• Journal of KIISE:Information Networking
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• v.29 no.5
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• pp.459-465
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• 2002

Ad-hoc networks have the dynamic topology characteristics and most of the applications on ad-hoc networks require the group communication capability. Previously proposed multicast mechanisms on mobile ad-hoc networks build multicast-infrastructures like the tree or mesh for the group communication and these infrastructures nay cause significant overhead especially in a highly dynamic mobile ad-hoc network environment. Therefore, in this paper, we propose a new multicast mechanism supporting multicast services based on only the underlying unicast routing tables, hence any multicast-related infrastructures like trees and meshes are not required to be constructed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.5
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• pp.525-532
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• 2004

In this paper, we proposed a multicast routing algorithm for QoS improvement in the wire/wireless integrated environment. We analyzed requests and characteristics of QoS, and then proposed a new algorithm that can improve QoS by adding node mobility to wire environment. This new algorithm constructs a dynamic multicast tree that can prevent a loss of packet and save the bandwidth. As a result of simulations comparing to another multicast algorithms, we showed that this new algorithm can simply and dynamically adjusts the construction of multicast tree with little delay and the most reducible bandwidth resources.

• Information and Communications Magazine
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• v.29 no.3
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• pp.75-82
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• 2012

스크린 기능을 갖는 다양한 종류의 디바이스들이 보급되고 개인당 여러 개의 디바이스를 소유함에 따라 하나의 컨텐츠 미디어를 여러 스크린 디바이스를 통해 서비스의 이용이 가능한 One-Source, Multi-Use (OSMU) 개념이 등장하였다. 이에 따라, 서비스 사용자는 특정 디바이스에 의존하지 않고 통일한 어플리케이션 서비스를 이용할 수 있다. 그러나 지금까지 연구된 멀티스크린 서비스 기술은 고정화된 노드간의 단순 컨텐츠 공유에만 초점이 맞춰져 있어, 서비스를 폭 넓게 확산시키는데 한계를 가지고 있어 왔다. 기존 멀티스크린 서비스를 실용화하고 발전시키기 위해서는 다양한 종류의 멀티미디어 스트리밍 지원과 사용자의 자유로운 이동성이 뒷받침되는 융합적인 이동성 관리의 프레임 워크의 마련이 요구된다. 본 논문은 기존 멀티스크린 서비스 연구에서 다뤄졌던 컨텐츠 공유 방안 및 비디오 코딩 연구 등과는 달리, 사용자의 다양한 이동성 시나리오를 전제로 세션 기반의 멀티스크린 서비스 지원을 위한 네트워크 구조 및 프로토콜 설계와 관련된 연구로서, 멀티스크린의 사용자의 이동성을 개인과 그룹으로 분류하고, 데이터 전송모드로서 유니캐스트/멀티캐스트 메커니즘의 사용을 가능케 하기 위한 멀티스크린 서비스 이동성 연구를 목적으로 이를 위한 요소기술 및 연구 내용의 소개에 초점을 맞춘다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.3
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• pp.258-267
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• 2013

Recently, Proxy Mobile IPv6(PMIPv6) networks have been drawing attention as the mobility management protocol that uses limited wireless resources effectively. And the multicast, which is a core technology of the Internet broadcast system such as mobile IPTV, has been widely discussed mainly based on PMIPv6 network. However, PMIPv6-based multicast cannot support the global mobility directly between different PMIPv6 domains because PMIPv6 is basically designed for local mobility in single PMIPv6 domain. Moreover, PMIPv6-based multicast causes the disconnection of services because it does not solve the packet loss problem during binding and group joining procedure. In this paper, we propose a global mobility scheme that supports the seamless multicast service in PMIPv6 networks. The proposed scheme supports the global mobility due to the addition of extra signalling messages between LMAs. Also, it achieves low latency because it performs fast binding and group joining procedure. We present the simulation results which show that the proposed scheme achieves the global mobility with low latency through the NS-2 simulation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.4B
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• pp.210-217
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• 2005

With rapid advance in wireless communication technologies, many researches are conducted for providing Internet data services while users are roaming around. Efficient management of mobility of mobile nodes is essential as the use of real-time application program grows. In this paper, we propose a multicast-based localized mobility support scheme in IPv6 networks. The proposed scheme utilizes a class of multicast routing protocol for the localized mobility support. Features of the proposed scheme are use of join to a multicast group and leave from that group to localize binding update information and provision of an extended multicast group management mechanism to reduce leave latency. The results of simulation show that the proposed scheme out-performs Mobile IPv6 and Hierarchical Mobile IPv6 in UDP and TCP traffic performance and in wasted bandwidth.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.8
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• pp.27-33
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• 2004

A new multicast scheme for mobile nodes is proposed to support real-time communication in a more efficient way. In the proposed multicast scheme, the Xcast (a very flexible data plane mechanism) is integrated with the SIP (a very flexible control plane protocol) to support multicast for mobile nodes. The simulation results verify that the proposed scheme reduces unnecessary network traffic and achieves low latency of packets in the network.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.9A
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• pp.838-849
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• 2005

Fast handover protocol provides seamless handover in mobile Ipv6 networks by reducing handover latency. This paper proposes FMIP-M mechanism to apply this advantage of fast handover protocol to multicast service. The FMIP-M is a fast handover mechanism that supports a reliable multicast service in mobile Ipv6 networks. When hosts move other networks, they may have seine data missing and out-of-synch problems of multicast data. The proposed mechanism provides reliable multicast transmission by compensating data losses from the previous AR. Also it provides an additional function that is able to change multicasting service types dynamically in accordance with network status related with multicasting. So that it is able to make multicast paths very close to the optimum and more efficient multicast service is possible. The performance of the proposed mechanism is evaluated by a time analysis and simulations in various conditions.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.6
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• pp.37-47
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• 2009

In this paper fast mobile multicast handover mechanism based on IEEE 802.21 MIH (Media Independent Handover) is proposed. We solve long multicast handover delay time caused by L3 movement detection mechanism of the existing mobile multicast methods. The proposed architecture adopts multicast manager concept to MIH framework in order to efficiently perform mobile multicast handover, and adds the new MIH messages dedicated for mobile multicast. Since multicast channel zapping operations of mobile users effectively make a mobile terminal handover, the architecture should consider the situations. Multicast network selection algorithm is designed by means of terminal speed and fair selection algorithm named AHP/GRA. Finally the performance of the proposed architecture against the legacy mobile multicast mechanisms is evaluated in terms of signaling cost and multicast handover delay time.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.1
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• pp.80-84
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• 2010

Data multicasting from a source to multiple sinks in wireless sensor networks is used to achieve both reducing communication costs and energy efficiency. Almost all existing schemes for the multicasting might be effectively performed by optimal construction of a multicasting tree between a source and multiple stationary sinks. However, in practical sensor applications, sinks could move around on the wireless sensor networks for own missions, such as scouting of soldiers and saving lives of victims by firefighters. Unfortunately, the sink mobility causes frequent entire reconstruction of the multicasting tree and thus it leads to exhaustion of battery power of sensors. Hence, we propose an energy-efficient multicast protocol to support multiple mobile sinks by the local multicast tree reconstruction, called Local Update-based geographic Multicasting for Mobile sinks (LUMM) for wireless sensor networks. Our simulation results show that our scheme for mobile sinks is more efficient in terms of energy resource management than other exist works.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10c
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• pp.598-600
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• 2004

다자간 데이터 송수신을 필요로 하는 다자간 화상 회의, 일대다 스트리밍, 일대다 파일 전송 등의 응용에서는 멀티캐스트를 사용하여 데이터 전송 부담을 줄일 수 있다. 그러나 IP 멀티캐스트가 인터넷 상에서 널리 지원되지 않고 있기 때문에, 멀티캐스트를 응용 계층에 구현하려는 연구가 활발히 진행되고 있다. 본 논문에서는 일대다 대용량 파일 전송에서 효과적으로 전송시간을 단축할 수 있는 응용계층 멀티캐스트 기법을 제시한다. 신뢰적 전송을 위하여 Forward Error Correction (FEC)를 사용하여, 전송시간 단축을 위해 데이터 소스 외에 수신자들이 가상적으로 소스의 역할을 수행하도록 한다. 즉, 임의의 수신자는 데이터 소스뿐만 아니라, 다중 가상 소스로부터도 데이터를 수신할 수 있으므로 파일 수신 시간을 단축시킬 수 있다.