• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.595-598
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• 2005

MPEG-4 Visual is, and international standard for the object-based video compression, designed for supporting a wide range of applications from multimedia communication to HDTV. To control the minimum decoding complexity required at the decoder, the MPEG-4 Visual standard defines the co-called video buffering mechanism, which includes three video buffer models. Among them, the VCV(Video Complexity Verifier) defines the control of the processing speed for decoding of a macroblock, there are two models: VCV and B-VCV distinguishing the boundary and non-boundary MB. This paper presents the evaluation results of decoding complexity by measuring decoding time of a MB for rectangular, arbitrarily shaped video objects and the various types of objects supporting the resolution of HDTV using the optimized MPEG-4 Reference Software. The experimental results shows that decoding complexity varies depending on the coding type and more effective usage of decoding resources may be possible.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.8A
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• pp.785-790
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• 2010

This paper proposes new suboptimum, yet very efficient demapping methods for Turbo coded noncoherent MFSK systems under AWGN and Rayleigh fading channels with channel state information. Simulation results show that the proposed methods achieve performance within 0.2 dB of the maximum-likelihood decoder and the previously proposed suboptimum demapping schemes with a fraction of the complexity.

• Journal of Communications and Networks
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• v.6 no.3
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• pp.209-215
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• 2004

In this paper, a butterfly Log-MAP decoding algorithm for turbo code is proposed. Different from the conventional turbo decoder, we derived a generalized formula to calculate the log-likelihood ratio (LLR) and drew a modified butterfly states diagram in 8-states systematic turbo coded system. By comparing the complexity of conventional implementations, the proposed algorithm can efficiently reduce both the computations and work units without bit error ratio (BER) performance degradation.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1984.04a
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• pp.22-24
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• 1984

In this paper, the (15,7) cylic codesused EG(2,2) were decoded by one step majority logic decoding. This decoding algorithm is based on the properties of finite geometries and can be simply implemented for moderate length n. especially one step majority logic decoding is attractive because the complexity and the cost of the majority logic decoder increase very rapidly with L, the number of decoding steps. The theorectical and experimental results show that the majority logic decoding presented in this paper is a relatively effective decoding scheme.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.11a
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• pp.132-132
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• 2004

• IEIE Transactions on Smart Processing and Computing
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• v.6 no.2
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• pp.93-101
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• 2017

This paper proposes an algorithm for adaptive loop filter (ALF) complexity reduction in the decoding process. In the original ALF algorithm, filtering for I frames is performed in the frame unit, and thus, all of the pixels in a frame are filtered if the current frame is an I frame. The proposed algorithm is designed on top of the local gradient calculation. On both the encoder side and the decoder side, homogeneous areas are checked and skipped in the filtering process, and the filter coefficient calculation is only performed in the inhomogeneous areas. The proposed algorithm is implemented in Joint Exploration Model (JEM) version 3.0 future video coding reference software. The proposed algorithm is applied for frame-level filtering and intra configuration. Compared with the JEM 3.0 anchor, the proposed algorithm has 0.31%, 0.76% and 0.73% bit rate loss for luma (Y) and chroma (U and V), respectively, with about an 8% decrease in decoding time.

• Proceedings of the IEEK Conference
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• 2001.09a
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• pp.249-252
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• 2001

TCM(Trellis Coded Modulation) has soft decision scheme so that BM(Branch Metric) calculates the ED(Euclidean Distance) between the received signal and each code words in signal space. For computing the ED, square and square root computations increase the hardware complexity. Some simplified method is known for convolutional codes with QPSK(Quadrature Phase Shift Keying), PSK(Phase Shift Keying) modulation. But it is not acceptable for QAM (Quadrature Amplitude Modulation)-TCM scheme. In this paper, we suggest that two modified BM computation methods, which is applicable for QAM-TCM. By comparative study, we also assessed two proposed method in the case of hardware complexity and BER (Bit Error Rate) performance.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.29A no.8
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• pp.99-109
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• 1992

First, the coupling faults of semiconductor memory are classified in detail. The chained coupling fault is introduced and defined, which results from sequential influencing of the coupling effects among memory cells, and its mapping relation is described. The linked coupling fault and its order are defined. Second, the deterministic “Algorithm GA” is proposed, which detects stuack-at faults, transition faults, address decoder faults, unlinked 2-coupling faults, and unlinked chained coupling faults. The time complexity and the fault coverage are improved in this algorithm. Third, it is proved that the march test of an address sequence can detect 97.796% of the linked 2-coupling faults with order 2. The deterministic “Algorithm NA” proposed can detect to the limit. The time complexity and the fault coverage are improved in this algorithm.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.3
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• pp.47-53
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• 1998

Multi-dimensional DC-free trellis codes based on two-dimensional constellation which can be omplemented more easily than conventional codes are proposed and their performances are analyzed in this paper. 2N-dimensional constellation of the proposed codes is constructed by concatenating N 2-dimensional constellation. Thus, for the proposed codes, information bits can be assigned easily to each signal point of the 2-dimensional consteellation and DC-free characteristic can be simply obtained by the symmetric structure of the constellation. In addition, since Viterbi decoder can calculate multi-dimensional Euchlidean distance between signals by simple sum of each 2-dimensional Euclidean distanc, decoding complexity can be reduced. The performance analysis shows that the proposed codes have almost same spectral characteristic and error performance as compared with conventional codes. However, the complexity is shown to be reduced further due to the construction method of contellation and the simple decoding algorithm of the proposed codes.

• ETRI Journal
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• v.37 no.5
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• pp.940-944
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• 2015

We present a frame synchronization algorithm for lowdensity parity-check (LDPC) coded burst transmissions, which combines a conventional pilots-assisted frame synchronization algorithm and a code-aided algorithm based on the mean magnitude of the soft outputs from the LDPC decoder. With moderate computational complexity, the proposed algorithm is more efficient in bandwidth than conventional pilots-assisted algorithms. When compared with other code-aided algorithms, the proposed algorithm offers a better trade-off between complexity and performance. Simulation results in the case of an 8-PSK system with (1944, 972) LDPC code show that the proposed algorithm can achieve a performance equivalent to that of the perfect frame synchronization, with a bandwidth efficiency loss of 0.06 dB due to the use of pilot symbols.