• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.12
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• pp.30-45
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• 2014

Recently, multimedia application users who demand for ubiquitous computing environment are rapidly increasing, and wireless mesh network is receiving attention as a cost-effective key technology for next generation wireless networking. When multiple flows are transmitting data at the same time in the network, routing for path selection of each flow and link resource allocation for data transmission of each flow are one of the key factors that influence to the effectiveness of the network directly. In this paper, we consider problems for path discovery and resource allocation of links at the same time and we propose an algorithm based on mathematical modeling using a technique for cross-layer optimization design in STDMA-based wireless mesh networks that can enhance transfer performance for each flow. We show by performance analysis that the proposed algorithm can enhance the throughput performance by maximally utilizing given bandwidth resources when the number of flows increase in multi-hop wireless mesh networks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.1B
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• pp.144-153
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• 2010

Flooding based routing protocols are usually used to disseminate information in wireless sensor networks. Those approaches, however, require message retransmissions to all nodes and induce huge collision rate and high energy consumption. In this paper, HoGoP (Hop based Gossiping Protocol) in which all nodes consider the number of hops from sink node to them, and decide own gossiping probabilities, is introduced. A node can decide its gossiping probability according to the required average reception percentage and the number of parent nodes which is counted with the difference between its hop and neighbors' ones. Therefore the decision of gossiping probability for network topology is adaptive and this approach achieves higher message reception percentage with low message retransmission than the flooding scheme. Through simulation, we compare the proposed protocol with some previous ones and evaluate its performance in terms of average reception percentage, average forwarding percentage, and forwarding efficiency. In addition, average reception percentage is analyzed according to the application requirement.

• The Journal of Korean Association of Computer Education
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• v.10 no.5
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• pp.81-88
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• 2007

To support the movement of a mobile network consisting of several mobile nodes, the IETF NEMO working group proposed NEMO basic support protocol using bi-directional tunneling between the home agent and the mobile router. Since NEMO basic support protocol is based on bi-directional tunneling, all communications to and from mobile nodes are suffer from inefficient routing all the cases. To solve the routing inefficiency problem, several proposals are proposed. However, those proposals results in new problems, such as binding update storm and changes in existing protocol. Especially, binding update storm problem may cause the delay in binding update, this subsequently causes the difficulty for a real time service and the handoff delay on the movement of mobile network. In this paper, we propose a new binding update scheme which reduces binding update latency and the handoff delay through the distribution of the transmission time of binding update messages. The performance of the proposed scheme is also evaluated to demonstrate its efficiency. Simulation results show that the proposed scheme can efficiently reduce the binding update latency.

• Convergence Security Journal
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• v.13 no.4
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• pp.101-108
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• 2013

Sensor network configurations are for a specific situation or environment sensors capable of sensing, processing the collected information processors, and as a device is transmitting or receiving data. It is presently serious that sensor networks provide many benefits, but can not solve the wireless network security vulnerabilities, the risk of exposure to a variety of state information. u-Healthcare sensor networks, the smaller the sensor node power consumption, and computing power, memory, etc. restrictions imposing, wireless sensing through the kind of features that deliver value, so it ispossible that eavesdropping, denial of service, attack, routing path. In this paper, with a focus on sensing of the environment u-Healthcare system wireless security vulnerabilities factors u-Healthcare security framework to diagnose and design methods are presented. Sensor network technologies take measures for security vulnerabilities, but without the development of technology, if technology is not being utilized properly it will be an element of threat. Studies suggest that the u-Healthcare System in a variety of security risks measures user protection in the field of health information will be used as an important guide.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.3B
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• pp.349-359
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• 2004

To provide multicasting service, several multicast protocols for mobile hosts have been proposed. But they include glitches such as a non-optimal delivery route, data loss when hosts move another network, therefore they have some insecure problems about multicast data transmission. In this paper, we consider these problems and propose a new reliable and efficient multicast routing protocol for Mobile If networks. The proposed protocol provides reliable multicast transmission by compensating data loss from the previous agent when a mobile host moves another network. Also it provides additional function that is directly to connect a multicast tree according to the status of agents. It provides more efficient and optimal multicast path. The performance of the proposed protocol is proved by simulation of various conditions.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.9A
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• pp.924-933
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• 2008

This paper proposes a novel LDPC code decoder architecture to improve throughput for DVB-S2, a second generation standard of ETSI for satellite broad-band applications. The proposed architecture clusters 360 bitnodes and checknodes into groups utilizing the property of IRA-LDPC code. Functional modules which perform calculations for bitnode groups and checknode groups have local memories and store the messages from the other type of functional modules connected by edges at their local memories. The proposed architecture can avoid memory conflicts by accessing stored messages sequentially, hence, increases throughput in the proposed DVB-S2 LDPC code decoder architecture. The proposed architecture was synthesized using the TSMC 90nm technology. Synthesis results show that throughput of the proposed architecture is improved by 104% and 478%, respectively, when compared with those of the architectures proposed by F. Kienle and J. Dielissen.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.402-405
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• 2006

Mobile IP has been designed to have mobile host users move from place to plate without changing their IP address. Ad-hoc network is a provisional network whose mobile host users construct networks by themselves without any assistance of infra structure network, using wireless interface. In this paper we discuss the scheme with which Ad-hoc network users ran access the Internet freely, using mobile IP protocol, and Ad-hot networks are access networks in the spotlight. In this paper we propose algorithm that support enhanced mobility between two Ad-hoc networks applying mobile IP at Ad-hoc routing protocol.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.12
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• pp.2769-2774
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• 2013

The key of USN(Ubiquitous Sensor Network) technology is low power wireless communication technology and proper resource allocation technology for efficient routing. The distinguished resource allocation method is needed for efficient routing in sensor network. To solve this problems, we propose an algorithm that can be adopted in USN with making up for weak points of PQ and WRR in this paper. The proposed algorithm produces the control discipline by the fuzzy theory to dynamically assign the weight of WRR scheduler with checking the Queue status of each class in sensor network. From simulation results, the proposed algorithm improves the packet loss rate of the EF class traffic to 6.5% by comparison with WRR scheduling method and that of the AF4 class traffic to 45% by comparison with PQ scheduling method.

• The KIPS Transactions:PartC
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• v.9C no.2
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• pp.227-234
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• 2002

MPLS which integrates routing of layer 3 and switching of layer 2, enables support for fast forwarding, traffic engineering and virtual private network services. GSMP is open interface protocol between a label switch and a controller, and it provides connection, configuration, event, performance management and synchronization. In the GSMP open interface, the functions of network management can be located either in the controller or in the label switch. To simplify the label switch and enhance the efficiency of resources, we adopt the network management model, in which the SNMP agent is located in the controller and is interworked with the GSMP. We presented the interworking scenrios between the GSMP and the network management of MPLS. We implemented the controller to verify the realization of our adopted network management model, and measured the connection setup delay of the provisioned connection.

• Journal of Internet Computing and Services
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• v.5 no.2
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• pp.75-84
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• 2004

Geocasting, a variant of the conventional multicasting problem, is one of communication type in which the data packets are delivered to a group of all nodes within a specified geographical region (i.e., the geocasting region) and is called location-based multicasting(LBM)(l). An Ad-hoc network is a dynamically reconfigurable and temporary wireless network where all mobile devices using batteries as energy resources cooperatively maintain network connectivity without central administration or the assistance of base stations. Consequently, the technique to efficiently consume the limited amounts of energy resources is an important problem so that the system lifetime is maximized. In this paper, we propose a LBPA(Location-Based Power Aware) geocasting algorithm that selects energy-aware neighbor to route a packet towards the target region In Ad-hoc network environments. The method Is such that the energy consumption is balanced among the nodes in proportion to their energy reserves. Through the simulations, the proposed LBPA algorithm shows better results, that is, as good as 40% on the average over the conventional LBM algorithm in terms of the network lifetime.