• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2423-2425
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• 2000

A wireless communication module for multiple PLC was developed. The function of the developed system are dual communication, concurrent multiple communication. PLC control, d interpretation of PLC command, and A/D D/A converting. The multiple communication approach is based on master-slave control concept. To show validity of the developed module, severial experiments are illustrated.

• Proceedings of the IEEK Conference
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• 2002.06a
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• pp.343-346
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• 2002

This paper presents a Prototype system developed for a Bluetooth interfaced VoIP system. The VoIP phone is developed based on tile implementation of a CELP coder on the TI 16bit DSP Processor A PC interfaced with Bluetooth module is used to designing a access point system. Host controller protocol stack is implemented to realize gateway between the wireless and wired line networks. A server application program for user management and call processing, which is based on TCP/IP peer to peer connection, is implemented for tile evaluation of overall interface system.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.277-280
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• 2005

In this paper, we propose a frequency synthesizer for dualband repeater. The dual-band RF technology for applications to the wireless repeater for CDMA and WCDMA mobile communications has been developed in this paper. The dualband PLL module consisted of dual-band VCO and one PLL IC has been developed. The main technological efforts for the dual-band PLL module is to suppress the intermodulation distortion by applying the miniature ceramic filter using the slow wave characteristics. The dual-band miniature RF module including dual-band PLL module and one MCU controller is very attractive for applications to the miniature dual-band RF mobile repeaters.

• Journal of Broadcast Engineering
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• v.18 no.3
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• pp.491-494
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• 2013

This paper proposes a stochastic/dynamic routing protocol which aims the minimization of the summation of time average expected power expenditure with buffer stability in mobile ad-hoc 60 GHz wireless networks. By using 60 GHz RF, the wireless devices can transmit/receive 1080p HD video signals without compression. In addition, our algorithm works without centralized controller, so that the distributed operation is available. The novelty of the proposed algorithm was also verified by simulations.

• Proceedings of the KIEE Conference
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• summer
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• pp.1445-1447
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• 2004

In recent years, the smart card is widely applied for wireless communication, tracking, transportation logistics, diagnostic monitoring, access control and security. RF-ID system is universally applicable. Passive RF-ID system consists of reader and passive tag. The reader transmits energy and simple information to a tag by wireless and the power from the reader is transformed for controller, FRAM and Bluetooth module. In this paper, proposed for the improvement of wireless power transmission and demonstrated the propriety through experiments in several conditions.

• Proceedings of the Korea Information Processing Society Conference
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• 2014.11a
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• pp.173-174
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• 2014

Handover is constantly a challenging issue in wireless networks. Most of the existing solutions are host-based, which are implemented on the wireless terminals and leave the decision making to the terminals. This paper studies the problem of network-based handover in the wireless networks with the constraints of low latency as well as low computational time. To address this problem, we employ the software-defined network (SDN) architecture to facilitate handover. According to the operational model of the SDN, we define a workflow for all involved network entities, and then design a framework implementing the workflow as a complete handover system. The proposed framework aims to establish a channel conveying the mobility-related information of devices and the context information of their vicinity from the switches/access routers to the controllers. Based on collected information, the controller can optimally execute the handover.

• Journal of Advanced Marine Engineering and Technology
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• v.29 no.4
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• pp.384-390
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• 2005

This paper addresses the design and implementation of a wireless network. proposed as a cost-effective support platform for PLCs. With this network. one or more supervising stations may access remote equipment like PLCs. An applicable communication methods are described and we applied efficient method among them to PLCs communication. The paper specifies these requirements and indicates methods to fulfill them. Also. it provides to the model of operation, and focuses on the implementation approach. The hardware and software design is described together with a number of critical points related to wireless communication on the Cnet. Furthermore, a discussion on system expandability and performance is tackled and some observations are stated. The main conclusion is, that the proposed method can feature good performance under normal operating conditions.

• ETRI Journal
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• v.41 no.4
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• pp.452-464
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• 2019

The use of wireless body area networks (WBANs) in healthcare applications has made it convenient to monitor both health personnel and patient status continuously in real time through wearable wireless sensor nodes. However, the heterogeneous and complex network structure of WBANs has some disadvantages in terms of control and management. The software-defined network (SDN) approach is a promising technology that defines a new design and management approach for network communications. In order to create more flexible and dynamic network structures in WBANs, this study uses the SDN approach. For this, a WBAN architecture based on the SDN approach with a new energy-aware routing algorithm for healthcare architecture is proposed. To develop a more flexible architecture, a controller that manages all HUBs is designed. The proposed architecture is modeled using the Riverbed Modeler software for performance analysis. The simulation results show that the SDN-based structure meets the service quality requirements and shows superior performance in terms of energy consumption, throughput, successful transmission rate, and delay parameters according to the traditional routing approach.

• The Journal of the Convergence on Culture Technology
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• v.5 no.1
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• pp.401-407
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• 2019

SDN(Softeware Defined Networking) has emerged to address the rapidly growing demand for cloud computing and to support network virtualization services. Therefor many companies and organizations have taken SDN as a next-generation network technology. However, unlike the wired network where the SDN is originally designed, the SDN in the wireless network has a restriction that it can not provide the mobility of the node. In this paper, we extended existing openflow protocol of SDN and developed SDN-based network platform, which enables the SDN controller to manage the radio resources of its network and support the mobility of the nodes. The mobility support function of this paper has the advantage that a node in the network can move using its two or more wireless interfaces by using the radio resource management function of the SDN controller. In order to test the functions implemented in this paper, we measured parameters related to various transmission performance according to various mobile experiments, and compared parameters related to performance using one wireless interface and two interfaces. The SDN-based network platform proposed in this paper is expected to be able to monitor the resources of wireless networks and support the mobility of nodes in the SDN environment.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.7
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• pp.577-583
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• 2014

In this study, we introduce how to apply "Information and Communication Technology (ICT) to injection molding system. We report the current state of IT technology applied to produce their products in micro lens injection molding system. And we explain key technology of ICT for injection molding system and how to implement. Especially, we also mention about an embedded controller, also called as "M2M device". It provides programmable intelligent functions, communication, various interfaces, amplifier functions and mobile device connection to our application.