• Title/Summary/Keyword: Adhoc

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Implementation of QoS Provisioning Model in VANET (VANET에서 QoS Provisioning모델의 구현)

  • Huh, Jee-Wan;Song, Wang-Cheol
    • Proceedings of the Korea Contents Association Conference
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    • 2009.05a
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    • pp.884-888
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    • 2009
  • Vehicular Adhoc Networks (VANET), a Vehicle-to-Infrastucture or Vehicle-to-Vehicle communication technology, is an area that makes more specific use of Mobile Adhoc Networks(MANET). VANET's Quality of Service(QoS) focuses on preventing possible emergencies like car crash from happening by immediately transmitting information to the cars around, while MANET's QoS is being studied for the quality of multimedia data such as Video on Demand(VoD), Video streaming, Voice over IP(VoIP), etc. In this paper, I structure the actual network configuration using Link State Routing(LSR), implement QoS Provisioning Model using Common Open Policy Service(COPS), and suggest more effective k-hop Cluster and inter-domain policy negotiation which fit better to the characteristics of VANET.

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Collision Avoidance Method Based-on Directional Antenna in Vehicular Ad Hoc Networks (Vehicular Ad Hoc Networks에서 방향성 안테나기반 충돌 회피 기법)

  • Kim, Kyung-Jun
    • Journal of Advanced Navigation Technology
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    • v.12 no.6
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    • pp.627-633
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    • 2008
  • In the case of traffic accidents, the broadcasting methods used in the mobile ad hoc network (MANET) cannot applied to transmit reliable message since moving high-speed in vehicular ad hoc networks (VANET) environments. In this paper, in order to guarantee transmitting reliable messages, we propose a collision avoidance method based-on directional antenna in VANET. In order to reduce interference from omni-broadcasting and to avoid hidden node problem from moving high-speed, we employed a forward-handed and backward directional antenna. The authors simulated the proposed method based on directional antenna and showed that the proposed method has been improved in respect to network utilization compared to existing VANET protocols.

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Jxta-based SmartPhone Collaboration Application Supporting Group Workspace (Jxta 기반의 그룹 작업공간을 지원하는 스마트폰 협업 어플리케이션)

  • Park, Jong-Eun;Lee, Hong-Chang;Lee, Myung-Joon
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.16 no.3
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    • pp.511-521
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    • 2012
  • JXTA technology is a set of open protocols that enable any connected device on the internet or MANET(Mobile Adhoc NETwork) to communicate in a P2P manner. In this paper, we present a JXTA-based smartphone collaborative application. For this, we define the core services and collaborative services necessary for a P2P network, and design proper protocols to support the services. The developed application provides the effective environment for group works in smartphones, supporting the various virtual workspaces. Since application supports the group works among users in close-range without relying on the mobile network, it could be very useful in various situations such as the disaster area.

Classification and Analysis of Mobility Patterns in Nested NEMO Network (중첩 NEMO 환경에서 이동 패턴 분류 및 분석에 대한 연구)

  • Lim, Hyung-Jin;Chung, Tai-Myoung
    • Journal of Internet Computing and Services
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    • v.9 no.4
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    • pp.29-41
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    • 2008
  • Currently, IETF MANEMO(Mobile Adhoc for NEMO) working group is working on standardization supporting internal routing in nested NEMO networks. Nested NEMO has a independent topology feature that Mobile IP and basic NEMO protocol did not caused. This is the reason that causes exceptional mobility pattern. Such mobility patterns also trigger each other reconfiguration requirements. This paper classified and analyzed probable new mobility patterns in nested NEMO network. In concludion, we derived configuration problem from the new mobility patterns and suggested differential reconfiguration requirements through analytical approach.

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An Efficient TCP Algorithm in Mobile ADHOC Networks (이동망 네트워크에서의 효율적인 TCP 알고리즘)

  • Hong, Sung-Hwa;Kim, Hoon-Ki
    • Journal of the Korea Society of Computer and Information
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    • v.14 no.6
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    • pp.73-81
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    • 2009
  • TCP assumes that packet loss is always happened by congestionlike wired networks because is can not distinguish between congestion loss and transmission error loss,. This assumption results in unnecessary TCP performance degradation in wireless networks by reducing sender's congestion window size and retransmitting the lost packets. Also, repeated retransmissions loed to waste the limited battery power of mobile devices. In this paper, we propose the new congestion control scheme that add the algorithms monitoring networks states and the algorithms preventing congestion to improve TCP throughput performance and energy efficiency in wireless ad-hoc networks. Using NS2, we showd our scheme improved throughput performance and energy efficiency.