We propose an extension of the BM4D volumetric filter to the denoising of data corrupted by spatially nonuniform noise. BM4D implements the grouping and collaborative filtering paradigm, where similar cubes of voxels are stacked into a four-dimensional “group”. Each group undergoes a sparsifying four-dimensional transform, that exploits the local correlation among voxels in each cube and the no...

the emergence of WiMAX has attracted significant interests from all the fields of wireless communications including students, researchers, systems engineers and operators. The WiMAX can also be considered to be the main technology in the implementation of other networks like wireless sensor networks. Developing an understanding of the WiMAX system can be best achieved by looking at a model of t...

The capacity and cutoff rate of frequency-shift keying (FSK) modulation and noncoherent reception when the signal is subject to Rician fading are calculated. Both hard and soft decisions with maximum likelihood combining are considered, as well as soft decisions with square-law combining. Optimal code rates are found that minimize the required signal-to-noise ratio for reliable communication.

Parallel magnetic resonance imaging (MRI) yields noisy magnitude data, described in most cases as following a noncentral χ distribution when the signals received by the coils are combined as the sum of their squares. One well-known case of this noncentral χ noise model is the Rician model, but it is only valid in the case of single-channel acquisition. Although the use of parallel MRI is increa...

Functional magnetic resonance (fMRI) studies intend to answer neuroscience questions by statistically analyzing a set of acquired images. Thereby, the aim is to determine those regions in the brain image in which the signal changes upon stimulus presentation. Although MR data are intrinsically complex valued, most tests are commonly applied to magnitude MR images, because these images have the ...

We have recently derived infinite-series expressions for performance measures of multiple-input multipleoutput (MIMO) spatial multiplexing with zero-forcing detection (ZF) for Rician–Rayleigh fading, which is relevant in heterogeneous networks. These expressions ensue from a well-known infinite-series expansion around σ = 0 of the confluent hypergeometric function 1F1(·, ·, σ). Theoretically, t...

1 Professor, Department of Electrical and Electronics Engineering, Erciyes university, kayseri, turkey . 2 Department of Electrical and Electronics Engineering, Erciyes university, kaysers, turkey. ---------------------------------------------------------------------***--------------------------------------------------------------------Abstract In traditional wireless cellular networks, wireles...

Noise in Parallel Imaging Parallel MRI (pMRI) techniques extended the applicability of multiple-coil systems by increasing the acquisition rate via subsampled acquisitions of the k-space data. Many reconstruction methods have been proposed in order to suppress the aliasing and underlying artifacts created by the subsampling. Dominant among these are SENSE and GRAPPA. One of the effects in accel...

The presence of Rician noise in magnetic resonance imaging (MRI) introduces systematic errors in diffusion tensor imaging (DTI) measurements. This paper evaluates gradient direction schemes and tensor estimation routines to determine how to achieve the maximum accuracy and precision of tensor derived measures for a fixed amount of scan time. We present Monte Carlo simulations that quantify the ...

Two unified expressions for computing the refined outage criterion (which considers the receiver noise) in cellular mobile radio systems are derived using the Laplace and Fourier inversion formulas. Since these expressions do not impose any restrictions on the signal statistics while being easy to program, they provide a powerful tool for outage analysis over generalized fading channels. We als...