• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.10
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• pp.1129-1136
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• 2008

In this paper, a dual polarized broadband antenna fed by L-shaped strip for the Korea PCS band and W-CDMA band is presented. To analyze the characteristics of the designed antenna, we used commercial simulation tool(HFSS). The designed antenna was fabricated and measured using HP8753D vector network analyzer. The measured impedance bandwidth(VSWR<1.5) is 560 MHz and the measured average gain is 6.56 dBi. The measured isolation characteristic between two ports is -14 dB(min.) $\sim$ -40 dB(max.). These results are proper for the mobile communication application and repeater antenna.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.10
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• pp.1945-1956
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• 1994

In this paper, a multiaccess network protocol for high-speed communication is proposed, which enables multimedia sevices with integrating the existing networks. We examine the traffic control mechanisms and configurations for the network architecture and compare with various protocols which are suitable to high speed LAN/MAN and propose an adaptive access control mechanism. ATMR has low channel utilization due to window size reset time, and that MetaRing is very sensitive over the change of traffic load. This suggested protocol, however, has quite a good performance for that situation by adding adaptive parameter condition. This mechanism may introduce a model of small-scaled Broadband Integrated Service Network and be used as an internetworking system for the ATM network.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.2
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• pp.275-280
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• 2013

With rapidly growing mobile wireless services, the existing copper-based mobile backhaul technologies suffer from reaching the capacity limits. PON technologies is drawing attention as a key solution to replace the existing mobile backhaul technologies due to not only providing innovative network capacity but also cost-effective maintenance caused by the bandwidth gain from optical fibers. With a PON-based mobile backhaul, broadband wireless multimedia services such as a video conference and IPTV can be seamlessly provided. In this paper, we first introduce overview of the PON-based mobile backhaul technology. For a example of practical integration, three types of EPON-WiMAX integrated architectures are proposed and comparatively analyzed in term of costs and network performance. Then, applicable plan and anticipated effects are presented when applying network coding on the PON-based mobile backhaul to improve the performance of delivering multicast traffic.

• Journal of KIISE:Information Networking
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• v.30 no.5
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• pp.668-675
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• 2003

In this paper, we propose an enhanced p-cycle (preconfigured protection cycle) scheme for WDM mesh networks with QoS constraints. In the previous researches on p-cycle, it is assumed that user's connection has a hi-directional connectivity and the same bandwidth on both direction. Therefore it is difficult to apply p-cycle based link protection to uni-directional connections for multicasting or asymmetric broadband multimedia communications with hi-directional connectivity. And it didn't consider QoS of backup path. We enhanced the p-cycles to accomodate uni-directional connections for multicasting or asymmetric bandwidth communications with hi-directional connectivity. And we propose a selection procedure of p-cycle to assure QoS of backup path. We were able to reduce a required backup bandwidth by applying a uni-directional p-cycle concept to asymmetric broadband multimedia communication environment. The proposed p-cycle selection procedure is applied to the U.S. sample network to evaluate whether the configured p-cycles can support QoS constraint of working path and backup path.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2014.06a
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• pp.144-145
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• 2014

IoT (Internet of Things) is connected to all things Internet-based people and things, things and objects that communicate information between said intelligent technologies and services. Shipping each of a variety of devices that act independently from each other, but, it is actively interlock with each other is not easy practically days. Ship it within the means of communication, the communication between the ship, the communication between ship and shore configuration, SAN (Ship Area Network), RFID/USN, broadband communications, satellite communications and IT technology to a variety of marine environments for the safe navigation the ship's safety management system for the configuration you want to discuss the plan.

• Journal of Advanced Navigation Technology
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• v.23 no.6
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• pp.507-514
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• 2019

Federal communications commissions (FCC) has announced the first set of rules for 3.5 GHz (3,550 - 3,700 MHz) band used Navy radar and fixed satellite service (FSS) earth stations as primary service to sharing for citizen broadband radio service (CBRS) enable development of relatively low powered network technologies like small cells. Since CBRS sharing technique based on the 3-tiered spectrum access system (SAS) is able to protect the higher tiered users from harmful interference from lower tiered users, it has been considered actively to be introduced in Korea. However, 3.5 GHz band had been already allocated to the 5G services in Korea, the sharing studies have been carried out for 3,700 - 5,000 MHz, As the result, the 3.8 GHz (3,800 - 3,900 MHz) band used for only FSS system is able to be sharing, and an introduction of CBRS has been proposed in Korea by analyzing the interference to the FSS earth stations.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.3
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• pp.461-467
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• 2003

This paper proposes the method of mobility implementation for location searching in the intelligence wireless ATM networks that expand and apply standard broadband signaling capabilities, and analyze the performance based on the numerical algorithm. The existing B-ISDN UNI protocol stack demands the location search mechanism to determine the location of mobile terminal in the wireless ATM networks because it use single protocol through the fixed PTP interface or PTM interface that don't support terminal mobility. The proposed method make possible the dynamic mobility at a part of wireless access by minimizing the signaling load without a falling-off in system performance by using the intelligence network technology according to the expansion of ATM and B-ISDN signaling integration based on the fixed networks. We implemented the performance analysis by MFC modeling based on numerical algorithm, and realized the efficiency of expenses by carrying out the comparative signaling performance evaluation to measure the relative gains of location search service in the intelligence wireless ATM system. The obtained results have the flexibility to operate in the public B-ISDN network environment without a change of existing B-ISDN/ATM NNI signaling reference to support the wireless ATM access system, and can easily expand to correspond to terminal mobility and various multimedia services in the next broadband PCS.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.4
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• pp.387-393
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• 2013

In shipyard site, a ship is constructed by integrating lots of modules that are made in several sites with different capabilities and specifications. Recently, it needs to make a shipyard to be smart with wired and wireless broadband networks between hierarchical shipyards. In this paper, we propose an installation of LTE femtocell local gateway at a remote shipyard, an information exchange method between hierarchical shipyards, and an offload method to separate the general traffic. We define the mode change in a femtocell gateway for supporting the offload of the general traffic between the headquarter and a remote shipyard, the offload data management and trigger message, and cache entry fields. To show the operation of our proposed off-loading function, we consider the transcipient message flow at the femtocell gateway with its state transition diagram. Hence, it is expected to increase the productivity of shipyard industry with mobile communications and broadband Internet technologies.

• Journal of Advanced Navigation Technology
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• v.14 no.6
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• pp.859-864
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• 2010

In the next generation system, a study on realization of Multi-Core system is in progress for applying it in multi service network. Therefore some mobile systems are expected to be appeared. These systems can support WiBro, WCDMA, CDMA, etc with single terminal. These systems have to support various FA using broadband frequency and hand over to other service network. Especially, in the telecommunication system composed of cell, the transmit power can be interference at adjacent system, has effect on system channel capacity and cell size. In this paper, we improve the unstable transmit power caused by unsettled system operation, propose the RF(Radio Frequency) Calibration method which can use the transmit power stably even during hand over between heterogeneous networks causing unstable power change. Also we used proposed method and analysed used electricity of system during hand over between heterogeneous networks.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.2
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• pp.95-100
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• 2011

This paper analyzes the interference effect of WLAN(Wireless Local Area Network) service on WiBro(Wireless Broadband) service in adjacent frequency band by using Monte Carlo method. For the analysis, we make scenario that WLAN service operates on frequency band of 2401 MHz ~ 2423 MHz and WiBro service operates on frequency band of 698 MHz ~ 704 MHz. In case of WiBro receiver is close to WLAN AP(Access Point), the interference will be increased. So, we calculate the protection distance between WiBro receiver and WLAN AP to meet interference probability of 5 % below and required interference power of WLAN AP to meet interference probability of 5 % below in the case of fixed protection distance. As a result, the protection distance of 60 m and -9.5 dBm of required interference power of WLAN AP at 10 m of the fixed protection distance are analyzed.