• 전자공학회논문지A
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• 제30A권8호
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• pp.19-26
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• 1993

The bit error probability of Reed-Solomon/convolutional concatenated codes can be more exactly calculated by using a more approximate bound of the symbol error probability of the convolutional codes. This paper obtains the unequal symbol error bound of the convolutional codes, and applies to the calculation of the bit error probability of the concatenated codes. Our results are tighter than the earlier studied other bounds.

• 디지털산업정보학회논문지
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• 제8권1호
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• pp.147-155
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• 2012

Fountain codes ensure reliability and robustness for time varying channels in wireless communication. In this paper, the concatenated fountain codes for AWGN and slow fading channels are investigated. Wireless system model, which includes the concatenated fountain code and modulation, is proposed. Maximum achievable rate is used for analyzing the performance of the system model for AWGN and fading channels. Belief Propagation (BP) algorithm is used for exploiting the soft information received at the decoder. Simulation results show that, concatenated fountain codes performs significantly better than that of a conventional Fountain codes with large packet lengths for higher Signal to Noise Ratio (SNR) in slow fading channels.

• ETRI Journal
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• 제37권1호
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• pp.54-60
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• 2015

The use of serial concatenated codes is an effective technique for alleviating the error floor phenomenon of low-density parity-check (LDPC) codes. An enhanced sum-product algorithm (SPA) for LDPC codes, which is suitable for serial concatenated codes, is proposed in this paper. The proposed algorithm minimizes the number of errors by using the failed check nodes (FCNs) in LDPC decoding. Hence, the error-correcting capability of the serial concatenated code can be improved. The number of FCNs is simply obtained by the syndrome test, which is performed during the SPA. Hence, the decoding procedure of the proposed algorithm is similar to that of the conventional algorithm. The error performance of the proposed algorithm is analyzed and compared with that of the conventional algorithm. As a result, a gain of 1.4 dB can be obtained by the proposed algorithm at a bit error rate of $10^{-8}$. In addition, the error performance of the proposed algorithm with just 30 iterations is shown to be superior to that of the conventional algorithm with 100 iterations.

• 한국통신학회논문지
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• 제24권6A호
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• pp.905-912
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• 1999

본 논문에서는 블록부호를 트렐리스상에서 구현하여 블록부호의 연판정 복호 알고리즘인 MAP 복호 알고리즘을 유도하였다. 또한 트렐리스상의 연판정 복호법인 비터비 알고리즘과 MAP 알고리즘을 사용한 모의실험을 통해 그 성능을 분석하였다. 그리고 비교적 간단한 블록부호인 해밍부호를 구성부호로 사용하여 다양한 형태의 직렬연접부호와 병렬연접부호에 대한 성능분석을 수행하였다. 모의실험 결과 블록부호에 연판정 복호 알고리즘을사용한 경우는 경판정 복호 알고리즘에 비해 높은 부호화 이득을 가짐을 알 수 있었다. 또한 구성부호로 블록부호를 사용하는 연접부호의 모의실험을 수행한 결과 반복복호함으로써 우수한 성능을 가진 연접부호를 얻을 수 있음을 검증하였다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -1
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• pp.536-539
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• 2002

The use of concatenated codes in noncoherent synchronous optical fiber CDMA networks is proposed. The concatenated code sequences are generated using balanced Walsh code sequences and Walsh code sequences. The selection of balanced Walsh code sequences is presented and the design of fully programmable transmitter and receiver is reported. The analysis of the system BER performance shows that multiple-access interference is completely eliminated and the BER performance of the proposed system is better than that of the non-coherent synchronous optical fiber CDMA system using optical orthogonal codes with double hard-limiters.

• 한국전자통신학회논문지
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• 제13권1호
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• pp.69-76
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• 2018

본 논문에서는 OFDM(Orthogonal Frequency-Division Multiplexing)에서 터보코드, RS(Reed-Solomon)코드를 연구하고, DVB-T(digital terrestrial video broadcasting)에서 OFDM에 적용된 FEC(Forward Error Correct)의 성능을 분석한다. 그리고 표준 AWGN 통신로의 경우와 비교한다. 모의실험을 한 결과 반복해서 터보코드를 사용하면 성능이 현저히 개선됨을 확인할 수 있었다. 이는 컨케이트네이티드 FEC에 적절한 인터리버를 적용해서 구현가능 할 것이다.

• 한국ITS학회 논문지
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• 제8권6호
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• pp.141-148
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• 2009

STBC는 부호이득을 얻을 수 없지만, 비교적 적은 부호기와 복호기의 복잡도를 가지고 완전한 다이버시티 이득을 얻을 수 있다. 따라서 STBC는 부호이득이 없기 때문에 부호이득을 얻을 수 있는 외부 부호와 결합되어 사용하여야 한다. 본 논문에서는 완전한 다이버시티 이득과 함께 상당한 부호이득을 얻기 위하여, MTCM부호와 STBC를 결합한 시스템을 고려하였다. 공정한 성능 비교를 위하여 동일한 전송 전력, 동일한 대역폭 효율 그리고 동일한 상태 수를 전제하고, 고려한 시스템과 기존에 알려진 STTC부호와 FER 성능 비교를 실시하였다. 모의실험 결과, MTCM부호와 STBC를 결합한 시스템의 성능은 빠른 레일리 페이딩 채널에서 2개의 송신기 안테나와 1개의 수신기 안테나를 사용하는 STTC부호 보다 우수한 성능을 보여주었다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 추계종합학술대회 논문집
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• pp.759-762
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• 1999

In this paper, we introduce the concept of a HAPS(High Altitude Platform Station) system which is expected to be a next generation communication system and suggest several error correcting codes to provide high quality services. Since a HAPS system encounters serious signal attenuation due to rain and scattering in the air, concatenated codes which have a high coding gain is considered to be a proper error correcting method. In this paper, we provide performance analyses result of two candidate coding schemes for a HAPS. The first one is a conventional concatenated coding scheme, and the second one is a iterative decoding method known as Turbo Codes.

• Journal of Advanced Marine Engineering and Technology
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• 제33권5호
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• pp.738-745
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• 2009

Underwater acoustic communication has multipath error because of reflection by sea-level and sea-bottom. The multipath of underwater channel causes receive signal to make error floor. In this paper, we propose the underwater communication system using various channel coding schemes such as RS coding, convolutional code, turbo code and concatenated code for overcoming the multipath effect in underwater channel. As shown in simulation results, characteristic of multipath error is similar to that of random error. So interleaver has not effect on error correcting. For correcting of error floor by multipath, it is necessary to use strong channel codes like turbo code. Turbo code is one of the iterative codes. And the performance of concatenated codes including RS code has better performance than using singular channel codes.

• 한국통신학회논문지
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• 제31권4C호
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• pp.324-330
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• 2006

The next generation mobile communication systems require error correcting schemes that can be adaptable to various code rates and lengths with negligible performance degradation. Serial concatenated convolutional codes can be a good candidate satisfying these requirements. In this paper, we propose new rate-compatible punctured serial concatenated convolutional code (RCPSCCC) which performs better than the RCPSCCC proposed by Chandran and Valenti in the sense of the rate compatibility. These codes are evaluated and analyzed by using computer simulation and SNR evolution technique. As their application, Type-II hybrid automatic repeat request (HARQ) schemes using both RCPSCCCs are constructed and new RCPSCCC is shown to have better throughput.