• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.6 no.4
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• pp.3-10
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• 1995

In this paper, application of PTCM to 2FSK / 4PSK signals is studied. The generator polynomial of punctured trellis coded 2FSK / 4PSK, metric computation techniques, decoding complexity considerations are provided. Simulation results shows that PTCM of 2FSK / 4PSK archieves equal coding gain in com- parison to Padovani and Wolf's system with less decoding complexity.

• Proceedings of the Acoustical Society of Korea Conference
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• 1998.06c
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• pp.155-158
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• 1998

IMBE(Improved Multi-Band Excitation) vocoders exhibit good performance at low data rates. The major drawback to IMBE coders is their large computational requirements. In this paper, thus, we propose a new pitch search method that preserves the quality of the IMBE vocoder with reduced complexity. The basic idea is to reduce computation complexity of the pitch searching by using the SAMDF. Applying the proposed method to the IMBE vocoder, we can get approximately 52.02% searching time reduction in the pitch search. There is no difference in voice quality between conventional IMBE and proposed IMBE.

• 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.

• Journal of Information Processing Systems
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• v.2 no.3 s.4
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• pp.153-158
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• 2006

In this paper, we propose an image interpolator for low computational complexity. The proposed image interpolator supports the image scaling using a modified cubic convolution interpolation between the input and output resolutions for a full screen display. In order to reduce the computational complexity, we use the difference in value of the adjacent pixels for selecting interpolation methods and linear function of the cubic convolution. The proposed image interpolator is compared with the conventional one for the computational complexity and image quality. The proposed image interpolator has been designed and verified by Verilog HDL(Hardware Description Language). It has been synthesized using the Xilinx VirtexE FPGA, and implemented using an FPGA-based prototype board.

• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.4
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• pp.488-496
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• 2016

This paper presents a low-complexity non-iterative soft-decision Bose-Chaudhuri-Hocquenghem (SD-BCH) decoder architecture and design technique for wireless body area networks (WBANs). A SD-BCH decoder with test syndrome computation, a syndrome calculator, Chien search and metric check, and error location decision is proposed. The proposed SD-BCH decoder not only uses test syndromes, but also does not have an iteration process. The proposed SD-BCH decoder provides a 0.75~1 dB coding gain compared to a hard-decision BCH (HD-BCH) decoder, and almost similar coding gain compared to a conventional SD-BCH decoder. The proposed SD-BCH (63, 51) decoder was designed and implemented using 90-nm CMOS standard cell technology. Synthesis results show that the proposed non-iterative SD-BCH decoder using a serial structure can lead to a 75% reduction in hardware complexity and a clock speed 3.8 times faster than a conventional SD-BCH decoder.

• Journal of Broadcast Engineering
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• v.18 no.6
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• pp.808-815
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• 2013

In this paper, we propose a novel fast and low-complexity Motion Estimation (ME) algorithm for Ultra High Definition (UHD) High Efficiency Video Coding (HEVC). Motion estimation occupies 77~81% of the amount of computation in HEVC. After all, the main key of video codec implementation is to find a fast and low-complexity motion estimation algorithm and architecture. We analyze the previous motion estimation algorithms and propose three optimal algorithm to reduce the computation proportion for HEVC. The proposed algorithm uses only 0.36% of the amount of operations compared to full search algorithm while maintaining compression performance with slight loss of 1.1%.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.11A
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• pp.862-869
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• 2009

We propose a new adaptive K-best Sphere Decoding (SD) algorithm for Multiple Input Multiple Output (MIMO) systems where the number of survivor paths, K is changed based on the characteristics of path metrics which contain the instantaneous channel condition. In order to overcome a major drawback of Maximum Likelihood Detection (MLD) which exponentially increases the computational complexity with the number of transmit antennas, the conventional adaptive K-best SD algorithms which achieve near to MLD performance have been proposed. However, they still have redundant computation complexity since they only employ the channel fading gain as a channel condition indicator without instantaneous Signal to Noise Ratio (SNR) information. hi order to complement this drawback, the proposed algorithm use the characteristics of path metrics as a simple channel indicator. It is found that the ratio of the minimum path metric to the other path metrics reflects SNR information as well as channel fading gain. By adaptively changing K based on this ratio, the proposed algorithm more effectively reduce the computation complexity compared to the conventional K-best algorithms which achieve same performance.

• The Journal of Korean Institute of Information Technology
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• v.16 no.12
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• pp.85-92
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• 2018

When using complicated image processing algorithms, we use superpixels to reduce computational complexity. Superpixel segmentation is a method of grouping pixels having similar characteristics into one group. Since superpixel is used as a preprocessing of image processing, it should be generated quickly, and the edge components of the image should be well preserved. In this paper, we propose a method of generating superpixels with a small amount of computation while preserving edge components well. In the proposed method, superpixels of an image are generated by using the existing k-mean method, and similar superpixels among the generated superpixels are merged to make final superpixels. When merging superpixels, the similarity is calculated only for superpixels. Therefore, the amount of computation is maintained small. It is shown by experimental results that the superpixel images produced by the proposed method are conserving edge information of the original image better than those produced by the existing method.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.12 no.2
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• pp.119-131
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• 2008

The paper considers the computation method in the performance evaluation of cellular network in the phase-type distribution assumptions that the channel holding times induced from mobility are modeled by well-fitted distributions to reflect an actual situation. When ww consider a phase-type distribution model instead of exponential distribution, the complexity of the computation increase exponential even though the accuracy is improved. We consider an efficient numerical algorithm to compute the performance evaluations in cellular networks such as a handoff call dropping probability, new call blocking probability, and handoff arrival rate. Numerical experiment shows that numerical analysis results are well approximated to the results of simulation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.6
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• pp.2202-2206
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• 2010

In this paper, an architecture for modified Euclidean(ME) algorithm is proposed, which is using finite-state machine(FSM) instead of degree computation. Since the proposed architecture does not have degree computation circuits, it is possible to reduce the hardware complexity of RS(Reed-Solomon) decoder, so that a very high-speed RS decoder can be implemented. RS(255,239) decoder with the proposed architecture is implemented using Verilog-HDL and requires about 13% fewer gate counts than conventional one.