• Title/Summary/Keyword: channel modeling

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MIMO Vector Channel Modeling and Performance Analysis in Underwater Channel Environments (수중 MIMO 벡터 채널 모델링 및 성능 분석)

  • Lee, Deok-Hwan;Ko, Hak-Lim;Lim, Yong-Kon
    • The Journal of the Acoustical Society of Korea
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    • v.26 no.8
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    • pp.426-431
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    • 2007
  • In this paper we have studied the underwater vector channel modeling for MIMO(Multiple Input Multiple Output) to increase the performance and efficiency for ultrasound communication in underwater channel environments. Also we have analyzed the MIMO techniques using the proposed channel modeling. For underwater MIMO channel modeling. experiments were done in real channel environments and the data were analyzed to estimate parameters such as fading, Doppler, time delay, angle of arrival, and receiving power. These were used for modeling of underwater vector channel modeling for MIMO. Additionally, we have analyzed the performance of MIMO systems using our proposed channel models. As a result we could see that the BER has decreased severely with the same SNR when using the MIMO system.

A Fundamental Study for Establishment of Channel Data Base in Power-Line Communications (전력선 통신 채널 Data Base 구축을 위한 기본 연구)

  • Oh Hui-Myoung;Kim Kwan-Ho;Lee Won-Tae;Lee Jae-Jo
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.52 no.2
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    • pp.107-111
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    • 2003
  • In the power-line communication systems, there are many factors of noise and attenuation in the power-line channels, because they were designed for not the communication but the power transmission. Also the transfer function of the channels is highly changed with the topology and the load of the power-lines. To cope with these poor channel situation, channel modeling, one of the many studies in progress, is being studied hard. Channel modeling is essential to apply the active schemes to overcome the bad channel(e.g. modulation technique, channel coding, signal coupling & filtering, etc.) to the power-line communications. In this paper, we have realized the statistical model(this model is suggested as the channel modeling method for the power-line channels) that is combined the transfer function with the various noises. And we have compared and examined the results with the measured data. Also we have studied the plan which can effectively establish the channel data base for the channel information consisted of the parameters that are derived from this modeling, and we have studied the plan to utilize the data base.

A Study of Channel Modeling and Simulation for Power Line Communication Systems using PSCAD/EMTDC (PSCAD/EMTDC를 이용한 전력선통신 채널모델링 및 시뮬레이션에 관한 연구)

  • Lee, Jong-Joo;Cha, Jae-Sang;Shin, Myong-Chul
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.55 no.6
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    • pp.279-285
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    • 2006
  • Power line communication channels are very complicated and models for communication channels vary with the types of electrical equipment, devices and load fluctuations. So, modeling and analysis of power line channels for implementation of power line communication systems is a very important process. Power line channel modeling and simulation are performed based on power system transient simulation models and power system CAD tools to create precise and accurate models. In this paper, a channel modeling and simulation method is proposed for power line communication systems using PSCAD/EMTDC, in which a PN 63 sequence code generator is applied for impulse response of the power line channel in the simulation model.

Modeling System for Unsteady Flow Simulations in Drainage Channel Networks of Paddy Field Districts (논 지구의 배수로 부정류 흐름 모의를 위한 모델링 시스템)

  • Kang, Min Goo
    • Journal of The Korean Society of Agricultural Engineers
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    • v.56 no.2
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    • pp.1-9
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    • 2014
  • A modeling system is constructed by integrating an one-dimensional unsteady flow simulation model and a hydrologic model to simulate flood flows in drainage channel networks of paddy field districts. The modeling system's applicability is validated by simulating flood discharges from a paddy field district, which consists of nine paddy fields and one drainage channel. The simulation results are in good agreement with the observed. Particularly, in the verification stage, the relative errors of peak flows and peak depths between the observed and simulated hydrographs range 8.96 to 10.26 % and -10.26 to 2.97 %, respectively. The modeling system's capability is compared with that of a water balance equation-based model; it is revealed that the modeling system's accuracy is superior to the other model. In addition, the simulations of flood discharges from large-sized paddy fields through drainage channels show that the flood discharge patterns are affected by drainage outlet management for paddy fields and physical characteristics of the drainage channels. Finally, it is concluded that to efficiently design drainage channel networks, it is necessary to analyze the results from simulating flood discharges of the drainage channel networks according to their physical characteristics and connectivities.

Indoor Obstacles Environments Channel Modeling of UWB Systems (실내 환경에서 장애물에 의한 UWB 채널모델링)

  • Kim, Woon-Gab;Lee, Suk-Hui;Lee, Sang-Ho;Bang, Sung-Il
    • Proceedings of the IEEK Conference
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    • 2006.06a
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    • pp.39-40
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    • 2006
  • This paper modeled UWB system transmission channel in indoor environment. For channel modeling, we extracted transmission channel parameter, and then measured from 10MHz to 16.01GHz by using method of CIR(Channel Impulse Response) and CTF(Channel Transfer Function) in small room($5.5{\times}5.5m^2$) environment.

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An analysis of the short-term variation of the power line as a communication channel (전력선 통신 채널의 단 구간 변화에 대한 분석)

  • Park, Chong-yeon;Choi, Won-Ho;Jung, Kwang-Hyun
    • Journal of Industrial Technology
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    • v.27 no.B
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    • pp.21-27
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    • 2007
  • The power line channel has time-variant characteristics caused by various kind of electrical devices. This characteristics are synchronized with the main voltage by their own characteristics. The main factors of disturbance are the variation of the channel impedance and noises. In other papers, the synchronous noise modeling has been achieved. But the modeling is not satisfied simultaneously with the time domain and the frequency domain and there are not any discussion about short-term variations of the channel impedance which cause to the signal fading. Therefore, this paper researched to solve problems about the signal fading by analyzing the short-term variation of the channel impedance, and proposed the synchronous noise modeling which is satisfied simultaneously in the time domain and the frequency domain.

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CFD MODELING VEGETATED CHANNEL FLOWS: A STATE-OF-THE-ART REVIEW

  • Choi Sung-Uk;Yang Won-Jun
    • Water Engineering Research
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    • v.6 no.3
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    • pp.101-112
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    • 2005
  • This paper presents the state of the art of the CFD applications to vegetated open-channel flows. First, important aspects of the physics of vegetated flows found through the laboratory experiments are briefly reviewed. Then, previous CFD applications to one-dimensional vertical structure, partly-vegetated flows, compound open-channel flows with floodplain vegetation, and fully three-dimensional numerical simulations are reviewed. Finally, topics for further researches such as relationship between the resistance and flexural rigidity, additional drag due to foliages, and melting the experience of CFD with the depth-averaged modeling, are suggested.

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A study on the iverse modeling of communication channel by HOS (HOS를 이용한 통신 채널의 역 모델링에 관한 연구)

  • 임성각;진용옥
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.21 no.5
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    • pp.1274-1282
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    • 1996
  • This paper deals with an inverse modeling of nonminimum phase communication channel utilizing the HOS (High Order Statistics) of the received signal. After the communication channel is separated into the minimum phase and maximum phase components, the inverse modeling is performed independently. The performance superiority is confirmed by monte-carlo computer simulation in comparison with the traditional CMA (Constant Modulus Algorithm) method. By utilizing the proposed algorithm employing the HOS of the received signal, the inverse frequency characteristics of the channel can be obtained withoug transmitted signal in digital communication. This algorithm is required in preprocessing or postprocessing in order to remove the channel effect, and effective in the self adaptive equalizer which can minimize the bit error rate or symbol error rate in the recovry of received signal.

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Design of CMOS Op Amps Using Adaptive Modeling of Transistor Parameters

  • Yu, Sang-Dae
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.12 no.1
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    • pp.75-87
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    • 2012
  • A design paradigm using sequential geometric programming is presented to accurately design CMOS op amps with BSIM3. It is based on new adaptive modeling of transistor parameters through the operating point simulation. This has low modeling cost as well as great simplicity and high accuracy. The short-channel dc, high-frequency small-signal, and short-channel noise models are used to characterize the physical behavior of submicron devices. For low-power and low-voltage design, this paradigm is extended to op amps operating in the subthreshold region. Since the biasing and modeling errors are less than 0.25%, the characteristics of the op amps well match simulation results. In addition, small dependency of design results on initial values indicates that a designed op amp may be close to the global optimum. Finally, the design paradigm is illustrated by optimizing CMOS op amps with accurate transfer function.

A study on the channel modeling for power line communication (전력선 통신 채널 모델링에 관한 연구)

  • Jeong Young-Hwa
    • The Journal of Information Technology
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    • v.6 no.3
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    • pp.1-10
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    • 2003
  • This paper is concerned with a power line channel modeling for the more fast and efficiently power line communication experiment. A capacitor load channel simulator is a essential equipment in the power line modem development for in-house network. We accomplished a channel modelling by the frequency response method about the total 298 capacitor load channels. This channel data is acquired by the capacitor load simulator modeling a real power line channel environment. When the experiment results acquired from the capacitor load simulator were compared with the result from a channel filter, we confirmed to substitute capacitor load experiments on the actual power line communication without big error.

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