• Journal of the Institute of Electronics Engineers of Korea TC
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• v.37 no.3
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• pp.9-17
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• 2000

In this paper we implement computer simulation system of 4FSK signal MODEM using Quadrature detector and analyze overall tranceiver system. We follow the FLEX wireless paging system standards and construct premodulation filter and data frame. We propose an efficient open loop symbol timing recovery algorithm which takes advantage of 128 bit length preamble pattern and also propose a 32 bit UW pattern which Is based on the optimal UW detection method, and excellent aperiodic autocorrelation characteristic. The BER simulation in the fading channel as well as AWGN is performed with BCH coding and Interleaving to the Quadrature detector system and it is shown that a high coding fain occurs in the fading channel rather than AWGN channel.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.9A
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• pp.1431-1440
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• 2000

In order to support efficiently the multimedia applications, such as virtual classroom, video conferencing and tele-medical, the efficient multipoint-to-multipoint(MP-to-MP) connection management function is essential. Shared tree is reported as the most useful method for this purpose. In this paper we propose a new MP-to-MP connection setup & management scheme, called CIMA(Cell Interleaved Multiplexing on ATM) scheme,which is a VC merging method for MP-to-MP communication using shared tree. In the CIMA scheme,MRM cell delivers the cell merging information to the next node. The receiving node can identfy cells which arrived through a channel using the same VPI/VCI by the merging information in the MRM cell. Therefore the CIMA scheme can solve easily the Cell Interleaving Problem(CIP) that happens in VC merging. We analyzed the overhead of the proposed CIMA by mathematical analysis,and simulated the buffer usage of CIMA with OPNET. As the result of analysis,we found that the CIMA scheme has acceptable merging overhead and doesn't cause the buffer scare problem.

• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.4
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• pp.405-414
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• 2011

Recently, the development of several hundreds of kW scale PCS for fuel cell generation is required as commercialization process of distributed generation systems using high temperature fuel cells such as MCFC begins. This paper proposes and optimized topology suitable for MCFC fuel cell generation system and LCL filter design method considering voltage quality of local loads such as MBOP. An interleaving technique is applied to step-up DC-DC converter, optimized number of phases is determined considering efficiency and volume. Also, a LCL filter design method is proposed considering quality of current injected to the grid as well as that of voltage across the local load. The proposed PCS system is validated through reduced 1kW prototype.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10a
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• pp.441-443
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• 1998

본 논문은 유무선 환경에서 ATM 멀티캐스트 서비스를 제공하기위한 방안으로서{{{{ { SM}^{2 }A }}}} 를 제안한다. 기존의ATM 멀티캐스트 서비스는 ATM자체의 제약으로 멀티캐스트 서비스가 제한적이며 비효율적이다. 한편, ATM의 중용한 응용으로서 인터넷서비스를 심각하게 고려해야하는데 {{{{ { SM}^{2 }A }}}}는 특히 인터넷 서비스를 제공하는데 적합한 구조를 갖도록 설계되었다.{{{{ { SM}^{2 }A }}}}는 기본적으로 양방향성 공유트리방식인 CBT(Core Based Tree)구조를 갖되 각 지역망 (Regional Network)에서 자체적인 코어스위치( Core Switch)를 보유함으로써 결과적으로 다중 코어 구조를 갖는다. 각 지역망을 잇기 위하여 PNNI 프로토콜을 이용하며 PGL(Peer Group Leader)에 가상 루트(Virtual Root) 및 가상 리프(Virtual Leaf)의 개념을 새로 도입한다. 멀티캐스트 통신의 경우 가장 문제되는 것이 셀끼워넣기(Interleaving)문제인데.{{{{ { SM}^{2 }A }}}}에서는 ITU-T표준 ATC(ATM Transfer Capability)인 ABT/IT(ATM Block Transfer/Immediate Transmission)

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.3
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• pp.57-70
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• 2008

This paper introduces a new paradigm of physical layer security through channel coding for wireless networks. The well known spread spectrum based physical layer security in wireless network is applicable when code division multiple access (CDMA) is used as wireless air link interface. In our proposal, we incorporate the proposed security protocol within channel coding as channel coding is an essential part of all kind of wireless communications. Channel coding has a built-in security in the sense of encoding and decoding algorithm. Decoding of a particular codeword is possible only when the encoding procedure is exactly known. This point is the key of our proposed security protocol. The common parameter that required for both encoder and decoder is generally a generator matrix. We proposed a random selection of generators according to a security key to ensure the secrecy of the networks against unauthorized access. Therefore, the conventional channel coding technique is used as a security controller of the network along with its error correcting purpose.

• Proceedings of the IEEK Conference
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• 2000.11a
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• pp.137-140
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• 2000

In this paper. we analyzed the performance of a SFH (slow frequency hopping) system under partial-band jamming, multiple access interference and wide-band random noise. For the correction of burst errors due to channel hit, Reed-Solomon coding followed by block interleaving is employed. Errors-and-erasures decoding with side information is exploited to enhance the correctional capability. We derived a closed-form solution for the BER estimation. Errors resulting from random noise and erasures resulting from burst interference are separately analyzed and finally BER is computed due to these composite noise sources. Estimated BER performance is verified by computer simulation.

• Proceedings of the IEEK Conference
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• 2004.06a
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• pp.147-150
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• 2004

In this paper, we propose a reduced-state sequence estimation (RSSE) for trellis coded modulation (TCM) in OFDM with two-stage IDFT/ DFTs, MMSE-LE, and interleaving on frequency selective Rayleigh fading channels. The Viterbi algorithm (VA) is used to search for the best path through the reduced-state trellis combined with equalization and TCM decoding. Computer simulations confirm the bit error probability of the proposed scheme.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.1105-1108
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• 2005

Media service model is divided into 3 models that are Client Pull, Server Push, and IPP(Interleaving Pull & Push) model. In most single VOD(Video On Demand) environment, Client Pull model was sufficient to play the movie Because most media contents has a low bitrate and resolution. But according to an increment of the demand of the high definition media, Client Pull model is not sufficient. Parallel VOD environment is made of several of VOD servers and provides the parallel media stream simultaneously for one client. We compared and analyzed the performance of service models with respect to network delay and data size in buffer in the single and parallel VOD environment and we found that IPP service model keeps the least network delay and stable client buffer state in the parallel VOD environment.

• Smart Structures and Systems
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• v.20 no.1
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• pp.35-42
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• 2017

Recently, compressive sensing based data loss recovery techniques have become popular for Structural Health Monitoring (SHM) applications. These techniques involve an encoding process which is onerous to sensor node because of random sensing matrices used in compressive sensing. In this paper, we are presenting a model where the sampled raw acceleration data is directly transmitted to base station/receiver without performing any type of encoding at transmitter. The received incomplete acceleration data after data losses can be reconstructed faithfully using compressive sensing based reconstruction techniques. An in-depth simulated analysis is presented on how random losses and continuous losses affects the reconstruction of acceleration signals (obtained from a real bridge). Along with performance analysis for different simulated data losses (from 10 to 50%), advantages of performing interleaving before transmission are also presented.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.11
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• pp.1502-1506
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• 2016

HEVC (High Efficiency Video Coding) is a recently proposed video compression standard that has a two times greater coding efficiency than previous video compression standards. The key factors of high compression performance and increasement of computational complexity are the various types of block partitions and modes of intra prediction in HEVC. This paper presents an intra prediction hardware architecture for HEVC utilizing pipelining and interleaving techniques to increase the efficiency and performance while reducing the requirement for hardware resources.