• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.4
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• pp.15-23
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• 2011

An interleaver rearranges a channel-encoded data in the symbol unit to spread burst errors occurred in channels into random errors. Thus, the interleaving process makes it difficult for a receiver, who does not have information of the interleaver parameters used in the transmitter, to de-interleave an unknown interleaved signal. Recently, various researches on the reconstruction of an unknown interleaved signal have been studied in many places of literature by estimating the interleaver parameters. They, however, have been mainly focused on the estimation of the block interleaver parameters required to reconstruct the de-interleaver. In this paper, as an extension of the previous researches, we estimate the convolutional interleaver parameters, e.g., the number of shift registers, a shift register depth, and a codeword length, required to de-interleave the unknown data stream, and propose the de-interleaving procedure by reconstructing the de-interleaver.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.1C
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• pp.81-89
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• 2003

For improving the performance of noise suppression in tactical communication environments, an enhanced MELP vocoder is suggested, in which an acoustic noise suppressor is integrated into the front end of the MELP algorithm, and an FEC code into the channel side of the MELP algorithm. The acoustic noise suppressor is the modified IS-127 EVRC noise suppressor which is adapted for the MELP vocoder. As for FEC, the turbo code, which consists of rate-113 encoding and BCJR-MAP decoding algorithm, is utilized. In acoustic noise environments, the lower the SNR becomes, the more the effects of noise suppression is increased. Moreover, The suggested system has greater noise suppression effects in stationary noise than in non-stationary noise, and shows its superiority by 0.24 in MOS test to the original MELP vocoder. When the interleave size is one MELP frame, BER 10-6 is accomplished at channel bit SNR 4.2 ㏈. The iteration of decoding at 3 times is suboptimal in its complexity vs. performance. Synthetic quality is realized as more than MOS 2.5 at channel bit SNR 2 ㏈ in subjective voice quality test, when the interleave size is one MELP frame and the iteration of decoding is more than 3 times.

• Journal of Communications and Networks
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• v.18 no.3
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• pp.387-396
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• 2016

Multiuser communication has been an important research area of underwater acoustic communications and networking. This paper studies the use of adaptive orthogonal frequency-division multiple access (OFDMA) in a downlink scenario, where a central node sends data to multiple distributed nodes simultaneously. In practical implementations, the instantaneous channel state information (CSI) cannot be perfectly known by the central node in time-varying underwater acoustic (UWA) channels, due to the long propagation delays resulting from the low sound speed. In this paper, we explore the CSI feedback for resource allocation. An adaptive power-bit loading algorithm is presented, which assigns subcarriers to different users and allocates power and bits to each subcarrier, aiming to minimize the bit error rate (BER) under power and throughput constraints. Simulation results show considerable performance gains due to adaptive subcarrier allocation and further improvement through power and bit loading, as compared to the non-adaptive interleave subcarrier allocation scheme. In a lake experiment, channel feedback reduction is implemented through subcarrier clustering and uniform quantization. Although the performance gains are not as large as expected, experiment results confirm that adaptive subcarrier allocation schemes based on delayed channel feedback or long term statistics outperform the interleave subcarrier allocation scheme.

• Proceedings of the IEEK Conference
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• 2004.08c
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• pp.631-635
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• 2004

The rapid development of digital media and communication network urgently brings about the need of data certification technology to protect IPR (Intellectual property right). This paper proposed a new watermarking method for embedding contents owner's audio signal in order to protect color image IPR. Since this method evolves the existing static model and embeds audio signal of big data, it has the advantage of restoring signal transformed due to attacks. Three basic stages of watermarking include: 1) Encode analogue ID owner's audio signal using PCM and create new 3D audio watermark; 2) Interleave 3D audio watermark by linear bit expansion and 3) Transform Y signal of color image into wavelet and embed interleaved audio watermark in the low frequency band on the transform domain. The results demonstrated that the audio signal embedding in color image proposed in this paper enhanced robustness against lossy JPEG compression, standard image compression and image cropping and rotation which remove a part of image.

• Proceedings of the KIPE Conference
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• 2011.11a
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• pp.195-196
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• 2011

본 논문은 높은 승,강압비를 가지는 배터리 충방전용 양방향 풀브리지 컨버터를 제안한다. 기존의 양방향 컨버터는 승강압비가 낮아 밧데리 방전시 발생된 전기에너지를 저항을 통해 방전 시켜서 운전하였다면, 본 논문에서 제안하는 방식은 밧데리 방전시 높은 승압비로부터 높은 DC 링크 전압을 얻어, 이 전압을 이용하여 계통으로 회생시킬 수 있도록 한 양방향 컨버터이다. 양방향 컨버터의 높은 승압비를 얻기 위해서 두 개의 DC-DC 컨버터를 입력 직렬, 출력 병렬 회로 형태로 연결하고, Battery 측을 Interleave 방식을 채택하여 전류 맥동을 줄이고, 높은 승강압비를 얻을 수가 있도록 하여, 배터리의 수명에 영향을 주는 전류리플을 감소하는 효과를 얻는다. 제안된 방식은 시뮬레이션을 통해 증명하였다.

• Journal of the Semiconductor & Display Technology
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• v.14 no.1
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• pp.51-53
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• 2015

H.264/AVC is international video coding standard, which shows improved code and efficiency than the existing video standards. H.264/AVC proposes data partitioning method that considerably to be an effective layering technique which separates important addressing data from the residual data. UEP(Unequal Error Protection) turbo code of H.264/AVC uses retransmission system to get the UEP effectively. However, Data partitioning system of H.264/AVC is inefficient method in turbo code of H.264/AVC. Based on this observation, we propose the new UEP turbo code algorithm that reconstructs input sequence of turbo code without retransmission system.

• Journal of the Institute of Convergence Signal Processing
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• v.8 no.3
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• pp.199-204
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• 2007

This paper presents design of interleave configured dc-dc converter for high power distributed power system applications. The multi channel interleaving buck converter with small inductance has proved to be suitable for micro-grid, requiring medium output voltages, high output currents and fast transient response. Integrated magnetic components are used to reduce the size of the converter and improve efficiency. Unlike conventional methods, the distributed approach requires no centralized control, automatically accommodates varying numbers of converter cells, and is highly tolerant of subsystem failures. A general methodology for achieving distributed interleaving is proposed, along with a specific implementation approach. The design and simulation verification of switching frequency 10 kHz system is presented with interleaved clocking of the converter cells. The simulation (simulated by PSIM 6.1) results corroborate the analytical predictions and demonstrate the tremendous benefits of the distributed interleaving approach.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.229-230
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• 2006

In this thesis, we analyze performance related to reduction scheme of inter-cell interference causing serious problems in portable internet system. Frequency reusing factor(FUF) is 1 in portable internet system, and it means that a adjacent cell uses same frequency band. This channel environment raises inter-cell interference problem, which provokes serious problems related to system performance and channel capacity. Consequently, it affects deterioration in system performance as a whole. We analyze inter-cell interference when appling a various schemes such as (DCA)Dynamic Channel Allocation, CS(Channel Segregation), IDMA(Interleave Division Multiple Access), FH-OFDM, CRSA(Conceptual Random Subcarrier Allocation), and HDD

• The Journal of Korean Institute of Communications and Information Sciences
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• v.11 no.4
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• pp.268-279
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• 1986

Recently, the improtance of the ISDN has been emphasized for the new services in the future information society. In this paper, new application of statistical multiplexer which can be used for CCITT D-channel multiplexing is suggested. The basic architecture of statistical multiplexer which can interleave eleven 16Kbps D-channels into one 64Kbps B-channel is also proposed. The necessary buffer size was estimated by computer simulation considering data traffic intensity, signal arrival length distribution and buffer overflow probability. Based on this buffer size, the basic architecture of the statistical multiplexer has been survetyed and hardware design principles are also studied.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10a
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• pp.568-570
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• 2004

Harel과 UML에서 제공하는 기존 개념의 상태챠트는 실시간 작업들의 동시성(concurrency)을 모델링하기 어려운 단점을 가진다. 본 논문에서는 이러한 문제점을 해결하기 위해 재진입 상태머신과 재진입 상태챠트라는 새로운 개념을 제안한다. 재진입 상태머신은 병렬적으로 실행할 작업들을 교차수행(interleave)함으로서, 상태챠트로 표현되는 실시간 작업들의 동시성(Concurrency)물 효과적으로 지원할 수 있다 이러한 재진입 상태머신을 기반으로, 재진입 상태챠트는 간결하고 풍부한 표현 의미를 제공하며, 아울러 동시적으로 처리되는 행동 모델들을 구체적으로 표현할 수 있다. 재진입 상태머신과 재진입 상태챠트를 이용하여 실시간 시스템을 구현하면 프로세스간 흑은 쓰레드간의 스위칭이 불필요해짐에 따라 그에 따른 실행 오버헤드를 최소화할 수 있다.