• Journal of KIISE:Information Networking
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• v.29 no.2
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• pp.174-180
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• 2002

With the invention of MPLS and the Improvement in traffic engineering, multipath packet forwarding and dynamic load control has become a reality. A dynamic load control, while it can improve network efficiency by controlling loads between paths according to the network state, can lead to unstable and oscillating state because of the staleness of the state information. In this paper, we propose a efficient load control scheme which remains stable. The proposed scheme introduces prediction to reduce the staleness of state message and to prevent oscillation.

• Journal of Navigation and Port Research
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• v.36 no.8
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• pp.631-635
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• 2012

Underwater acoustic communication has multipath error because of reflection by sea-level and sea-bottom. The multipath of underwater channel causes signal distortion and error floor. In this paper, in order to design an efficient packet structure, we employ channel coding scheme and phase recovery algorithm. For channel coding scheme, half rate LDPC channel coding scheme with N=1944 and K=972 was used. Also, decision directed phase recovery was used for correcting phase offset induced by multipath. Based on these algorithms, we propose length of data for optimal packet structure in the environment of oceanic experimentation.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.11a
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• pp.651-653
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• 2011

본 논문에서는 모바일 노드들의 움직임이 심한 MANET 환경에서의 데이터의 전송을 안정적이고 신뢰성있게 하기 위한 방법을 제시하고자 한다. 우회경로가 적은 경우보다 우회경로가 많이 확보되었을 때 상호간의 통신이 더욱 안정적이나, 기존 연구에서는 이러한 고려가 충분히 되어있지 않고, 경로 설정 당시 알고리즘에 의해 최적화된 경로라고 판단된 경로만 기억해 놓기때문에 경로 손실이 되었을 때에 우회경로가 존재 함에도 불구하고 패킷 전송을 실패하게 된다. 본 논문에서는 확률에 기반한 안정도를 측정하고 MANET 환경에서 패킷전달 가능성이 높은 다중경로 라우팅 프로토콜 아이디어를 제시한다.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10e
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• pp.529-531
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• 2002

VoIP기술의 확산과 그에 따른 IP기반의 망을 포함한 packet, Multimedia서비스를 제공하는 서비스가 늘고있다. 그러나 실시한 서비스를 필요로 하는 이 서비스의 경우에는 그에 따르는 경로에 확실한 대역폭의 조건이 요구되고 있다. 하지만 best-effort방식을 사용하는 기존의 망에서는 대역폭의 확실한 보장이 이루지기 힘들다. 하지만 MPLS와 트래픽 엔지니어링 기술의 발전으로 다중경로 패킷 전달 및 동적인 부하 제어가 가능하게 되었다. 곧 차별화된 서비스에 따른 대역폭의 할당이 이루어질 수 있다. 동적인 부하 제어는 네트웍의 상태를 고려하여 경로간의 부하를 조절함으로써 네트웍의 효율성을 높일 수 있으나, 상태 정보의 시간차이에 의해 불안정한 상태에 이르기 쉽다. 본 논문에서는 차별화된 서비스를 하기 위해 부하의 할당을 안정적으로 변화시키면서도 효율적인 부하로 용량에 맞게 흐름을 받아들이고 패킷을 전송하는 기법을 제안한다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.4
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• pp.9-17
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• 2010

The mobility of nodes are different in wireless ad hoc networks. Routes have to be refreshed frequently due to the mobility of the nodes acting as routers. Path consists of a few highly mobile nodes should be avoided to forward packets, because even only one highly mobile node may result in the break of path. We develop a mobility aware method to evaluate path stability for multipath routing in wireless Ad Hoc networks. Specifically, we extend it to a well-studied multipath routing protocol known as ad hoc on-demand multipath distance vector (AOMDV). The resulting protocol is referred to as path stability evaluation (PSE). Performance comparison of AOMDV with PSE are studied through ns-2. Simulation shows that PSE has optimistic results in performance metrics such as packet delivery, end-to-end delay, routing overhead and throughput.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.1A
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• pp.82-89
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• 2011

The Proxy Mobile IPv6 is a network-based localized mobility management protocol. In the PMIPv6, Mobile Nodes are topologically anchored at a Local Mobility Anchor, which forwards all data packets for registered Mobile Nodes. Since all data packets destined for the Mobile Nodes a1ways traverse the Mobile Nodes's Local Mobility Anchor, the LMA might be bottleneck and the end-to-end de1ay are increased. Therefore, in this paper, we proposed an enhanced Route Optimization scheme in Multiple Local Mobility Anchors environment. In order to rapid1y detect Route Optimization, we designed Domain Information Table in Mobility Access Gateway. Furthermore, we use Correspondent Binding Cache in Local Mobility Anchor to maintain Route Optimization information during Mobile Nodes's handover. To solve packet loss and reodering problems during handover, we propose a new buffering and forwarding scheme.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.11a
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• pp.1109-1112
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• 2005

모바일 애드혹 네트워크에서의 멀티캐스트는 멀티캐스트 그룹 내의 다중 노드들의 상호 협력을 필요로 하는 많은 응용분야에 기본적으로 사용되기 때문에 광범위하게 연구되어 오고 있다. 본 논문에서는 k-홉 중복 경로를 갖는 트리 기반 멀티캐스트 메쉬를 제안한다. 여기서, k 는 노드 이동성을 포함한 네트워크의 동적 특성에 따라 결정될 수 있다. 네트워크가 불안정하고 노드들이 활발히 움직이면, 멀티캐스트 패킷의 보다 확실한 전달을 위하여 k 값을 크게 설정한다. 성능 평가 결과에 의하면, 제안한 트리 기반 멀티캐스트 메쉬의 패킷 손실율은 낮은 노드 속도 및 높은 노드 속도 모두에서 멀티캐스트 트리의 패킷 손실율보다 낮다. 주어진 시뮬레이션 환경에서 수용 가능한 k 값은 2 이며, 이는 상당히 낮은 패킷 손실율을 달성하기에 충분한 값이다.

• The KIPS Transactions:PartC
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• v.12C no.3 s.99
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• pp.429-436
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• 2005

A mobile ad hoc network (MANET) is a collection of mobile nodes without any fixed infrastructure or my form of centralized administration such as access points and base stations. The ad hoc on-demand distance vector routing (AODV) protocol is an on-demand routing protocol for MANETs, which is one of the Internet-Drafts submitted to the Internet engineering task force (IETF) MANET working group. This paper proposes a new multipath routing protocol called maximally disjoint multipath AODV (MDAODV), which exploits maximally node- and link-disjoint paths and outperforms the conventional multipath protocol based on AODV as well as the basic AODV protocol. The key idea is to extend only route request (RREQ) message by adding source routing information and to make the destination node select two paths from multiple RREQs received for a predetermined time period. Compared to the conventional multipath routing protocol, the proposed MDAODV provides more reliable and robust routing paths and higher performance. It also makes the destination node determine the maximally node- and link-disjoint paths, reducing the overhead incurred at intermediate nodes. Our extensive simulation study shows that the proposed MDAODV outperforms the conventional multipath routing protocol based on AODV in terms of packet delivery ratio and average end-to-end delay, and reduces routing overhead.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.12B
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• pp.1259-1266
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• 2010

M2M communication is considered as a key enabling technology to monitor the status of objects, vehicles, humans through auto-configuring wireless networks. In M2M network, there are active research activities to enhance the reliability on data while being collected from wireless sensor network. The reliability issue becomes more important as wireless sensor networks carry multimedia data, which is delay sensitive. The interference caused by the adjacent neighbor sensor nodes is a major factor in network performance degradation, which becomes more severe in multi-hop routing environment. In this paper, we propose inerfernce-free multipath routing protocol for M2M wireless network for enhancement of packet delay performance. The simulation results show that the proposed routing algorithm outperforms the existing routing protocols in terms of packet delay and throughput.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.5
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• pp.21-29
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• 2010

In Ad-Hoc Networks, the limited energy is the key issue for longer network operation time. To solve this problem, various energy-aware routing techniques have been proposed including PSR (Power-aware Source Routing), HPSR (Hirachical Power-aware Source Routing), and etc. Those techniques generally select the most adequate route considering the energy consumption so that the energy efficiency can be improved. However, There are problems in those techniques that traffic can be concentrated in some specific area in a network. In this paper, a new energy aware routing technique called MPSR is proposed to achieve longer network lifetime and fewer rerouting attempts.