• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.79-81
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• 2009

NEMO is technique to support mobility of a network, not a node, and ensures session continuity for all the nodes in a Mobile Network. However NEMO basic support protocol causes high handover latency, thus it is incongruent real-time services such as VoIP. One of schemes to reduce handover latency is FNEMO. FNEMO that combines conventional NEMO and FMIPv6, reduces latency during the handover, thus it supports fast handover. In this paper, we compare/analyze handover of FNEMO in heterogeneous/homogeneous network, and propose schemes to reduce handover latency.

• The KIPS Transactions:PartC
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• v.14C no.6
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• pp.503-508
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• 2007

Since the Wibro service realize mobile network on the public, it has been considered that it is not enough to support real time service at vehicular speed. The standard Fast Mobile IPv6 Handover Protocol using HMIPv6 may guarantee seamless service as long as the Mobile Node moves in the same domain MAP however it does not regard fast handover over inter-MAP domain. Thus Macro Mobility Handover in HMIPv6 was proposed to reduce handover latency in inter-MAP domain. But it is still not enough to support real-time service. So we propose an Improved FHMIPv6 over 802.16e network to reduce the overall handover latency. We embedded Layer 3 handover messages of the FHMIPv6 into the Layer 2 handover messages. So the MN is able to $^-nish$ overall handover procedure earlier in our scheme. The numerical results show the performance of IFHMIPv6 has improved about 32% in comparison with FHMIPv6.

• Journal of Communications and Networks
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• v.8 no.4
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• pp.451-460
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• 2006

Since low earth orbit (LEO) satellite constellations have important advantages over geosynchronous earth orbit (GEO) systems such as low propagation delay, low power requirements, and more efficient spectrum allocation due to frequency reuse between satellites and spotbeams, they are considered to be used to complement the existing terrestrial fixed and wireless networks in the evolving global mobile network. However, one of the major problems with LEO satellites is their higher speed relative to the terrestrial mobile terminals, which move at lower speeds but at more random directions. Therefore, handover management in LEO satellite networks becomes a very challenging task for supporting global mobile communication. Efficient and accurate methods are needed for LEO satellite handovers between the moving footprints. In this paper, we propose a new seamless handover management scheme for LEO satellites (SeaHO-LEO), which utilizes the handover management schemes aiming at decreasing latency, data loss, and handover blocking probability. We also present another interesting handover management model called satellite mobility pattern based handover management in LEO satellites (PatHO-LEO) which takes mobility pattern of both satellites and mobile terminals into account to minimize the handover messaging traffic. This is achieved by the newly introduced billboard manager which is used for location updates of mobile users and satellites. The billboard manager makes the proposed handover model much more flexible and easier than the current solutions, since it is a central server and supports the management of the whole system. To show the performance of the proposed algorithms, we run an extensive set of simulations both for the proposed algorithms and well known handover management methods as a baseline model. The simulation results show that the proposed algorithms are very promising for seamless handover in LEO satellites.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.2
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• pp.277-284
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• 2009

With significant development in wireless communication technologies, the needs to handover from one network to another have grown dramatically. Recently IETF developed MIPv6 and FMIPv6 which are used to handover between different access networks. These handover mechanisms have some known weaknesses. MIPv6 can not serve time-critical application because it causes long handover latency and packet loss. By these reasons, MIPv6 does not guarantee session continuity. FMIPv6 uses handover preparation phase to reduce DAD latency. However FMIPv66 still suffers from long handover latency, because it must perform binding update at the end of handover procedure. In this paper we propose new handover mechanism FMIPv6-PBU which eliminates binding update latency. The proposed mechanism has compatability with lagacy FMIPv6. In this paper propose FMIPv6-PBU handover procedure and explain its procedures and evaluate it with MIPv6 and FMIPv6.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.1
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• pp.15-20
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• 2010

This paper proposes a multihoming-based vertical handover scheme using Proxy binding update to minimize handover delay and packet loss while a mobile node moves to a heterogeneous access network. When a mobile node moves to a heterogeneous access network, the proposed scheme can provide a mobile node with fast and seamless handover by performing layer-3 handover using its new interface while the other interface is still communicating in the old access network. The proposed Proxy binding update is different from the Mobile IP binding update in that it includes home addres (HoA) of the old interface instead of the new interface. The performance analysis shows that the proposed scheme can efficiently reduce vertical handover delay and packet loss.

• Journal of Communications and Networks
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• v.6 no.3
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• pp.245-257
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• 2004

Driven by the growing number of the mobile subscribers, efficient channel resource management plays a key role for provisioning multimedia service in the next generation personal communication systems. To reuse limited channel resources, diminishing the coverage areas of cells seems to be the ultimate solution. Thus, however, causes more handover events. To provide seamless connection environment for mobile terminals and applications, this article presents a novel handover scheme called the intelligent channel reservation (ICR) scheme, which exploits the location prediction technologies to accurately reserve channel resources for handover connections. Considering the fact that each mobile terminal has its individual mobility characteristic, the ICR scheme utilizes a channel reserving notification procedure (CRNP) to collect adequate parameters for predicting the future location of individual mobile terminals. These parameters will be utilized by the handover prediction function to estimate the expected handover blocking rate and the expected number of idle channels. Based on the handover prediction estimations, a cost function for calculating the damages from blocking the handover connections and idling channel resources, and a corresponding algorithm for minimizing the cost function are proposed. In addition, a guard channel decision maker (GCDM) determines the appropriate number of guard channels. The experimental results show that the ICR scheme does reduce the handover-blocking rate while keeping the number of idle channels small.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.3A
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• pp.266-275
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• 2004

Recently, wireless networks require an efficient handover scheme due to increase of mobile devices. But Bluetooth has several problems to support the efficient handover, which are the additional increase of signaling traffic and long time of the initial setup processes of inquiry and paging processes. This paper suggests an efficient Soft Handover method for Bluetooth (eSoHoB), which reduces the eplased time of the inquiry and paging process and supports a soft handover using the anticipation method. This paper implements the eSoHoB using two Bluetooth hardware modules and a testbed to be able to receive streaming data while a Bluetooth terminal is moving. This paper measures handover delays and the operation of the soft handover to verify the proposed mhthod.

• The Korean Journal of Emergency Medical Services
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• v.25 no.1
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• pp.105-124
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• 2021

Purpose: This study aims to identify the present handover status and the difference in performance and importance of handover between 119 paramedics and emergency department (ED) staff to improve the quality of handover. Methods: The study involved a questionnaire survey of 171 paramedics and 108 ED staff in four regions from August 28 to September 23, 2020. Subsequently, 279 questionnaires were collected and 277 copies were used for this study. Data were analyzed by SPSS 26.0 version. Results: The results showed that most of the paramedics and the ED staff rely on memory and verbally handover, without formal education about the handover process. And there were significant differences in performance in important information of prehospital. Some of the handover items were a difference in performance and importance between the paramedics and the ED staff. Conclusion: The unified education based on required and optional items is necessary to reduce the loss of information between the paramedics and ED staff, and standardized tools need to be developed in the handover process.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.11
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• pp.3680-3693
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• 2022

The handover procedure of IEEE 802.11 wireless local area networks (WLANs) introduces significant delay, which can degrade the quality of service (QoS) especially for delay-sensitive applications. Although studies have been conducted to support handover in SDN-based WLAN, there is no research to reduce the channel scanning procedure that takes up the most delay time in the handover process. The channel scanning procedure is essential to determine the appropriate access point (AP). To mitigate this problem, this paper proposes a SWITCH: SDN-WLAN integrated handover scheme for QoS-Guaranteed mobile service. In SWITCH, each AP periodically broadcasts beacon frames through different channels in a predetermined order that includes the operating channel information of the AP. This allows mobile stations (MSs) to receive the beacon frames of nearby APs, and therefore they can determine the appropriate APs for handover without the channel scanning procedure. By reporting the information of the newly moved AP to the SDN controller, a flow rule is installed in advance to provide fast handover, and packet loss is reduced by buffering data destined for MS. In addition, the proposed scheme can adaptively operate SWITCH to consider the user location and QoS requirement of flow to save radio resource overhead. Performance evaluation results demonstrate that SWITCH can reduce the handover delays, flow table utilization ratio and radio resource overhead while improving the network throughput.

• The KIPS Transactions:PartA
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• v.17A no.3
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• pp.137-144
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• 2010

Recently, as the consumer market of the mobile device is explosively getting bigger and bigger, both of the usability and applicability of the mobile device are also growing rapidly. The customers prefer to transfer data between the different mobile devices and download multimedia data via the wireless connection even wherever they are. The trend of mobile devices also shows the tendency of employing the various connectivity technologies such as Bluetooth, Wi-Fi, W-USB, NFC, and so on in a single mobile device. With this market trend, the importance of the technology associating different devices is getting increased gradually. In this paper, we present how to support the NFC association of the W-USB technology by extending the existing NFC's handover protocol. We also explain the differences between the NFC association and the handover protocol, and propose the method to resolve the differences by extending the handover protocol of the NFC technology. Finally, we describe how to implement the NFC system supporting the W-USB handover protocol.