• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.14 no.3
• /
• pp.216-226
• /
• 1989

In this paper, we explain about an outline of the decoding method for double encoding system using the error correcting capacitance and a simple decoding method. We have been taken formation two-dimension code word of doubly-encoded code using $C_1$(32, 28, 5) and $C_2$(32, 26, 7) Reed-Solomon codes, and had computer simulation of the erroe correcting processes in frequency domain. On these processes, the newly developed digital signal processing technology such as error correction using Berlekamp-Massey algorithm in frequency domain have been proven.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.17 no.4
• /
• pp.1296-1309
• /
• 2023

In this paper, based on the soft cancellation (SCAN) bit-flipping (SCAN-BF) algorithm, a generalized SCAN bit-flipping (GSCAN-BF-Ω) decoding algorithm is carried out, where Ω represents the number of bits flipped or corrected at the same time. GSCAN-BF-Ω algorithm corrects the prior information of the code bits and flips the prior information of the unreliable information bits simultaneously to improve the block error rate (BLER) performance. Then, a joint threshold scheme for the GSCAN-BF-2 decoding algorithm is proposed to reduce the average decoding complexity by considering both the bit channel quality and the reliability of the coded bits. Simulation results show that the GSCAN-BF-Ω decoding algorithm reduces the average decoding latency while getting performance gains compared to the common multiple SCAN bit-flipping decoding algorithm. And the GSCAN-BF-2 decoding algorithm with the joint threshold reduces the average decoding latency further by approximately 50% with only a slight performance loss compared to the GSCAN-BF-2 decoding algorithm.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.37 no.7A
• /
• pp.535-544
• /
• 2012

Multi-Input Multi-Output (MIMO) transmission is now considered as one of essential techniques enabling high rate data transmissions in wireless communication systems. In addition, severe channel impairments in wireless systems should be compensated by using highly efficient forward error correction (FEC) codes. Turbo codes or low density parity check (LDPC) codes, using iterative decoding with soft decision detection information (SDDI), are the most common examples. The excellent performance of these codes should be conditioned on accurate estimation of SDDI from the MIMO detection process. In this paper, we propose a soft MIMO detection scheme using QR decomposition of channel matrices as an efficient means to provide accurate SDDI to the iterative decoder. The proposed method employed a two sequential soft MIMO detection process in order to reduce computational complexity. Compared to the soft ZF method calculating the direct inverse of the channel matrix, the complexity of the proposed method can be further reduced as the number of antennas is increased, without any performance degradation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2001.10a
• /
• pp.648-651
• /
• 2001

This paper describes the 8-error-correction (204, 188) Reed-Solomon Decode. over GF(2$^{8}$ ) for a satellite communication. It is synthsized using a CMOS library. Decoding algorithm of Reed-Solomon codes consists of four steps which are to compute syndromes, to find error-location polynomial, to decide error-location, and to slove error-values. The decoder is designed using Modified Euclid algorithm in this paper. First of all, The functionalities of the circuit are verified through C++ programs, and then it is designed in Verilog HDL. It is verified through the logic simulations of each blocks. Finally, The Reed-Solomon Decoder is synthesized with Synopsys Tool.

• IEIE Transactions on Smart Processing and Computing
• /
• v.3 no.3
• /
• pp.142-152
• /
• 2014

Vehicular Ad-hoc Networks (VANETs) are comprised of wireless mobile nodes characterized by a randomly changing topology, high mobility, availability of geographic position, and fewer power constraints. Orthogonal Frequency Division Multiplexing (OFDM) is a promising candidate for the physical layer of VANET because of the inherent characteristics of the spectral efficiency and robustness to channel impairments. The susceptibility of OFDM to Inter-Carrier Interference (ICI) is a challenging issue. The high mobility of nodes in VANET causes higher Doppler shifts, which results in ICI in the OFDM system. In this paper, a frequency domain com-btype channel estimation was used to cancel out ICI. The channel frequency response at the pilot tones was estimated using a Least Square (LS) estimator. An efficient interpolation technique is required to estimate the channel at the data tones with low interpolation error. This paper proposes a robust interpolation technique to estimate the channel frequency response at the data subcarriers. The channel induced noise tended to degrade the Bit Error Rate (BER) performance of the system. Parallel concatenated Convolutional codes were used for error correction. At the decoding end, different decoding algorithms were considered for the component decoders of the iterative Turbo decoder. A performance and complexity comparison among the various decoding algorithms was also carried out.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.17 no.3
• /
• pp.213-223
• /
• 1999

This study provides a improved model of digital basemap production that can efficiently identify and correct the various errors generated in digital map production process. In order to fulfill the requirements that the new model calls for, this study provides a typology of errors by analyzing the errors in digital basemap data. Computer programs for automatic error searching and for checking the correctness of the digital codes in the data have also been developed. Exsiting visual error-checking process has also been analyzed and more systematic process is suggested. As a result, it is found that the improved model of digital basemap production suggested in this study contributes to improving the quality of the digital map database by providing a systematic method for efficient error-searching and correction of digital map data.

• The Journal of the Convergence on Culture Technology
• /
• v.7 no.3
• /
• pp.565-570
• /
• 2021

A soft-decision decoding scheme of a channel code for correcting an error occurring in a receiver of a digital communication systems is proposed. A method for efficiently decoding by use of the linear and arithmetic structure of linear block codes is presented. In this way, the probability of decoding errors has been reduced. In addition, it is possible to reduce the complexity of decoding as well. Sufficient conditions for achieving optimal decoding has been derived. As a result, the sufficient conditions enable efficient search for candidate codewords. With the proposed decoding scheme, we can effectively perform the decoding while lowering the block error probability.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.8 no.8
• /
• pp.1613-1619
• /
• 2004

Turbo codes of long block sizes have been known to show very good performance in an AWGN channel and the turbo code has been strongly recommended as error correction code for W-CDMA in 3GPP(3rd Generation Partnership Project). Recently, turbo codes of short block sizes suitable for real time communication systems have attracted a lot of attention. Thus, in this paper we consider the turbo code of 1/3 code rate and short frame size of 192 bits in ITU-R channel model. We analyzed the performance of W-CDMA systems of 10MHz bandwidths employing RAKE receiver with not only MRC diversity but also SOVA-based turbo code.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.10 no.10
• /
• pp.2766-2770
• /
• 2009

Recently, the Green IT is noticed because of the effects of greenhouse gas emissions, a drain on natural resources and pollution. In this paper, Visible Light Communication (VLC) systems with Turbo Coded scheme using LED is proposed and simulated in an optical wireless channel. As a forward error correction scheme to reduce information losses, turbo coding was employed. To decode the codewords, The Map (Maximum a Posteriori) algorism and SOVA (Soft Output Viterbi Algorithm) is used. The above mentioned schemes are described and simulation results are analyzed. As using turbo codes scheme, BER performance of proposed VLC systems is improved about 5 [dB].

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.8 no.6
• /
• pp.73-81
• /
• 2009

Wireless media communication has lower robustness and stability than wired communication because of narrow bandwidth and unstable channel state. To make up for the deficient points of wireless communication, we used the diversity effect of cooperation communication and the error correction effect of channel coding schemes. In this paper, the cooperative communication system with RCPC codes and Hybrid ARQ transmission scheme is proposed for improving reliability on wireless communication, and we executed these simulations. From the simulation results, proposed system is showed lower BER performance than legacy system. In addition, we confirm the fact that the channel state of Relay-node and source-node is more important than the channel state of Relay-node and destination-node.