• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.11
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• pp.2069-2074
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• 2006

The Next generation network may describe one integrated network by IP (Internet Protocol) convergence and combining various access technologies. The IP version 6 (IPv6) becomes fundamental protocol and the terminal offered various services is having mobility, multihoming, and intelligent as well as smaller. In this convergence network, which integrate mobile network, broad cast network, and Internet as well as PSTN, can provide all of the service. In this context, we will briefly present that the end node should be required ubiquitous computing and networking. That is to say that we must guarantee the end node in any time, my place, my where, and offer continuously services to the node. As like this, Service Mobility is given if a user can obtain subscribed and personalized services consistently even if connected to a foreign network service provider. In other words, Service mobility allows users to maintain access to their services even while moving or changing devices and network service providers. In this paper, we have to refer technical consideration items to make the service mobility framework.

• Electronics and Telecommunications Trends
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• v.27 no.3
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• pp.164-174
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• 2012

향후 10년 내에 전 세계적으로 인터넷 인구가 50억 명에 이르고 사물지능통신의 발달로 인해 인터넷에 접속되는 기기가 1,000억 대로 급증할 것으로 전망된다. 또한, video 콘텐츠를 비롯한 초대용량 서비스, 무선 인터넷 서비스 등이 활성화되고, 트래픽이 폭증할 것으로 예측된다. 그러나 60년대 후반에 만들어진 인터넷은 이러한 새로운 서비스의 등장 및 인터넷 트래픽의 폭증에 적절히 대응하기에는 많은 한계를 가지고 있다. 따라서 미국, EU, 일본 등 선진국들은 네트워크의 양적인 확충은 물론, 새로운 인터넷 기술을 개발하고 그 구조를 재설계하기 위해서 경쟁적으로 대대적인 투자를 전개하고 있다. 광가입자망은 이러한 급변하는 가입자망의 변화에 효과적으로 대처할 수 있는 기술로써, 인터넷 서비스 사업자와 가입자를 연결하는 중요한 네트워크이다. 본고에서는 대표적인 광가입자망 기술인 TDM-PON(Time Division Multiplexing-Passive Optical Network) 및 WDM-PON(Wavelength Division Multiplexing-Passive Optical Network)의 전반적인 기술 현황, 국제 표준화 동향 및 시장 동향에 대해 소개하고, 앞으로 미래를 대비하기 위해 필요한 광가입자망의 기술개발 방향에 대해 논하고자 한다.

• Electronics and Telecommunications Trends
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• v.28 no.6
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• pp.63-74
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• 2013

모바일, 클라우드, 빅데이터 등 최근 IT 산업의 패러다임의 변화로 인해 매년 25% 이상 증가하는 트래픽 추세에 따라 광 가입자망의 전송 기술도 빠르게 진화하고 있다. 가입자 망의 영역 확장을 위해 분기 수, 전송 거리 확대를 위한 기술개발 및 표준화 노력 또한 끊임없이 이어지고 있다. 링크당 40Gbps 이상의 전송 속도를 요구하는 차세대 광 가입자망 기술 중의 하나인 OFDM 기반 PON은 멀티캐리어 방식으로 대용량, 장거리 전송이 가능하며, 서브캐리어 별로 서비스를 분리할 수 있고, 유연한 서브캐리어 관리를 통해 동적 대역 할당이 가능하므로 향후 유무선 융합 가입자 망에 적합한 기술로써, 기존 광 분배망의 구조 및 시설 교체없이 WDM(Wavelength Division Multiplexing)-PON(Passive Optical Network), T(Time)DM-PON 기술과 융합하여, 전송 용량을 확장할 수 있는 큰 장점을 가지고 있다. 본고에서는 OFDMA-PON 기술을 소개하고, EU, 미국 등 선진 연구 기관의 연구동향을 소개하고 향후 전망에 대해 논하고자 한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.603-606
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• 2013

Mobile and wireless communication technologies to the development of a variety of next-generation mobile networks such as smart phones, tablet PC and mobile terminals will coexist various access networks. In a variety of network service continuity and quality of service degradation due to network conditions, and the EPC network traffic overload phenomenon still remains a problem. In this paper, the EPC network traffic overload in distributed cloud servers is proposed to select. Our proposed scheme using an efficient network handover can provide optimal service according to the network condition.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.1C
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• pp.107-115
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• 2005

ATC (Abnormal traffic controller) is presented as next generation security technology to securely support reliable Internet service and to guarantee network survivability, which is deployed in Internet access point. The key concept of the ATC is abnormal traffic monitoring and traffic control technology. When fault factors exist continuously and/or are repeated, abnormal traffic control guarantees service completeness as much as possible. The ATC with control policy on abnormal traffic is superior to the ATC with blocking policy as well as conventional network node, when the ratio of effective traffic to abnormal traffic is higher than $30{\%}.$ When traffic intended unknown attack occurs, network IDS is high false positive probability and so is limited to apply. In this environment, the ATC can be a key player to help the network node such as router to control abnormal traffic.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.9
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• pp.4492-4497
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• 2013

An important features of next-generation wireless networks will be heterogeneous environment in which a mobile terminal will be able to connect to multiple radio access networks and network selection mechanisms play an important role in ensuring QoS for users in this environment. In this paper, our study is concerned with an extension of the well known AHP to the group decision making methods. The users requested specific QoS divide into a group and the access networks with similar characteristics split into a group. Between each group, the one group is selected and within that group, the best access networks will be assigned according to priority order by network selection algorithm. The experimental results of MATLAB simulation show that the every user in each services can select the same network with decision value as large as 0.9. Consequently, the proposed network selection mechanism is more effective than conventional one in integrated UMTS and WLAN networks.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.1
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• pp.79-95
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• 2016

In order to improve the Quality-of-Service (QoS) of latency sensitive applications in next-generation cellular networks, multi-path is adopted to transmit packet stream in real-time to achieve high-quality video transmission in heterogeneous wireless networks. However, multi-path also introduces two important challenges: out-of-order issue and reordering delay. In this paper, we propose a new architecture based on Software Defined Network (SDN) for flow aggregation and flow splitting, and then design a Multiple Access Radio Scheduling (MARS) scheme based on relative Round-Trip Time (RTT) measurement. The QoS metrics including end-to-end delay, throughput and the packet out-of-order problem at the receiver have been investigated using the extensive simulation experiments. The performance results show that this SDN architecture coupled with the proposed MARS scheme can reduce the end-to-end delay and the reordering delay time caused by packet out-of-order as well as achieve a better throughput than the existing SMOS and Round-Robin algorithms.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.1
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• pp.48-59
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• 2009

Next generation mobile communication system will have various access networks and provide seamless multimedia data service to mobile nodes. The WiNGS system, one of these access network, has superior RAT(Radio Access Technology) and network connectivity other than previous ones. In this paper, we propose link-layer SR-ARQ between mobile node and WAGW to solve packet re-ordering problem during handover. In the proposed scheme, we apply the adaptive timer at the SR-ARQ sender to reduce unnecessary packet retransmission during handoff and delayed NAK algorithm at the SR-ARQ receiver for delaying NAK response due to temporary out-of-sequenced frames. We evaluate the performance of the proposed scheme by implementing the new SR-ARQ protocol at the link-layer using ns-2 simulator, and show the handover performance is improved greatly by preventing unnecessary retransmission.

• The KIPS Transactions:PartC
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• v.12C no.2 s.98
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• pp.235-242
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• 2005

As the demands in a wireless network are recently increasing, it is necessary to promote the power efficiency of a wireless terminal, and to reduce the overhead of a network. To resolve such problems, we propose the paging technology and the structure of paging area with the joint access point in HPi (High-speed Portable Internet) network, which is being studied as the domestic next-generation IP packet data network. The application of the paging technology to the HPi network possesses the advantage of reducing the registration cost while a terminal in dormant state moves around, and the reporting cost of the terminal's location by the joint access point. The technology suggested in this paper causes the advantages that it promotes the power efficiency in user's point of view while it reduces the network overhead and makes the easy rearrangement of joint APs according to the changes of users' moving pattern in the network manager's point of view.

• Journal of Satellite, Information and Communications
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• v.5 no.2
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• pp.14-18
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• 2010

The future of communication systems is expected to combine with the terrestrial and satellite networks. A commonality between wireless interfaces is important consideration for cost of user equipment in the integrated satellite and the terrestrial system. Because IMT-Advanced system take into account LTE based on the terrestrial system for the next generation of communication, a study of the LTE-based satellite system is especially required. A frame of the existing terrestrial wireless networks is designed to use for a random access up to the maximum cell radius of 100 km. However, the random access scheme for the terrestrial system cannot be used in the satellite system, because the satellite systems generally have large coverage than the terrestrial system. Therefore, we propose that the efficient random access procedure to reduce latency and complexity for the satellite system maintaining commonality with the terrestrial system in this paper.