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Spectrum sensing based on sequential testingMa, Xiao January 2010 (has links)
Recently, interest has been shown in cognitive radio (CR) systems since they can op-
portunistically access unused spectrum bands thereby increasing usable communication
capacity. Spectrum sensing has been identified as a key function to ensure that CR can
detect spectrum holes. In a CR network, a fast and accurate spectrum sensing scheme is
important.
Spectrum sensing can be viewed as a signal detection problem. Most of the existing
spectrum sensing schemes are based on fixed sample size detectors which means that their
sensing time is preset and fixed. However, the work of Wald [27] showed that a detector
based on sequential detection requires less average sensing time than a fixed sample size
detector.
In this thesis, we have applied the method of sequential detection to reduce the average
sensing time. Simulation results have shown that, compared to the fixed sample size
energy detector, a sequential detector can reduce sensing time by up to 85% in the AWGN
channel for the same detection performance. In order to limit sensing time, especially
in a fading environment, a truncated sequential detector is developed. The simulation
results show that the truncated sequential detector requires less sensing time than the
sequential detector, but the performance degrades due to truncation. Finally, a cooperative
spectrum sensing scheme is used where each individual sensor uses a sequential detector.
The combining rule used at the fusion center is a selection combining rule. Simulation
results show that the proposed cooperative spectrum sensing scheme can reduce the sensing
time compared to the individual spectrum sensing scheme.
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Simulation Study of Sequential Probability Ratio Test (SPRT) in Monitoring an Event RateYu, Xiaomin 16 July 2009 (has links)
No description available.
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A CUSUM test for discrete monitoring of intensity of a Poisson processEger, Karl-Heinz 13 June 2010 (has links) (PDF)
This paper deals with CUSUM tests for monitoring
of intensity parameter of a Poisson process if this
process can be observed in a restricted manner only at pregiven
equidistant time points. In this case the process can
be monitored by means of a CUSUM test for the parameter
of a corresponding Poisson distribution.
For rational reference parameter values the computation
of average run length is reduced to that of solving of a
system of simultaneous linear equations. The performance
of obtained CUSUM tests is discussed by means of corresponding
examples.
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Sequential probability ratio tests based on grouped observationsEger, Karl-Heinz, Tsoy, Evgeni Borisovich 26 June 2010 (has links) (PDF)
This paper deals with sequential likelihood ratio
tests based on grouped observations.
It is demonstrated that the method of conjugated
parameter pairs known from the non-grouped case
can be extended to the grouped case obtaining
Waldlike approximations for the OC- and ASN-
function.
For near hypotheses so-called F-optimal
groupings are recommended.
As example an SPRT
based on grouped observations for the parameter
of an exponentially distributed random variable is
considered.
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Robustness of Sequential Probability Ratio Tests in Case of Nuisance ParametersEger, Karl-Heinz, Tsoy, Evgeni Borisovich 27 June 2010 (has links) (PDF)
This paper deals with the computation of OC- and ASN-function of sequential probability ratio tests in the multi-parameter case. In generalization of the method of conjugated parameter pairs Wald-like approximations are presented for the OC- and ASN-function. These characteristics can be used describing robustness properties of a sequential test in case of nuisance parameters.
As examples tests are considered for the mean and the variance of a normal distribution.
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A CUSUM test for discrete monitoring of intensity of a Poisson processEger, Karl-Heinz 13 June 2010 (has links)
This paper deals with CUSUM tests for monitoring
of intensity parameter of a Poisson process if this
process can be observed in a restricted manner only at pregiven
equidistant time points. In this case the process can
be monitored by means of a CUSUM test for the parameter
of a corresponding Poisson distribution.
For rational reference parameter values the computation
of average run length is reduced to that of solving of a
system of simultaneous linear equations. The performance
of obtained CUSUM tests is discussed by means of corresponding
examples.
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Robustness of Sequential Probability Ratio Tests in Case of Nuisance ParametersEger, Karl-Heinz, Tsoy, Evgeni Borisovich 27 June 2010 (has links)
This paper deals with the computation of OC- and ASN-function of sequential probability ratio tests in the multi-parameter case. In generalization of the method of conjugated parameter pairs Wald-like approximations are presented for the OC- and ASN-function. These characteristics can be used describing robustness properties of a sequential test in case of nuisance parameters.
As examples tests are considered for the mean and the variance of a normal distribution.
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Sequential probability ratio tests based on grouped observationsEger, Karl-Heinz, Tsoy, Evgeni Borisovich 26 June 2010 (has links)
This paper deals with sequential likelihood ratio
tests based on grouped observations.
It is demonstrated that the method of conjugated
parameter pairs known from the non-grouped case
can be extended to the grouped case obtaining
Waldlike approximations for the OC- and ASN-
function.
For near hypotheses so-called F-optimal
groupings are recommended.
As example an SPRT
based on grouped observations for the parameter
of an exponentially distributed random variable is
considered.
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