• Journal of Electrical Engineering and Technology
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• v.11 no.2
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• pp.480-489
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• 2016

Hidden station problem can occur in power-line communication (PLC) networks. A simple solution to the problem has been proposed to use request-to-send (RTS)/clear-to-send (CTS) exchange, but this approach cannot solve the hidden station problem perfectly. This paper revisits the problem for PLC networks and designs a protocol to solve it. We first analyze the throughput performance degradation when the hidden station problem occurs in PLC networks. Then, we propose an interferer aware multiple access (IAMA) protocol to enhance throughput and fairness performances, which uses unique characteristics of PLC networks. Using the RTS/CTS exchange adaptively, the IAMA protocol protects receiving stations from being interfered with neighboring networks. Through extensive simulations, we show that our proposed protocol outperforms conventional random access protocols in terms of throughput and fairness.

• Proceedings of the KIPE Conference
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• 2004.07a
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• pp.163-166
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• 2004

The conventional fluorescent lamp dimming system using an another control line is complex and will increased the cost. Therefore, many studies have focused on the wireless communication, but it is not fit for dimming system because of the interference generated by the infra-red light of lamp or switching noises in ballast. So, we applied the power line communication on the dimming system and we proposed a new coupling circuit using the voltage controlled impedance convertor for improving the performance of the FH/SS PLC modem. The performance for the proposed modem is evaluted by the BER.

• 한국정보통신설비학회:학술대회논문집
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• 2006.08a
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• pp.162-165
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• 2006

This paper describes a measurement method for electromagnetic field strength of power-line communications(PLC) modem. First it outlines the technology used in PLC modems, and the technical regulation being offered to the technology, from the point of view of its effect on electromagnetic compatibility (EMC). The radio spectrum needs protection from other interferers, and there is a regime in place to provide this protection. Difficulties in achieving compatibility between the requirements for radio protection and the requirements for operation of the PLC modem mean that there is no consensus as yet as to how PLC modem components can be made compliant with EMC requirements globally. It is concluded that there is a measurement method according to CISPR standards which satisfy requirements in domestic regulation.

• Proceedings of the KIEE Conference
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• 2002.07d
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• pp.2559-2561
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• 2002

This paper presents a systematic method of probing channel characteristics and communication reliabilities of home PLC (power line communication) network applied to the Internet accessed control of home appliances. The effects of the three performance deterioating factors, i.e., additive noise, channel attenuation, and intersymbol interference, can be systematically measured by applying the channel probing waveform in the frequency range from 100kHz to 450kHz. The agreement between the derived probability of bit error and the measured probability of bit error supports the validity of the proposed approach of probing home power line channel characteristics. The experimental results performed with the constructed test-bed applying the proposed channel probing method also support the feasibility of commercially deploying the PLC modem installed home appliances and their services for the Internet accessed home automation.

• Journal of Satellite, Information and Communications
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• v.12 no.2
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• pp.46-50
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• 2017

In this paper, we propose an artificial intelligence based spectrum allocation scheme for power line communication system. The frequency band of the transmitted signal can be adjusted through the spectrum allocation technique, thereby avoiding interference. This improves the performance of the transmission signal and the spectral efficiency. Through the simulation results, we show that the proposed spectrum allocation technique improves the spectral efficiency and improve the communication performance.

• International journal of advanced smart convergence
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• v.8 no.2
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• pp.199-203
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• 2019

In this paper, we propose the efficient impulsive noise mitigation scheme for power line communication (PLC) systems in smart grid applications. The proposed scheme estimates the channel impulsive noise information of receiver by applying machine learning. Then, the estimated impulsive noise is updated in data base. In the modulator, the impulsive noise which reduces the PLC performance is effectively mitigated through proposed technique. As an impulsive noise model, Middleton Class A interference model was employed. The performance is evaluated in terms of bit error rate (BER). From the simulation results, it is confirmed that the proposed scheme has better BER performance compared to the conventional model. As a result, the proposed noise mitigation improves the signal quality of PLC systems by effectively removing the channel noise. The results of the paper can be applied to PLC systems for smart grid.

• The Transactions of the Korean Institute of Power Electronics
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• v.5 no.6
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• pp.632-637
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• 2000

In this paper, to control with light dimming levels of the fluorescent lamps, we have used the power line instead of the signal line to transmit the control signals. To reduce the BER(Bit Error Rate) on the power line communication with the serious noise interferences. We have adapted the FSK(Frequency Shift Keying) modulation and demodulation technique. Since the electronic ballast produced the EMI(ElctroMagnetic Interference) noise in some frequency bands, we have reduced the EMI levels in the band below -50dB. By varying the switching frequency of the ballast for the FL032/T8 from 18kHz to 25kHz, it is possible that the dimming levels are controled with the range of 5∼100%

• Publications of The Korean Astronomical Society
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• v.14 no.1
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• pp.39-45
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• 1999

We have carried out measurements of 1.2-1.6GHz radio interferences around Seoul Radio Astronomy Observatory located in the campus of Seoul National University. We received interference signals using a pyramidal horn antenna and measured its power using a spectrum analyzer with 1MHz resolution after $\~60dB$ amplification. In order to check the spatial characteristics, we made observations at every $30^{\circ}$ in azimuth at elevation of $30^{\circ}\;and\;60^{\circ}$. Also, in order to check the temporal characteristics, we repeated the all-sky observations five times at every six hours. The results may be summarized as follows: (1) There are strong $({\geq}-20dBm)$ interferences between 1.2 and 1.4GHz. Particularly strong interferences are observed at 1.271 and 1.281GHz, which have maximum powers of -0.34dBm and -0.56dBm, respectively. (2) The characteristics of the interferences do not depend strongly on directions, although the interferences are in general weak at high elevation and in east-west direction. (3) The interferences appear for a very short $(\leq0.01s)$ period of time, so that the average power is much smaller than the maximum power. Strong interferences with large $(\leq-49.0dBm)$ average power have been observed at 1.271, 1.281, 1.339, and 1.576GHz. At these frequencies, the interferences appear repeatedly with a period of $\leq0.1s$ By analyzing the observed power, we find that, for the strongest 1.271GHz interference, the average intensity is $-171dBW/m^2/Hz$ and that the maximum intensity is $-122dBW/m^2/Hz$. If this interference is delivered to the detector without any shielding, then its power would be much greater than the rms noise of a typical line spectrum. Therefore, it is important to shield all the parts of receiver carefully from radio interferences. Also, without appropriate shielding, the sensitivity of a receiver could be limited by the interference.

• Proceedings of the KIEE Conference
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• 2000.07a
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• pp.458-460
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• 2000

In this paper, we analyze the inductive coupling between overhead power transmission lines and neighbouring gas pipelines or other conductors, when they parallel to a line section in a phase-to-earth fault is assumed on the transmission line. A numerical procedure employing the finite-element method(FEM) is used in conjunction with Faraday's law, in order to predict the current in a faulted transmission line as well as the induced voltages across points on a pipeline running parallel to the faulted line and remote earth. The results lead to conclusion that may be useful to power system engineers.

• Proceedings of the KIEE Conference
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• 2008.09a
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• pp.72-75
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• 2008

The Electromagnetic Interference(EMI) in railway applications is largely due to doing the power conversion for traction and Auxiliary system on the Highspeed Electric Multiple Unit-400X(HEMU-400X). In order to research on EMI in railway applications, it were included how much the HEMU-400X generates it and it has an effect on the equipments of electric system which resulted from Power Line Disturbance (PLD) phenomenon by the loss of contact during its running. In this study, the dynamic characteristic of a contact wire and pantograph suppling electrical power to high-speed trains are investigated. The analysis of the loss of contact based on Power Simulator program software is performed to develop power line disturbance model suitable for high speed operation. It is confirmed that a contact wire and pantograph model are necessary for studying the dynamic behavior of the pantograph system.