1,369 research outputs found
CRLBs for Pilot-Aided Channel Estimation in OFDM System under Gaussian and Non-Gaussian Mixed Noise
The determination of Cramer-Rao lower bound (CRLB) as an optimality criterion for the problem of channel estimation in wireless communication is a very important issue. Several CRLBs on channel estimation have been derived for Gaussian noise. However, a practical channel is affected by not only Gaussian background noise but also non-Gaussian noise such as impulsive interference. This paper derives the deterministic and stochastic CRLBs for Gaussian and non-Gaussian mixed noise. Due to the use of the non-parametric kernel method to build the PDF of non-Gaussian noise, the proposed CRLBs are suitable for practical channel environments with various noise distributions
Algorithms for the selection of the active sensors in distributed tracking: Comparison between Frisbee and GNS methods
This paper compares two different
approaches for sensor selection for distributed tracking:
1) The Frisbee method, and 2) Global Node Selection
(GNS). The Frisbee method is based on the proximity of
the nodes to the predicted location of the target; GNS is
based on minimizing the unbiased Cramer Rao lower
bound (CRLB). Both theoretical and experimental
results indicate that the Frisbee method is as effective as
GNS. Furthermore, the Frisbee method is attractive
due to its very light computational load
Cramer-Rao lower bound for the estimation of the degree of polarization in active coherent imagery at low photon level
International audienceThe degree of polarization (DOP) is an important tool in many optical measurement and imaging applications. We address the problem of its estimation in images that are perturbed with both speckle and photon noises, by determining the Cramer-Rao Lower Bound (CRLB) when the illuminated materials are purely depolarizing. We demonstrate that the CRLB is simply the sum of the CRLBs due to speckle noise and to Poisson noise. We use this result to analyze the influence of different optical parameters on DOP estimation
Theoretical Limits on Time Delay Estimation for Ultra-Wideband Cognitive Radios
In this paper, theoretical limits on time delay estimation are studied for
ultra-wideband (UWB) cognitive radio systems. For a generic UWB spectrum with
dispersed bands, the Cramer-Rao lower bound (CRLB) is derived for unknown
channel coefficients and carrier-frequency offsets (CFOs). Then, the effects of
unknown channel coefficients and CFOs are investigated for linearly and
non-linearly modulated training signals by obtaining specific CRLB expressions.
It is shown that for linear modulations with a constant envelope, the effects
of the unknown parameters can be mitigated. Finally, numerical results, which
support the theoretical analysis, are presented.Comment: IEEE ICUWB 200
35 Transient Multiexponential Data Selection Using Cramer Rao Lower Bound
Previously, analysis of transient multiexponential data using a combination of Gardner
transform and parametric methods was shown to yield good results. However, one
problem that remains unsolved is that of the nonstationarity of the data resulting from the
associated deconvolution. Hitherto, trial and error methods have been used to select the
qualitative length of the deconvolved data. In this paper, Cramer Rao Lower Bound
(CRLB) is used to select the data truncation points for use with the MUSIC (Multiple Signal
Classification), minimum norm and ARMA (autoregressive moving average) methods.
Several simulations are made based on which truncation points are recommended for
each of the three parametric methods
Geolocation of a Known Altitude Target Using TDOA and GROA in the Presence of Receiver Location Uncertainty
This paper considers the problem of geolocating a target on the Earth surface using the target signal time difference of arrival (TDOA) and gain ratio of arrival (GROA) measurements when the receiver positions are subject to random errors. The geolocation Cramer-Rao lower bound (CRLB) is derived and the performance improvement due to the use of target altitude information is quantified. An algebraic geolocation solution is developed and its approximate efficiency under small Gaussian noise is established analytically. Its sensitivity to the target altitude error is also studied. Simulations justify the validity of the theoretical developments and illustrate the good performance of the proposed geolocation method
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