• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 하계종합학술대회 논문집(1)
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• pp.5-8
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• 2000

In this paper, we present a new cぉnet coding method, so called MLC (Multi-Level Codes), for error detection and correction in digital wireless communication. MLC coding method we the same coding procedure wed in the convolutional coding but it is distinguished from the existing convolutional coding in point of generating the code word by using multi-level information data (M-ary signal) and in point of speed of coding procedure Through computer simulation, we analyze the performance of the coding method suggested here compared to convolutional coding method in case of modulo-operation and in case of non-binary coding Procedure respectively under various channel environments.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 통신소사이어티 추계학술대회논문집
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• pp.277-280
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• 2003

In this paper, we analyze the performance of transmitter and receiver of W-CDMA system using the channel coding and space time code in downlink over ITU-R realistic channel model. We can improve the reliability of communications and increase the data rate by channel coding, and we can get a diversity gain by using the space time code over fading channels. We also apply the RAKE receiver to improve tile performance in multi-Path fading channel environment.

• 한국통신학회논문지
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• 제36권5B호
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• pp.517-529
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• 2011

본 논문에서는 차세대 해상 통신 시스템인 SANET (Ship Ad-hoc NETwork)의 우선 전송 규격 파라미터를 설정하고, VHF 대역의 실측 해상 채널을 분석하여 SANET 채널 모델링을 수행한다. 또한, 프리앰블, guard time, 파일롯을 포함한 단일 및 다중 반송파 시스템을 위한 프레임 구조를 제안하며, 제안된 프레임 구조 하에서 채널 보상과 채널 부호화 기법에 의한 SANET 시스템의 BER (Bit Error Rate) 성능을 평가 및 분석한다. 결과로 ${\pi}$/4-DQPSK와 ${\pi}$/8-D8PSK를 적용한 단일 반송파 SANET의 경우, differential 변조방식 채택에 의하여 별도의 채널 보상을 하지 않으며, 부호화 이득을 얻을 수 있는 컨볼루션 부호화를 적용하기로 한다. 다중 반송파 SANET의 경우에는 해상환경, 파도에 의한 선박의 움직임 등에 의한 K값의 변화를 고려하여 시스템의 성능을 최대화 하도록 채널 보상 기법과 컨볼루션 부호화를 적용한다.

• 한국통신학회논문지
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• 제36권3C호
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• pp.170-174
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• 2011

본 논문은 양방향 중계 채널(Two-Way Relay Channel) 에서 기존에 연구되었던 협력 통신(Cooperative Communication) 에서 네트워크 부호화(Network Coding)에 대해 간단히 소개한다. 협력 통신 시스템에서의 직교성을 이용한 새로운 네트워크 부호화 기법을 제안한다. 제안된 직교 사상 네트워크 부호화 기법은 기존에 널리 사용되고 있는 DF(Decode-and-Forward) 모듈러 합 기법의 전송률을 유지하면서 DF 기법의 단점인 오류 전파(Error Propagation) 현상을 제거하여 향상된 BER(Bit Error Rate) 성능을 보인다.

• 정보와 통신
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• 제12권6호
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• pp.88-100
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• 1995

본 고에서는 디지털 위성방송 시스템의 구성요소중 channel부의 구조 및 기능분석을 국내 디지털 DBS를 기준으로 설명하였다. channel부는 channel coding과 modulation 기능을 수행한다. Channel coding은 Reed Solomon code, interleaving, convolutional code를 연집하여 사용하고, modulation은 QPSK와 raised cosine pulse shaping을 한다. 수신기의 channel부는 antenna, LNB, tuner, QPSK 복조기, Viterbi, deinterleaver, RS decoder로 구성되어있다.

• Journal of Communications and Networks
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• 제10권4호
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• pp.371-383
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• 2008

Application of network coding in wireless two-way relay channels (TWRC) has received much attention recently because its ability to improve throughput significantly. In traditional designs, network coding operates at upper layers above (including) the link layer and it requires the input packets to be correctly decoded. However, this requirement may limit the performance and application of network coding due to the unavoidable fading and noise in wireless networks. In this paper, we propose a new wireless network coding scheme for TWRC, which is referred to as soft network coding (SoftNC), where the relay nodes applies symbol-by-symbol soft decisions on the received signals from the two end nodes to come up with the network coded information to be forwarded. We do not assume further channel coding on top of SoftNC at the relay node (channel coding is assumed at the end nodes). According to measures of the soft information adopted, two kinds of SoftNC are proposed: amplify-and-forward SoftNC (AF-SoftNC) and soft-bit-forward SoftNC (SBF-SoftNC). We analyze the both the ergodic capacity and the outage capacity of the two SoftNC schemes. Specifically, analytical form approximations of the ergodic capacity and the outage capacity of the two schemes are given and validated. Numerical simulation shows that our SoftNC schemes can outperform the traditional network coding based two-way relay protocol, where channel decoding and re-encoding are used at the relay node. Notable is the fact that performance improvement is achieved using only simple symbol-level operations at the relay node.

• 정보처리학회논문지B
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• 제9B권1호
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• pp.91-98
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• 2002

In this paper, an implementation method of the efficient image transmission stage using watermarking and channel ceding is proposed. Usually, image communication system consists of both a transmitter part and a receiver part. The transmitter part takes charge of copyright protection of the generated image data, and image coding and compression that can deal with channel noises when transmitting. In the transmitter part, we propose a channel coding method which protects both the watermark signal and the original signal for protecting the copyright of image data and solving channel noises when transmitting. Firstly, copyright protection of image data is conducted. For this, image structure analysis is performed, and both the improvement of image quality and the generation of the watermark signal are made. Then, the histogram is constructed and the watermark signals are selected from this. At this stage, by embedding of the coefficients of curve fittness into the lower 4 bits of the image data pixels, image quality degradation due to the embedding of watermark signals are prevented. Finally, turbo coding, which has the most efficient error correction capability in error correction codes, has been conducted to protect signals of watermark and preserved original image quality against noises on the transmission channel. Particularly, a new interleaving method named "semi random inter]easer" has been proposed.

• 전자공학회논문지A
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• 제30A권7호
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• pp.1-11
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• 1993

The bit error rates of DS/SSMA DPSK system with diversity and FEC channel coding in Rayleigh fading and log-normal shadowing channel are evaluated. Microscopic postdetection diversity and macroscopic selection diversiity are used to mitigate the effects of Rayleigh fading and log-normal shadowing, respectively. The numerical results show that the composite use of diversity and channel coding is very efficient for improving system performance compared to their respective uses.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 ITC-CSCC -1
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• pp.478-481
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• 2000

In this paper, we propose a joint coding system for still images using source coding and powerful error correcting code schemes. Our system comprises an LVQ (lattice vector quantization) source coding for wavelet transformed images and turbo coding for channel coding. The parameters of the image encoder and channel encoder have been optimized for an n-D (dimension) cubic lattice (D$_{n}$, Z$_{n}$), parallel concatenation fur two simple RSC (recursive systematic convolutional code) and an interleaver. For decoding the received image in the case of the AWGN (additive white gaussian noise) channel, we used an iterative joint source-channel decoding algorithm for a SISO (soft-input soft-output) MAP (maximum a posteriori) module. The performance of transmission system has been evaluated in the PSNR, BER and iteration times. A very small degradation of the PSNR and an improvement in BER were compared to a system without joint source-channel decoding at the input of the receiver.ver.

• 전기학회논문지P
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• 제64권4호
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• pp.321-326
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• 2015

Smart metering is one of the most implementable internet-of-thing service. In order to implement the smart metering, a wireless communication network should be newly designed and evaluated so as to satisfy quality-of-service of smart metering. In this paper, we consider a wireless network for the smart metering implemented with multi-purpose wireless chips and channel coding-functioned micro controllers. Especially, channel coding is newly adopted to improve successful frame transmission probability. Based on the successful frame transmission probability, average transmission delay and delay violation probability are analyzed. Using the analytical results, service coverage expansion is evaluated. Through the delay analysis, service feasibility can be verified. According to our results, channel coding needs not to be utilized to improve the delay performance if the smart metering service coverage is several tens of meters. However, if more coverage is required, chanel coding adoption definitely reduces the delay time and improve the service feasibility.