• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.6
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• pp.1184-1189
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• 2001

In this paper was analyzed the performance of turbo code using semi-random interleaver which proposed a reference numbers 11. Which was analyzed comparison the performance of between the current mobile communication system had been used the viterbe decoding algorithm of convolutional code and turbo codes when fixed constraint length. The result was defined that the performance of turbo code rose a $E_{b/}$ $N_{o}$=4.7[㏈] than convolutional code, when convolutional code and turbo code was fixed by BER = 10$^{-4}$ and constraint length K 5.5.5.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.5
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• pp.861-868
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• 2001

In this paper, the performance of Reed Solomon(RS)/convolution리 concatenated codes and turbo code using semi random interleaver over the radio communication channel was analyzed. In the result, we proved that the performance of decoder was excellent as increase the interleaver size, constraint length, and iteration number. When turbo code using semi random interleaver and Hsiconvolutional concatenated codes was constant constraint length L=5, BER=10-4 , each value of $E_b/N_o$ was 4.5〔dB〕 and 2.95〔dB〕. Therefore, when the constraint length was constant, we proved that the performance of turbo code is superior to RS/Convolutional concatenated codes about 1.55〔dB〕 in the case of BER=10-4.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.5
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• pp.1067-1075
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• 2000

In this paper, the performance of turbo code using semi random interleaver over the radio communication channel was analyzed. In the result, we proved that the performance of decoder was excellent as increase the interleaver size, constraint length, and iteration number. When the constraint length of turbo code using seim random interleaver and convolutional code is constant, and BER $10^{-4}$ each value of $E_b/N_o$ was 6.4(DB) and 1.7(dB). There(ore, when the constraint length was constant, we proved that the performance of turbo code using semi random interleaver is superior to convolutional code about 4.7(dB) in the case of BER=$10^{-4}$.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.9-12
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• 1999

전력선은 백색 가우시안 배경 잡음뿐 아니라 임펄스 잡음, 고조파 잡음 등의 비 가우시안 잡음들로 인해 통신 채널로서 열악한 전송 특성을 나타낸다. 또한 좁은 가용 대역폭으로 인해, 광대역 특성이 요구되는 DS-CDMA 방식과 같은 대역 확산 시스템의 적용에 한계가 있다. 본 연구에서는 차세대 고속이동통신을 위한 다원접속/변조방식인 멀티코드 (multi-code) CDMA 방식과 이에 길쌈 부호와 인터리빙 등의 부호화 기능을 더한 시스템을 전력선 통신 시스템에 적용하고, 모의실험을 통해 전력선 채널의 비 가우시안 잡음의 영향을 매우 효과적으로 보상할 수 있음을 확인하였다.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.11
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• pp.1239-1244
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• 2015

In this paper, a new method for finding optimal and short span in Convolutional Self-Doubly Orthogonal(CDO) codes are proposed. This new algorithm based on Parallel Implicitly-Exhaustive search, where we applied dynamic search space reduction methods in order to reduce computational time for finding Optimal Span for R=1/2 rate CDO codes. The simulation results shows that speedup and error correction performance of the new algorithm is better.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.1A
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• pp.43-47
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• 2000

In regions of low signal-to-noise ratio (SNR), performance analysis uses simulations of hybrid concatenated coding systems. However, for higher SNR regions beyond simulation capabilities, average upper bounds to bit error rate (BER) and word error rate (WER) are used. In [1], all weight enumerating functions are needed to obtain average bounds. In this paper, we use RSC as constituent codes, by using effective free distances instead of WEF, we derive average BER and WER bounds of hybrid concatenated convolutional codes (HCCC) and analyze the BER and WER over AWGN and Rayleigh/Rician fading channels.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.8A
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• pp.1441-1449
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• 2001

차세대 멀티미디어 이동통신인 IMT-2000의 규격에서는 3GPP와 3GPP2에서 모두 터보 코드를 채널 코덱으로 채택하고 있다. 그 중 3GPP 에서는 용도에 따라 길쌈부호와, 제한길이 4인 1/3 터보코드를 선택적으로 사용하도록 정의되어 있다. 터보코드는 복호기의 출력으로 경판정 복호 비트에 대한 신뢰도 값을 동시에 생성하여, 이를 이용한 반복복호로 우수한 BER 특성을 얻을 수 있어야 한다. 본 논문에서는 먼저 3GPP 규격의 터보 복호기에 적용할 수 있는 내부 복호기로서 SOVA 복호기를 설계하였다. 또한 터보 복호기에서의 연판정 출력값의 중요성을 감안하여, 누적메트릭 정규화에 있어서 신뢰도 값에 영향을 주지않는 구조를 제안하여 적용하였다. 본 연구에서는 효율적인 구조의 3GPP SOVA 복호기를 설계하기 위하여 C++를 이용하여 알고리즘에 대한 성능을 검증하였으며, 이를 기반으로 VHDL을 이용하여 복호기를 설계하였다. 마지막으로 Altera사의 EPF10K100GC503 FPGA를 이용하여 복호기를 하드웨어로 구현하였다.

• The Journal of the Acoustical Society of Korea
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• v.32 no.6
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• pp.494-501
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• 2013

The convolution code(CC) of code rate 1/2 as a forward error correction (FEC) in Quadrature Phase Shift Keying (QPSK) is applied to decrease bit error rate (BER) by background noise and multipath in shallow water acoustic channel. Ratio of transmitting signal bandwidth to channel coherence bandwidth is defined as frequency selectivity index. BER and bit energy-to-noise ratio gain of transmitted signal according to frequency selectivity index are evaluated. In the results of indoor water tank experiment, BER is well matched theoretical results at frequency selectivity index less than about 1.0. And bit energy-to-noise ratio gain is also matched theoretical value of 5 dB. BER is effectively decreased at frequency selective multipath channel with frequency selectivity index higher than 1.0. But bit energy-to-noise ratio greater than a certain size in terms of CC weaving is effective in reducing bit errors. In the results, the defined frequency selectivity index in this study could be applied to evaluate a performance of CC in multipath channel. Also it could effectively reduced BER in a low speed underwater acoustic communication system without an equalizer.

• Journal of the Korea Society of Computer and Information
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• v.3 no.3
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• pp.121-127
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• 1998

In this paper, using diversity and convolution code in the DS/CDMA system, have been the performance analized. In this modulation shceme is using QPSK. Channel to CDMA system has been approximated by Rayleight fading channel considering effect for multi-path. In this assumed that receiver is WTDL(Wide-band Tappped Delay Line) receiver, and in this condition, average error probability of DS/CDMA.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.1
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• pp.21-28
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• 2004

In this paper we apply block turbo coding at the transmitter and iterative decoding algorithm at the receiver for different operating modes, based on the 5 ㎓ IEEE 802.1 la WLAN system, instead of convolutional coding and soft decision viterbi algorithm to improve forward error correcting performance. Experimental results showed that each coding scheme outperforms coding gains of up to 3.5 ㏈ at the BER of 10$\^$-3/.