• The Transactions of the Korea Information Processing Society
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• v.4 no.6
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• pp.1589-1600
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• 1997

The construction of optical access network costs upper 40% in total installation cost of total optical network. Optimization of access network therefore is core in optical network. Advanced countries include EU, Japan and USA already have researched access network. This paper presents analysis of three broad-band fiber-optics subscriber loop architectures(HFC, ATM-PON, Super PON). The analyses focus on the specific demonstrated architectures and use component cost projections to estimate future network costs on a per-subscriber basis. We use TITAN(Tool for Introduction Scenarios and Techno-Economic Evaluation of The Access Network) model. We find that ATM-PON can deliver voice and ISDN data at installed first costs than the other architectures. This is due to the sharing bandwidth among a cluster of subscribers within Curb. This work intends to support establishing guidelines for strategic decisions regarding the development of the access network alternatives of different operators.

• Convergence Security Journal
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• v.21 no.2
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• pp.3-10
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• 2021

Nowadays, data-based scientific research is a trend, and the transmission of large amounts of data has a great influence on research productivity. To solve this problem, a separate network structure for transmitting large-scale scientific big data is required. ScienceDMZ is a network structure designed to transmit such scientific big data. In such a network configuration, it is essential to establish an access control list(ACL) for users and resources. In this paper, we describe the R&E Together project and the network structure implemented in the actual ScienceDMZ network structure, and define users and services to which access control policies are applied for safe data transmission and service provision. In addition, it presents a method for the network administrator to apply the access control policy to all network resources and users collectively, and through this, it was possible to achieve automation of the application of the access control policy.

• ETRI Journal
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• v.30 no.2
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• pp.301-307
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• 2008

As broadband access is evolving from digital subscriber lines to optical access networks, Ethernet passive optical networks (EPONs) are considered a promising solution for next generation broadband access. The point-to-multipoint topology of EPONs requires a time-division multiple access MAC protocol for upstream transmission. In this paper, we propose a new enhanced dynamic bandwidth allocation algorithm with fairness called EFDBA for multiple services over EPONs. The proposed algorithm is composed of a fairness counter controller and a fairness system buffer in the optical line terminal. The EFDBA algorithm with fairness can provide increased capability and efficient resource allocation in an EPON system. In the proposed EFDBA algorithm, the optical line termination allocates bandwidth to the optical network units in proportion to the fairness weighting counter number associated with their class and queue length. The proposed algorithm provides efficient resource utilization by reducing the unused remaining bandwidth made by idle state optical network units.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.12
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• pp.4293-4304
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• 2014

In order to ensure the wireless connectivity and seamless service to mobile users, the next generation network system will be an integration of multiple wireless access networks. In a heterogeneous wireless access system, bandwidth allocation becomes crucial for load balancing to avoid network congestion and improve system utilization efficiency. In this article, we propose a new dynamic bandwidth allocation scheme for hierarchical wireless network systems. First, we derive a multi-objective decision criterion for each access point. Second, a bargaining strategy selection algorithm is developed for the dynamic bandwidth re-allocation. Based on the intervenient Stackelberg game model, the proposed scheme effectively formulates the competitive interaction situation between several access points. The system performance of proposed scheme is evaluated by using extensive simulations. With a simulation study, it is confirmed that the proposed scheme can achieve better performance than other existing schemes under widely diverse network environments.

• Journal of the Korea Society for Simulation
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• v.8 no.2
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• pp.1-11
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• 1999

Advanced information communication processing system mainly consists of network access subsystems and a switching system. This paper provides performance analysis of a typical network access subsystem. The network access subsystem is modeled as a queueing network including a server providing polling services. The arrival process of messages to an input buffer is regarded as a Poisson process. Performance measures such as mean input buffer length and mean waiting time of meassages are obtained through simulation, for it is impossible to calculate the performance measures using an analytical method. Hybrid simulation is used to reduce the variance of estimators. The variance reduction effect on the mean waiting time is reported.

• ETRI Journal
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• v.28 no.3
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• pp.311-319
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• 2006

This paper presents a terminal-assisted frame-based packet reservation multiple access (TAF-PRMA) protocol, which optimizes random access control between heterogeneous traffic aiming at more efficient voice/data integrated services in dynamic reservation TDMA-based broadband access networks. In order to achieve a differentiated quality-of-service (QoS) guarantee for individual service plus maximal system resource utilization, TAF-PRMA independently controls the random access parameters such as the lengths of the access regions dedicated to respective service traffic and the corresponding permission probabilities, on a frame-by-frame basis. In addition, we have adopted a terminal-assisted random access mechanism where the voice terminal readjusts a global permission probability from the central controller in order to handle the 'fair access' issue resulting from distributed queuing problems inherent in the access network. Our extensive simulation results indicate that TAF-PRMA achieves significant improvements in terms of voice capacity, delay, and fairness over most of the existing medium access control (MAC) schemes for integrated services.

• Journal of the Korean Operations Research and Management Science Society
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• v.35 no.3
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• pp.45-58
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• 2010

Due to rapid developments of IT technologies, convergence services like IPTV (Internet protocol television) are shown up. Even though expert and customer had great expectations for this innovative service, commercialization was delayed for years by the legal dispute between industry players. One of the biggest problems was that whether internet backbone providers have to share their internet network backbone with IPTV service providers (which don't have network backbone) or not. As other countries, Korean government set the rules that ISP have to offer indiscriminate access to other IPTV service provider. At the same time, internet backbone providers can charge access charge based on cost by way of compensation. Thus access charge is very critical to the IPTV industry players. The objective of this paper is to provide model that can calculate the reasonable access charge by system dynamics, based upon real data in Korean telecommunication industry.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.9A
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• pp.762-771
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• 2005

In this paper, an efficient Adaptive quality-of-service (QoS) traffic control scheme with priority scheduling is proposed for the multimedia traffic transmission over wireless access networks. The objective of the proposed adaptive QoS control (AQC) scheme is to realize end-to-end QoS, to be scalable without the excess signaling process, and to adapt dynamically to the network traffic state according to traffic flow characteristics. Here, the reservation scheme can be used over the wireless access network in order to get the per-flow guarantees necessary for implementation of some kinds of multimedia applications. The AQC model is based on both differentiated service model with different lier hop behaviors and priority scheduling one. It consists of several various routers, access points, and bandwidth broker and adopts the IEEE 802.1 le wireless radio technique for wireless access interface. The AQC scheme includes queue management and packet scheduler to transmit class-based packets with different per hop behaviors (PHBs). Simulation results demonstrate effectiveness of the proposed AQC scheme.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.7
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• pp.76-91
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• 1996

In this paper, we proposed the new medium access control protocol for the virtual token bus netowrk. The network is applied to inter-processor communication network of large capacity digital switching system and digital mobile system with distributed control architecture. in the virtual token bus netowrk, the existing medium access control protocols hav ea switchove rtime overhead when traffic load is light or asymmetric according ot arbitration address of node that has message to send. The proposed protocol optimized average message delay using cyclic bus access chain to exclude switchover time of node that do not have message to send. Therefore it enhanced bus tuilization and average message delay that degrades the performance of real time communication netowrks. It showed that the proposed protocol is more enhacned than virtual token medium access control protocol and virtual token medium access control protocol iwth reservation through performance analysis.

• ETRI Journal
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• v.26 no.1
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• pp.13-20
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• 2004

We propose a new optical code division multiple access (OCDMA) scheme for reducing multiple access interference (MAI) and enhancing performance for optical subscriber access networks using modified pseudorandom noise (PN)-coded fiber Bragg gratings with bipolar OCDMA decoders. Through the bipolar OCDMA decoder and the modified PN codes, MAI among users is effectively depressed. As the data are encoded either by a unipolar signature sequence of the modified PN code or its complement according to whether the data bit is 1 or 0, the bit error ratio (BER) can be more improved with the same signal to interference plus noise ratio over the conventional on-off shift keying-based OCDMA system. We prove by numerical analysis that the BER of the proposed bipolar OCDMA system is better than the conventional unipolar OCDMA system. We also analyze the spectral power distortion effects of the broadband light source.