• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.5A
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• pp.457-465
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• 2010

When a sensor network is used for monitoring environments in large area or transmitting information in a u-City the number of nodes becomes very large. One of the problems with this application is the increased time delay, especially in reverse direction. In this paper, we propose a new algorithm that can minimize the latency of reverse packet in large sensor network. Analysis shows that the proposed scheme can reduce the latency by more than 90% when compared to Zigbee, while the energy consumption is maintained.

• The Transactions of the Korea Information Processing Society
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• v.6 no.11S
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• pp.3190-3198
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• 1999

Because of the rapid growth of the mobile communication, the need for the mobile internet access has grown up as well. since the current mobile communication network, however, is optimized for a voice communication system, which exclusively occupies a channel for a given time, it is not suitable for variable rate packet data. In order to support the mobile internet access, it is essential do design a reasonable packet switching network which supports the mobility. Since mobile packet network has longer latency, high speed switching and QoS are required to meet the user's requirements. In this paper, we suggest an resonable way to construct a network and its operation procedures utilizing GPRS(General Packet Radio Service) network and MPLS(Multi Protocol Label Switching) to provide a high speed switching and QoS mobile internet access. GPRS is used as a network which supports the mobility and MPLS guarantees the QoS and high speed IP protocol transmission based on the ATM switching technology.

• ETRI Journal
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• v.43 no.1
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• pp.64-73
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• 2021

Two-dimensional torus network nodes are typically interconnected using XY routing algorithm for transmitting a packet from a source node to a destination node. In XY routing, if all the paths are used efficiently, the throughput and latency can be improved. In this paper, to utilize all the paths efficiently, we propose a novel binary optical routing algorithm (BORA) to improve the throughput and latency. The throughput is calculated according to the injection rate and number of packets received at the destination. The XY routing algorithm and proposed BORA are implemented using objective modular network testbed in C++ simulation software and the results are analyzed and compared. In this paper, the simulation results show that the network latency reduces to 50% while using the proposed algorithm; moreover, the throughput is also improved.

• Journal of Communications and Networks
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• v.12 no.5
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• pp.510-517
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• 2010

In this paper, an adaptive MAC protocol (variable load adaptive (VLA)-MAC) is proposed for wireless sensor networks. This protocol can achieve high energy efficiency and provide low latency under variable-traffic-load conditions. In the case of VLA-MAC, traffic load is measured online and used for adaptive adjustment. Sensor nodes transmit packets in bursts under high load conditions to alleviate packet accumulation and reduce latency. This also removes unnecessary listen action and decreases energy consumption in low load conditions. Simulation results show that the energy efficiency, latency, and throughput achieved by VLA-MAC are higher than those achieved by some traditional approaches.

• Journal of KIISE:Information Networking
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• v.31 no.6
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• pp.620-632
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• 2004

IP is not suitable for mobile nodes by network-based routing because mobile nodes are dynamically change their network attachment point. Mobile-IP is an IETF standard providing continuous access to the Internet for mobile nodes, but it has the triangle routing problem. Also it has a performance degradation problem by massive packet loss during layer 3 handoff of mobile nodes. Especially, two IETF multicast support schemes for Mobile-IP do not guarantee the quality of realtime multimedia services because they have several problems such as long routing path, packet duplication(hi-directional tunneling) and massive packet loss(remote subscription). In this paper, we propose a lossless remote subscription scheme that guarantees the quality of realtime multimedia services over Mobile-IP. From the result of simulation, we verified that the proposed scheme in this paper can reduce the delay time of remote subscription by the effect of the low latency handoff scheme that is extended to apply to the multicast group management and it requires only 0.58% buffer spaces of the previously proposed lossless remote subscription scheme.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.699-700
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• 2008

In this paper, we implement Mobile AP system, which has Multihoming function providing vertical handover between WiBro and HSDPA networks. We monitor packet drop in networks during binding updates(BU) and acknowledgement(BA) and analyze handover latency. We propose methodology to reduce handover latency and describe the further development direction of Mobile AP system.

• ETRI Journal
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• v.35 no.4
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• pp.726-729
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• 2013

For secure multimedia communications, existing encryption techniques use an online session key for the key exchange, for which key size is limited to less than 10 digits to accommodate the latency condition caused by user devices only being able to handle low computational loads. This condition results in poor security of recorded encrypted data. In this letter, we propose a packet key scheme that encrypts real-time packets using a different key per packet for multimedia applications. Therefore, a key of a relatively small size can provide after-transmission confidentiality to data of a real-time session.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.11
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• pp.56-65
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• 2009

As increasing the number of IPs integrated in a single chip and requiring high communication bandwidth on a chip, the trend of SoC communication architecture is changed from bus- or crossbar-based architecture to packet switched network architecture, NoC. However, highly complex control logics in routers require multiple cycles to switch packet. In this paper, we design low complex router to improve the communication latency. Our NoC design is verified by simulation platform modeled by ESL tool, SoC Designer. We also evaluate our NoC design comparing to the previous NoC architecture based on VC router. Our results show that our NoC architecture has less communication latency, even small throughput degradation (about 1-2%).

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.3
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• pp.93-99
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• 2009

The Internet Engineering Task Force (lETF)proposed the Mobile IPv6 protocol to provide host mobility in IPv6-based network and to offer a standardized technology. However, Mobile IPv6 (MIPv6) is not applied in actual network because of long handover latency and packet loss problems. Therefore, to compensate these drawbacks, many studies are in progress and FMIPv6 (Fast handover for Mobile IPv6) is one of the studies that has been proposed to supplement the shortcomings of MIPv6. But there are problems occurred in using router tunneling which causes packet loss and out of sequence problems. In this paper, we propose an Advanced Mobile IPv6 (AMIPv6) protocol to minimize the handover latency when Mobile Node frequently moves in each subnet. We compared the performance analysis of AMIPv6 handover latency with MIPv6 handover latency in the same network environment to prove that AMIPv6 is more efficient.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.5
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• pp.105-111
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• 2008

Mobility support for mobile networks will be important to minimize the packet overhead, to optimize routing, to reduce handoff latency, and to reduce the volume of handoff signals. Mobile IPv6 (MIPv6) and Hierarchical MIPv6 (HMIPv6) are one of mobility management protocols (MMPs) that provides network layer mobility over all access technologies. However, the communication quality of these candidates is severely degraded during handoffs. As another way to improve the handoff performance of a mobile network by conventional MMPs such as MIPv6 and HMIPv6, we propose a Low Latency Handoff Scheme (LLHS) combining Fast MIPv6 (FMIPv6) with HMIPv6 extension with buffering function, in which Mobility Anchor Points (MAPs) buffer packets destined to the Mobile Routers (MRs) or MNs within a mobile network during handoffs. The simulation results show that the proposed scheme reduces transmission delay and packet loss in UDP communication.