• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.4
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• pp.819-830
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• 2017

An FM radio based PCL system is a passive radar technique for detecting the multiple moving targets from FM radio signals and tracking the trajectories of the targets by calculating the cross-correlation function of direct-path signal and target echo signals. However, the interference signals are received from a surveillance channel, which is designed to receive the target echo signals. Because of this problem, the target echo signals are masked by the strong interference signals and this makes it difficult to detect the true targets from the cross-correlation function. Adaptive filters are known as effective methods for suppressing the interference signals but there is a problem to present their accurate performances in the PCL system because many literatures used the cross-correlation function and the ratio of input and output power as a measure of the performance analysis. In this paper, a performance analysis method is proposed to evaluate the performance of interference cancellation algorithms. By using the property that each component of the filter weight vector is adjusted to suppress the specific interference signal, a performance measure of the interference signal suppression is defined by a function of adaptive filter weights. Based on the proposed method, we compare the performance of the adaptive filters used in the PCL system. Simulation results show that the proposed method can be very effective for evaluating the performance of interference cancellation algorithms.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.10B
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• pp.1995-2003
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• 1999

Since the cross-correlation function which is due to communication channel distortion or interference is not orthogonal, near far problem and multi-user interference are generated in the DS-CDMA system. Those problems degrade performance of the system so that the efficient algorithm to suppress the interference in the DS-CDMA system is required. In this paper, a blind adaptive interference suppressor using constant modulus algorithm is proposed. Simulation results present that the gain of SIR for the blind adaptive receiver is about 7[dB] at steady state over Gaussian channel in forward channel. The gain of noise to interference ration is about 4[dB] over Rayleigh fading channel, is about 11[dB] over multipath channels. Thus the proposed receiver has higher performance than a conventional receiver in the DS-CDMA system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.4C
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• pp.433-439
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• 2007

This paper derives an approximate expression for the output SINR(Signal to Interference plus Noise Ratio) of Applebaum type adaptive array under the scenario of the interferer's proximity to the desired signal. The approximation is made in terms of array geometry, the arrival direction of desired signal and that of an interfering signal. An interferer in the close proximity of target signal is shown to drastically impair the away performance. An approximate expression for interferer arrival direction which results in a predetermined performance loss is also obtained in terms of array configurations. Proposed approximation agrees with the computer calculated performance impairment when the two signals are apart by less than eight degrees. The allowable proximity of the interfering signal increases with the number of array elements.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.1
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• pp.55-61
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• 2011

In this paper, the outage probability of device-to-device (D2D) uplink communication underlaying cellular networks is analyzed over Rayleigh fading. We assume that a D2D pair and M cellular user equipments share the same frequency resources. To prevent any harmful interference from a D2D transmitter to the BS, the maximum transmit power of the D2D transmitter is strictly limited. Under these assumptions, the outage probability is represented as a function of the interference-to-signal ratio from M cellular user equipments to a D2D receiver and the number of cellular user equipments, M. In addition, the interference-to-signal ratio is represented as a function of distances among D2D equipments, cellular user equipments and the BS. Simulation results validate these analytical results.

• ETRI Journal
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• v.7 no.4
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• pp.3-10
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• 1985

After the light from an incoherent LED was transmitted through the multimode fibers which were linked over 10 km, the nearfield power distribution reached the steady-state independent of launching conditions. It has been also found that the steady-state output power distribution showed the pattern of Gaussian function. In this steady-state Gaussian function pattern, the measured losses of fibers were very repeatable values. In case of using LD source, the speckle phenomena in near -field power distribution appeared until the distance of 10 km. And the output power distribution did not reach the steady-state shown in LED even over 20km on account of the coherence and the nonuniform lasing modes of LD. But the measured losses of fibers were nearly stable in this long distance.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.2
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• pp.564-574
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• 1996

This paper describes as Electronic Speckle Pattern Interferometry system which has been designed for measuring vibration patterns and quantitative measurement of vibration amplitude fields by using the time average method on a object. Visbility of fringe patterns is more improved by using the phase stepping and frame average method to reduce speckle and electric noise. And a bias vibration is introduced into the reference beam to shift the $\frac{2}{0}$ fringes so that fringe shift algorithms can be used to determine vibration amplitude. The experimental results are compared to those of the FFT analyzer and the FEM model analysis.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.7 no.4
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• pp.167-172
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• 1982

We have studied and discussed the error rate performance of Quadrature Amplitude Modulation(QAM) in an environment of cochannel QAM interference and impulsive noise. A general equation of error probability for L-level QAM signal has been derived and the error rate of the 16-QAM signal, as an example, has been calculated as functions of carrier-to-noise power ratio(CNR), carrier-to-interferer power ratio(CIR), impulsive indes, and the phase difference between signal and interferer.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.3
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• pp.395-402
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• 2003

The capacity of a CDMA cellular system is determined by the amount of interference, therefore the exact estimation of interference is important to evaluate the system performance. In this paper, we propose an approximated equation which calculates reverse link other cell interference in the CDMA cellular systems. The equation using Riemann-Zeta function has a property that it is useful in case of any radio propagation loss exponents. And we compare calculation results with simulation results in other to verify it's usefulness. The upper bound of system capacity calculated with the proposed approximated equation gives almost alike result with the simulation. The proposed interference bound is useful to calculate system capacity and to evaluate some algorithm in a hierarchical cellular system which must be considered various propagation exponents.

• Proceedings of the Optical Society of Korea Conference
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• 2004.07a
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• pp.214-215
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• 2004

• Proceedings of the Optical Society of Korea Conference
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• 2004.07a
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• pp.194-195
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• 2004