• Title/Summary/Keyword: Spectrum estimation

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A New Null-Spectrum for Direction of Arrival Estimation (신호의 도착방향을 추정하는 새로운 Null-Spectrum)

  • 최진호;김상엽;김선용;박성일;손재철;송익호;윤진선
    • Proceedings of the Korean Institute of Communication Sciences Conference
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    • 1991.10a
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    • pp.123-126
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    • 1991
  • A generalization of null-spectrum for use in the estimation of directions of arrival of signal sources is considered in this paper. The upper and lower bounds of the generalized null-spectrum, the maximum and minimum null-spectra, are also derived. We observed that the maximum null-spectrum has higher resolution capability than other null-spectra including the two well-known null-spectra, the multiple signal classification null-spectrum and the Min-Norm null-spectrum.

Study on ARMA spectrum estimation using circular lattice filter (환상격자 필터를 이용한 ARMA 스펙트럼 추정에 관한 연구)

  • 장영수;이철희;양흥석
    • 제어로봇시스템학회:학술대회논문집
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    • 1987.10b
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    • pp.442-445
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    • 1987
  • In this paper, a new ARMA spectrum estimation algorithm based on Circular Lattice filter is presented. Since APMA model is used in signal modeling, high-resolution spectrum can be obtained. And the computational burden is reduced by using Circular Lattice filter. By modifying the input estimation part of other proposed methods, we can get high-resolution spectrum with less computation and less memory compared with other Lattice methods. Some computer simulations are performed.

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Estimation of Spectrum Requirements for 3G Mobile Communications Based on the Analysis of Korean Mobile Communications Traffic (국내 이동 통신 트래픽 분석에 의한 3G 이동 통신 주파수 소요량 산출)

  • Chung, Woo-Ghee
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.20 no.3
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    • pp.257-263
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    • 2009
  • Recently, as the 3G services of Korea have stepped into the developing stage and the traffic has been rapidly increasing, the spectrum requirements have been getting very large. Therefore spectrum reforming is considered actively and firstly exact methodology of spectrum requirement estimation is needed. But existing methodology depends on the future's service forecast than the present substantial data. This paper proposed the exact methodology of spectrum requirement estimation is based on the real data. So this paper analyzed the characteristics of Korean mobile communication traffic based on the real data and the algorithm suitable for estimation of spectrum requirements for 3G mobile communications, and calculated the parameters needed to estimate the spectrum requirements. Based on the traffic parameters of December 2007, simulations to Bet the estimation of annual spectrum requirements were implemented for the two different cases: one of which is 44 % annual increase in the data traffic and the other is 21 % annual increase. The simulation results show 90 MHz for the first case and 60 MHz for the second case in December 2011.

Efficient Doppler Spectrum Estimation in Radar Systems (레이다 시스템에서의 효율적인 도플러 스펙트럼 추정)

  • Lee, Jonggil
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2009.05a
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    • pp.605-608
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    • 2009
  • It is necessary to estimate the Doppler spectrum for each range cell for the extraction of useful information from the return echoes in radar systems used for the remote sending purpose. However, The conventional spectrum estimation method, FFT(Fast Fourier Transform), called the Doppler filter bank, causes the frequency resolution problem if the dwell time is relatively short. This short acquisition time also spreads the side lobe levels of return echoes further, resulting in difficulties for the discrimination of weak target signals included in relatively strong target echoes. Therefore, in this paper, the efficient Doppler spectrum estimation methods are compared and investigated through the parameter spectrum estimation in the time domain to overcome these problems.

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Fast Estimation of Low Frequency Parameter for Real-Time Analysis in Wide Area Systems (광역계통의 실시간해석을 위한 고속 저주파수 파라미터 추정)

  • Kim, Eun-Ju;Shim, Kwan-Shik;Kim, Yong-Gu;Kim, Eui-Sun;Nam, Hae-Kon;Lim, Young-Chul
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.6
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    • pp.1078-1086
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    • 2009
  • This paper presents a Fourier based algorithm for estimating the parameters of the low frequency oscillating modes. The proposed methods estimates various parameters(frequency, damping factor, mode magnitude, phase) by fitting Fourier spectrum and phase with a damped exponential cosine function. Dominant frequency is selected by taking frequency corresponding to the peak spectrum, and damping factor is estimated using the left/right spectra of Fourier spectrum. In addition, mode magnitude is calculated by the normalized peak spectrum, and phase is estimated from spectrum phase. Also, we introduce an accuracy index in order to determine the accuracy of the estimated parameters, and the index is calculated using the deviations of the peak spectrum and the left/right spectra. The parameter estimation methods proposed in this paper include very simple arithmetical processes, so the algorithms are simple and the calculation speed is very fast. The proposed methods are applied to test functions with two dominant modes. The results show that the proposed methods are highly applicable to low frequency parameter estimation.

A Comparative Study on the Methods Estimating Wave Directional Spectrum (파향스펙트럼 추정법의 비교 연구)

  • 오병철;심재설
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.2 no.3
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    • pp.119-127
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    • 1990
  • Wave directional spectrum estimation methods for irregular waves were considered in this study. Until now, the Longuet-Higgins Method (LHM) initiated by Longuet-Higgins et al. (1963) has been widely used, but resolutions of the estimation were found to be low. Kobune's Maximum Entropy Method (MEM) for the estimation of wave directional spectrum, bas-ed on the entropy Principle showed higher resolutions comparing with the LHM . If the wave directional spectrum is of Delta functions, the MEM is exact in its estimation. It was also found that for a unimodal spectrum, if the Mitsuyasu's spreading coefficient is above 5, the estimation resolutions were high. In bimodal spectrum, as the angle difference between the two peaks increased, the resolution improved. The energy seems to transfer to the smoother peak in the smoothing of peak's peakedness. LHM has a tendency to estimate bimodal spectrum as a unimodal spectrum ; thus, except for its computational speed, the resolution of LHM falls far below that of MEM.

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Cognitive Relay Networks with Underlay Spectrum Sharing and Channel Estimation Error: Interference Probability and BER Analysis

  • Ho-Van, Khuong
    • Journal of Communications and Networks
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    • v.16 no.3
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    • pp.301-304
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    • 2014
  • This paper proposes accurate interference probability and bit error rate formulas for cognitive relay networks with underlay spectrum sharing and channel estimation error (CEE). Numerous results reveal that the CEE not only degrades the performance of secondary systems (SSs) but also increases interference power caused by SSs to primary systems (PSs), eventually unfavorable to both systems. A solution to further protect PSs from this effect through reducing the power of secondary transmitters is investigated and analyzed.

Parameter Estimation Method of Low-Frequency Oscillating Signals Using Discrete Fourier Transforms

  • Choi, Joon-Ho;Shim, Kwan-Shik;Nam, Hae-Kon;Lim, Young-Chul;Nam, Soon-Ryul
    • Journal of Electrical Engineering and Technology
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    • v.7 no.2
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    • pp.163-170
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    • 2012
  • This paper presents a DFT (Discrete Fourier Transform) based estimation algorithm for the parameters of a low-frequency oscillating signal. The proposed method estimates the parameters, i.e., the frequency, the damping factor, the mode amplitude, and the phase, by fitting a discrete Fourier spectrum with an exponentially damped cosine function. Parameter estimation algorithms that consider the spectrum leakage of the discrete Fourier spectrum are introduced. The multi-domain mode test functions are tested in order to verify the accuracy and efficiency of the proposed method. The results show that the proposed algorithms are highly applicable to the practical computation of low-frequency parameter estimations based on DFTs.

A Fast Parameter Estimation of Time Series Data Using Discrete Fourier Transform (이산푸리에변환과 시계열데이터의 고속 파라미터 추정)

  • Shim, Kwan-Shik;Nam, Hae-Kon
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.55 no.7
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    • pp.265-272
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    • 2006
  • This paper describes a method of parameter estimation of time series data using discrete Fourier transform(DFT). DFT have been mainly used to precisely and rapidly obtain the frequency of a signal. In a dynamic system, a real part of a mode used to learn damping characteristics is a more important factor than the frequency of the mode. The parameter estimation method of this paper can directly estimate modes and parameters, indicating the characteristics of a dynamic system, on the basis of the Fourier transform of the time series data. Real part of a mode estimates by subtracting a frequency of the Fourier spectrum corresponding to 0.707 of a magnitude of the peak spectrum from a peak frequency, or subtracting a frequency of the power spectrum corresponding to 0.5 of the peak power spectrum from a peak frequency, or comparing the Fourier(power) spectrum ratio. Also, the residue and phase of time signal calculate by simple equation with the real part of the mode and the power spectrum that have been calculated. Accordingly, the proposed algorithm is advantageous in that it can estimate parameters of the system through a single DFT without repeatedly calculating a DFT, thus shortening the time required to estimate the parameters.

Performance Analysis of Sequential Estimation Schemes for Fast Acquisition of Direct Sequence Spread Spectrum Systems (직접 수열 확산 대역 시스템의 고속 부호 획득을 위한 순차 추정 기법들의 성능 분석)

  • Lee, Seong Ro;Chae, Keunhong;Yoon, Seokho;Jeong, Min-A
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.39A no.8
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    • pp.467-473
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    • 2014
  • In the direct sequence spread spectrum system, the correct synchronization is very important; hence, several acquisition schemes based on the sequential estimation have been developed. Typically, the rapid acquisition sequential estimation (RASE) scheme, the seed accumulating sequential estimation (SASE) scheme, the recursive soft sequential estimation (RSSE) scheme have been developed for the correct acquisition. However, the objective performance comparison and analysis between former estimation schemes have not been performed so far. In this paper, we compare and analyze the performance of the above sequential estimation schemes by simulating the correct chip probability and the mean acquisition time (MAT).