• Title, Summary, Keyword: Error Estimation

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Power Control for D2D Communication in the Cellular System: The Impact of Channel Estimation Error

  • Oh, Changyoon
    • Journal of the Korea Society of Computer and Information
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    • v.23 no.8
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    • pp.51-57
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    • 2018
  • In this paper, we investigate the impact of channel estimation error on the D2D power control algorithm. In the previous work, D2D power control algorithm has been proposed under the assumption that the channel between the transmitter and the corresponding receiver is perfectly estimated. In reality, the channel estimation error is more often the case. The first question is that the power control algorithm designed for perfect channel estimation is still valid under the channel estimation error environment ? The second question is, if it is not valid, what could be the possible remedy for the channel estimation error ? In this paper, to answer the first question, we investigate the impact of the channel estimation error on the power control algorithm. We first review the D2D power control algorithm designed for perfect channel estimation. Then, we model the channel estimation error. Finally, we summarize the main results observed from the analysis of the simulation.

An OFDM Frequency Offset Estimation Scheme Robust to Timing Error (시간 오차에 강인한 OFDM 주파수 옵셋 추정 기법)

  • Kim Sang-Hun;Yoon Seok-Ho
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.31 no.6C
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    • pp.623-628
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    • 2006
  • This paper addresses the frequency offset estimation problem in the presence of the timing error for OFDM systems. When the timing error exists, the correlation value used for the frequency offset estimation could be reduced significantly due to the timing error, resulting in considerable degradation in estimation performance. In this paper, using the coherence phase bandwidth (CPB) and a threshold, a novel frequency offset estimation scheme is proposed and based on which, an efficient timing error estimation scheme is also proposed for the re-estimation of the frequency offset. The performance comparison results show that the proposed frequency offset estimation scheme is not only more robust to the timing error but also has less computational complexity, as compared with the conventional schemes. It is also demonstrated by simulation that theproposed timing error estimation scheme gives a reliable estimate of the timing error.

Rainfall Seasonality and Estimation Errors of Area-Average Rainfall (강수의 계절성과 면적평균강수량의 추정오차)

  • Yoo, Chul-Sang
    • Journal of Korea Water Resources Association
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    • v.35 no.5
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    • pp.575-581
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    • 2002
  • This study evaluates the variation of estimation error of area-average rainfall due to rainfall seasonality. Both the cases considering and not considering the spatial correlation are compared to derive the characteristics of estimation error. Similar cases with different accumulation time without considering the rainfall seasonality are also investigated. This study was applied to the Geum-river basin with total 28 rain gauge measurements haying more than 30 years of daily rainfall measurements. As results of the study we found that: (1) The absolute estimation error of monthly area-average rainfall show strong seasonality like the total rainfall amount. However, the relative estimation error normalized by its mean was estimated to have similar values about 5 to 8% except January and December. (2) The relative estimation error of annual area-average rainfall estimated was found to have the estimation error about 3% of its annual mean. (3) However, the relative estimation error normalized by the standard deviation remains almost the same for both monthly and annual rainfall amounts, which was estimated about 11% of its standard deviation. (4) Finally, the estimation error without considering the spatial correlation was found to become almost twice the estimation error with considering the spatial correlation.

Industrial application of gross error estimation and data reconciliation to byproduction gases in iron and steel making plants

  • Yi, Heui-Seok;Hakchul Shin;Kim, Jeong-Hwan;Chonghun Han
    • 제어로봇시스템학회:학술대회논문집
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    • pp.69.2-69
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    • 2002
  • Process measurements contain random and gross errors and the size estimation of gross errors is required for production accounting. Mixed integer programming technique had been applied to identify and estimate the gross errors simultaneously. However, the compensate model based on mixed integer programming used all measured variables or spanning tree as gross error candidates. This makes gross error estimation problem combinatorial or computationally expensive. Mixed integer programming with test statistics is proposed for computationally inexpensive gross error identification /estimation. The gross error candidates are identified by measurement test and the set of gross error candidates are...

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A Study on the Measurement Time-Delay Estimation of Tightly-Coupled GPS/INS system (강결합방식의 GPS/INS 시스템에 대한 측정치 시간지연 추정 연구)

  • Lee, Youn-Seon;Lee, Sang-Jeong
    • Journal of the Korea Institute of Military Science and Technology
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    • v.11 no.4
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    • pp.116-123
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    • 2008
  • In this paper we study the performance of the measurement time-delay estimation of tightly-coupled GPS/INS(Global positioning system/Inertial Navigation system) system. Generally, the heading error estimation performance of loosely-coupled GPS/INS system using GPS's Navigation Solution is poor. In the case of tightly-coupled GPS/INS system using pseudo-range and pseudo-range rate, the heading error estimation performance is better. However, the time-delay error on the measurement(pseudo-range rate) make the heading error estimation performance degraded. So that, we propose the time-delay model on the measurement and compose the time-delay estimator. And we confirm that the heading error estimation performance in the case of measurement time-delay existence is similar with the case of no-delay by Monte-Carlo simulation.

Target Localization using Combination of the IV and QCLS Method in the Sensor Network (센서네트워크 내의 IV 기법과 QCLS 기법을 결합한 위치 추정)

  • Kim, Yong-Hwi;Choi, Ga-Hyoung;Yoon, Tae-Sung;Park, Jin-Bae
    • Proceedings of the KIEE Conference
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    • pp.1768-1769
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    • 2011
  • The nonlinear estimation and the pseudo-linear estimation are used to treat the target localization in sensor network which provides range difference of arrival (RDOA) measurements. It is known that the nonlinear estimation has sensitive problem for the initial estimate and the pseudo-linear estimation has a large estimation error. The QCLS method is the typical estimator of the methods for pseudo-linear estimation. However the estimate by using the QCLS method includes the estimation error because the first stage of two estimation processes of the QCLS method causes the biased estimation error. Therefore we propose a instrumental variables(IV) method for minimizing the estimation error of the first stage. The simulation shows that the performance of the proposed method is superior to the QCLS method.

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The wavelet based Kalman filter method for the estimation of time-series data (시계열 데이터의 추정을 위한 웨이블릿 칼만 필터 기법)

  • Hong, Chan-Young;Yoon, Tae-Sung;Park, Jin-Bae
    • Proceedings of the KIEE Conference
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    • pp.449-451
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    • 2003
  • The estimation of time-series data is fundamental process in many data analysis cases. However, the unwanted measurement error is usually added to true data, so that the exact estimation depends on efficient method to eliminate the error components. The wavelet transform method nowadays is expected to improve the accuracy of estimation, because it is able to decompose and analyze the data in various resolutions. Therefore, the wavelet based Kalman filter method for the estimation of time-series data is proposed in this paper. The wavelet transform separates the data in accordance with frequency bandwidth, and the detail wavelet coefficient reflects the stochastic process of error components. This property makes it possible to obtain the covariance of measurement error. We attempt the estimation of true data through recursive Kalman filtering algorithm with the obtained covariance value. The procedure is verified with the fundamental example of Brownian walk process.

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지자기 전달함수의 로버스트 추정

  • Yang, Jun-Mo;O, Seok-Hun;Lee, Deok-Gi;Yun, Yong-Hun
    • Journal of the Korean Geophysical Society
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    • v.5 no.2
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    • pp.131-142
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    • 2002
  • Geomagnetic transfer function is generally estimated by choosing transfer to minimize the square sum of differences between observed values. If the error structure sccords to the Gaussian distribution, standard least square(LS) can be the estimation. However, for non-Gaussian error distribution, the LS estimation can be severely biased and distorted. In this paper, the Gaussian error assumption was tested by Q-Q(Quantile-Quantile) plot which provided information of real error structure. Therefore, robust estimation such as regression M-estimate that does not allow a few bad points to dominate the estimate was applied for error structure with non-Gaussian distribution. The results indicate that the performance of robust estimation is similar to the one of LS estimation for Gaussian error distribution, whereas the robust estimation yields more reliable and smooth transfer function estimates than standard LS for non-Gaussian error distribution.

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A Gradient Method Based Near-Field Range Estimation Technique Robust to Direction-of-Arrival Error (방위각 오차에 강인한 경사법 기반 근접장 표적 거리 추정 기법)

  • Kim, Joon-Doo;Cho, Chom-Gun;Lee, Chung-Yong
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.49 no.2
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    • pp.130-136
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    • 2012
  • In this paper, we propose a near-field range estimation method for a uniform linear array that can calibrate bearing estimation error which give a bad influence on a range estimation process. When a range is fixed, the bearing error is calibrated to maximize the beamformer output by the proposed algorithm based on the gradient method. Simulation results show that the proposed algorithm can compensate the bearing error which is less than the mainlobe beamwidth so that reduce the range estimation error as similar as the case of no bearing error.

A Study on Maximum Posterior Probability Estimator for Direction of Arrival Estimation of Incoming Signal (입사신호의 도래방향 추정을 위한 최대 사후 확률 추정기에 대한 연구)

  • Lee, Kwan-Hyeong;Park, Sung-Kon;Jeong, Youn-Seo
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.9 no.2
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    • pp.190-195
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    • 2016
  • In this paper, we are comparative analysis both class method and proposal method in order to estimation of incident signal direction on uniform array antenna system. Proposal method of this paper decrease error probability for a signal direction of arrival estimation using maximum posterior probability estimator. If it decrease to signal estimation direction error probability, signal direction of arrival can correctly estimate. Through simulation, we were comparative analysis proposed method and class method. Also, we were comparative analysis about signal estimation error probability with increasing array antenna element. We show the superior performance of the proposed method relative to the class method to decrease of signal estimation error probability about 12%.