• The Journal of Korean Institute of Communications and Information Sciences
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• v.16 no.6
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• pp.489-497
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• 1991

The error rate pquations of digital radio signals transmitted throught the Nakagami's m-distribution fading channel have been both for nondiversity reception and for diversity reception cases in the environmment of Gaussin noise. Using the derived equation. erro rate performance has been evaluated and represented in figures as a function of carrier to noise ratio, fading figure, and the power correlation coefficient between two diversity branches. By comparing the diversity reception case with nondiversity reception case. We could measure the amount of error rate performance improvenment of digital radiosignals in fanding enviroment.

• Journal of the Institute of Electronics Engineers of Korea TE
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• v.37 no.5
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• pp.77-84
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• 2000

In this paper, we modelized the multipath fading to Nakagami-m distribution fading channel which can be applied to the extended mobile communication channel environment. We assumed that the phase difference with reference signal happened in the received signal and in the receiver PLL(Phase Locked Loop) is the phase error. To correct the error we propose new RAKE receiver using PLL. In addition, we analyze the performance of DS/SS(Direct Sequence/spread Spectrum) system according to the gain of PLL,$\gamma_n$, the number of RAKE receiver branch L and MIP(Multipath Intensity Profile)'s exponential decay $\delta$. As a result, when the proposed RAKE receiver L Is increased and the $\delta$ is decreased the performance of the system gets better. Futhermore when PLL gain was 30dB, phase is identified. That is when the PLL gain is 30dB, the performance equals with the perfect coherent system's. Therefore, we can correct the phase error by using the proposed RAKE receiver and we proved that the PLL's requested limit gain should be 30dB.

• Journal of the Korea Society of Computer and Information
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• v.7 no.3
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• pp.128-134
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• 2002

In this paper, the performance on the PN code acquisition of DS/CDMA system was analyzed using the Nakagami-m probability density function considered fading environment. The equations on detection probability, $P_D$ and false alarm probability, $P_{FA}$, decision variables affecting the PN code acquisition time were derived and proved using simulation in order to analyze the performance. In conclusion, It was necessary increasing the gain of PLL for correcting phase errors and improving the acquisition performance of PN code in apply to the rake receiver.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.6
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• pp.567-574
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• 2003

It is important to design and evaluate the chip waveform with the minimum MAI under the bandwidth constraint in the interference-limited DS-CDMA system. In this paper, by approximation we present the analytical chip waveforms that are proposed and optimized in the reference. Their performances are compared with performances of three conventional chip waveforms: rectangular, half-sine and raised-cosine. Waveform 1 of the proposed chip waveform outperforms the conventional ones. BER and throughput performance are evaluated in the Rayleigh and Nakagami-m fading channels when DPSK modulation is used. When the required BER is 10$\^$-3/ in two fading channels, the capacity of the waveform 1 is improved about 20 % rather than raised-cosine one. When the offered traffic is 30 and the number of packet per bit(N$\sub$d/) is 14, maximum throughput of the waveform 1 is better than raised-cosine chip waveform about 18 % in two fading channels.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.5C
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• pp.439-444
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• 2010

In this paper, we derive and analyze the channel capacity of the spread spectrum watermarking (SSW) system as an information-theoretic point of view in closed-form approximation formula in order to analyze the effect of the wireless multipath/shadowing channel. It is important to analyze the channel capacity to transmit an additive data through existing wireless channel by the SSW system. From the results, we confirm that the channel capacity of the SSW system can be determined by the HWR, WNR, PN length and host sampling frequency. Also, we verified that the variation of the channel capacity when the SSW system applied to Nakagami-m fading and Log-normal shadowing channel. The results of this paper can be applied to general spread spectrum watermarking system.

• Journal of the Institute of Electronics Engineers of Korea TE
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• v.39 no.4
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• pp.403-408
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• 2002

In this paper, the performance on the PN code acquisition of DS/CDMA system was analyzed using the Nakagami-m probability density function considered fading environment. The equations on detection probability, $P_D$ and false alarm probability, ($P_{FA}$, decision variables affecting the PN code acquisition time were derived and proved using simulation in order to analyze the performance. In conclusion, It was necessary increasing the gain of PLL for correcting phase errors and improving the acquisition performance of PN code in apply to the rake receiver.