• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.9
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• pp.744-749
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• 2013

We propose soft user data input on LDPC codes with parity encoded by the (1, 7) run length limited (RLL) code for perpendicular magnetic recording channel. The user data are encoded by maximum transition run (MTR) (3;11) code. In order to minimize the loss of code rate, the (1, 7) RLL code only encode the parity of LDPC. Also, to increase performance, we propose only user data part applied soft output Viterbi algorithm (SOVA). The performance using the SOVA showed good performance lower than 26 dB. In contrast, it showed worse performance high than 26 dB. This is because of incorrect soft information by high jitter noise and two different input types for LDPC decoder.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.11C
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• pp.712-719
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• 2011

In this paper, we analyzed the performance of soft decision e-BCH codes which presented in DVB-RCS NG system. However, the performance of soft-decision decoding for e-BCH is not much improved as to increase the iterations. Therefore this paper proposed rate-compatible TPC which makes various coding rates by zero padding the row and/or column to adapt next generation (NG) DVB-RCS system. And so we proposed new model of extended BCH code and researches how to develop performance of extended BCH code.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.10
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• pp.1020-1023
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• 2011

In this paper, we present a symbol remapping method of BRGC M-ary QAM signal by using LLR soft bit decision information which is obtained after iterative decoding process. In order to reconstruct estimated transmitted signal constellation, we have to use exponential or hyperbolic tangent(tanh) function resulting in high implementation complexity. The BRGC mapping rule enables us to use a recursive operation. In addtion, we reduce the implementing complexity by using a curve fitting algorithm.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.9
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• pp.528-534
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• 2014

In this paper, we propose an iterative detection and decoding scheme for the LDPC coded multiuser uplink massive-MIMO systems. We consider the simple maximal ratio combining (MRC) detector and LDPC decoder. We formulate the soft output of MRC detector and the relation between the extrinsic informations of the detector and decoder. The performance improvement of the proposed iterative detection and decoding scheme is shown by computer simulation.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.8
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• pp.61-66
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• 2013

In this paper, we propose an iterative soft dimension reduction based multi-input multi-output (MIMO) detection for coded spatial multiplexing system. In spite of better performance of iterative MIMO detection, its computational complexity gives a significant burden to the receivers. To mitigate this problem, we propose a scheme employing all ordering successive interference cancellation (AOSIC) for hard-decision detection and dimension reduction soft demodulator (DRSD) with iterative decoding for soft-decision detectors, respectively. This scheme can reduce complexity of iterative soft MIMO detection and provide better performance than other conventional detectors.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.3
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• pp.473-479
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• 2005

A key issue toward mobile multimedia communications is to create technologies for broadband signal transmission that ran support high quality services. Such a broadband mobile communications system should be able to overcome severe distortion caused by time-varying multi-path fading channel, while providing high spectral efficiency and low power consumption. For these reasons, an adaptive suboptimum decision feedback equalize. (DFE) for the single-carrier short-burst transmissions system is considered as one of the feasible solutions. For the performance improvement of the system with the short-burst format including the short training sequence, in this paper, the multiple-training least mean square (MTLMS) based DFE scheme with soft decision feedback is proposed and its performance is investigated in mobile wireless channels throughout computer simulation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.2C
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• pp.117-122
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• 2006

In this paper, we present a simple and general soft bit decision expression for a Gray coded PAM signal over additive white Gaussian noise(AWGN) channel with the log likelihood ratio(LLR). In order to reduce the complexity of the LLR calculation, we make the bitwise LLR expression simple by replacing the mathematical max functions of the conventional Max-Log-MAP expression with simple arithmetic functions associated with some deterministic parameters, such as a received value and distance between symbols on a signal space. Taking the implementation issues, like the area of silicon, the power consumption, the timing latency, and so on, into consideration, we submit that the proposed method is a promising alternative way to conventional methods for reconfigurable systems.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37A no.9
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• pp.738-745
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• 2012

This paper proposes an approximated soft decision demapping algorithm with low computational complexity for coded 4+12+16 amplitude phase shift keying (APSK) in an additive white Gaussian noise (AWGN) channel. To derive the proposed algorithm, we approximate the decision boundaries for 4+12+16 APSK symbols, and then decide the log likelihood ratio (LLR) value for each bit from the approximated decision boundaries. Although the proposed algorithm shows about 0.6~1.1dB degradation on the error performance compared with the conventional max-log algorithm, it gives a significant result in terms of the computational complexity.

• Journal of Broadcast Engineering
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• v.24 no.6
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• pp.1072-1075
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• 2019

In this letter, we propose a new soft decoding method for a Core-Layer(CL) signal in ATSC3.0 Layered-Division-Multiplexing Multiple-Inputs-Multiple-Outputs broadcasting systems. Unlike a conventional Gaussian-Approximation(GA) method, the proposed method decodes the CL signal by reducing a Enhanced-Layer signal simply to a QPSK signal, and thus exhibits greatly improved performance compared to the GA method especially for a lower CL injection-level.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2000.11a
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• pp.63-67
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• 2000

본 논문에서는 IEEE 802.11a 무선 LAN에 적합한 16QAM/OFDM 시스템의 성능을 AWGN과 two-ray 다중 경로 페이딩 채널에서 시뮬레이션을 통하여 분석하고 성능 향상을 위한 방법으로 비터비 복호를 하는 길쌈 부호와 단일 탭의 LMS 등화기를 사용한다. 길쌈 부호를 사용하면 AWGN과 다중 경로 페이딩 채널에서 각각 경판정(hard-decision)은 2dB, 6 dB, 연판정(soft-decision)은 4.5 dB, 10 dB의 이득을 얻는다. 또한 다중 경로 페이딩 환경에서 경판정 비터비 복호와 단일 탭의 LMS 등화기를 함께 사용하는 경우에는 경판정 복호만을 사용하는 경우보다 5 dB 향상됨을 알 수 있다.