• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.8A
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• pp.846-851
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• 2008

With rapid development of communication industry, the kinds of communication service vary. According to the increasing use of radio waves, the intelligent and effective radio monitoring system needs to be developed, which is replaced for previous radio monitoring system. Next-generation intelligent radio monitoring system based on ITU-R, Rule of wireless facilities, and Radio Waves Act is used, and which can accurately and effectively function as effective radio monitoring system through spectrum analysis of channel power, frequency deviation, offset, and an occupied frequency bandwidth(99% or x-dB), about the analog and digital signal in On-Air of V/UHF bandwidth. Main function of the system has an radio quality measurement, unwanted electromagnetic signals (spurious, harmonic) measurement, high-speed spectrum measurement, frequency usage efficiency investigation, illegal radio exploration, working monitoring, In this paper, we proposes radio quality measurement, high-speed spectrum measurement of next-generation intelligent radio monitoring system.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.2
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• pp.51-56
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• 2017

With the rapid increase in the number of mobile terminals, demand for wireless technologies has sharply increased these days. While wireless communication provides advantages such as ease of deployment, mobility of terminals, continuity of session, and almost comparable transmission bandwidth to the wired communication, it has vulnerability to malicious radio attacks such as eavesdropping, denial of service, session hijacking, and jamming. Among a variety of methods of preventing wireless attacks, the MTD(Moving Target Defense) is the technique for improving the security capability of the defense system by constantly changing the ability of the system to be attacked. In this paper, in order to develop a resilient software defined radio communication testbed system, we present a novel MTD approach to change dynamically and randomly the radio parameters such as modulation scheme, operating frequency, packet size. The probability of successful attack on the developed MTD-based SDR communication system has been analysed in a mathematical way and verified through simulation.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.3
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• pp.379-388
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• 2020

The contents and scope of this study are to analyze the problems of the current radio service and radio station classification system, and to investigate the radio wave management cases in the United States to provide a reasonable and efficient radio wave management method. The results of this study can be used as basic data when revising the legal system regarding radio wave enforcement regulations, radio service and radio station classification standards. It is expected that in the future, a detailed commentary on the definition and classification system of new radio / radio stations will be prepared to increase policy compliance in practice, while contributing to enhancing the consistency and efficiency of radio station licensing and inspection.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.11a
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• pp.380-380
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• 2004

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.527-530
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• 2002

The frequencies for HAPS used in fixed wireless access are allocated in the millimeter wave bands. The systems using these frequencies can have a serious impact on the radio communication qualities due to rain. In this paper, we compare the specific rain attenuation using CM(combined) raindrop size distribution with those using different sevral raindrop size distributions for the frequency bands 28/48㎓. The rain attenuations using CM raindrop size distribution for the path between the earth and HAPS platform according to the elevation angle are described.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.4
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• pp.1502-1519
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• 2020

Recently, new devices have been developed for the Internet of Things concept. The devices commonly use RF (Radio Frequency) based wireless communication. With the increase in the number of devices, the space allocated for the radio frequency band in wireless communication fills rapidly. Visible Light Communication (VLC) is an alternative, secure and economical communication technology that uses light instead of radio frequencies. While Web of Things (WoT) is the adaptation of the experience and knowledge acquired from the web into the internet of things ecosystems. By combining these two technologies, the development of the Visible Light Communication for Web of Things (VLC4WoT) system, which can use VLC and WoT technologies, has been our motivation. In our study, microcontroller control circuit was created for VLC4WoT system. Control of the circuits over the internet was performed. VLC based receiver and transmitter units have been developed for wireless communication. Web based interface was created for control. The test apparatus consisting of four objects with four outputs and a transfer unit was carried out. In this test, communication was achieved successfully. It was presented in the study that VLC can be used in the web of things architecture. In the future, it is envisaged to use this system as a safe and economical system in indoor environments.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.7
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• pp.1149-1159
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• 2008

Since the demand for radio wave due to proliferation of radio wave communication is increased rapidly, policy for efficient use of radio wave is a challenge of sustainable research for technology development in this field with focus on service supply and distribution. Therefore, this paper analyzed and reviewed radio wave related international agreements and overseas institutions and policies, and proposed the improvement method for systematic and efficient countermeasure on radio wave management policy and system according to radio wave promotion policy circumstance changes, radio wave environmental change and technology development.

• Current Optics and Photonics
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• v.5 no.2
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• pp.114-120
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• 2021

Free-space optical (FSO) communication is considered to be a potential solution to congestion in the radio-frequency spectrum and last-mile-access bottleneck issues in future cellular communication networks, such as 5G and beyond. However, FSO link performance may degrade significantly due to irradiance fluctuations and random temporal fluctuations from atmospheric turbulence. Therefore, in this work the main objective is to reduce the effect of the atmospheric turbulence by considering a multihop FSO communication system with amplify-and-forward relaying supported by a radio-frequency (RF) link, which form a hybrid FSO/RF communication system. The FSO link is assumed to follow the gamma-gamma fading model, which represents strong turbulence. Also, the RF link is modeled by a Rayleigh distribution. The performance of the considered system, in terms of the outage probability and average bit-error rate (BER), is investigated and analyzed under various weather conditions and pointing errors. Furthermore, the effect of the number of employed relay nodes on the performance of the system is investigated. The results indicate that the considered system reduces outage probability and average BER significantly, especially for low channel quality. Finally, the closed-form expressions derived in this work are compared to the results of Monte Carlo simulations, for verification.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.11
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• pp.1214-1219
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• 2010

In this paper, a software radio system, supporting the physical layer of IEEE 802.15.4 standard, has been developed using USRP(Universal Software Radio Peripheral) board and GNU Radio package of an open source development kit for software radio. The software radio system supports the standards of BPSK and OQPSK modulations for 868/915 MHz band and OQPSK modulation for 2.45 GHz band. To verify the operation of the developed system, it has been tested under the standard signals according to the frequency band and packet structures for the transmitting and receiving operation. At 2.4 GHz, the Smart RF EV board and CC2430 modules are used to check the proper operation of the software radio system. The system performance test shows that the emission power spectrum, the eye-pattern, and PER(Packet Error Rate) meet the standard. It has been confirmed that the developed system supports the PHY layer of IEEE 802.15.4.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.5
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• pp.745-758
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• 2022

As the unlimited natural source of a country, radio waves are widely being used in the daily life toward knowledge based information society. Therefore it is necessary to provide a long term policy of radio waves management policies based on market situation to cope with rapidly changing wireless technology and effective use of radio resources. Literary survey and analysis were accomplished for the rules and regulations in the radio station approval system and post-approval policies for mobile communication service. In conclusion, this study propose an blanket radio approval policy as well as self declaration of conformity(SDoC) of radio waves technical regulation and advanced radio inspection procedure. This study has significance in providing reference for introducing deregulation policy in the radio communication imdustry.