• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.7
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• pp.3238-3246
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• 2013

The progress of Information Technology enables people can communicate each others using the Internet. As a smartphone proliferates, many free mobile VoIP(Voice over IP) application are developed and accepted by smartphone users. In this study we investigate the factors affecting the acceptance of mobile VoIP applications and the structural relationship among these factors. We review the related works and extract the related factors and build a research model describing the causal relationship among these factors. We conduct an empirical study - a survey and statistical analysis - to verify the research model. EFA(Exploratory Factor Analysis) is applied for variables in the survey and SEM(Structural Equation Model) is used to reveal the structural relationship among the factors. We can find that two factors - usefulness of mobile VoIP and social influence - positively affect usage intention and actual use. These findings imply that it is required to emphasize the benefits of mobile VoIP use and add S/W functionalities enhancing social influence.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.6
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• pp.297-302
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• 2012

RAN in mobile backhaul network connects base station to mobile backhaul network. This the interfaces for several generations mobile communication technologies, such as TDM, ATM, and Ethernet in cell site, and then Ethernet in mobile backhaul site. In near future, the mobile communication network will be changed to all IP/Ethernet one, and then ultimately Ethernet and TDM traffics will be transferred through IP network. So these technologies have to be encapsulated for transferring to the mobile backhaul network. The performances are measured for each encapsulation, such as ATM, MPLS, IP/UDP, and MEF8.

• Journal of the Korea Society for Simulation
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• v.12 no.3
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• pp.55-68
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• 2003

As mobile IP has been suggested only to support mobility of mobile station(MS) by which it dose nothing but guarantee MS's new connection to the network, it is for nothing in Quality of Service(QoS) after handoff of MS. QoS is very important factor in mobile IP network to provide multimedia applications and real-time services in mobile environment, and it is closely related to handoff delay Therefore as a main issue in mobile IP research area, handoff delay problem is actively studied to guarantee and promote QoS. In this paper, in order to resolve such a problem, we suggest Simple Network Management Network(SNMP) information-based routing that adds keyword management method to information-based routing in active network, and then propose QoS controlled handoff by SNMP information-based routing. After setting up routing convergence time, modeling of suggested method and existing handoff method is followed in order to evaluate the simulations that are carried out with NS-2. The result of simulation show the improvement of handoff delay, and consequently it turns off the QoS has been improved considerably.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.858-861
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• 2002

As mobile devices have become widely popular, users want to use devices not only wireless but also mobile. Mobile IP is used to support mobility on TCP/IP network. In mobile IP, when a terminal changes location, the terminal requests a registration to Home Agent through Foreign Agent in new location. After the request is accepted by Home Agent, the terminal can use network again. We call this process as handoff. In mobile n, handoff provokes loss of data packets and network delay. In this paper, we describe the implementation of pre-registration which is a solution of the handoff problems. Pre-registration improves the traditional handoff mechanism by requesting registration through current FA before location change. This muchanism can decrease packet loss and network delay.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.04b
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• pp.1459-1462
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• 2002

3GPP(Third Generation Partnership Project)와 3GPP2 등의 국제 표준화 기구에서는 초기 IMT-2000 망 구조로부터 All IP 망으로 진화할 것으로 예상하고 있다. 이에 본 논문에서는3GPP와 3GPP2를 중심으로 All IP 망의 기존에 제시된 All IP 망의 진화 시나리오를 분석하고, 이를 바탕으로 기존 PSTN/ISDN 연동, VoIP, Mobile IP 등과 같은 새로운 기술, 기존회선 모드 단말기 수용 등을 고려한 All IP 진화 시나리오에 따른 단계별 망 구조를 제시한다.

• Journal of information and communication convergence engineering
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• v.8 no.1
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• pp.1-5
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• 2010

In this paper, we propose for improving QoS in wireless micro cellular network using Cellular-IP/PRC(Paging Route Cache) with Paging Cache and Route Cache in Cellular-IP and propose for performance of realtime and non-real time handoff service using Handoff state machine Paging Route Cache. Although the Cellular-IP/PRC technology is devised for mobile internet communication, it bas its vulnerability in frequent handoff environment. On the other hand, Cellular IP combines the capability of cellular networks to provide high performance handoff and efficient location management of active and idle mobile users with the inherent flexibility, robustness and scalability found in IP networks. Also Cellular-IP/PRC use semi-soft handoff. During semi-soft hand off a mobile host may be in contact with either of the old and new base stations and receive packets from them. Packets intended to the mobile node are sent to both base stations and buffered, so when the mobile host eventually moves to the new location it can continue to receive packets without interruption. It should be suitable for realtime service such as multimedia traffic. But, much waste of resource will occur in this method, especially for non-real time services such as FTP and E-mail. Therefore, a new algorithm that performs different handoff according to characteristic of each traffic by use of reserved field in IP packet is proposed in this thesis. This hand off state machine using differentiated handoff improves quality of services in Cellular-IP/PRC. Suggested algorithm shows better performance than existing technology in wireless mobile internet communication environment. Matlab simulation results are improving QoS, show call drop and call blocking provided to Paging Router Cache during handoff state machine in Cellular-IP/PRC.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.275-278
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• 2002

이동성을 제공하기 위해 IETF에서는 Mobile IP 라는 프로토콜을 제안하였다. IETF에서는 주소고갈 문제를 해결하기 위해 앞으로도 계속적인 수요를 충족시킬 만큼의 충분한 주소를 제공할 수 있는 IPv6의 차세대 인터넷 프로토콜을 채택하였다. 본 논문에서는 Mobile IP에서 핸드오프가 발생할 때 패킷의 손실을 최소화하는 과정을 알아본다. 또한 Mobile IP기능을 IPv6에서 재설계함으로써 이동 노드가 접속점을 변경시킬 때 핸드오버가 발생하는데 이때, 성능 향상을 위한 바인딩 캐쉬 서버 도입과 지역등록 방안을 제안한다. 제한 사항에 대한 시뮬레이션을 하기 위해 Linux Machine을 이용한 Network Simulator(version-2)를 사용 하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.6B
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• pp.563-572
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• 2003

When the Mobile IP is applied for mobility management protocol in the next-generation mobile communication networks, it can cause a serious performance degradation called micro-mobility problem. In this paper, we propose ANMM(Access Network Mobility Management) to efficiently support micro-mobility in the IP-based wireless access network. The ANMM scheme can reduce the handoff latency and signaling overhead resulting in performance enhancement by managing the mobility of mobile nodes within access network.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.2
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• pp.75-82
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• 2008

Mobile IP was proposed to overcome identity problem of original IP address system caused by mobility of wireless mobile host. To complete its network handoff procedure, it must receive a mobile advertisement broadcasted by mobile agent. Generally, in a mobile IP system, mean time delay, 500ms, in a network handoff procedure is a critical problem of wireless service such as Voip, multimedia streaming. A caching agent caches a latest mobile advertisement, and replays it by receiving solicitation message from a mobile node finishing link layer detection. But, during the procedure of mobile registration, many packets from service provider to the mobile host would be lost and handoff time delay would be increased. In this thesis, we propose an unproved caching agent technique which can forward data packets while handoff procedure, and CoA pool for fast mobile IP registration.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10c
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• pp.433-435
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• 2001

IETF Mobile IP는 이동 컴퓨팅 환경에서 IP 멀티캐스트를 지원하기 위한 메커니즘으로 HA 기반 라우팅과 FA 기반 라우팅을 간략히 언급하고 있다. FA 기반 라우팅의 경우, 단말기 이동 시 멀티캐스트 트리를 재구성하는 오버헤드가 존재하는 단점이 있다. 반면. HA 기반 라우팅의 경우, 단말기 이동시 경로 최적화가 이루어지지 않는 단점에도 불구하고. 멀티캐스트 트리 수정에 대한 오버헤드가 존재하지 않은 장점이 있다. 이러한 장점은 망의 안정성을 놓일 수 있기 때문에 많은 연구에서 HA 기반 라우팅을 채택하고 있다. 하지만, 기존의 HA 기반 라우팅 방법에서 가장 큰 장애 요소는 터널링 집중화 현상이며, 이를 해결하기 위해 Mobile Multicast (MOM) 등에서 정성적인 방법을 제안하고 있지만, 구체적인 프로토콜이 없으며 모든 HA들이 관여하는 복잡도로 인해 실제로 망에 배치되는 데 한계성을 가진다. 본 논문에서는 현재의 Mobile IP 메시지의 간단한 확장과 FA메 멀티캐스팅을 위한 기능을 첨가하여. 터널링 집중화 현상을 해결하는 프로토콜을 제안하고자 한다. 제안되는 프로토콜은 현재의 모든 IP 멀티캐스트를 수용하고, Mobile IP와의 호환성을 유지한다.