• Title/Summary/Keyword: multi-radio multi-channel

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Implementation of a Multimodal Controller Combining Speech and Lip Information (음성과 영상정보를 결합한 멀티모달 제어기의 구현)

  • Kim, Cheol;Choi, Seung-Ho
    • The Journal of the Acoustical Society of Korea
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    • v.20 no.6
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    • pp.40-45
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    • 2001
  • In this paper, we implemented a multimodal system combining speech and lip information, and evaluated its performance. We designed speech recognizer using speech information and lip recognizer using image information. Both recognizers were based on HMM recognition engine. As a combining method we adopted the late integration method in which weighting ratio for speech and lip is 8:2. By the way, Our constructed multi-modal recognition system was ported on DARC system. That is, our system was used to control Comdio of DARC. The interrace between DARC and our system was done with TCP/IP socked. The experimental results of controlling Comdio showed that lip recognition can be used for an auxiliary means of speech recognizer by improving the rate of the recognition. Also, we expect that multi-model system will be successfully applied to o traffic information system and CNS (Car Navigation System).

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Performance Comparison of Trellis Coded Multi-Carrier CDMA SYstem with Transmite/Rceive Antenna Diversity in Indoor Radio Channel (실내 무선 채널에서 송신/수신 안테나 다이버시티를 적용한 Trellis 부호화된 Multi-Carrier CDMA 시스템의 성능 비교)

  • 노재성;이찬주;김언곤;조성준
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.25 no.8B
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    • pp.1348-1356
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    • 2000
  • In this paper, we proposed a trellis coded Multi-Carrier CDMA 16 QAM system with multiple transmit/receive antenna diversity technique, which is simple and suitable for indoor wireless communications. The proposed multiple transmit/receive antenna diversity technique is that the transmitter sends a trellis coded Multi-Carrier CDMA 16 QAM signal from multiple transmitting antennas with intentional time delays, which makes a receiver possible to distinguish and combine the signals from different antennas. In wireless indoor communication system, if we allow the increase of the complexity of the system, it is also possible to achieve additional diversity gain in the performance with the combination of the proposed technique and the conventional receiving antenna diversity. Furthermore, we have found that the proposed trellis coded Multi-Carrier CDMA 16 QAM system, which employs multiple transmit/receive antenna, is less sensitive to the multiple user interference and fading than conventional receiving antenna diversity systems.

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Performance Analysis of Acoustic Communication Using OFDM Modulation in Underwater (수중에서 OFDM 변조를 이용한 음향 통신의 성능분석)

  • Han, Jeong-Woo;Son, Yoon-Jun;Kim, Ki-Man
    • Journal of Navigation and Port Research
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    • v.34 no.10
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    • pp.769-774
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    • 2010
  • The performance of underwater communication system is influenced on channel characteristic. Delay spread cause by reverberation and multi-path happen the ISI (Inter Symbol Interference) and reduces the communication performance. In this paper, we analyze the performance of acoustic communication experiment in underwater to use the OFDM (Orthogonal Frequency Division Multiplexing) technique for overcome the reverberation and multi-path. As a result, we acquired the BER of modulation techniques. The BER of 2kbps data rate is $1.22{\times}10^{-1}$ and BER of 4 kbps data rate is $2.47{\times}10^{-2}$.

Real-Time Frequency Interference Analysis System for Performance Degradation Analysis of MIMO-OFDM WLAN Due to WPAN Interferer (WPAN 간섭원에 의한 MIMO-OFDM WLAN의 성능 열화 분석을 위한 실시간 주파수 간섭 분석 시스템)

  • Yoon, Hyungoo;Park, Jin-Soo;Jang, Byung-Jun
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.27 no.1
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    • pp.88-91
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    • 2016
  • In this paper, we have proposed the frequency interference analysis system using both LabVIEW and Universal Software Radio Peripheral(USRP) for performance degradation analysis of Multi Input Multi Output-Orthogonal Frequency Division Multiplexing(MIMO-OFDM) Wireless Local Area Network(WLAN) due to Wireless Local Area Network(WPAN) interferer. The proposed system consists of three part, i.e., victim, channel, and interferer. Both victim and interferer are implemented by LaBVIEW and a USRP board. Then interfering signal and additive white Gaussian noise are combined with the wanted signals of a victim. Measured Bit Error Rate(BER) at the victim receiver is compared with theoretical BER according to various signal to interference plus noise power ratio (SINR) values. Measured and theoretical BER curves show good agreement.

A MULTI-DIMENSIONAL REDUCTION METHOD OF LARGE-SCALE SURVEY DATABASE

  • Lee, Y.;Kim, Y.S.;Kang, H.W.;Jung, J.H.;Lee, C.H.;Yim, I.S.;Kim, B.G.;Kim, H.G.;Kim, K.T.
    • Publications of The Korean Astronomical Society
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    • v.28 no.1
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    • pp.7-13
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    • 2013
  • We present a multi-dimensional reduction method of the surveyed cube database obtained using a single- dish radio telescope in Taeduk Radio Astronomy Observatory (TRAO). The multibeam receiver system installed at the 14 m telescope in TRAO was not optimized at the initial stage, though it became more stabilized in the following season. We conducted a Galactic Plane survey using the multibeam receiver system. We show that the noise level of the first part of the survey was higher than expected, and a special reduction process seemed to be definitely required. Along with a brief review of classical methods, a multi-dimensional method of reduction is introduced; It is found that the 'background' task within IRAF (Image Reduction and Analysis Facility) can be applied to all three directions of the cube database. Various statistics of reduction results is tested using several IRAF tasks. The rms value of raw survey data is 0.241 K, and after primitive baseline subtraction and elimination of bad channel sections, the rms value turned out to be 0.210 K. After the one-dimensional reduction using 'background' task, the rms value is estimated to be 0.176 K. The average rms of the final reduced image is 0.137 K. Thus, the image quality is found to be improved about 43% using the new reduction method.

MLKA Scheme Based on Periodic Ranging Code Group for Detecting Abnormal AT in WiBro System (WiBro시스템에서 주기적 레인징 코드를 이용한 다중 레벨 Keep - Alive 알고리즘)

  • Lee, Sook-Jin;Kim, Whan-Woo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.32 no.6A
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    • pp.600-607
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    • 2007
  • In this paper, we propose a MLKA (Multi-Level Keep-Alive) algorithm based on PRCG (Periodic In this paper, we propose a MLKA (Multi-Level Keep-Alive) algorithm based on PRCG (Periodic Ranging Code Group), in which periodic ranging codes are divided into groups. The AP (Access Point) performs this algorithm when a periodic ranging code arrives at the AP in a WiBro (Wireless Broadband Internet) system. In order to increase the traffic radio bandwidth resource efficiency in this system, we propose the multi-level keep-alive algorithm for finding abnormal AT (Access Terminal). From simulation results, it is verified our proposed MLKA algorithm based on PRCG can provide higher traffic radio resource efficiency compared to message-driven keep-alive algorithms.

A Study on RF Calibration Method of Next Generation Mobile Communication System (차세대 이동통신 시스템의 RF Calibration 기법에 관한연구)

  • Kim, Wan-Tae;Cho, Sung-Joon
    • Journal of Advanced Navigation Technology
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    • v.14 no.6
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    • pp.859-864
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    • 2010
  • In the next generation system, a study on realization of Multi-Core system is in progress for applying it in multi service network. Therefore some mobile systems are expected to be appeared. These systems can support WiBro, WCDMA, CDMA, etc with single terminal. These systems have to support various FA using broadband frequency and hand over to other service network. Especially, in the telecommunication system composed of cell, the transmit power can be interference at adjacent system, has effect on system channel capacity and cell size. In this paper, we improve the unstable transmit power caused by unsettled system operation, propose the RF(Radio Frequency) Calibration method which can use the transmit power stably even during hand over between heterogeneous networks causing unstable power change. Also we used proposed method and analysed used electricity of system during hand over between heterogeneous networks.

Implementation of Multi-channel Concurrent Detection Homodyne Frequency-domain Diffuse Optical Imaging System (다채널 동시측정을 적용한 호모다인 주파수영역 확산 광 이미징 시스템의 구현)

  • Jun, Young Sik;Baek, Woon Sik
    • Korean Journal of Optics and Photonics
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    • v.23 no.1
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    • pp.23-31
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    • 2012
  • In this paper, we developed a frequency-domain diffuse optical imaging (DOI) system for imaging non-invasively using near-infrared (NIR) light sources and detectors. 70-MHz modulation and a homodyne scheme were adopted. By calibration of the coupling coefficients, concurrent detection measurements by 4 detector sets were optimized. We presented experimental reconstruction images of absorption and scattering coefficients in a liquid phantom, located an anomaly in the phantom and determined its optical properties. The images by the multi-channel concurrent detection were improved over the results by single-channel sequential detection. Tomographic slices of absorption and scattering coefficients in the phantom with an anomaly were also presented.

Performance Analysis of OFDM-DSRC System Using LMMSE Equalization Technique (LMMSE 등화기법을 적용한 OFDM-DSRC 시스템의 성능분석)

  • Sung Tae-Kyung;Kim Soon-Young;Rhee Myung-Soo;Cho Hyung-Rae
    • Journal of Navigation and Port Research
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    • v.29 no.1 s.97
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    • pp.23-28
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    • 2005
  • The signal in wireless multi-path channel is affected by fading and ISI because of high data rate transmission, so the signal has the high error rate. The present modulation and demodulation method of DSRC system can not expect sufficient for providing data service over 1 Mbps, so the channel equalization and advanced modulation and demodulation methods are required. OFDM is generally known as an effective technique for high data rate transmission system, since it can prevent ISI by inserting a guard interval. However, a guard interval longer than channel delay spread has to be used in each OFDM symbol period, thus resulting a considerable loss in the efficiency of channel utilization Therefore the equalizer is necessary to cancel ISI to accommodate advanced ITS service with higher bit rate and longer channel delay spread condition In this paper, the channel equalizer for the OFDM -DSRC system was designed and its performance in a multi-path fading environment was evaluated with computer simulation.

Efficient Resource Allocation Scheme for Improving the Throughput in the PB/MC-CDMA System (PB/MC-CDMA 시스템에서 처리량 향상을 위한 효율적인 자원 할당 기법)

  • Lee, Kyujin;Seo, HyoDuck;Han, DooHee
    • Journal of Convergence Society for SMB
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    • v.4 no.1
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    • pp.1-6
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    • 2014
  • PB/MC-CDMA is an efficient system which divides the whole frequency band into several blocks, unlike a conventional MC-CDMA system. We propose an efficient resource allocation scheme in Multi-Block PB/MC-CDMA (Partial Block Multi-Carrier Code Division Multiple Access). This system aims to improve frequency efficiency and maximize the total throughput while satisfying predefined threshold over various channel conditions. Through computer simulations, we confirm that the performance of the proposed system is more effective in terms of throughput.

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