• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1988.10a
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• pp.114-117
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• 1988

In mobile radio communication system involving geostationary satellites the field intensity of electromagnetic wave varies with frequency shape and location of an obstacle between a tramamitter and a receiver. In this paper a ring type obstacle between the propagation paths is presented. On the basis of Fresnel diffraction theory, the field intensity varying with ring-type obstacle’s radius is obtained by computer simulation.]

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.5
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• pp.1069-1076
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• 2017

C-ITS(Cooperative-Intelligent Transportation System) provides services that require strict real-time such as forward collision warning, road safety service and emergency stop. WAVE(Wireless Access in Vehicular Environments), a core technology of C-ITS, is a technology designed for high-speed driving. However, in order to provide stable communication service by applying to real road environment, various performance tests of real vehicular environment are required. In the real road environment, WAVE communication performance is influenced by the surrounding environment such as moving vehicle, road shape and topography. Especially, when the vehicle is moving at high speed, the traveling position according to the speed of the vehicle, The surrounding environment changes rapidly. Such changes are factors affecting the communication performance, therefore a system and methods for analyzing them are needed. In this paper, we propose the configuration and test method of an effective performance evaluation system under high-speed driving and describe the results of analyzing the communication performance based on the data measured through the actual vehicle test.

• 한국정보통신설비학회:학술대회논문집
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• 2008.08a
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• pp.233-236
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• 2008

There are several kinds of service standards for 3G($3^{rd}$-Generation) wireless communication as WCDMA, CDMA2000 and WiBro(Wireless Broadband Internet). Especially WiBro Wave2 system is a marked currnt issue. In this paper, we describe on the cell plan tool to desgin WiBro Wave2 network. For this, we treat from basic theory to practical substance to produce new(or modified) path loss prediction model for 2.3GHz. And we explain the method how to implement new technology MIMO(Multiple Input Multiple Output) deployed in Wave2 system. Also we emphasize on the importance of LOS(Line Of Sight) analysis in WiBro network design.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1984.04a
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• pp.33-36
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• 1984

An underwater communication technic using AM modulated ultrasonicwave was studied. The experiment were performed in the ahechoic water tank with 60KHz carrier wave and the frequency response of the system by demodulated signals were measured varing the degree of modulation and distance between transmitter and receiver. The bandwidth of transmitted signals was limited by the acoustic characteristics. As the result, it was found out that this kind of system is applicable to the underwater speech communication.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.7 no.1
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• pp.1-14
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• 1996

The purpose of this paper is to analyze the performance of M-ary PSK communication system according to the types of electromagnetic interference in an impulsive noise environment. We have introduced Gaussian, sinusoidal and rectangular waves as a electromagnetic interference. Using the derived equations, we evaluated the error performance of the BPSK and QPSK system in the presence of electromagnetic interference and impulsive noise. From results, we have obtained that the Gaussian wave produced the most significant performance degradation and that sinusoidal wave produced more performance degradation than rectangular wave. Therefore, without knowing the types of electromagnetic interference, it is best to regard it as Gaussian wave when designing a communication system. In addition, we could found out that the error performance degrades as impulsive noise becomes strong and the error performance can not be improved significantly even the electromagnetic interference becomes weak. Therefore, this describes that the impulsive noise affects dominantly to the performance degradation.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.6
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• pp.1069-1074
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• 2021

Recently, mobile communication technology has new eras with supply of 5G commercial communication. 5G mobile communication service is currently supplied with city area, services will be quickly expanded to entire area of country. This mmWave based 5G mobile communication is under spreading for human communication with voice and Internet service. After completion of construction of this human communication, this technology will be expanded to industrial communications. Railway communication system is an example of this industrial communications. In this, performance of traffic transmission for railway communication network based on this 5G railway communication networks will be analyzed with computer simulations. Construction requirements of 5G railway communication networks will be suggested with this analysis results.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.6
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• pp.1005-1013
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• 2015

In this paper, an uplink pilot signal structure is proposed for millimeter wave(mmWave)-based mobile wireless backhaul. For the transmit diversity of two antenna ports, uplink pilot signals generated from the Zadoff-Chu sequence can be mapped in an interleaved mode or continuous mode on the frequency axis, and channel estimation algorithms are different depending on the pilot signal mapping schemes. Through a simulation under Rayleigh fading channel assuming a subway scenario, the interleaved mapping scheme showed no performance degradation compared to the continuous mapping scheme and the implementation complexity of the uplink channel estimator was reduced due to the interleaved mapping scheme.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.231-234
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• 2008

The paper proposed the new underwater wireless communication system fitted to non-linear acoustic channel. Generally, in non-linear acoustic channel, one used to do acoustic communication using parametric effect that is some effect caused from acoustic wave having frequency different of two primary acoustic wave frequency. In the paper, Offset PSK communication method fitted to non-linear acoustic channel was proposed, and it was demonstrated through simulations.

• The Journal of the Korea institute of electronic communication sciences
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• v.4 no.1
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• pp.1-6
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• 2009

The dissertation on today information communication technique development consist according to new broadcasting and communication appearanced fusion-service in earnest legislation's change about broadcasting and communication regulate the while separation. on that score, radio wave law's change on environment change has been lively producing.

• International journal of advanced smart convergence
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• v.11 no.4
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• pp.41-46
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• 2022

This study is a Ku-band array antenna for the manufacture of low-orbit satellite communication terminals, designed to have miniaturization, high gain, and wide beam width. The transmission of low-orbit satellite communication has a right-rotating circularly polarized wave, and the reception has a left-rotating circularly polarized wave. The 4×8 array antenna was separated for transmission and reception, and it was combined with the RF circuit part of the transmitter and receiver, and was terminated in the form of a waveguide for RF signal impedance matching in the form of a transition from the microstrip line to the waveguide. The 30° beam width of the receiver maximum gain of 19 dBi and the 29° beam width of the transmitter maximum gain of 18 dBi are shown. Through this antenna configuration, the system was configured to suit the low-orbit satellite transmission/reception characteristics.