• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.4A
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• pp.189-196
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• 2012

A WAVE(Wireless Access for Vehicular Environment) system is a vehicle communication technology. The system provides the services to prevent vehicle accidents that might occur during driving. Also, it is used to provide various services such as monitoring vehicle management and system failure. However, the scrambler bit operation of WAVE system becomes less efficient in the organizations of software and hardware design because the parallel processing is impossible. Although scrambler algorithm proposed in this paper has different processing speed depending on input data 8 bit, 16 bit, 32 bit, and 64 bit. it improves the processing speed of the operation because it can make parallel processing possible depending on the input unit.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.8
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• pp.1465-1471
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• 2007

The electro-magnetic wave propagates through the air in the terrestrial communications, but the acoustic wave propagates through the seawater in the underwater acoustic communication(UAC). It makes the differences between the UAC link and the well hon air communication links. In this paper, we have studied path loss, absorption and ambient noise of the ocean as a medium for UAC. We have analyzed the absorption coefficient and ambient noise level of the coastal area of South Korea and suggested a strategy for the selection of the frequency band by considering the absorption coefficient and ambient noise level. Also, we present an illustrative example of a link budget for the QPSK UAC system which has carrier frequency 25kHz, bit rate 10kbps, range 1km and BER $10^{-3}$ in the shallow water environment with an ideal AWGN assumption.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.3D
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• pp.355-361
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• 2011

In order to properly evaluate ITS services exposed in SMART Highway project, a confident dynamic origin-destination (OD) is inevitably needed. This paper used WAVE communication information as a part of call and response (C&R) communication which constitutes core part of the technology for constructing OD. This information includes node information and vehicle information (e.g., latitude and longitude) as well as trajectory data and sample path volume date calculated using node information and vehicle information. A procedure developed to construct a dynamic OD and to validate OD is consist of 1) making toy network and one-hour 00 (random distribution), 2) collecting link information and vehicle information, 3) constructing five-minute OD, and 4) validating estimated OD result using traffic volume and travel time simultaneously. The constructed OD is about 84.79% correct within less than 20% error range for 15min traffic volume, and about 85.42%, within less than 20% error rate of 15 min travel time. Some limitations and future research agenda have also been discussed.

• Electrical & Electronic Materials
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• v.10 no.2
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• pp.179-184
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• 1997

고주파화로 진행되고 있는 이동통신에서 사용주파수대가 고주파화로 향해감에 따라, 시스템은 소형화, 고기능화가 요구된다. 이러한 요구상황에 SAW 필터가 부응하기 위해서는 삽입손실 개선, Submicron 전극제작기술, 소형화를 위한 면실장기술 등이 앞으로 해결해 나아가야할 과제라고 생각된다. 이상으로 SAW 필터는 그 우수한 특성으로 앞으로 이동통신용 핵심부품으로 발전해 갈 것으로 생각된다. 이에 발맞추어 새로운 기술 향상과 신규시장에 대응하는 시기 적절한 상품화가 주된 관건이며, 국내업체는 위에 기술한 상황에 신속한 대응이 있어야만 세계 시장경쟁에서 살아남을 수 있을 것이라 생각된다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.8
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• pp.890-895
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• 2016

As the wireless communication technique is developing rapidly, the use of smart devices is increasing. Due to gradually increasing data traffic, a new area, more than 6GHz of bandwidth to increase capacity of the network, has been studied. Millimeter Wave(MmWave) communications utilizes the bandwidth above 6GHz, which makes it possible to achieve one gigabit per second data rate. To overcome the path loss due to the smaller wavelength, the mass of the antenna arrangement is used. This paper presents an algorithm that maximizes the spectral efficiency of the system in the pre-coding process using a hybrid beamforming. Also it is suggested with the optimization of the number of beams that maximizes the spectral efficiency was maximized by the propose method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.1
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• pp.51-57
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• 2016

This paper describes the physical layer modem structure of Giga KOREA 5G system which is being developed by ETRI as a 5G telecommunications prototype. The objective of Giga KOREA 5G system is supporting maximum 100 Gbps data rate for each cell with wide-bandwidth baseband station and mobile station prototypes in mmWave (10~40 GHz) environment. To achieve this objective, its physical layer is composed of high performance baseband station as well as mobile station and their OFDM TDD modems. The important features of Giga KOREA 5G physical layer are carrier aggregation, multiple receiving beam searching in mobile station, high data rate channel encoder and decoder and high speed modulation and demodulation functions.

• Information and Communications Magazine
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• v.29 no.2
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• pp.3-10
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• 2012

산업화, 도시화가 이루어지면서 자동차가 현대인의 필수품으로 자리잡았다. 그러나 차량 소유가 증가함에 따라 도로를 포함한 사회 인프라 구축에 한계를 드러내고 있으며, 이로 인한 교통 혼잡 등의 문제가 사회적으로 대두되고 있다. 또한 기계 장치 및 센서 디바이스 등 기존의 자차의 정보만을 이용한 차량 안전 서비스에서 한계를 드러내고 있다. 따라서 주변 차량 정보를 활용한 교통 및 안전 서비스를 개발하기 위해서는 차량 통신기술이 필수적이다. 이를 위한 국제적인 표준화 활동이 활발히 진행되고 있으며, 대표적인 국제단체로 ISO와 IEEE가 있다. 이곳에서 각각 CALM(Communications Access for Land Mobiles) 및 WAVE(Wireless Access in Vehicular Environments) 통신 기술에 대한 표준이 제정되고 있으며, 다양한 프로젝트를 통해 관련 기술과 서비스가 제시되고 검증되고 있다. 따라서 차량 통신을 활용한 ITS(Intelligent Transport System) 분야의 새로운 시장확대와 경제적 효과를 선점하기 위해서는 이러한 표준동향을 주시하고 참여할 필요가 있다. 본고에서는 차량 통신에 대한 최신 국제 표준화 현황 및 민간 표준화 기구에 대해 살펴보고 전망을 제시한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.389-392
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• 2016

As technologies evolve, 3D measurement techniques using cameras have been developed continuously. In 3D measurement, high accuracy, fast speed, and easy implementation are very important factors. Recently, 3D measurement using multi-frequency fringes has been widely used. This method is generally a method of measuring the height of a image obtained by projecting a sine wave through the projector. The sine wave is produced by software. However, this sine wave is not a perfect sine wave by gamma of projector. This is given a bad influence on the height measurement, and can not measure the correct height. In this paper, we propose a method for correcting the phase of the sine wave to avoid being affected gamma. Through this method it will be able to make more accurate height measurement.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.2
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• pp.143-149
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• 2021

BLDC motors are getting better performance due to the improvement of material technology including high performance of permanent magnets, advancement of driving IC technology with high integration and high functionality, and improvement of assembly technology such as high point ratio. While having the advantage of such a square wave driven BLDC motor, interest in the design and development of a square wave driven BLDC permanent magnet motor and development of a position detection circuit and driver is increasing in order to more meet the needs of users. However, in spite of the cost and functional advantages due to reduced efficiency, switching loss and vibration, noise, etc., the application is somewhat limited. Therefore, in this paper, we study a position detection circuit that generates a sinusoidal signal in proportion to the magnetic flux of a BLDC motor rotor using a Hall Effect Sensor that generates a sinusoidal wave to increase the efficiency of the motor, reduce ripple, and drive a sinusoidal current with excellent speed and torque characteristics.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.497-498
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• 2011

In 21 century, we use a variety of new wireless technologies focuses on broadcasting and Communications. Because of widely spread wireless-service, demand a lot of frequency. It requires various wireless access technologies. Especially UWB, SER, Millimeter Wave etc. Among them, UWB can use wide Frequency band, because it is different from Non-traditional approach which Frequency Band Using the exclusive rights granted by. Furthermore, it does not cause interference to other existing frequency, therefore this technology is attracting attention. In this paper, describe study on a UWB technology, design about useable antenna for UWB communication.