• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.8A
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• pp.1338-1347
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• 2001

CDMA와 같은 다중 접속 무선 통신 방식에서 문제가 되는 심벌간 간섭신호와 다중 사용자 접속 간섭신호를 제거하기 위해 제안된 기존의 CDMA 수신 알고리즘들은 여전히 간섭신호들을 포함하고 있다. 본 논문에서는 이 잔존하는 간섭신호를 제거하여 더욱 향상된 BER 성능을 얻기 위해서 CMA를 이용하는 간섭신호 제거를 위한 블라인드 적응 후처리 기법을 제안하였다. 제안한 후처리 기법은 기존의 어떠한 알고리즘에도 적용이 가능한 범용 후처리 기법으로 부가적으로 요구하는 정보가 없으며 추가로 요구되는 계산량이 매우 적다. 또한 제안한 방법이 수학적으로 안정된 수렴 특성을 갖는다는 것을 증명하였다. 컴퓨터 모의 실험을 통하여 제안한 CMA 후처리 기법이 여러 수신 알고리즘에 적용될 때 BER 성능이 향상됨을 확인하였다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.11
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• pp.34-41
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• 2003

In this paper, 60GHz band transmitter and receiver for wireless LAN are designed and implemented using the broband amplifier and mixer fabricated by standard 0.1${\mu}{\textrm}{m}$ MIMIC process of MINT. Output power and gain of the RF transmitter are 0 ㏈m and 1.7㏈, respectively. Noise figure and gain of the receiver are 4.2㏈ and l5.7dB, respectively. Considering the sensitivity and LOS test, this system can communicate with BER of below than 10$^{-6}$ at a distance more than 35m. DSSS, which is strong for concealment and disturbance, is adopted.

• Information and Communications Magazine
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• v.13 no.8
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• pp.103-122
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• 1996

초고속정보통신망의 구축이 효율적이고 신뢰성 있는 서비스를 제공하기 위하여 위성/지상망을 통합한 혼합망 구조로 개발됨에 따라 지상 광파이버를 기반으로 개발된 ATM 전송프로토콜을 위성망에 직접적으로 적용하기 위한 기술개발이 요구된다. 이러한 점을 고려하여 본 고에서는 위성 ATM(Asynchronous Transfer Mode) 전송에 따른 문제점 분석, 개선방안 및 성능평가를 수행하였다. 혼합망 구성에 따른 위성망의 구조를 접속된 지상노드의 유형 및 위성시스템 특성에 따라 3가지 유형으로 분류하여 제시하였고, 위성 ATM 전송에 따른 기술적인 문제점을 채널 BER과 위성지연 측면으로 분류하여 제시하였다. 위성채널 BER 성능개선을 위한 2가지 방안(인터리빙, HEC 보강)을 제시하였으며 위성지연분석은 고정지연(Fixed delay)과 셀지연변이(CDV : Cell Delay Variation) 측면에서 성능평가를 수행하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.9 no.2
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• pp.62-69
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• 1984

The performance of direct-sequence spread spectrum(DS-SS) receiver may be enhanced by using the digital whitening filter. In this paper, the hard limited feedback whitening filter that whiten the interference and noise alone is proposed to obtain the additional resistance to narrowband interference. The recursive solution for the calculation of tap weights is presented and the expression for SNR and BER is derived and compared with the conventional digital whitening filter. As the result of computer simulation it is proved that the error performance is improved considerably.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.6A
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• pp.845-854
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• 1999

In the reverse link of DS/CDMA systems, the Peak-to-Average Ratio(PAR) performance can be analyzed by phase variations of spread signals. In the paper, we propose s PAR analysis method using phase variations of signals. Using this method, we analyze the PAR performances of existing spreading methods and suggest several methods improving the PAR performances. Also we show the proposed methods have negligible BER degradation compared to the existing ones.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.12
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• pp.864-869
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• 2014

In this paper, we propose an OFDM system with a pre-equalizer which pre-distorting a transmission signal to compensate for the degradation of the system by the intersymbol interference and multi-path fading at the high-speed multimedia communications. We model an OFDM system by using C language, a simulation was performed. As a result, there was a performance of BER is about 7dB at $10^{-3}$, improved to $10^{-4}$ on the MMSE property also $10^{-3}$.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.30A no.9
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• pp.6-13
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• 1993

In is well-known that system performance in the high speed digital radio communication system is usually deteriorted due to the frequency selective fading distortion. In this paper, bit error rate(BER) performance by the reception phase error in cellular mobile communication systems is derived and analyzed. The system is modeled as a frequency selective fast Rayleigh fading channel corrupted by additive white gaussian noise(AWGN) and co-channel interference(CCI). Our numerical results show that for the 24KBaud(48Kb/s) $\pi$/4-DQPSK operated at carrier frequency 800 MHz and C/I<20 dB, the BER will be dominated by CCI if the vehicular speed is below 100 Km/h. The results show that performance, when reception phase error is below $\pi$/12, is deterioreted less than 3 dB, and that performance, when reception phase error is above $\pi$/12, is degraded over 3 dB.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.40 no.3
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• pp.164-170
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• 2003

This paper proposes a novel method to detect Furon's asymmetric watermark by using a correlation detector that is mathematically tractable and simple. The performance of the proposed method is tested under various conditions. The experimental results matched the theoretical results well, showing that the correlation detector can indeed be used for the detection of asymmetric watermark. The proposed detector is aplied to both single and multiple bit embedded watermark. Bit error rate (BER), obtained from the experiment, was compared to the one obtained from the theory. As the embedded information increases, the BER of the Furon's asymmetric watermarking method also increases rapidly.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.49 no.5
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• pp.22-29
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• 2012

By using the cyclic properties of symmetric balance incomplete block design(BIBD) codes and arrayed-waveguide grating(AWG) routers, a compact optical CDMA network coder-decoder(codec) can be constructed. It can be observed that the various code families obtained by BIBD improve the BER performance compared to M-sequence code.

• 한국정보통신설비학회:학술대회논문집
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• 2008.08a
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• pp.309-312
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• 2008

We study signal characteristics of the injection-locked Fabry-Perot laser diodes(FP-LDs) for the development of a costeffective WDM-PON solution. The output power and system performance of WDM-PON using injection locked FP-LD are depend on optical characteristics of injection source. The effect of optical power and polarization state of the injection source experimentally investigated. We also measured BER characteristics of the directly modulated FPLD and its power penalty at the BER of $10^{-9}$.