• 대한전자공학회논문지
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• 제23권3호
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• pp.309-316
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• 1986

A concatenated coding system using a binary code as the inner code and a nonbinary code as the outer code has been constructed for the purpose of error correction. The complexity of a conventional coding system grows exponentially as the code length of a block code becomes longer. To reduce the complexity for ling code, an effective communication system has been proposed by cascading two codes-binary and norbinary codes. Using a parallel-to-serial circuit and a serial-to-parallel circuit, the concatenated coding system has been designed and constructed by empolying a (7,3) burst error correcting code as the inner code and a (7,3) Reed-Solomon code as the outer code. This system has been simulated and tested using a micro-computer. For the (49,9) concatenated coding system, the error probability of the channel has been evaluated and compared to different coding systems.

• Journal of Communications and Networks
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• 제5권2호
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• pp.135-140
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• 2003

In this paper, we investigate the error performance of a serially concatenated system using a nonrecursive convolutional code as the outer code and a recursive QPSK space-time trellis code as the inner code on quasi-static and rapid Rayleigh fading channels. At the receiver, we consider iterative decoding based on the maximum a posteriori (MAP) algorithm. The performance is evaluated by means of computer simulations and it is shown that better error performance can be obtained by using low complexity outer and/or inner codes and the Euclidean distance criterion based recursive space-time inner codes. We also obtain new systems with large number of trasmit and/or receive antennas providing good error performance.

• ETRI Journal
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• 제37권4호
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• pp.736-742
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• 2015

A serial concatenated decoding algorithm with dynamic threshold is proposed for low-density parity-check codes with short and medium code lengths. The proposed approach uses a dynamic threshold to select a decoding result from belief propagation decoding and order statistic decoding, which improves the performance of the decoder at a negligible cost. Simulation results show that, under a high SNR region, the proposed concatenated decoder performs better than a serial concatenated decoder without threshold with an Eb/N0 gain of above 0.1 dB.

• 방송공학회논문지
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• 제12권4호
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• pp.373-376
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• 2007

최근 DTV 전송규격으로 채택되고 있는 VSB 방식의 성능 개선을 위한 연구가 진행되었다. 이미 상당수가 보급되어 있는 기존수신기의 수신 성능에는 영향을 주지 않으면서 개선된 스트림 (enhanced stream)의 수신을 가능하게 하기 위하여 기존 방식과 후방 호환성이 있는 부호 방식의 연구가 진행되었다. 이제까지 제안된 방식들은 기존의 8-VSB 부호기의 외부에 외측 부호기로 주로 격자 부호기 (trellis encoder)를 직접 연접하는 방식만이 제안되었다. 본 논문에서는 기존의 격자 부호기와 외측 부호기를 인터리버로 연결하는 직렬 연접 터보 격자부호변조(Turbo Trellis Coded Modulation) 방식을 제안하고, 전산 모의실험을 통해서 제안된 방식의 성능을 기존 방식과 비교한다

• Journal of Communications and Networks
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• 제7권3호
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• pp.307-312
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• 2005

In this work, we study the performance of a serial concatenated scheme comprising a convolutional code (CC) and an orthogonal space-time block code (STBC) separated by an inter-leaver. Specifically, we derive performance bounds for this concatenated scheme, clearly quantify the impact of using a CC in conjunction with a STBC, and compare that to using a STBC code only. Furthermore, we examine the impact of performing antenna selection at the receiver on the diversity order and coding gain of the system. In performing antenna selection, we adopt a selection criterion that is based on maximizing the instantaneous signal-to­noise ratio (SNR) at the receiver. That is, we select a subset of the available receive antennas that maximizes the received SNR. Two channel models are considered in this study: Fast fading and quasi-static fading. For both cases, our analyses show that substantial coding gains can be achieved, which is confirmed through Monte-Carlo simulations. We demonstrate that the spatial diversity is maintained for all cases, whereas the coding gain deteriorates by no more than $10\;log_{10}$ (M / L) dB, all relative to the full complexity multiple-input multiple-output (MIMO) system.

• 대한전자공학회논문지TC
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• 제40권9호
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• pp.366-372
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• 2003

본 논문에서는 직렬연접 길쌈부호를 사용한 다중레벨 부호변조방식을 제안하고 그 성능을 분석한다. 다중레벨 부호변조의 첫 번째 레벨에서 직렬연접 길쌈부호를 구성부호로 사용할 경우 높은 부호이득과 대역폭효율성을 얻을 수 있다. 모의실험 결과 Ambroze의 길쌈부호를 사용한 다중레벨 부호변조의 성능은 병렬연접 길쌈부호를 사용한 다중레벨 부호변조의 성능과 같이 성능이 포화된다. 그러나 Benedetto의 직렬연접 길쌈 부호를 사용한 다중레벨부호변조는 성능포화현상을 보이지 않을 뿐만 아니라 성능도 병렬연접 길쌈부호를 사용한 것과 Ambroze의 직렬연접 길쌈부호를 사용한 것보다 우수하다. 따라서 Benedetto의 직렬연접 길쌈부호를 사용한 다중레벨부호변조는 제한된 대역폭에서 고품질을 요구하는 시스템에 적합하다고 할 수 있다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권1호
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• pp.162-177
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• 2012

In this paper we present a novel method of applying image scrambling technology which belongs to the information hiding field in the error control coding to introduce confidentiality in wireless machine to machine communication. The interleaver in serial concatenated convolutional codes, which is the key module in overcoming burst errors, is deliberately designed with the scrambling function to provide a low error rate for those authorized transceivers. By contrast, the unauthorized transceivers without keys would get so high an error rate that decoding bits could bring little value, thus realizing both the confidentiality and reliability in wireless machine to machine communication.