• Journal of information and communication convergence engineering
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• v.9 no.5
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• pp.515-522
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• 2011

In this paper, we investigate cooperative diversity in a spectrum sharing environment where secondary users utilize primary users' spectrum only if the interference power received at the primary users is maintained below a predetermined level. The outage probability of a selective decode-and-forward (DF) based cooperative diversity scheme in the secondary network is derived to analyze the effects of spectrum sharing on cooperative diversity. Our analytical and simulation results show that the outage probability is saturated at a certain level of transmit power of secondary users due to interference regulation, and, hence, cooperative diversity gains are lost. Through asymptotic analysis, we also identify the critical value of transmit SNR beyond which the outage probability is saturated.

• Proceedings of the KAIS Fall Conference
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• 2009.12a
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• pp.968-972
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• 2009

본 논문에서는 8.2MHz 대역의 국내 미약 전계 강도 무선기기의 출력제한치를 다른 외국의 기준치와 비교하였다. 이를 통해 국내의 규정이 미국이나 유럽에 비해 낮음을 확인하였고, 이를 검증하기 위해 8.2MHz EAS 시스템의 출력을 측정하였다. 측정 결과, 전계강도값이 각각 $70.6dB{\mu}V/m$와 $68.3dB{\mu}V/m$로 측정되었는데, 이러한 값은 국내의 현재 기준인 $102.7dB{\mu}V/m$를 초과하는 값임을 확인하였다. 따라서 8.2MHz 대역의 국내기준의 사양 검토가 필요하다고 사료된다.

• Electronics and Telecommunications Trends
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• v.17 no.6 s.78
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• pp.108-116
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• 2002

2001년 4월 이후 유럽연합지역에서는 유.무선통신기기 인증 지침(R&TTE Directive: 1999/5/EC)이 발효됨에 따라 유럽연합과 개별회원국 간에는 1980년 후반 이후 유럽연합의 합의 정책의 목표였던 ‘새롭고도 광범위한 접근방식’에 의한 유.무선 통신기기의 기술 규제 운영체제가 정립되게 되었다. 이하에서는 무선통신기기 부분을 중심으로 유럽연합과 개별 회원국인 영국의 사례를 살펴봄으로써 국내 무선통신기기 기술규제체제의 정립에 기여하는 것을 목적으로 삼는다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.6
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• pp.37-42
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• 2009

Cognitive radio (CR), which is proposed as a technology that utilizes the frequency resources effectively, has studied to relive scarcity of the frequency resources. Also, FCC revises the regulation to reuse the TV white spaces for applying CR system and allows to use the TV white spaces by CR devices and use of CR device may be regularized after conversion by DTV in 2009. If CR system's signal appeared in pilot's position, pilot sensing performs false alarm detection because pilot sensing scheme confuse DTV signal and CR system. In order to improve false alarm detection, we propose distinction scheme between DTV and CR system using PN511 sequence in this paper.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.3
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• pp.384-390
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• 2008

Chaotic OOK modulation method can be used in LDR(Low Data Rate) UWB systems. In this paper, UWB chaotic-OOK transmitter system is designed and verified using TSMC 0.18 um CMOS process. A transmitter system is composed of Quasi-chaotic signal generator, OOK Modulator, and driving amplifier. The traditional chaotic signal generators using analog feedback method is weak to process variation. In order to solve this problem, a quasi-chaotic signal generator using digital feedback technique is get wide band signal and OOK Modulator using T-type switching structure is used to enhance the isolation characteristic. A driving amplifier has differential to single structure to avoid an external balun for low cost communication. The measured output power spectrum of the transmitter meet the FCC regulation and the result of the modulation test at data rate of 20 Kbps, 200 Kbps, 2 Mbps, and 10 Mbps is conformed to LDR UWB system. It is shown that the transmitter in this paper can be used for the UWB chaotic-OOK system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.9
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• pp.2319-2325
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• 2009

This paper compared the output limits value of the Korean weak electric field strength wireless device in the 58kHz band with the standard values of foreign countries. Through this, the study confirmed that the Korean regulation was lower by about 50dB than those of the USA or Europe. In order to prove this, the study measured outputs by entrusting the 58kHz EAS system to two measuring companies. As a result of these measurements, electric field strengths were shown to be $112dB{\mu}V/m$ and $08dB{\mu}V/m$ respectively, and these values were confirmed to exceed the current Korean standard of $102.7dB{\mu}V/m$. Accordingly, it is deemed necessary to review the specifications of the Korean standard in the 58kHz band.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.1421-1423
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• 2003

Ultra Wideband is a new technology from commercial or civilian application viewpoint. It uses already allocated radio spectrum without causing significant interference to other users. It uses very low power, which is below the thermal noise of the receiver and is inherently difficult to detect by un-intentional users. Since, FCC approved the regulation for the commercial use of UWB in February 2002, the development of UWB technology is drastically gaining momentum. However, the technology itself is not new. It has already been used in military applications. UWB has three basic areas of applications, which are communication, positioning and imaging (UWB Microwave). The main commercial application will be for communication since it has very high data transfer rate for short distance. It can also be used for both indoor and outdoor 3-D positioning. Another important application is imaging like microwave remote sensing. An UWB sensor can pass through doors and walls and hence detect the objects inside the room. In this paper, we will introduce about UWB technology along with it’s various possible applications. We will also present some models to generate UWB signal and it’s analysis using signal-processing tools.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.1
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• pp.32-41
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• 2014

Currently, the three major Korean mobile operators hold a total of 390MHz of bandwidth, but at the current data traffic increase of almost 6 times per year, more frequency bandwidth should be secured in order to meet the exploding data traffic in the future. It is believed that 2.1GHz frequency band is suitable for mobile communication in the light of frequency characteristics and continuity of the band. In this paper, we perform compliance analysis with the international radio regulation for coexistence with the adjacent region in order to use 2.1GHz band for LTE-Advanced. In addition, we verify that 2.1GHz band can coexist with the adjacent band by conducting an interference evaluation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.1
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• pp.9-15
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• 2010

This paper analyzed the problems of the Korean output regulation in the relevant band through an analytic comparison of the current trend of each country and their standard values concerning electric field strength (technical standard) of weak wireless stations with less than 135kHz. In connection with the standard value of electric field strength of each country, which has been proposed in the registration of the appropriate electric wave, the paper aims to propose the standard value of electric field strength that could actually be introduced for suitable unauthorized wireless devices (weak wireless devices) in Korea. Provided that the Korean standard may be upgraded based on the tolerances of electric field strength proposed m this paper, this is expected to be committed to the distribution and advancement of weak wireless devices; and further it is anticipated to be prepared with competitiveness not only in the Korean communications market, but also in the international communications market.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.12
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• pp.2498-2504
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• 2009

This paper compared the output limit value of the Korean weak electric field strength wireless device in the 8.2MHz band with the standard values of foreign countries. Through this, the study confirmed that the Korean regulation was lower by about 10-20dB than those of the USA or Europe. In order to prove this, the study measured outputs by entrusting the 8.2MHz EAS system to two measuring companies. As a result of these measurements, electric field strengths were shown to be $70.6dB{\mu}V/m$ and $68.3dB{\mu}V/m$ respectively, and these values were confirmed to exceed the current Korean standard of $59.8dB{\mu}V/m$. Accordingly, it is deemed necessary to review the specifications of the Korean standard in the 8.2MHz band.