摘要 :
The presence of frequency offsets in the received signal for an orthogonal frequency division multiplexing (OFDM) based multicarrier system leads to inter carrier interferences (ICI). The degradation in the performance of an OFDM ...
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The presence of frequency offsets in the received signal for an orthogonal frequency division multiplexing (OFDM) based multicarrier system leads to inter carrier interferences (ICI). The degradation in the performance of an OFDM system is severe when there is frequency error, which is caused by the loss of orthogonality in the received carrier frequencies. Here, we look into the correction of frequency errors in the received OFDM signal, by means of a correlator based maximum likelihood (ML) frequency estimator. We analyse the system performance of the frequency corrected OFDM system and study the statistical nature of the frequency uncertainty in the receiver when the ML frequency estimator is used. The statistical distribution of the estimates made by the receiver is also determined.
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摘要 :
The presence of frequency offsets in the received signal for an orthogonal frequency division multiplexing (OFDM) based multicarrier system leads to inter carrier interferences (ICI). The degradation in the performance of an OFDM ...
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The presence of frequency offsets in the received signal for an orthogonal frequency division multiplexing (OFDM) based multicarrier system leads to inter carrier interferences (ICI). The degradation in the performance of an OFDM system is severe when there is frequency error, which is caused by the loss of orthogonality in the received carrier frequencies. Here, we look into the correction of frequency errors in the received OFDM signal, by means of a correlator based maximum likelihood (ML) frequency estimator. We analyse the system performance of the frequency corrected OFDM system and study the statistical nature of the frequency uncertainty in the receiver when the ML frequency estimator is used. The statistical distribution of the estimates made by the receiver is also determined.
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摘要 :
Summary form only given. Modulation of voltage and current signals with low frequency component during power swing creates difficulty in accurate phasor estimation. Sequence component based relaying principles are therefore being ...
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Summary form only given. Modulation of voltage and current signals with low frequency component during power swing creates difficulty in accurate phasor estimation. Sequence component based relaying principles are therefore being affected. In this paper, fundamental and modulating frequency components are incorporated in phasor estimation formulation to improve the accuracy. The method estimates the two frequencies first and then the phasor using least squares technique. As an application of the proposed method, the sequence component of current is used for detection of unbalanced fault during power swing. The method is tested for numerous power swing and fault conditions of a WSCC 9-bus system and compared with conventional methods.
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摘要 :
Summary form only given. Modulation of voltage and current signals with low frequency component during power swing creates difficulty in accurate phasor estimation. Sequence component based relaying principles are therefore being ...
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Summary form only given. Modulation of voltage and current signals with low frequency component during power swing creates difficulty in accurate phasor estimation. Sequence component based relaying principles are therefore being affected. In this paper, fundamental and modulating frequency components are incorporated in phasor estimation formulation to improve the accuracy. The method estimates the two frequencies first and then the phasor using least squares technique. As an application of the proposed method, the sequence component of current is used for detection of unbalanced fault during power swing. The method is tested for numerous power swing and fault conditions of a WSCC 9-bus system and compared with conventional methods.
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摘要 :
For bandwidth efficiency and burst transmission reason, the carrier frequency synchronization usually tends to be resolved by non-data aided frequency offset estimation technique. The autocorrelation based frequency offset estimat...
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For bandwidth efficiency and burst transmission reason, the carrier frequency synchronization usually tends to be resolved by non-data aided frequency offset estimation technique. The autocorrelation based frequency offset estimators can achieve a mean square estimation error close to MCRB. However, the frequency ranges of this class of estimators are usually very poor, which badly limits their implementations. In this paper, the factors that limit the frequency range of an autocorrelation based estimator are discussed in detail. Based on that, an improved estimator scheme is proposed, which extends the estimation range to the upper bound of the frequency range for NDA estimator. Simulation results shows that the proposed scheme well addresses the frequency range extending whereas introduces no accuracy loss when E_S/N_0 is above the threshold.
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Summations of cumulants (projections) along parallel lines in the cumulant domain are formed. The projection procedure first relies on a change of variables through rotation of the cumulant axes. The cumulants are effectively deco...
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Summations of cumulants (projections) along parallel lines in the cumulant domain are formed. The projection procedure first relies on a change of variables through rotation of the cumulant axes. The cumulants are effectively decoupled. Summing the cumulants reduced the dimensionality of the system from six cumulant terms to one term. An eigenstructure-based method for frequency and biphase estimation is offered as an alternative to Fourier schemes on the slice after biphases have been converted to estimable amplitudes by forming symmetric and skew-symmetric projections.
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摘要 :
A methodology is developed to estimate the revenue of a bus trip based on data available on passenger boarding & alighting. Three scenarios are explained. First is when individual passenger data on boarding and alighting is available. The second is when the boarding and alighting data at stop level or by fare section and the third is when, only the total demand or only the past demand distribution pattern is available. First step is to determine passenger cumulative boarding and alighting by fare sections of a route based on bus ticket information or boarding and alighting counts. Then the cumulative boarding and alighting information is used for revenue estimation. To estimate the revenue, the bus fare for a given trip length is used for the first scenario and the moving average of sectional fare increments is used for others. A computer algorithm is developed to accommodate any scenarios. This algorithm helps to estimate the revenue of buses based on passenger boarding and alighting information and can estimate revenue for a given route or sections of a route, different passenger demand situations, different bus capacities and any service frequencies....
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A methodology is developed to estimate the revenue of a bus trip based on data available on passenger boarding & alighting. Three scenarios are explained. First is when individual passenger data on boarding and alighting is available. The second is when the boarding and alighting data at stop level or by fare section and the third is when, only the total demand or only the past demand distribution pattern is available. First step is to determine passenger cumulative boarding and alighting by fare sections of a route based on bus ticket information or boarding and alighting counts. Then the cumulative boarding and alighting information is used for revenue estimation. To estimate the revenue, the bus fare for a given trip length is used for the first scenario and the moving average of sectional fare increments is used for others. A computer algorithm is developed to accommodate any scenarios. This algorithm helps to estimate the revenue of buses based on passenger boarding and alighting information and can estimate revenue for a given route or sections of a route, different passenger demand situations, different bus capacities and any service frequencies.
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摘要 :
A methodology is developed to estimate the revenue of a bus trip based on data available on passenger boarding & alighting. Three scenarios are explained. First is when individual passenger data on boarding and alighting is available. The second is when the boarding and alighting data at stop level or by fare section and the third is when, only the total demand or only the past demand distribution pattern is available. First step is to determine passenger cumulative boarding and alighting by fare sections of a route based on bus ticket information or boarding and alighting counts. Then the cumulative boarding and alighting information is used for revenue estimation. To estimate the revenue, the bus fare for a given trip length is used for the first scenario and the moving average of sectional fare increments is used for others. A computer algorithm is developed to accommodate any scenarios. This algorithm helps to estimate the revenue of buses based on passenger boarding and alighting information and can estimate revenue for a given route or sections of a route, different passenger demand situations, different bus capacities and any service frequencies....
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A methodology is developed to estimate the revenue of a bus trip based on data available on passenger boarding & alighting. Three scenarios are explained. First is when individual passenger data on boarding and alighting is available. The second is when the boarding and alighting data at stop level or by fare section and the third is when, only the total demand or only the past demand distribution pattern is available. First step is to determine passenger cumulative boarding and alighting by fare sections of a route based on bus ticket information or boarding and alighting counts. Then the cumulative boarding and alighting information is used for revenue estimation. To estimate the revenue, the bus fare for a given trip length is used for the first scenario and the moving average of sectional fare increments is used for others. A computer algorithm is developed to accommodate any scenarios. This algorithm helps to estimate the revenue of buses based on passenger boarding and alighting information and can estimate revenue for a given route or sections of a route, different passenger demand situations, different bus capacities and any service frequencies.
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摘要 :
Carrier recovery system is a very important part of the digital radio frequency receivers. Tracking frequency estimators are able to compensate Doppler shifts of the signal coming from fast moving objects. There are many algorithm...
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Carrier recovery system is a very important part of the digital radio frequency receivers. Tracking frequency estimators are able to compensate Doppler shifts of the signal coming from fast moving objects. There are many algorithms based on several approaches, but the noisy environment stays the big issue. The paper introduces novel approach to the frequency estimation suited for weak suppressed carrier BPSK signal even below the noise level. Both the open loop version suitable for acquisition and the closed loop version with narrow band input more convenient for tracking are described.
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摘要 :
Carrier recovery system is a very important part of the digital radio frequency receivers. Tracking frequency estimators are able to compensate Doppler shifts of the signal coming from fast moving objects. There are many algorithm...
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Carrier recovery system is a very important part of the digital radio frequency receivers. Tracking frequency estimators are able to compensate Doppler shifts of the signal coming from fast moving objects. There are many algorithms based on several approaches, but the noisy environment stays the big issue. The paper introduces novel approach to the frequency estimation suited for weak suppressed carrier BPSK signal even below the noise level. Both the open loop version suitable for acquisition and the closed loop version with narrow band input more convenient for tracking are described.
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