This paper presents a method of constructing single signal subspace for high-resolution estimation the angles arrival multiple wide-band plane waves. The technique relies on an approximately coherent combination spatial spaces temporally narrow-band decomposition received vector from array sensors. algorithm is presented, and followed by statistical simulation examples. performance contrasted with other suggested methods bounds in terms determination correct number sources (detection), bias,...

In a distributed spatial diversity wireless system, not all antennas are located at one station as in classical transmit systems, but dispersed different, possibly mobile, stations the network. Transmit is created when selected assist sender by relaying its information signal to destination. this letter, we present an exact average symbol error rate analysis for system with K amplifying relays Rayleigh-fading environment. The formula allows us clearly illustrate advantage that has overcoming...

We propose a new shadowed Rice (1948) model for land mobile satellite channels. In this model, the amplitude of line-of-sight is characterized by Nakagami distribution. The major advantage that it leads to closed-form and mathematically-tractable expressions fundamental channel statistics such as envelope probability density function, moment generating function instantaneous power, level crossing rate. very convenient analytical numerical performance prediction complicated narrowband...

A class of fourth-order partial differential equations (PDEs) are proposed to optimize the trade-off between noise removal and edge preservation. The time evolution these PDEs seeks minimize a cost functional which is an increasing function absolute value Laplacian image intensity function. Since at pixel zero if planar in its neighborhood, attempt remove preserve edges by approximating observed with piecewise image. Piecewise images look more natural than step anisotropic diffusion (second...

This paper presents an asymptotic statistical analysis of the null-spectra two eigen-assisted methods, MUSIC [1] and Minimum-Norm [2], for resolving independent closely spaced plane waves in noise. Particular attention is paid to average deviation from zero at true angles arrival waves. These deviations are expressed as functions signal-to-noise ratios, number array elements, angular separation emitters, snapshots. In case MUSIC. approximate expression derived resolution threshold with equal...

Analysis and design of multielement antenna systems in mobile fading channels require a model for the space-time cross correlation among links underlying multiple-input multiple-output (MIMO) channel. In this paper, we propose general cross-correlation function frequency nonselective Rice MIMO channels, which various parameters interest such as angle spreads at base station user, distance between mean directions signal arrivals, array configurations, Doppler spread are all taken into...

In this paper, we analyze the behavior of anisotropic diffusion model Perona and Malik (1990). The main idea is to express equation as coming from a certain optimization problem, so its can be analyzed based on shape corresponding energy surface. We show that steepest descent method for solving an minimization problem. It demonstrated well posed when there exists unique global minimum functional ill posedness caused by fact has infinite number minima are dense in image space. give sufficient...

A class of focussing matrices is proposed for use in the coherent signal-subspace method (CSM) (H. Wang and M. Kaveh, ibid., vol.ASSP-33, Aug. 1985). When directions-of-arrival wideband sources fall into more than one group beamwidth each, this leads to performance substantially better those suggested previous studies on direction-of-arrival estimation. New insight structures various their effect CSM presented. The compared several classes these simulations as well relative sufficiency...

One of the main assumptions in Clarke's classic channel model is isotropic scattering, i.e., uniform distribution for angle arrival (AOA) multipath components at mobile station. However, many radio channels we encounter nonisotropic which strongly affects correlation function and power spectrum complex envelope receiver. We propose use versatile von Mises (1918) angular distribution, includes and/or closely approximates important distributions like uniform, impulse, cardioid, Gaussian,...

Computer technology has brought about a revolution in radiology. By combining the computer with X rays it is possible (in principle) to obtain tomographic images of any cross section human body. These techniques are now used for medical diagnosis all major hospitals world. But not only kind radiation which computer-assisted tomography feasible. Microwaves, electron beams, ultrasound, fast subatomic particles from accelerators, gamma such sources as positron annihilation, and even magnetic...

The primary difficulty with blind image restoration, or joint blur identification and is insufficient information. This calls for proper incorporation of a priori knowledge about the point-spread function (PSF). A well-known space-adaptive regularization method restoration extended to address this problem. new effectively utilizes, among others, piecewise smoothness both PSF. It attempts minimize cost consisting error measure two terms (one other blur) subject hard constraints. scale problem...

Capitalizing on the Moschopoulos (1985) single gamma series representation of probability density function (PDF) sum variates, we provide a PDF-based approach for performance analysis maximal-ratio combining and postdetection equal-gain diversity techniques as well cochannel interference cellular mobile radio systems over Nakagami (1960)-fading channels with arbitrary parameters. Aside from putting under same umbrella many past results obtained via characteristic (CF) or moment generating...

The Rayleigh-lognormal distribution, which has proved useful for modelling fading-shadowing wireless channels, a complicated integral form. authors have accurately approximated it by the K distribution. This distribution is simpler and thus more appropriate analysis design of communication systems.

We study the statistical performance of two moment-based estimators for K parameter Rice fading distribution, as less complex alternatives to maximum-likelihood estimator. Our asymptotic analysis reveals that both are nearly asymptotically efficient, and there is a compromise between computational simplicity efficiency these estimators. also show, by Monte Carlo simulation, correlation among envelope samples deteriorates However, simpler estimator, which employs second fourth moments signal...

The authors present an adaptive estimator of the complete noise or signal subspace a sample covariance matrix as well estimator's practical implementations. general formulation proposed results from asymptotic argument, which shows computation to be equivalent constrained gradient search procedure. A highly parallel algorithm, denoted inflation method, is introduced for estimation subspace. simulation these estimators show that algorithms perform substantially better than P.A. Thompson's...

Shadow fading causes random fluctuations of the envelope mean at mobile. The lognormal distribution is widely accepted for this phenomenon. In paper we argue that, based on theoretical results and measured data, gamma does job as well. Then show that by using in contrast with use distribution, can obtain easy-to-use closed-form composite PDFs channels, which turn extremely simplify analytic calculations.

In sensor array processing, high-resolution eigenbased direction-finding algorithms are known to be sensitive gain, phase, and mutual coupling errors. order approach the algorithms' theoretical performance in actual arrays, methods required measure these errors compensate for them. The authors develop calibration procedures based on least squares fitting of measured direction vectors. After any appropriate algorithm may applied. Experimental results from an ultrasonic testbed demonstrate...

Abstract Estimation of signal strength, a measure channel quality, and Doppler spread which is proportional to the mobile speed, are important for handoff algorithms optimal tuning system parameters changing conditions in adaptive transmission systems. This paper provides survey existing techniques estimating statistical channel. We discuss current state art estimation received velocity, other related parameters, illustrate their performance, compare techniques. The sensitivity these schemes...

This paper presents anisotropic regularization techniques to exploit the piecewise smoothness of image and point spread function (PSF) in order mitigate severe lack information encountered blind restoration shift-invariantly shift-variantly blurred images. The new techniques, which are derived from diffusion, adapt both degree direction spatial activities orientations PSF. matches PSF may be characterized by sharp transitions magnitude nature these transitions. For images whose underlying...

This paper presents an analytical evaluation of detection (determination the number sources) and estimation performances narrow-band signal-subspace processing for multiple-source direction finding. The probabilities underestimating overestimating sources are derived, under asymptotic conditions around threshold regions, in terms choice a penalty function signal, noise, array parameters cases at most two closely spaced spatially white noise. A scalar measure is introduced quality estimated...

Spatial diversity can be induced by using wireless relay stations, which cooperate amplifying and retransmitting the information received from a source to destination station. In this context we propose distributed space-time coding (DSTC) system based on Alamouti codes. We characterize symbol error rate of systems with one two non-regenerative relays bounds high signal-to-noise ratio (SNR) approximations. The asymptotic (high SNR) probability formulas are used optimize power allocation in...

In this paper, the sparse spectrum fitting (SpSF) algorithm for estimation of directions-of-arrival (DOAs) multiple sources is introduced, and its asymptotic consistency effective regularization under both finite sample cases are studied. Specifically, through analysis optimality conditions method, we prove asymptotic, in number snapshots, SpSF estimators DOAs received powers uncorrelated a spatial spectra model. Along with result, an explicit formula best parameter estimator infinitely many...

Level crossing rate (LCR) and average fade duration (AFD) of the signal envelope are two important second-order channel statistics, which convey useful information about dynamic temporal behavior multipath fading channels. In this paper for a general non-isotropic scattering scenario, in mobile receives only from particular directions with different probabilities, we derive expressions LCR AFD Rayleigh, Rice Nakagami (1960) models, including effect non-uniform angle-of-arrival distribution....

Nakagami distribution has proven useful for modeling the multipath faded envelope in wireless channels. The shape parameter of distribution, known as m parameter, can be estimated different ways. In this contribution, performance inverse normalized variance, Tolparev-Polyakov, and Lorenz estimators have been compared through Monte Carlo simulation, it observed that variance estimator is superior to others over a broad range values.