• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.1
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• pp.186-205
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• 2019

Intercell interference coordination (ICIC) is considered as a promising technique to increase the spectral efficiency of OFDMA cellular systems. The soft frequency reuse (SFR) and fractional frequency reuse (FFR) are representative and efficient management techniques for ICIC. Herein, to enhance the performance of the SFR scheme, we propose a call admission (CAC) scheme. In this CAC scheme, called Spectrum handoff-SFR(S-SFR), the spectrum handoff technique is applied to the user equipment (UE) located near the cell center. We derive the traffic analysis model to describe the S-SFR. In addition, a two-dimensional (2-D) Markov chain and an outage analysis are used in our analytical model. From the traffic analysis, the significant performance measures are the outage probability, call blocking probability, system throughput and resource utilization. Based on those, the outage probability and system throughput are obtained using resource utilization as an interference pattern. The analytical results are verified with computer simulation results. Finally, we compare our proposed scheme with other ICI schemes.

• Journal of Advanced Navigation Technology
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• v.13 no.3
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• pp.372-377
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• 2009

This paper evaluates the performance of three methods for predicting resources requested by mobile's calls and a call admission algorithm based on these predicting methods respectively in wireless networks. The first method is based on Wiener prediction model and the second method is based on the MMOSPRED algorithm and the third method is based on the neural network. The proposed call admission algorithm is based on prioritized handoff call in resource allocation. The resources for future handoff calls are therefore predicted and reserved in advance, and then new calls are admitted as long as the remaining resources are sufficient. We compare their performances in terms of prediction error, new call blocking and handoff dropping probabilities by simulation. Results show that the CAC based on Wiener prediction model performs favorably due to exact resources prediction.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.37 no.6
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• pp.1-11
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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 Communications and Networks
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• v.11 no.2
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• pp.104-114
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• 2009

In this paper, a technique is proposed that enables secondary users to evaluate channel availability in cognitive radio networks. Here, secondary users estimate the utilization of channels via predicting the traffic pattern of primary user, and select a proper channel for radio transmission. The proposed technique reduces the channel switching rate of secondary users (the rate of switching from one channel to another) and the interference on primary users, while maintaining a reasonable call blocking rate of secondary users.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1987.04a
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• pp.79-81
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• 1987

The traffic characteristicsof digitalswich network depend on the structure blocking probability, path searching method and etc. This paper presents the study of TDX-1 swicth network traffic capacity by considering some decisive factors such as call processing software, switch network structrure and control schme Conclusively the study shows that the switch network of TDX-1 can handle approximately up to 1650 Erlang.

• Journal of applied mathematics & informatics
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• v.33 no.1_2
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• pp.211-217
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• 2015

A dynamic spectrum access scheme with channel partitioning for secondary handover calls in cognitive radio networks is proposed to reduce forced termination probability due to spectrum handover failure. A continuous-time Markov chain method for evaluating its performance such as blocking probability, forced termination probability, and throughput is presented. Numerical and simulation results are provided to demonstrate the effectiveness of the proposed scheme with channel partitioning.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.158-161
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• 1999

This Paper proposes the architecture of WDM(wavelength division multiplexed) based large scale photonic packet switch network, which is composed of the FC(frequency converter) and OM (output module). The features of the proposed WDM based photonic packet switch network are 2-stage switch network, and WDM based internal optical link that is connected between FC and OM. This paper evaluates the internal call blocking characteristics of the photonic packet switch network. In results, we confirmed that the proposed WDM based photonic packet switch network has the potentiality in the practical implementation.

• Journal of the Korea Society for Simulation
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• v.8 no.2
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• pp.101-109
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• 1999

In a commercial facsimile network system, a simulation analysis has been performed using ARENA due to the unavailability of theoretical models. The effect of a priority is compared with that of the current FCFS rule on the arriving call blocking rate and transmission time delay. The result shows that the priority rule reduces more service time delay as the arrival rate increases. A simulation analysis procedure is proposed to select optimal in/out port ratio at various hourly arrival rates with a given multiple-place transmission requests ratio.

• ETRI Journal
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• v.28 no.3
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• pp.371-374
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• 2006

We propose and analyze a priority queuing scheme that gives priority in the same class of calls according to their total resource requirements (TRRs). The proposed scheme gives a higher priority to the calls that have a lower TRR over the calls that have a higher TRR. The numerical results show that the proposed priority queuing scheme provides better performance than the traditional queuing schemes in call blocking probability.

• 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.