• Journal of Communications and Networks
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• v.18 no.3
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• pp.460-475
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• 2016

The existing Proxy Mobile IPv6 suffers from a long handover latency which in turn causes significant packet loss that is unacceptable for seamless realtime services such as multimedia streaming. This paper proposes an OpenFlow-enabled proxy mobile IPv6 (OF-PMIPv6) in which the control of access gateways is centralized at an OpenFlow controller of a foreign network. The proposed OF-PMIPv6 separates the control path from the data path by performing the mobility control at the controller, whereas the data path remains direct between a mobile access gateway and a local mobility anchor in an IP tunnel form. A group of simple OpenFlow-enabled access gateways performs link-layer control and monitoring activities to support a comprehensive mobility of mobile nodes, and communicates with the controller through the standard OpenFlow protocol. The controller performs network-layer mobility control on behalf of mobile access gateways and communicates with the local mobility anchor in the Proxy Mobile IPv6 domain. Benefiting from the centralized view and information, the controller caches the authentication and configuration information and reuses it to significantly reduce the handover latency. An analytical analysis of the proposed OF-PMIPv6 reactive and proactive handover schemes shows 43% and 121% reduction in the handover latency, respectively, for highly utilized network. The results gathered from the OF-PMIPv6 testbed suggest similar performance improvements.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.7B
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• pp.1009-1017
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• 2010

Offering of different attractive opportunities by different wireless technologies trends the convergence of heterogeneous networks for the future wireless communication system. To make a seamless handover among the heterogeneous networks, the optimization of the power consumption, and optimal selection of interface are the challenging issues. The access of multi interfaces simultaneously reduces the handover latency and data loss in heterogeneous handover. The mobile node (MN) maintains one interface connection while other interface is used for handover process. However, it causes much battery power consumption. In this paper we propose an efficient interface selection scheme including interface selection algorithms, interface selection procedures considering battery power consumption and user mobility with other existing parameters for overlaying networks. We also propose a priority based network selection scheme according to the service types. MN‘s battery power level, provision of QoS/QoE and our proposed priority parameters are considered as more important parameters for our interface selection algorithm. The performances of the proposed scheme are verified using numerical analysis.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.975-978
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• 2005

Vertical handoff is the process of maintaining a mobile user's active connections in the heterogeneous network. In vertical handoff, many frames can be lost since the connection between a server and a client is broken off during handoff latency. To solve this problem, in this paper, we propose an effective video streaming method for video on demand (VOD) services that provides seamless playout at the client in vertical handoff. Performance evaluations are presented to demonstrate the effectiveness of the proposed method.

• International Journal of Advanced Culture Technology
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• v.2 no.2
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• pp.7-10
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• 2014

In order to develop smart grid communications infrastructure, a high level of interconnectivity and reliability among its nodes is required. Sensors, advanced metering devices, electrical appliances, and monitoring devices, just to mention a few, will be highly interconnected allowing for the seamless flow of data. Reliability and security in this flow of data between nodes is crucial due to the low latency and cyber-attacks resilience requirements of the Smart Grid. In particular, Artificial Intelligence techniques such as Fuzzy Logic, Bayesian Inference, Neural Networks, and other methods can be employed to enhance the security gaps in conventional IDSs. A distributed FPGA-based network with adaptive and cooperative capabilities can be used to study several security and communication aspects of the smart grid infrastructure both from the attackers and defensive point of view. In this paper, the vital issue of security in the smart grid is discussed, along with a possible approach to achieve this by employing FPGA based Radial Basis Function (RBF) network intrusion.

• Journal of information and communication convergence engineering
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• v.9 no.5
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• pp.523-529
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• 2011

In this paper an inter-layer protocol, referred to as a Multi-Network Selector (MNS) is proposed for multiband maritime networks. A MNS is located between the data-link layer and the network layer and performs vertical handover when a ship moves another radio network. In order to provide seamless data transfer to different radio networks, the MNS uses received signal strength (RSS) and ship's location information as decision parameters for vertical handover, which can avoid ping-pong effect and reduces handover latency. In addition, we present related issues in order to implement the MNS for a multiband maritime network.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.10
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• pp.12-19
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• 1996

Many recent supercomputers employ a kind of switch-based multistage interconnection network architectrues (MINs) for constructing scalabel parallel compters. This paper proposed a new routing method, hybrid wormhole and virtual-cut through routing (HWCR) for the prevention of rapid performance degradation comming from a conflict in links usage at hot traffic situation. This HWCR through (VCT) for the fast removing temporal stagger, result in seamless flow of packet stream. When the blocked link is removed, wormhole routing is resumed. The HWCR method adopted a hierachical buffer scheme for improving the network performance and reducing the cost in BMINs. We could get optimum buffer size and communicatin latency through the computer simulation based on proposed HWCR, and the results were compared to those using wormhole and VCT.

• Proceedings of the Korea Information Processing Society Conference
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• 2021.11a
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• pp.128-130
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• 2021

Smart cities collect data from thousands of IoT-based sensor devices for intelligent application-based services. Centralized cloud servers support application tasks with higher computation resources but introduce network latency. Fog layer-based data centers bring data processing at the edge, but fewer available computation resources and poor task allocation strategy prevent real-time data analysis. In this paper, tasks generated from devices are distributed as high resource and low resource intensity tasks. The novelty of this research lies in deploying a virtual node assigned to each cluster of IoT sensor machines serving a joint application. The node allocates tasks based on the task intensity to either cloud-computing or fog computing resources. The proposed Task Allocation Strategy provides seamless allocation of jobs based on process requirements.

• Electronics and Telecommunications Trends
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• v.39 no.1
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• pp.48-61
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• 2024

The integration of high-capacity terrestrial networks with non-terrestrial communication using satellites has become essential to support seamless low-latency services based on artificial intelligence and big data. Tunable light sources have been instrumental in resolving the complexity of channel management in wavelength division multiplexing (WDM) systems, contributing to increased network flexibility and serving as optical sources for long-distance coherent systems. Recently, these light sources have been applied to beam-steering devices in laser communication and sensing applications across ground, aerial, and satellite transport. We examine the utilization and requirements of tunable lasers in WDM networks and describe the relevant development status. In addition, performance requirements and development directions for tunable lasers used in optical interference systems and beam-steering devices are reviewed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.7B
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• pp.710-720
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• 2009

The Future Generation Networks(FGNs) are proposed to integrate various heterogeneous access technologies, and further expected to support both vertical and seamless handovers. In this motivation, the IEEE 802.21 specifies Media Independent Handover(Mlli) services to enhance the mobile user experience by optimizing handovers between heterogeneous access networks. Additionally, Fast handover for MIPv6(FM1Pv6) is introduced to provide transparent host mobility and to improve handover performance by reducing handover delay as well. This paper focuses on the coordination of FMIPv6 and MIH, and introduces an enhanced mobility management framework suited for FGN. This novel framework replaces handover signaling messages used in wireless networks with novel MIH messages and local primitives. Moreover, Serving Access Router(SAR) performs most of handover processes instead of Mobile Node(MN). Therefore, the proposed mobility management framework reduces handover latency, packet loss, and signaling overhead significantly. We further evaluate the performance of the proposed framework by using both numerical analysis and network simulations.

• Journal of the Korea Society of Computer and Information
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• v.26 no.3
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• pp.1-7
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• 2021

In this paper, optimized media data retrieval and transmission based on the Hybrid CDN/P2P architecture and selective storage through user's prediction of requestability enable seamless data transfer to users and reduction of unnecessary traffic. We also propose a new media management method to minimize the possibility of transmission delay and packet loss so that media can be utilized in real time. To this end, we construct each media into logical segments, continuously compute weights for each segment, and determine whether to store segment data based on the calculated weights. We also designate scattered computing nodes on the network as local groups by distance and ensure that storage space is efficiently shared and utilized within those groups. Experiments conducted to verify the efficiency of the proposed technique have shown that the proposed method yields a relatively good performance evaluation compared to the existing methods, which can enable both initial latency reduction and seamless transmission.