• Title/Summary/Keyword: Geographical Handoff

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A Simple Path Prediction Scheme to Improve Handoff Efficiency in All-IP Wireless Networks

  • Zhu, Huamin;Kwak, Kyung-sup
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.29 no.7A
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    • pp.781-785
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    • 2004
  • Mobile IP maintains Internet connectivity while Mobile Hosts moving from one Internet attachment point to another. However, Mobile If is not appropriate for seamless mobility. Some micromobility protocols were proposed to complement Mobile IP by offering fast and seamless handoff control in limited geographical areas. In this paper, a new scheme, based on path prediction and resource reservation, is proposed to reduce the handoff latency by trying to eliminate the link setup time for fast handoff in all-IP wireless networks. Analytical results show that the proposed scheme offers shorter handoff delay and can improve the handoff efficiency.

An Efficient Hand-off Mechanism in Micro-Domain (마이크로 도메인에서의 효율적인 핸드오프 방안)

  • Kim Eung do;Kim Hwa sung
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.30 no.3A
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    • pp.195-202
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    • 2005
  • The third generation cellular system requires the seamless macro/micro mobility support. Mobile IP provides a simple and scalable macro mobility solution but lacks the support for fast handoff control in micro-domain. However, A lot of micro-mobility protocols have been proposed to complement the Mobile IP capability by providing the fast, seamless, and local handoff control. Cellular If also provides the seamless mobility support in limited geographical area. But semi-soft handoff mechanism of Cellular IP produces the packet loss and the duplication problem due to the difference of propagation delay between the new path and the old path. In this paper, we present an efficient handoff mechanism in micro-domain. The proposed handoff mechanism uses the SCD (Suitable Cross Delay) in order to minimize the packet loss and the duplication problem during the handoff. Also, the proposed mechanism is verified by the performance evaluation through the NS-2 Simulation.

An Enhanced Indirect Handoff for Cellular IP Network (Cellular IP 네트워크에서 인다이렉트 핸드오프 성능 개선)

  • Jung Won-soo;Yun Chan-young;Oh Young-hwan
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.31 no.1B
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    • pp.1-8
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    • 2006
  • Currently, there are many efforts underway to provide Internet service on integrated wireless and wired networks. Supporting IP mobility is one of the major issues to construct IP based wireless network. Mobile IP has been proposed to solve the IP Mobility problem. But, in processing frequent handoffs in cellular based wireless access network, Micro mobility protocols have been proposed to solve these problems. Micro mobility protocols proposed the Cellular IP, HAWII, and Hierarchical Mobile IP. Cellular IP attracts special attention for it's seamless mobility support in limited geographical areas. New BS must be known to occur begging of handoff in Cellular IP indirect handoff. Therefore during perceiving of hanoff, packet loss or packet duplication still can occur in Cellular IP indirect handoff, which results in the degradation of UDP and TCP performance. In this paper, we propose a enhanced indirect handoff scheme for Cellular IP. Proposed handoff scheme is using a crossover node to minimize the signalling procedure and using a buffering to minimize the packet loss or packet duplication.

Design and Implementation of Geographical Handoff System Using GPS Information (GPS정보를 이용한 위치기반 핸드오프 시스템의 설계 및 구현)

  • Han, Seung-Ho;Yang, Seung-Chur;Kim, Jong-Deok
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.35 no.1A
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    • pp.33-43
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    • 2010
  • Recently, users want to use real-time multimedia services, such as internet, VoIP, etc., using their IEEE 802.11 wireless lan mobile stations. In order to provide such services, a handoff among access points is essential to support the mobility of a node, in such an wide area. However, the legacy handoff methods of IEEE 802.11 technology are easy to lose connections. Also, the recognition of a disconnection and channel re-searching time make the major delay of the next AP to connect. In addition, because IEEE 802.11 decides the selection of an AP depending only on received signal strength, regardless of a node direction, position, etc., it cannot guarantee a stable bandwidth for communication. Therefore, in order to provide a real-time multimedia service, a node must reduce the disconnection time and needs an appropriate algorithm to support a sufficient communication bandwidth. In this paper, we suggest an algorithm which predicts a handoff point of a moving node by using GPS location information, and guarantees a high transmission bandwidth according to the signal strength and the distance. We implemented the suggested algorithm, and confirmed the superiority of our algorithm by reducing around 3.7ms of the layer-2 disconnection time, and guaranteed 24.8% of the communication bandwidth.

Bandwidth Reservation Policy for Cellular Networks Using Geographical Information (지리적 정보를 사용한 셀룰러 네트워크 대역폭 예약 정책)

  • Yu, Jae-Bong;Park, Chan-Young;Park, Joon-Seok
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.31 no.10B
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    • pp.891-899
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    • 2006
  • Generally, a geographical area consists of many regions called cells in wireless networks. Each mobile host(MH) in a cell communicates with a base station(BS) located in the center of the cell. The BSs are connected to each other by a static wired network. Since users are expected to move around during communication sessions, one of the most important QoS factors is related to the handoff. But, the handoff could fail due to unavailability of sufficient bandwidth in the next cell. As the individual cell size gradually shrinks to accommodate increasing the number of MHs, the probability of successful handoffs can be dropped. In this paper, we suppose a bandwidth reservation method to guarantee MHs against connection failure in case of frequent handoffs. This method predicts the mobility based on the geographical information and assigns the bandwidth reservation in proportion to the speed of MHs' motion. As a result, we can expect more exact moving path of MH and to reduce the waste of bandwidth.

Design and Implementation of High Throughput Geographical Handoff Using GPS Information (GPS정보를 이용한 위치기반 핸드오프의 설계 및 구현)

  • Han, Seung-ho;Yang, Seung-chur;Kim, Jong-duok
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2009.05a
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    • pp.80-83
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    • 2009
  • The most popular communication protocol is those defined by the IEEE 802.11 WLAN to support broadband internet connection. The demand for real-time multimedia service is increasing through WLAN on the road. The Hand-off function of mobile terminal is essential to support mobility. But, the hand-off function of IEEE 802.11 WLANs has the latency up to 300ms, and recent research has focusing on channel scanning and reconnection to AP and certification process of AP. It is also the lack of consideration in related works that hand-off happens frequently when the mobile node is moving. This paper proposed the hand-off algorithm that guarantees high throughput and estimates the point which may occur hand-off using GPS information and RSSI. We implement the proposed hand-off function that achieves the best performance.

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