• Journal of IKEEE
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• v.23 no.3
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• pp.941-946
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• 2019

In this paper, the author analyzed the PCI (Physical Cell Identification) allocation methods in the LTE (Long Term Evolution) SON (Self Organization Network) environment. A variety of techniques have been proposed for how to allocate PCI, and the LTE standard fundamentally explained that collision between a cell and neighbor cells arise while a cell assign the PCI. Therefore, in this paper, the author examined the scenarios of PCI collision, weak collision, and confusion proposed by LTE specification. In addition, the cell central approach and the distributed approach were discussed as solutions for each scenario. In this paper, the author reviewed the approach of graphic coloring technique which was studied recently and explained the strategy of central approach.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.4
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• pp.451-455
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• 2014

In LTE (Long Term Evolution)/LTE-A (Long Term Evolution-Advanced) networks, hierarchical macro/femto-cell structure is adopted to enhance system capacity. Such a femto-cell is deployed as a Closed Subscriber Group (CSG) eNB. However, the inbound handover to CSG cell experiences longer delay than normal handover because it spends more time detecting the associated CSG cells due to its sparse deployment. Most of all the legacy UEs (User Equipments) have been implemented without considering the inbound CSG handover. Accordingly, they may not meet the performance requirements on the cell discovery described in the LTE/LTE-A standards. Therefore, in this paper, the performance of the CSG femto-cell detection is evaluated using computer simulation. The evaluation results will provide a basis to tackle the latency problem of inbound CSG handover.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.12
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• pp.1045-1053
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• 2013

In this paper, we propose a new power-saving mechanism (PSM) for Long-Term Evolution (LTE) systems by considering a round-trip delay between a user equipment (UE) and its correspondence node. The proposed PSM changes the order of the operational procedures of the legacy LTE PSM by taking the traffic arrival pattern suffering the round-trip delay into account. After modeling the round-trip delay, we numerically analyze the proposed PSM with respect to energy consumption and buffering delay. Then, we characterize these performances by employing a simple energy-delay tradeoff (EDT) curve according to the operational parameters. The resulting EDT curve clearly shows that the proposed PSM outperforms the legacy LTE PSM in terms of both the energy consumption and buffering delay.

• Information and Communications Magazine
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• v.24 no.12
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• pp.31-38
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• 2007

본고에서는 현재 3GPP(3rd Generation Partner Project)에서 표준화 작업이 진행중인 LTE(Long Term Evolution) 시스템에서, Layer 2와 Layer 3에 해당되는 무선프로토콜 기술에 대해서 알아본다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.864-867
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• 2016

In high speed railway system, LTE(Long Term Evolution) based LTE-R(LTE-Railray) mobile technology is used to supply various control signal required for safty operation of train. In this paper, railway communication technology be used in railway communication system based on LTE-R is investigated in focused on application services. Standardization trends for LTE-R technology are also considered. Results of this study can be used as basic data for research and development of LTE-R and railway mobile communication.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.05a
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• pp.549-552
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• 2018

One of railway communication technology, LTE(Long Term Evolution) based LTE-R(LTE-Railway) is rapidily adopted to supply various control signal and to supply diverse communication service be needed for safety operation of train. In this paper, railway communication technology and service based on LTE-R is studied. And domestic an international standardization trends of related on railway communications are investigated. Results of this study can be used as basic data for research of railway communication based on LTE-R and development of railway communication systems.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.527-530
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• 2017

LTE-R(Long Term Evolution-Railway) based on LTE technology is expected to use core communication technology for high speed railway as one of standards for railway communications. In this paper, transmission performance of video traffic as an application is analyzed on LTE-R networks. Performance is evaluated with compter simulation based NS(Network Simulator)-2, open video traffic is used, RTP(Real Time Protocol) is used for transmission protocol. Results and methods of this paper can be used for research and developmemt of LTE-R networks.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.4
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• pp.983-990
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• 2010

In this paper, we designed and implemented the MIMO antenna for LTE(Long Term Evolution), supposed to be a next generation communications network, DCS1800, DCS1900 and WCDMA. Using conventional monopole antenna with MD material results in good characteristics, miniaturization for LTE band and as well as broadbanding for DCS, WCDMA band. The performance of the proposed MIMO antenna shows VSWR < 2, under -10 dB of isolation and the gain is -1.66 ~ 1.33 dBi for LTE(Long Term Evolution), DCS1800, DCS1900 and WCDMA, which has omnidirectional radiation pattern.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.8
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• pp.712-723
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• 2013

Recent exploration of smart-phone user is fueling the deployment of long term evolution (LTE) service that offers higher data rates service over 3G HSPA networks. In particular, Korea, mobile powerhouse, recently launched the service of LTE-Advanced (LTE-A) which is the latest release in LTE standard. Multiple-input-multiple-output (MIMO) technology is the one of key enablers for LTE and LTE-A for achieving high data rate. MIMO technology has received much attention since it is possible to achieve channel capacity in proportion to the number of antennas without increasing frequency and power. In this paper, we overview of the theoretical background of MIMO technology regarding from single-user MIMO, multiuser MIMO, and massive MIMO and design considerations to implement the communication system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.641-644
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• 2017

Usage of LTE(Long Term Evolution) technology is expanded to industrial an emergency service field beyond commercial communications of mobile internet focused on smartphone. In this paper, transmission performance of LTE technology be supplied to various service area is analyzed on the level of application traffics. Performance is evaluated with compter simulation based NS(Network Simulator)-2, CBR(Constant Bit Rate), VBR(Variable Bit Rate File) traffic is used as simulation target. Results and methods of this paper can be used for research and developmemt of LTE based networks.