in emergency situation to guarantee passenger safety. For the goal, firstly the system tries to connect to a control room. If it fails the system attempts to call numbers for emergency contact and a rescue team sequentially. The system is designed to quickly support emergency contact as well. Finally, the information of elevator failure is rapidly transferred to the failure process device by the proposed system.