• Journal of Satellite, Information and Communications
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• v.9 no.2
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• pp.101-106
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• 2014

As ESL(Electronic Shelf Label) system is increased at the market in the world, the interference between ESL system and Wi-Fi(Wireless Fidelity) Cellular Phone at 2.4GHz becomes issue. The interference scenario and propagation of the Extended HATA Model were established to analyze the interference from Wi-Fi Cellular Phone into ESL system. Through simulation results based on SEAMCAT(Spectrum Engineering Advanced Monte Carlo Analysis Tool), separation distance was obtained to protect ESL system from Wi-Fi Cellular Phone interference.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.3 s.357
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• pp.51-60
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• 2007

Cellular OFDMA systems may suffer from various amounts of inter-cell interferences according to subcarriers. If it is possible to estimate the interference level of each subcarrier, the performance can be improved by adjusting the magnitude of channel decoder input signals inversely proportional to the interference amounts. While conventional cellular systems prefer to use interference averaging techniques for mitigating inter-cell interferences, this paper shows that localizing inter-cell interferences to the reduced number of subcarriers can significantly improve the system performance assuming thatinterference estimation can be employed. If interference estimation is not used, it is more favorable to use interference averaging techniques to avoid excessive interference levels to certain subcarriers. On the other hand, if interference estimation can be employed, interference localization is more beneficial than interference averaging.

• Proceedings of the IEEK Conference
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• 2000.06b
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• pp.92-95
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• 2000

본 논문에서 항만 자동게이트통관시스템에 사용하기 위하여 단거리전용통신(DSRC)용 OBE에 사용되는 5.8㎓ 송신기 MMIC를 설계하였다. 능동소자로는 GaAs MESFET을 사용하였고, 회로의 복잡도를 줄이기 위해 직접변조방식을 채택하였다. 인접채널간섭의 영향을 줄이기 위하여 드레인 재어 변조회로를 사용하여 -40dBc이하의 인접채널간섭과 70dB 이상의 on/off비를 갖는 5.8㎓ ASK송신기 회로를 설계하였다.

• Journal of Advanced Navigation Technology
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• v.25 no.3
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• pp.236-241
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• 2021

This paper presents a methodology to analyze the interference of maritime traffic control radar by wind turbines installed in the sea, and the interference result of the maritime traffic control radars by a small number of wind turbines installed in sea near Gunsan port (Gunsan vessel traffic services). A ray based electromagnetic analysis software is used to analyze the interference. The geographic information system map containing altitude data, drawing of wind turbines, and sea with waves are imported to the software to analyze the effect of the terrain and the wind turbines. According to the analysis, a small number of wind turbines, not large scale wind farms, has no severe impact on the operation of the radar.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.11 s.353
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• pp.141-148
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• 2006

This paper deals with the performance improvement by eliminating loop interference signal and inserting adaptive equalizer for phase compensation in OFDMA based Wibro relay station. The Wibro relay station is used for the extension of communication service area and for throughput improvement of base station. The loop interference is important factor of performance determination of relay station when transmitter and receiver is very closely located. In order to design interference canceller, we generated base-band OFDMA signal and then transmitted the signal along with pilot tones alined with two different combinations for training mode. And then, we generated received fading signal due to the loop interference added noise to the received signal. In the receiver, the transmitted signal is recovered by elimination of the interference signal with channel estimate and compensating phase by adaptive equalizer. The performance improvement was verified by computer simulation which show channel estimation, constellation of signal and BER characteristics according to the variation of SNR ratio.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.7 s.361
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• pp.35-40
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• 2007

As the mobile communication service is widely used and the demand for wireless repeaters is rapidly increasing because of the easiness of extending service areas. But a wireless repeater has a problem that the output of the transmit antenna is partially fed back to the receive antenna, which results in feedback interference. In this paper, we propose a new varable step-size LMS algorithm which utilizes correlation between reference and error signals to adjust the step sizes, for cancelling the feedback interference signals in the WCDMA repeater under time-varying multi-path channels. The proposed algorithm was evaluated through computer simualation by being applied to the feedback canceling filter of the WCDMA repeater. The simulation results demonstrated that the proposed one is superior to the conventional ones in terms of the cancelation perormance.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.11
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• pp.26-35
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• 2007

We characterized the properties of the fabricated filter with the total internal reflection mirror (TIR) in the rectangular ring resonator and very small multimode interference (MMI) couplers on an InP material platform for photonic integrated circuits. Coupling power in and out of a resonator is increased by using an optimum MMI length of 110 ${\mu}m$ and a width of 9 ${\mu}m$, respectively. The semiconductor optical amplifier with the length of 120 ${\mu}m$ is integrated in the resonator to compensate the loss of the internal waveguide and the TIR mirror. A free spectral range of approximately 2 nm (244 GHz) is observed with an on-off ratio of 13 dB. The curve fitting also yields the power coupled per pass as 42%. To reach critical coupling at this coupling level would require a round trip loss of about 2.4 dB.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.6
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• pp.78-85
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• 2009

In time-varying multipath fading channels, orthogonal frequency division multiple access (OFDMA) uplink systems suffer severe performance degradation caused by inter-channel interference (ICI). In this paper, we propose a hybrid interference cancellation (HIC) for suppressing the degradation effect of ICI. The proposed HIC can achieve both exact interference cancellation and low detection complexity through efficient combination of parallel detection and serial cancellation. Simulation results show that, as the effect of Doppler increases, the proposed HIC achieves bit error rate (BER) performance enhancement in compared with severe performance degradation of conventional OFDMA receivers. In addition, both the computational complexity and total detection time are reduced.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.271-272
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• 2014

비례-적분(PI) 제어기는 전동기의 간섭성분을 고려하지 않기 때문에 고속회전영역에서 오버슈트가 커지고, 적분기 포화로 인해 정착 시간이 느려지는 단점이 있다. 고속회전영역에서 느린 응답성을 보완하기 위해 전동기의 간섭성분을 고려하는 Cascade PI 전류제어기가 제안되었지만 오버슈트를 증가시키는 문제점이 발생한다. 본 논문에서는 Cascade PI 제어기를 소개하고 Cascade PI 제어기의 오버슈트 특성을 개선하기 위한 전류제어기를 제안하였다. 시뮬레이션을 통하여 각 제어기의 성능을 비교, 분석하였으며 실험을 통해 이를 검증하였다.

• Journal of IKEEE
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• v.13 no.4
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• pp.75-81
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• 2009

The cellular system in the next generation decreases the range of transmission of a signal as well as increases the rate of transmission adapting the method of multi-hop relaying with the relay. However, the fact of decreasing the range of transmission with the method of multi-hop relaying means increasing interferential amount in the outer cell; therefore, the deployment of the relay can affect to the function of the cellular system. In this thesis, the deployment of the relay is determined for the maximum rate of transmission, based on the transmission power of the relay and the variation of interferential amount. The condition to determine the deployment of the relay is analyzed with the mathematical model; in addition, its performance is verified through the result of a simulation. Based on the analysis of this thesis, the established deployment and transmission power of the relay to minimize the average outage probability exist. Furthermore, the relay contributes to enlargement of capacity of cells, decreasing the average outage probability in the situation of less severe interference between cells with reuse of frequency. However, the relay should be restrained in use in the situation of severe interference between cells due to the fact that the outage probability of inter-cells can be increased.