• Journal of Broadcast Engineering
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• v.16 no.6
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• pp.1026-1035
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• 2011

This paper presents generalization and application for the conventional SISO decoding algorithm of Block Turbo Codes. R. M. Pyndiah suggested an iterative SISO decoding algorithm for Product Codes, two-dimensionally combined linear block codes, on AWGN channel. It wascalled Block Turbo Codes. Based on decision of Chase algorithm which is SIHO decoding method, SISO decoder for BTC computes soft decision information and transfers the information to next decoder for iterative decoding. Block Turbo Codes show Shannon limit approaching performance with a little iteration at high code rate on AWGN channel. In this paper we generalize the conventional decoding algorithm of Block Turbo Codes, under BPSK modulation and AWGN channel transmission assumption, to the LLR value based algorithm and suggest an application example such as concatenated structure of LDPC codes and Block Turbo Codes.

• JSTS:Journal of Semiconductor Technology and Science
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• v.14 no.4
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• pp.407-418
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• 2014

As the high-throughput requirement in the next generation communication system increases, it becomes essential to implement high-throughput SISO (Soft-Input Soft-Output) decoder with minimal hardware resources. In this paper, we present the comparison results between cascaded radix-4 ACS (Add-Compare-Select) and LUT (Look-Up Table)-based radix-4 ACS in terms of delay, area, and power consumption. The hardware overhead incurred from the retiming technique used for high speed radix-4 ACS operation is also analyzed. According to the various analysis results, high-throughput radix-4 SISO decoding architecture based on simple path metric recovery circuit is proposed to minimize the hardware resources. The proposed architecture is implemented in 65 nm CMOS process and memory requirement and power consumption can be reduced up to 78% and 32%, respectively, while achieving high-throughput requirement.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.2
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• pp.44-51
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• 2008

In this paper, we propose a modified clipping scheme for iterative decoding of superposition coding system by losing less power than clipping scheme. Our proposed scheme in superposition coding system shows good performance in peak-to-average power ratio(PAPR) and system performance with the same Clipping Ratio especially in low Clipping Ratio case. Finally in order to alleviate the performance degradation due to clipping noises, we combine a soft compensation algorithm that is combined with soft-input-soft-output(SISO) decoding algorithms in an iterative manner proposed by [1][2]. Simulation results show that with the proposed scheme, most performance loss can be recovered.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.3
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• pp.1131-1143
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• 2016

Differential detection schemes do not require any channel estimation, which can be employed under user mobility with low computational complexity. In this work, a soft-input soft-output (SISO) differential detection algorithm is proposed for amplify-and-forward (AF) over time-varying relaying channels based cooperative communications system. Furthermore, maximum-likelihood (ML) detector for M-ary differential Phase-shift keying (DPSK) is derived to calculate a posteriori probabilities (APP) of information bits. In addition, when the SISO is exploited in conjunction with channel decoding, iterative detection and decoding approach by exchanging extrinsic information with outer code is obtained. Finally, simulation results show that the proposed non-coherent approach improves detection performance significantly. In particular, the system can obtain greater performance gain under fast-fading channels.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.5
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• pp.895-901
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• 2016

The next generation wireless and satellite communications require high transmission efficiency and high reliability to provide various services with subscribers. To satisfied these requirements, incorporated MIMO (Multiple Input Multiple Output) system with FTN (Faster Than Nyquist) techniques based on layered space time coded method are considered in the paper. To improve performance, STTC (Space Time Trellis Code) was employed as an inner code. As the same as SISO (Single Input Single Output) system, the outer codes are turbo codes. In receiver side, BCJR algorithm is used for STTC decoding in order to eliminate interferences induced by FTN transmission. They can yield significantly increased the data rates and improved link reliability without additional bandwidth. Therefore, we proposed a new decoding model for MIMO FTN model and confirmed that performance was improved compared to conventional SISO model according to amount of interference for FTN.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.2C
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• pp.175-180
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• 2009

When we apply the LDPC code for high density optical storage channel, it is necessary to make an algorithm that the modulation code decoder must feed the LDPC decoder soft-valued information because LDPC decoder exploits soft values using the soft input. Therefore, we propose the soft-input soft-output run-length limited 17PP decoding algorithm and compare performance of LDPC codes. Consequently, we found that the proposed soft-input soft-output decoding algorithm using 17PP is 0.8dB better than the soft-input soft-output decoding algorithm using (1, 7) RLL.

• Proceedings of the IEEK Conference
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• 2000.07a
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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.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.7
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• pp.1291-1298
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• 2017

In this paper, we propose a decoding method that improves the transmission rate and reliability by integrating MIMO(Multiple Input Multiple Output) communication scheme using turbo code and FTN(Faster Than Nyquist) scheme among high rate and high reliability wireless communication schemes in wireless communication. The existing MIMO-FTN(Multiple Input Multiple Output-Faster Than Nyquist) scheme based on hierarchical space-time coded method induced data rate loss due to the application of the space-time trellis coding scheme to remove adjacent symbol interference due to FTN scheme. To solve these problems, this paper proposes a method using W-ZF(Weighted-Zero Forcing) which overcomes the disadvantages of ZF(Zero Forcing) scheme in MIMO-FTN scheme using ZF scheme. In this paper, we compared the performance and the transmission rate of the MIMO-FTN scheme based on the hierarchical space-time coding, the MIMO-FTN scheme using W-ZF and the SISO-FTN scheme. As a result, the MIMO-FTN scheme using the W-ZF scheme is two times better than the other two schemes.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.3C
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• pp.215-223
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• 2003

Turbo codes are selected as FEC(Forward error correction) codes with convolution code in 3GFP(3rd generation partnership project) and 3GPP2 standard of IMT2000. Especially, l/3 turbo code with K=4 is employed for 3GPP standard. In this paper, we proposed a hardware structure of a turbo decoder and denveloped the decoder for 3GPP standard turbo code. For its efficient operation, we design a SOVA decoder by employing a register exchange decoding block and new path metric normalization block as a SISO constituent decoder. In addition, we estimate its performance under MATLAB 6.0 and designed the turbo decoder including control block, input control buffer, SOVA constituent decoder with VHDL. Finally, we synthesized the developed turbo decoder under Synopsys FPGA Express and verified it with ALTERA EPF200SRC240-3 FPGA device.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.7
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• pp.2614-2632
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• 2015

A multiple symbol detection (MSD) algorithm is proposed relying on soft information for ultra-wideband systems, where differential space-time block code is employed. The proposed algorithm aims to calculate a posteriori probabilities (APP) of information symbols, where a forward and backward message passing mechanism is implemented based on the BCJR algorithm. Specifically, an MSD metric is analyzed and performed for serving the APP model. Furthermore, an autocorrelation sampling is employed to exploit signals dependencies among different symbols, where the observation window slides one symbol each time. With the aid of the bidirectional message passing mechanism and the proposed sampling approach, the proposed MSD algorithm achieves a better detection performance as compared with the existing MSD. In addition, when the proposed MSD is exploited in conjunction with channel decoding, an iterative soft-input soft-output MSD approach is obtained. Finally, simulations demonstrate that the proposed approaches improve detection performance significantly.