• 한국광학회:학술대회논문집
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• 한국광학회 2006년도 하계학술발표회 논문집
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• pp.525-526
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• 2006

Ethernet Passive Optical Networks (EPON) are an emerging access network technology that provide a low-cost method of deploying optical access lines between a central office (CO) and a customer site. This paper shows that subscriber unit manages traffic data between a central office (CO) and a customer site in economic solution.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 1998년도 추계학술대회 논문집
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• pp.245-248
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• 1998

In this paper, as a forecasting method, the market survey for forecasting demand is introduced for the estimation of subscriber line demand in the optical access networks. The market survey method for the new multimedia services is attempted to collect information directly from customers using the questionnaires for home-users and business-users in local loops. Analysis rationale of questionnaires is suggested to estimate the number of subscriber lines. Also, two measures are presented to quantify the credibility on survey responses; one is the probability that the customer will use the multimedia services and the other is the rate that the subscriber line demand will be actually realized. The former measure is calculated based on the information on customers and the Logit analysis. The latter is obtained by the degree of customer's knowledge about specific services and the customer's willingness to use the services. Based on the values of two measures, the number of subscriber line demand can be developed for installing the optical access networks.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2008년도 정보통신설비 학술대회
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• pp.287-291
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• 2008

DWDM(dense wavelength division multiplexing)-PON technology is applied to subscriber network as the same as E-PON or G-PON. And its network components consist of OLT, ONU and RN. Legacy DWDM technologies have been applied on the long-haul part of optical network due to its excessive high cost. But many researchers have successfully devised a few methods which can considerably reduce the cost of equipment. Nowadays DWDM-PON equipment's has arrived to a level having a competitive price in comparison to E-PON or G-PON on condition of giving equal bandwidth. Recently a major domestic ISP has deployed DWDM-PON equipments in one apartment complex area in the purpose of satisfying ever-increasing bandwidth demand. The ISP increased data transmission capacity from 1 G to 16G without any additional fiber deployment. In this paper we introduce roughly three technologies of implementing DWDM-PON's optic module and related optic devices. And we also describe pre-test of vendor's DWDM-PON equipment and discuss the result. Lastly we propose some of network configurations which adopt DWDM-PON technology. By adopting DWDM-PON technology ISP can greatly save the cost of deploying broadband subscriber network.

• 정보통신설비학회논문지
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• 제9권2호
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• pp.56-67
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• 2010

Optical fiber subscriber receive communication system is a core technology of multimedia home networks because it provides the high-level quality of data and services. This paper executes an analysis and research on this communication systems and presents the theoretical background for the purpose of understanding the optical communication system principal and explaining signal process flows to divide each block for the implementing ASIC design.

• 산업공학
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• 제18권3호
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• pp.277-287
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• 2005

In this paper, we deal with a new techno-economic modeling and analysis for optical access networks. In deploying the fiber-to-the-home (FTTH) architecture, network planner needs to consider the following techno-economic issues: when do we need to upgrade existing local access network to FTTH network? how much do we invest to maximize profit? In order to answer these techno-economic questions, we need to consider the impact of emerging technologies and business environment. Toward this end, we develop a new techno-economic modeling to deal with the inherent complexity of technology evolution and cost economics. In particular, the new modeling approach provides us with an techno-economic analysis of technology alternatives such as ethernet passive optical network (E-PON) and wavelength division multiplex passive optical network (WDM-PON). In this analysis, we focus on the impact of critical factors such as the cost characteristic of proposed architecture and digital subscriber line (DSL) subscriber's churn-in to FTTH service and churn-out. We develop mixed integer-programming models for finding the evolution path of local access networks to broadband network architectures.

• 한국정보통신학회논문지
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• 제12권9호
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• pp.1666-1674
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• 2008

본 논문에서는 광 가입자망 구성의 여러 형태에 대하여 알아보고, 경제성을 비교분석하여, 어떤 방식의 망 구축이 미래의 광가입자 망으로 가장 경제적인지를 고찰 하였다. 비교분석은 현재 우리나라에서 사용 중인 VDSL2, Ethernet-LAN 그리고 FTTH-R 방식의 세 가지 형태 광 가입자망을 대상으로 하였으며, 각 각의 구성 방식별 회선당 초기투자 비용과 운용 비용 중에서 회선당 고장율 및 소비 전력을 비교분석 하였다. 분석 결과 FTTH-R망이 가장 경제적이었으나 기존에 포설된 동선 가입자망을 고려할 경우 댁내까지 완전한 광케이블 포설로 변환하는 과정의 중간 단계로 동선인 UTP 선로와 혼합하여 사용하는 방식의 중간 단계를 거치는 점진적인 전환이 효율적일 것으로 판단된다.

• ETRI Journal
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• 제26권1호
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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.

• Journal of the Optical Society of Korea
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• 제13권3호
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• pp.361-366
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• 2009

We propose the performance enhancing method optimization of an asynchronous 2.5 Gbps/1.25 Gbps optical subscriber network with inverse RZ (Return to Zero) coded downstream and NRZ (Non Return to Zero) upstream re-modulation by adjusting threshold level control of a receiver. We theoretically analyze the BER (Bit Error Rate) performance by modeling the occurrence of BER by simulation with MATLAB according to the types of downstream data. The results have shown that the normalized threshold level in an optical receiver could be saturated at 1/3 as the SNR (Signal to Noise Ratio) increases. The needed SNR for obtaining the BER $10^{-9}$ can be reduced by $\sim$5 dB by optimizing the normalized threshold level at 1/3 instead of by using the conventional receiver with threshold level of 0.5. The proposed system can be a useful technology for asynchronous optical access networks with asymmetric upstream and downstream data rates, because the improved minimum receiving power could replace a light source with a source with lower power and lower cost in an OLT (Optical Line Termination).

• 정보처리학회논문지C
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• 제11C권5호
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• pp.671-676
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• 2004

다양한 데이터 속도와 버스트 타입과 같은 다양한 형태의 신호가 혼재하는 멀티미디어 서비스를 전송하기 위한 초고속 광 가입자망을 구축하기 위하여 수정한 PN 코드를 사용한 주파수영역에서 확산하는 광 CDMA 시스템을 제안한다. 광 멀티미디어 가입자망에서 동시 가입자의 수를 늘리고, 간섭잡음을 경감시키기 위하여 수정한 PN 코드를 사용한 FBG형 광 CDMA에 대하여 광원의 SPD(spectral power distortion)에 의한 특성변화를 수치적으로 분석한다. 다양한 데이터의 속도의 신호가 혼재한 멀티미디어 시스템에서 데이터의 속도에 관계없이 동시 가입자의 수가 같을 경우 BER 특성이 동일하다는 것을 알 수 있다. 그리고 제안한 광주파수영역 CDMA를 이용한 초고속 멀티미디어 네트워크에서의 BER 특성이 종래방식보다 훨씬 향상되는 것을 알 수 있다.

• ETRI Journal
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• 제30권2호
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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.