• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.12B
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• pp.1565-1573
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• 2011

In this paper, we present a MIMO-OFDM broadband power line communication (BPLC) for Smart Grid and its associated applications and analyze its performance over the 3-phase 4-wire power line channels. For practical BPLC system simulation, we adopt the statistical power line fading channel model instead of the existing deterministic fading channel models (Zimmermann model, MTL model, and so on). In this paper, we implement $2{\times}2$ and $3{\times}3$ MIMO schemes using 3-phase 4-wire power lines. We investigate the capacity loss and BER performance of the proposed MIMO system by considering the effect of cross-talk between antenna paths. We choose space-frequency coding in order to reduce frequency interference between subcarriers and employ maximum ratio combining (MRC) that achieves both multiple antenna path diversity gain and multiple fading path diversity gain. We evaluate the proposed system performance through computer simulation in terms of the impulse noise index and the capacity loss ratio and compare the different signal combining schemes including MRC, equal gain combing (EGC), and selection combining (SC).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.5
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• pp.990-1006
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• 1997

This paper describes an interface function and its performance assessment for high-bit-rate digital subscriber line (HDSL) under ATM. The interface of HDSL function of ATM system was achieved by HDSL subscriber physical layer board assembly(HSPA) which was modeled as design standard for ATM. We have presented a new worst case of subscriber line conditions from existing results of investigations on impairments such as crosstalk, impulse noise, longitudinal, power line noise and others. We have measured the maximum service loop length available by HDSL, and found that HSPA, at a 2.048Mbps data transmission, is possible within a carrier serving area(CSA) under the worst case loop noise conditions at an error rate or 10$^{-7}$ on a two coordinated unshielded twisted pairs in the presense of impairments. We conclude tht, in terms of a performance-per-lin simulator, the HSPA is an excellent candidate for HDSL implementation under ATM.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.9
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• pp.963-971
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• 1992

A (4,6) block binary line code is proposed. In addition to being de-free and runlength-limited, the new code called MB46 is strictly bandwidth-limited to the Nyquist frequency, thus achieving improved bandwidth efficiency over previously known binary line code. A technique specially employed in the design of the code is described in depth, and some performance measures including the eye pattern and the power spectrum are presented as obtained by simulation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.10
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• pp.1074-1080
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• 1992

A(5,8) block binary line code is proposed. The new line code called MB58 has the properties of being dc-free and runlength-limited, and it is strictly bandwidth-limited to the Nyquist frequency, such that bandwidth efficiency is improved. This new code is a memoryless code with a simple decoding rule and capability of error monitoring. The power spectrum and the eye pattern of the new code are obtained by simulation, wherein spectral nulls at DC(f=0) and Nyquist frequency (f=1/2Ts) are clearly identified.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.11C
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• pp.871-876
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• 2010

Currently the development of powerline communication technology has become possible due to the high-speed communications. But the communication lines used for power line communication, not wires carrying power wiring is because when sending high-frequency wireless communication system unintentionally be influenced. To compensate for these shortcomings by using notch filters to reduce interference has been studied. Wavelet-based OFDM on the other hand by the method has been used to reduce interference. Wavelet-based OFDM has been used in the existing powerline OFDM scheme using FFT instead of the general structure of the CMFB filters to generate a signal. By doing so, subtly signals per frequency band, cut it, is to realize how efficient highways. It brought a deep filter characteristics, a flexible notch filter can be achieved without an external circuit has an advantage. In this paper, Using Wavelet OFDM powerline communication system is designed and presented the results of simulations.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.11
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• pp.2228-2237
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• 1994

This paper describes the development of a Ku-band ($12.25GHz\sim12.75GHz$) SSPA intended as a replacement for TWTAs used in communication satelite transponder. The power stage of the amplifier consists of tow intrmally matched 8W FET divices combined using the branch-line coupler. To operate this stage, the drive stage has been designed with intermally matched 2W, 4W, 8W FET and two medium power FETs. The entire amplifier is made up by a aluminum chassis housing both the RF circuit and the bias circuitry. A regrlator/sequencing circuitry is used for FET biasing. The amplifier results implemented in this way show $41\pm0.3dB$ small-signal gain, 15W saturation power, a typical two tone $IM_3=-21.5dBc$ with single carrier backed off 5dB from saturation, $2^*/dBmax$ AM/PM conversion, and $3.47\pm0.25nsec$ group delay.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.2
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• pp.285-290
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• 2010

We investigate the outage probability in terms of QoS (quality of service) in indoor PLC network. We consider various kinds of appliances for realistic indoor PLC network. For estimation of the outage probability, we calculate the time-varying channel responses considering the loading conditions based on regular human activities and include the additive noise. We calculate the outage probability for each terminal and investigate relationship between the outage probability and the channel length, and transmit powers. Our results suggest that the outage probability is increased when the channel length becomes longer because more appliances affect the amount of reduced channel capacity and is not improved distinctly for very high and low outage threshold by increasing the transmit power. However, we can see outage probability improvement for 30% outage threshold case by increasing the transmit power.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.3
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• pp.582-590
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• 1994

This paper introduce a highly verstile and simple data transmission system designed for commercial power distribution lines. The system operates on the DSSS principle but utilizes two independent carrier frequencies each represents polarity of DS MODEM outiputs. At the receiving terminal, outputs of two envelope detectors are directly applied to separate DS correlators before the two components are compared. The recovered signals which represents data and line noise are then compared at comparator. With the noise power greatly rudused at the correlator, the error rate of the data observed at comparator desplays great improvement comparing to the conventional FSK-DS system in which the detector output are compared before the correlator stage. Despite its simplest structure, the prototype MODEM transmitts 2400 bps with the error rate 10 , about 10dB improved compared to conventional FSK system.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.3
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• pp.292-297
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• 2015

In this paper, we reported the bypass unit for ship area networks in order to detour the communication failure regions and poor communication links. The device was composed of three parts of circuits for power cut-off, protection, and coupling transformer. Since the coupling transformer exerts a dominant influence on the performance of the by-pass unit, we have tried to find the optimal magnetic core materials and its dimensions. The prototype was passed through the performance test of insertion loss, temperature, and vibration characteristics. The insertion loss was around -2 dB in the range of 90 kHz ~ 30 MHz and the average communication speed was 59.2 Mbps in the laboratory. A pilot communication test using the developed tool was conducted in the training ship of the Korea Maritime and Ocean University. As a results of experiment, we showed that the wired communication among the heterogeneous-links in the ship area networks are possible by the bypass unit and also a high speed communication services are available in ~ Mbps by using a power-line.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.6A
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• pp.510-516
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• 2005

In this paper, we discuss parameters of line code and simulate a same optical ethernet having minimum bandwidth(MB810) and non-minimum bandwidth line code(8B/10B) to present the possibility of improving of transmission performance using minimum bandwidth line code on the high speed optical ethernet. We design the high speed optical ethernet using Serial type LAN PHY 10GBASE-E(WDM type LAN PHY 10GBASE-LX4) for the single(multi) channel link. To compare the transmission performance of MB810, 8B/10B line code we measure the bit error rate(BER) according to the received optical power of single and multi channel link.