• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.2
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• pp.1-8
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• 2010

Multi antenna techniques using space-time codes can achieve diversity gains in a multi-path environment without additional bandwidth requirement. Most of the 4G candidate standards including the IEEE 802.16e adopt multi-input multi-output (MIMO) schemes to achieve either high throughput performance or diversity gains. In these 4G candidate standards, turbo codes using an iterative decoder with soft input soft output are used to overcome serious channel fading. For this reason, the estimated signal values from MIMO detectors should be soft decision detection values. In this paper, we propose efficient methods to estimate soft decision detection values for various space time coding schemes, and provide the simulation results of turbo coded space time coding scheme over an IEEE 802.16e link.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.5
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• pp.185-192
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• 2011

In this paper, we simulate and analyze performance of iterative coding scheme, double binary turbo code, for high speed power line communication (PLC) systems. PLC system has hostile environment for high speed data transmission, so error correction method is necessary to compensate effects of PLC channel. We employ the PLC model proposed by M. Zimmerman and Middleton Class A interference model, and system performance is evaluated in terms of bit error rate (BER). From the simulation results, we confirm double binary turbo code provides considerable coding gains to PLC system and BER performance is significantly improved as the number of iteration increase. It is also confirmed that BER performance increases as code rate is lager, while it decreases as the code rate is smaller.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.1
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• pp.69-76
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• 2018

This paper studies the Turbo Codes, the concatenation of Turbo Codes and Reed-Solomon (RS) codes on Orthogonal frequency-division multiplexing (OFDM) in digital communication channel, and then analysis the performances of the new concatenated Forward Error Correct (FEC) scheme applied to an OFDM system based on the digital terrestrial video broadcasting (DVB-T) scheme. We compared the results with the standard DVB-T convolutional codes performances on Additive White Gaussian Noise (AWGN) channels. The simulation results shown that by employing turbo codes with only a few numbers of iterations, the performances of the overall system can be improved significantly. These results will be obtained by applying an appropriate interleaver technique in the concatenated FEC procedure.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.5A
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• pp.423-430
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• 2010

The performances of turbo-coded space-time block coding (STBC) schemes are subject to how soft decision detection (SDD) information are generated from the STBC decoder. For this reason, we have to pay particular attention to estimation of SDD. In this paper, we evaluate the performance of a turbo coded STBC scheme depending on the accuracy of the SDD. Recently, a new quasi orthogonal STBC (QO-STBC) scheme using a noise whitened filter was proposed in order to reduce noise enhancing effect of zero forcing detection process. This QO-STBC scheme was proven to be efficient in computational complexity compared to the other conventional QO-STBC schemes. In this paper, we first present detailed mathematical analysis on the noise whitened QO-STBC scheme, and by using the result we propose the optimum SDD method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.7A
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• pp.994-1004
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• 2000

In this paper, bitstreams are composed of using H.263 for a moving picture coding in the band-limited and error-prone environment such as wireless environment. EREC sub-frames are implemented by applying the proposed EREC algorithm in order to be UEP for the real data parts of implemented bitstreams. Because those are able to do resynchronization with a block unit, propagation of the error can be minimized, and the position of the important bits such as INTRADC and MVD can be known. Class is separated using the position of these important bits, and variable puncturing tables are designed by the class informations and the code rates of turbo codes are differently designed in according to the class. Channel coding used the turbo codes, and an interleaver to be designed in the turbo codes does not eliminate redundancy bits of the important bits in applying variable code rates of EREC sub-frames unit and is always the same at the transmitter and the receiver although being variable frame size. As a result of simulation, UEP with the code rate similar to EEP is obtained a improved result in the side of bit error probability. And the result of applying it to image knows that the subjective and objective quality have been improved by the protection of important bits.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.10
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• pp.1065-1074
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• 2008

T-DMB(Terrestrial Digital Multimedia Broadcasting) system, is based on the Eureka-147 standard, provides various multimedia data services. However T-DMB system needs upgrades for more various services and better services. Therefore, we proposed advanced T-DMB system using unequal error protection system and hierarchical modulation in this paper while maintaing backward compatibility. And we simulated various bit split methods and double binary turbo code of DVB-RCS standard as method of LP data stream for additional service of advanced T-DMB. As the simulation results, double binary turbo code of proposed advanced T-DMB system have each coding gain of over 2 dB compared to conventional T-DMB.

• Proceedings of the IEEK Conference
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• 2000.06a
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• pp.181-184
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• 2000

In this paper, performance of an optical CDMA system with PCCC and SCCC is simulated and compared. It is assumed that optical channel is an intensity modulated (IM) channel and direct-detection scheme is employed to detect the received optical signal. The modulation scheme used is pulse-position-modulation (PPM). The performance is evaluated in terms of bit error probability. From the simulation results, it is shown that turbo coding offers considerable coding gain with reasonable encoding/decoding complexity.

• Information and Communications Magazine
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• v.18 no.6
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• pp.74-91
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• 2001

본 고에서는 통신 시스템에 응용되고 있는 블록부호에 대한 소개와, IMT-2000 시스템의 표준화에서 채널 부호화 기법으로 규격에 반영된 길쌈부호(Convolutional code) 및 터보부호(Turbo code)에 대하여 소개하고, 현재 3세대 이동통신 표준화에서 논의중인 Hybrid ARQ(Adaptive Modulation and Coding), AMC(Adaptive Modulation and Coding) 기술에 대하여 설명한다. 그리고, 고속의 데이터 전송을 요하는 4세대 이동통신 시스템의 채널 부호화 기술로 현재 활발히 연구가 이루어지고 있는 Space-Time Code 및 LDPC(Low Density Parity Check Code)에 대해 소개하고, 차세대 이동통신 시스템의 채널 부호화 기술 전반에 대하여 전망한다.

• Journal of Broadcast Engineering
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• v.7 no.2
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• pp.192-201
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• 2002

This paper develops a novel robust information hiding technique that uses channel codes derived from the error-correcting coder. The message encoded by the cover encoder is hidden in DCT transform domain of the cover image. The method exploits the sensitivity of human eyes to adaptively embed a visually recognizable message in an image without affecting the perceptual quality of the underlying cover image. Experimental results show that the proposed data hiding technique is robust to cropping operations, lossy JPEG compression, noise interference and secure against known stego attacks. The performance of the proposed scheme with turbo coder is superior to that without turbo coder.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.8 no.4
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• pp.207-215
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• 2009

In recent digital communication systems, the performance of Turbo Code used as the error correction coding method depends on the interleaver size influencing the free distance determination and iterative decoding algorithms of the turbo decoder. However, some iterations are needed to get a better performance, but these processes require large time delay. Recently, methods of reducing the number of iteration have been studied without degrading original performance. In this paper, the new method combining ME (Mean Estimate) stopping criterion with SDR (sign difference ratio) stopping criterion of previous stopping criteria is proposed, and the fact of compensating each method's missed detection is verified Faster decoding realizes that reducing the number of iterative decoding about 1~2 times by adopting our proposed method into serially concatenation of both decoder. System Environments were assumed DS-CDMA forward link system with intense MAI (multiple access interference).