• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.11
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• pp.1320-1331
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• 1992

The error rate equation of FH/MFSK signal of repeated diversity received over m-distribution fading channel with partial-band interference has been derived and the error rate has been evaluated to show in figures as a function of signal to noise ratio, signal to interference ratio, fading figure, repeated number, partial-band interference fraction and power correlation coefficient between signal and interference. In this paper, we assumed that repeated diversity technique is used in transmitter against fading occurred in mobile radio channel. By comparing the error rate performance in diversity against fading and the obtainable degree of improvement of error performance with diversity technique has been found out. From the result, it is known that error rate performance deteriorates more as $\rho$ becomes small i.e., the partial-band interference gives more effect on error performance than full-band interference. Also when the values of $E_b/N_1$ and $\rho$ are small. as depth of fading diversity technique.

• The Journal of the Acoustical Society of Korea
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• v.12 no.1
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• pp.47-54
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• 1993

Performance analysis is very important to transmit the high quality information and to construct the optimal system for the minimze the noise from the channel of spread spectrum system. In this paper the error rate performance is analyzed with computer simulation in noncoherent frequency hopping M-qry frequency shift keying(FH/MFSk) systems with regard to thermal noise under the partial band jamming environments. AS a result, in case the thermal noise is disregarded, bit error probability of system in jamming fraction ρ and Eb/Nj(bit energy to jamming power density) is reduced with the increase of K and in worst case 32FSK system is better than 2FSK system by 3.23dB with the variatio of Eb/Nj. In case thermal noise is considered, bit error probability of system by 3.23dB with the variation of Eb/Nj. In case thermal noise is considered, bit error probability of system are reduced with the increase of K and Eb/No(bit energy to thermal noise density). Bit error probability in connection with worst case ρ is not largely influenced form over the 14dB to K=1 and 8dB to K=5 accordingly thermal noise disregarding. These results may be useful for avoiding the common vulnerabilities when the spread spectrum system is designed.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2004.11a
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• pp.204-209
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• 2004

It is well known fact that acoustic positioning systems are absolutely needed for various underwater operations. According to the distances between their sensors they are classified into three parts: long baseline(LBL), short baseline(SBL), and ultra-short baseline(USBL). Among them the USBL system is widely used because of its simplicity, although it is the most inaccurate. Recently, in order to increase the positioning accuracy, various USBL systems using broadband signal such as MFSK(Multiple Frequency Shift Keying) are produced. However, their positioning accuracy is still limited by background noise and reflected waves. Therefore, there is difficulty in applying the USBL system using MFSK signal in a shallow water with noisy conditions. In order to examine the effect of the noise and wave reflections this paper analyze position errors for various conditions using numerical simulations. The simulation results say that tile SNR must be greater than 20dB and errors in the vertical direction are slightly increased by wave reflections by upper and lower boundaries.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.14 no.3
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• pp.227-234
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• 1989

In this paper, a new receiver for a frequency-hopped multilevel FSK system for mobile Communications is presented. This new receiver provides an implementation advantage by eliminating unecessary energy detection of all the frequency channels. A performace analysis of the proposed system is carried out by using the union bound. We show that an optimim number of message bits that minimize the word error probability exists for a given number of simultaneous users. This scheme is a generalization of the MFSK system that allows the message bits to be uaried, making it possible for designers to increase the flexibility of implementation. Error probabilities are calculated in the case of fixed bandwidth and fixed tone repetition number. The effect of using error-correcting coding is considered.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1990.06a
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• pp.91-96
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• 1990

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1992.06a
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• pp.668-674
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• 1992

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1987.10a
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• pp.126-129
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• 1987

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1991.10a
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• pp.307-310
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• 1991

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1995.06a
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• pp.105-114
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• 1995

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.7
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• pp.1176-1185
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• 2000

In this paper, we analyze the distribution of the envelope of the received signal over frequency-nonselective slow Rician fading channels with aadditive white Gaussian noise(AWGN). Especially, we can obtain the error rate performance of noncoherent M-ary FSK(MFSK) over slow and flat Rician fading channels and AWGN from the new probability density function(PDF) of the envelope, not PDF of the instantaneous signal-to-noise ratio(SNR) published before, of the received signal. When coherent MFSK signals experience the Rician fading channel, the performances are derived, using the union bound.