• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.175-178
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• 1998

In this paper, turbo codes with the DC-free trellis codes based on partition chain as constituent codes are presente. And efficient methods to design the DC-free turbo codes are introduced. An iterative decoding with the MAP algorithm is used for the decoding of the turbo codes designed by various methods. As results of simulations, the presented DC-free turbo codes show better error performances than the DC-free trellis codes.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.3C
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• pp.205-215
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• 2007

This paper presents low latency and/or computation algorithms of iterative codes of turbo codes, turbo product codes and low density parity check codes for use in wireless broadband communication systems. Due to high coding complexity of iterative codes, this paper focus on lower complexity and/or latency algorithms that are easily implementable in hardware and further accelerate the decoding speed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.9C
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• pp.537-545
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• 2011

This paper analyzed performance of three dimensional turbo code and turbo ${\Phi}$ codes proposed in the next generation DVB-RCS systems. In the view of turbo ${\Phi}$ codes, we proposed the optimal permutation and puncturing patterns for triple binary input data. We also proposed optimal post-encoder types and interleaving algorithm for three dimensional turbo codes. Based on optimal parameters, we simulated both turbo codes, and we confirmed that the performance of turbo ${\Phi}$ codes are better than that of three dimensional turbo codes. However, the complexity of turbo ${\Phi}$ is more complex than that of three dimensional turbo codes by 18%.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.4C
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• pp.191-199
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• 2005

Space-time turbo codes have been studied extensively as a powerful and bandwidth efficient error correction code over the wireless communication environment. In this paper, the efficient algorithm for decoding space-time turbo codes is proposed. The proposed method reduces the computational complexity by approximating a prior information for a iterative decoder. The performance of space-time turbo codes is also analyzed by using the fixed point implementation and the efficient method for approximating the Log-MAP algorithm is proposed. It is shown that the BER performance of the proposed method is close to that of the Log-MAP algorithm.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.5 no.5
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• pp.409-412
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• 2004

This paper shows that the proposed Turbo TCM(Turbo Trellis Coded Modulation) has a good performance with a little complexity of decoder. The encoder structure, which is connected with Turbo Codes, is the proposed modulation technique for an efficient bandwidth, This method is used symbol by symbol MAP decoder of iteration similar to binary Turbo Codes in the receiver. The result shows that the BER performance according to iteration is improved about 2,5dB at $BER=10^{-2}$ compared to Turbo Codes with Gray mapping.

• Proceedings of the IEEK Conference
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• 2000.11a
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• pp.165-168
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• 2000

The bit error rate(BER)of the data passed through Wideband-Code Division Multiple Access (W-CDMA) system with turbo-codes structure is presented. The performance of turbo-codes under W-CDMA system is estimated for various users and iteration numbers of decoding. The channel model is Additive White Gaussian Noise(AWGN) and Rayleigh fading channel. When iteration number increases, bit error probability of turbo-codes decreases. and when the number of users increase, bit error probability of turbo-codes increases.

• Proceedings of the IEEK Conference
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• 2001.06a
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• pp.273-276
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• 2001

In this thesis we propose symbol-based decoding for turbo codes which is used SOVA as a decoding algorithm. The proposed turbo codes that is interleaved on symbol-by-symbol basis and inputted as n-bit symbols to the decoder. This method makes that the stages of the original trellis are merged together and the trellis depth is reduced by 1/n. We research turbo codes with symbol size n=2 in this paper and its performance.

• Journal of Satellite, Information and Communications
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• v.10 no.3
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• pp.73-77
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• 2015

In this paper, we present two simulation methods to investigate the effect of excluding bit errors on generating the extrinsic information transfer (EXIT) chart for low density parity check (LDPC) and turbo codes. We utilized the simulation methods including and excluding bit errors to generate EXIT chart which was originally proposed for turbo codes. The generated EXIT charts for LDPC and turbo codes shows that the presented methods appropriately demonstrates the performance behaviours of iterative decoding for LDPC and turbo codes. Analysis on the simulation results demonstrates that the EXIT chart excluding the bit errors shows only a small part of the curves where the amount of information is too large.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.11C
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• pp.1045-1051
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• 2003

The SOVA, which produces the soft decision value, can be used as a sub-optimum solution for concatenated codes such as turbo codes, since it is computationally efficient compared with the optimum MAP algorithm. In this paper, we propose an efficient implementation of the SOVA used for decoding turbo codes, by reducing the number of calculations for soft decision values and trace-back operations. In order to utilize the memory efficiently, the whole block of turbo codes is divided into several sub-blocks in the proposed algorithm. It is demonstrated that the proposed algorithm requires less computation than the conventional algorithm, while providing the same overall performance.

• 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.