• Proceedings of the Korean Institute of Communication Sciences Conference
• /
• 2004.07a
• /
• pp.118-118
• /
• 2004

• Proceedings of the Optical Society of Korea Conference
• /
• 2006.07a
• /
• pp.355-356
• /
• 2006

• ETRI Journal
• /
• v.26 no.2
• /
• pp.185-188
• /
• 2004

In this paper, we design a two-step scheduling algorithm to support multiple bandwidth allocation policies for upstream channel access in an Ethernet passive optical network. The proposed scheduling algorithm allows us a simultaneous approach for multiple access control policies: static bandwidth allocation for guaranteed bandwidth service and dynamic bandwidth allocation for on-demand, dynamic traffic services. In order to reduce the scheduling complexity, we separate the process of the transmission start- time decision from the process of grant generation. This technique does not require the timing information of other bandwidth allocation modules, so respective modules are free from a heavy amount of timing information or complex processing.

• IE interfaces
• /
• v.18 no.3
• /
• pp.277-287
• /
• 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.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2009.04a
• /
• pp.1241-1244
• /
• 2009

인터넷을 기반의 멀티미디어 정보화 사회에서, 대용량 멀티미디어 데이터 서비스에 대한 요구가 확산되고 있다. 그러나 현재의 가입자 접속망으로는 데이터 전송 속도 및 거리 제약으로 인해 만족스러운 서비스를 사용자들에게 제공해 줄 수 없다. 가입자 접속망에서 현저하게 떨어지는 속도문제를 해결하고, QoS(Quality of Service)를 보장해 줄 수 있는 방안의 하나로 우선순위 큐를 고려한 가중치 기반의 차등 대역폭 할당 방식과 대역폭을 분할하여 파장에 배정하는 파장 분할 방식의 EPON(Ethernet Passive Optical Network)을 제안한다. OPNET 으로 구현한 시뮬레이션 모델을 이용하여 고순위 및 저순위 트래픽의 비율에 따라 각 트래픽의 최대 및 평균 지연시간, 제안한 알고리즘의 사용율, 분배율을 구하여 적합성을 검증한다.

• Korean Journal of Optics and Photonics
• /
• v.19 no.5
• /
• pp.343-348
• /
• 2008

This study was carried out to commercialize FTTH by developing a burst mode optical receiver for E-PON. The optical receiver was manufactured by minimizing the capacitance of a photodiode to improve sensitivity for meeting 10, 20 km OLT Rx standard of E-PON at the transmission speed of 1.25 Gb/s. When bit-error ratio is $10^{-12}$ and PRBS is $2^5-1$, sensitivity is -26 dBm, loud/soft ratio is 23 dB. Both preamble time and guard time were set to 102.4 ns (128 bit). After comparing a photodiode whose capacitance is 0.53 pF with another photodiode whose capacitance has been minimized to 0.26 pF, we could see that sensitivity improved to 0.7 dBm and so did bandwidth to 190 MHz of burst mode for the optical receiver manufactured by the photodiode whose capacitance is 0.26 pF.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.9 no.5
• /
• pp.15-21
• /
• 2009

An Ethernet passive optical network (EPON) is an economical and efficient access network that received significant research attention in recent year. A MAC protocol of the PON, the next generation access network, is based primarily on TDMA (Time Division Multiple Access). In this paper, we addressed the problems of a dynamic bandwidth allocation (DBA) in Fairness and QoS Performance. We augmented the advanced bandwidth allocation algorithms to support efficient resource utilization by reducing the unused remaining bandwidth made by idle state ONUs. Our new proposed advanced bandwidth allocation algorithm can allocate effectively and fairly the bandwidths between end-users.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.29 no.11B
• /
• pp.891-899
• /
• 2004

Ethernet passive optical network (EPON) has drawn many attention as a promising access network technology because it can provide a high bandwidth with a low cost. Since the uplink in the EPON system is shared by many users, it is necessary for an EPON system to have an efficient bandwidth allocation mechanism. In addition, as the users demand more QoS-oriented applications, it is necessary for an EPON system to have an efficient mechanism supporting QoS. In this paper, we propose a variable window dynamic bandwidth allocation (DBA) algorithm for the EPON system. Unlike the previously proposed DBA algorithms, the variable window algorithm guarantees the QoS for the highest priority class, and at the same time provides more enhanced QoS for the lower priority classes by dynamically allocating bandwidth if necessary. It is verified through the simulations that the variable window algorithm can provide more enhanced QoS performance than other DBA algorithms.

• ETRI Journal
• /
• v.34 no.6
• /
• pp.838-846
• /
• 2012

This paper proposes a cost-effective hybrid-type power budget extender (PBEx) that can provide a high power budget of over 45 dB in an asymmetric 10-Gb/s Ethernet passive optical network (10/1G-EPON). The hybrid-type 10/1G-EPON PBEx comprises a central office terminal (COT) and remote terminal (RT) module supporting four channels and uses a coarse wavelength division multiplexing (CWDM) technology between the COT and RT for a reduction of fiber cost and efficient access network design. The proposed 10/1G-EPON PBEx can provide over a 40-km reach and 128-way split per CWDM wavelength with no modification of a legacy 10/1G-EPON system and can satisfy the error-free service in $10^{10}$ packet transmission.

• Proceedings of the KIEE Conference
• /
• 2008.10c
• /
• pp.205-207
• /
• 2008

Much signaling equipments are installed along railway tracks, and these are working in cooperation with each other, referring to other signaling equipment status. Existing railway signaling system uses signal cables to transmit this information. This system requires high cost for construction and have the problems like many faults from mistakes in cable connection, etc To solve these problems, JREast Inc. has developed a new signaling system based on network technology, utilizing Ethernet-Passive Optical Network(E-PON). In this paper, we review the system proposed by JREast Inc. and field test results performed on railway.