AbstructAdaptive beamforming techniques are now widely used to reject interference Uammerklutter) signals in radar, communication, and sonar applications. In adaptive arrays using the sample matrix inversion (SMI) algorithm, inadequate estimation of the covariance matrix results in adaptive antenna patterns with high sidelobes and distorted mainbeams. In this paper, a method is proposed to prec...

We propose a blind multiuser detection technique for array processing and code division multiple access (CDMA) systems that does not require knowledge of the array geometry or transmitter signature sequences. The technique has two key elements: an adaptive algorithm for separating the signal subspace from the noise subspace and an adaptive whitener based on linear prediction. The proposed algor...

Sensor arrays have been used widely in applications including radar, sonar, seismology, biomedicine, communications, geophysical exploration, astronomy, and imaging. A very popular type of sensor array is circular array. It has several advantages such as the fact that it can perform 360 scan around its center very conveniently and during the scan the array pattern can be kept almost invariant. ...

In this article, the particle swarm optimization algorithm is used to calculate the complex excitations, amplitudes and phases, of the adaptive circular array elements. To illustrate the performance of this method for steering a signal in the desired direction and imposing nulls in the direction of interfering signals by controlling the complex excitation of each array element, two types of arr...

Title of Dissertation: ANALYSIS AND EXPERIMENTAL DEMONSTRATION OF CONFORMAL ADAPTIVE PHASE-LOCKED FIBER ARRAY FOR LASER COMMUNICATIONS AND BEAM PROJECTION APPLICATIONS Ling Liu, Doctor of Philosophy, 2008 Dissertation Directed By: Professor Mikhail A. Vorontsov Institute for Systems Research and Department of Electrical and Computer Engineering, University of Maryland at College Park The primar...

In this paper, we propose subband adaptive array processing for mitigation of both intersymbol interference (ISI) and cochannel interference (CCI) in digital mobile communications. Subband adaptive array processing employs filter banks in a front end to an adaptive array receiver. By decomposing the signals into a set of subband signals, the analysis filters enhance the correlation of multipath...

This paper describes a new interface for a barge-in free spoken dialogue system combining an adaptive sound field control and a microphone array. In order to actualize robustness against the change of transfer functions due to the various interferences, the barge-in free spoken dialogue system which uses sound field control and a microphone array has been proposed by one of the authors. However...

The packet throughput is analyzed for a slow FH/SSMA packet radio network with adapt ivc o i i t e r i r m array and packet combznzng in a Rayleigh fading channel with shadowing. The packet throughput is defined as the average number of captured packets per slot. To enhance the throughput performance, the adaptive antenna array and packet combining are employed. As a random access protocol, slo...

Abstract— Orthogonal frequency division multiplexing (OFDM) has been attracting much attention as the next generation wireless transmission technique. In a cellular network, the same carrier frequency is reused at different base stations and therefore, cochannel interference (CCI) limits the transmission performance. By suppressing the CCI, the uplink transmission performance can be improved an...

Adaptive array processing algorithms have achieved widespread use because they are very effective at rejecting unwanted signals (i.e., controlling sidelobe levels) and in general have very good resolution (i.e., have narrow mainlobes). However, many adaptive high-resolution array processing algorithms suffer a significant degradation in performance in the presence of environmental mismatch. Thi...