• Title/Summary/Keyword: transmission technique

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A Study on a New Carrier Recovery Algorithm for Coherent Burst-mode Communication Systems (동기식 버스트 통신시스템 적용을 위한 새로운 반송파 동기 기법에 관한 연구)

  • Park, Sung-Bok
    • Journal of the Korea Institute of Military Science and Technology
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    • v.14 no.6
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    • pp.1043-1048
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    • 2011
  • In this paper, a newsynchronization technique applied to burst-mode communication is proposed. A synchronization technique is to estimate carrier frequency and phase offsets in a noisy channel environment. A fundamental problem for estimating the parameters(carrier phase and frequency offsets) in burst-mode transmission is that the ways of pursuing estimation accuracy and transmission efficiency are always trade-off. To solve this problem, a new carrier recovery technique is proposed to improve the transmission efficiency with reliable performance especially at low S/N. In the proposed technique, the synchronization parameters are first estimated based on a data-aided feed-forward estimation scheme. Then, a phase tracker using decision-directed DPLL estimates the phase offset for the data portion of the burst data. From simulation results, it shows fast synchronization with shorter preamble maintaining reasonable BER performance at low S/N.

A study on the Measurement of Field Transmission Loss through Doors in Buildings Using the Surface Intensity Method. (Surface Intensity 법에 의한 건물내 출입문의 차음성능 현장측정에 관한 연구)

  • 손장열;오재응;김흥식
    • The Journal of the Acoustical Society of Korea
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    • v.4 no.2
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    • pp.3-12
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    • 1985
  • The surface intensity method is a relatively new tool which can identify the noise source or path and measure the radiation power. One microphone and one accelerometer are used in this new technique. In this study, this new technique has been used to measure the field transmission loss trough doors. The results of the experiment indicate that the surface intensity method produces reliable data and can be applied to the transmission loss measurement.

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A study on the Measurement of Field Transmission Loss through Doors in Buildings Using the Surface Intensity Method. (Surface Intensity 법에 의한 건물내 출입문의 차음성능 현장측정에 관한 연구)

  • Son, Jang Yeol;O, Jae Eung;Kim, Heung Sik
    • The Journal of the Acoustical Society of Korea
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    • v.4 no.2
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    • pp.3.1-3.1
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    • 1985
  • The surface intensity method is a relatively new tool which can identify the noise source or path and measure the radiation power. One microphone and one accelerometer are used in this new technique. In this study, this new technique has been used to measure the field transmission loss trough doors. The results of the experiment indicate that the surface intensity method produces reliable data and can be applied to the transmission loss measurement.

An Efficient Transmission Coding Technique of Digitized Speech Data

  • Shimamura, Tetsuya;Yaguchi, katsuaki
    • Proceedings of the IEEK Conference
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    • 2002.07c
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    • pp.1796-1798
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    • 2002
  • Speech transmission is common in many communications systems. In this paper, a technique to reduce the total bits required for expressing the speech data is proposed for the purpose of a packet transmission. A novel coding method is derived based on the concept of finding common information in sequential speech samples. Computer simulations demonstrate that the proposed scheme reduces the total bits re- quired in PCM approximately by half.

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Hybrid Diversity-Beamforming Technique for Outage Probability Minimization in Spatially Correlated Channels

  • Kwon, Ho-Joong;Lee, Byeong-Gi
    • Journal of Communications and Networks
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    • v.9 no.3
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    • pp.274-281
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    • 2007
  • In this paper, we present a hybrid multi-antenna technique that can minimize the outage probability by combining the diversity and beamforming techniques. The hybrid technique clusters the transmission antennas into multiple groups and exploit diversity among different groups and beamforming within each group. We analyze the performance of the resulting hybrid technique for an arbitrary correlation among the transmission antennas. Through the performance analysis, we derive a closed-form expression of the outage probability for the hybrid technique. This enables to optimize the antenna grouping for the given spatial correlation. We show through numerical results that the hybrid technique can balance the trade-offs between diversity and beamforming according to the spatial correlation and that the optimally designed hybrid technique yields a much lower outage probability than the diversity or beamforming technique does in partially correlated fading channels.

DSSS-Based Channel Access Technique DS-CDMA for Underwater Acoustic Transmission

  • Lee, Young-Pil;Moon, Yong Seon;Ko, Nak Yong;Choi, Hyun-Taek;Huang, Linyun;Bae, Youngchul
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.15 no.1
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    • pp.53-59
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    • 2015
  • This paper proposes a novel method for acoustically and wirelessly transmitting data underwater with a high transmission rate. The method uses the most promising physical layer and multiple access technique (i.e., the code division multiple channel access technique) to divide the channel into subchannels. Data is transmitted through these subchannels. The codes are pseudo-random noise (PN) sequences. In the spread-spectrum technique, a signal such as electrical, electromagnetic, acoustic signal generated in a particular bandwidth is deliberately spread in the frequency domain, which results in a signal with a wider bandwidth. This paper reviews the possibility of application of the direct-sequence code division multiple access (DS-CDMA) technique in an underwater system using MATLAB. As the result of our review, we recognize that the DS-CDMA technique can be applied to underwater environments.

Performance Enhancement Technique using Iterative Decoding and Maximal Ratio Receive Combining Technique for Multiplexed STBC OFDM Systems (복호 및 최대수신결합을 반복적으로 이용한 Multiplexed STBC OFDM 성능향상 기법)

  • Jung Hyeok-Koo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.30 no.5C
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    • pp.391-397
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    • 2005
  • Since space time block code (STBC) technique of a transmission diversity technique was introduced, multiple input multiple output techniques using transmission diversity at the basestation for improving transmission data rate, have been studied extensively. Multiplexed STBC OFDM technique uses multiple groups of two transmit antennas and suppresses the interference signals of other STBC OFDM groups at the receivers. In this paper, I propose a new method of iterative decoding and maximal ratio receive combining technique for multiplexed STBC OFDM systems, and simulated and showed the results in comparison with the conventional methods.

A Resonance Power Combining Technique Using CRLH-Transmission Line (CRLH 전송 선로를 이용한 공진 기법의 전력 결합 기술)

  • Kim, Ell-Kou;Kim, Young;Kwon, Sang-Keun;Yoon, Young-Chul
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.20 no.8
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    • pp.673-679
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    • 2009
  • This paper proposes a resonance power-combining technique using CRLH-transmission line. The circuits using proposed technique consist of the parallel capacitances and transmission lines to satisfy matching conditions and to combine power of amplifiers. The CRLH(Composite Right/Lefi-Handed) transmission lines are used to reduce the circuit size. As a result, the power combining amplifier using proposed techniques is measured that a gain is equal and the output power is increased about 2.2 dB higher than the single amplifier. Also, a size of amplifier is 78.3 % smaller than the conventional amplifier using RH transmission line.

Analysis of Via Fence Effects in PCB Transmission Lines (PCB 전송선에서 비아 펜스의 효과 분석)

  • Kim Jong-Ho;Park Sang-Wook;Ju Jae-Cheol;Park Dong-Chul
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.16 no.4 s.95
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    • pp.402-409
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    • 2005
  • In analog and digital electronic systems, crosstalk between transmission lines on the printed circuit board can degrade the performance of equipment operations. This paper presents a technique to analyze the effects of via fence, which is based on additional transmission lines grounded by vias. The technique is composed of a circuit concept approach for transmission line sections md an impedance modeling of via hole sections. All sections are represented by ABCD parameters and they are cascaded. Finally, this technique was verified by comparing the measurement results with the simulation ones.

Regional Grouping of Transmission System Using the Sequential Clustering Technique (순차적 클러스터링기법을 이용한 송전 계통의 지역별 그룹핑)

  • Kim, Hyun-Houng;Lee, Woo-Nam;Park, Jong-Bae;Shin, Joong-Rin;Kim, Jin-Ho
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.5
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    • pp.911-917
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    • 2009
  • This paper introduces a sequential clustering technique as a tool for an effective grouping of transmission systems. The interconnected network system retains information about the location of each line. With this information, this paper aims to carry out initial clustering through the transmission usage rate, compare the similarity measures of regional information with the similarity measures of location price, and introduce the techniques of the clustering method. This transmission usage rate uses power flow based on congestion costs and similarity measurements using the FCM(Fuzzy C-Mean) algorithm. This paper also aims to prove the propriety of the proposed clustering method by comparing it with existing clustering methods that use the similarity measurement system. The proposed algorithm is demonstrated through the IEEE 39-bus RTS and Korea power system.