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The Minimum Variance (MV) criterion is widely used for weight vector estimation of the adaptive microphone array (AMA). The drawback of this criterion is the cancellation of the desired speech signal and its degradation when the microphone array is in a room with reverberation. Applying the Maximum Likelihood (ML) instead of MV criterion has two benefits. The first is the cancellation of interference...
In this paper, we present a method for estimating the signal sources steering vector using an arbitrary planar array with omnidirectional elements. The proposed method improves the initial estimation of the signal steering vector in two steps. In the first step of this algorithm we minimize of the distance between the steering vector and the signal subspace. The second step improves the estimation...
We propose a novel method for applying real-valued independent component analysis (ICA) to complex-valued multi-sensor data that comprises instantaneous linear mixtures of co-channel non-Gaussian independent signals. We examine, for non-ideal practical conditions, the optimahty of cumulant-based ICA and blind signal separation approaches in terms of the standard criterion for statistical independence...
Traditional adaptive beamformers have robustness just for specific error condition. They suffer performance degradation in the presence of multiple errors such as sample covariance matrix estimation error and steering vector mismatch. In this article, a new robust adaptive beamforming algorithm based on jointly estimating the covariance matrix and steering vector mismatch is proposed to overcome both...
Recently, neural minor component analysis (MCA) has attracted much attention. It has features of high calculation speed and strong fault tolerant property. In this paper, neural MCA network is applied in adaptive beam forming. In order to get over the disadvantages that MCA based beam former cannot form null steering beams at the direction of interference and avoid stagnation behavior of algorithm...
The minimum variance distortionless response (MV-DR) beamformer is very sensitive to the steering vector mismatch. Such mismatch can lead to serious degradation of the beamforming performance especially at high signal-to-noise ratio (SNR). In this paper, a new robust beamformer based on the DOA matrix is proposed to solve the steering vector mismatch. Through the left eigendecomposition of the DOA...
Conventional phased-array radar forms a transmit beam pointed to a target of interest, whereas a multiple-input-multiple-output (MIMO) radar employs omni-directional transmission. In both systems, the transmission process takes place without accounting for any interference sources present in the radar scene; and interference mitigation is performed primarily through a receive beamformer. In this paper,...
When the desired signal is present in the training snapshots, the performance of conventional orthogonal projection (OP) adaptive beamforming degrades severely due to the desired signal cancellation effect. To overcome this deficiency, the improved orthogonal projection (IOP) adaptive beamforming by using reconstructed interference covariance matrix is proposed. In the proposed algorithm, the interference...
Adaptive array signal processing is widely used to improve anti-jamming capability for satellite navigation receivers. Robust beamforming approaches based on steering vector uncertainties, which have been proposed in recent years, have better performance than standard minimum variance distortionless response (MVDR) beamformer in space adaptive processing (SAP). In some practice applications, the attitude...
Single-array and multiple-array structures were applied to a large-scale planar array for use in uplink space-division multiple access, and their simulated data throughputs were compared. In both structures, a subarray-processing iterative soft-input-soft-output multi-user detector efficiently recovers multi-user signals from multiple RF chains. The phased-array directivity is controlled on the basis...
A novel RB-WC-FI-FB (robust worst-case frequency invariance forward-backward) wideband beam former is proposed in this paper. It is developed to improve the robustness against estimation errors of direction of arrival (DOA) and limited sample number, as well as reduce the number of constraints. By incorporating forward-backward estimation and worst-case performance optimization method into the linearly...
Large scale MIMO is a new field for wireless communication. Theoretical analysis was usually done with independent distributed complex Gaussian channels and unlimited antennas. In this work, we exhibit the performance of linear precoding under the three dimension (3D) channel model calibrated by 3GPP in the 3D-UMÌ scenario. Considering the multi-cell multiuser MIMO (MU-MIMO), we assume that the base...
MVDR algorithm which is based on adaptive uniform linear array produces optimal weight to each element in the array and gets perfect signal direction of arrival (DOA). Any mismatch in the signal DOA estimation mitigates the behavior of MVDR. Mismatch in MVDR is affected by the reference element location assumption in the elements' array. In this paper a new method is proposed to modify the standard...
Smart antenna is a system based on the antenna elements which are distributed uniformly as array and on the beamformig (BF) algorithm. Each element in the array receives the wave plane signals individually, and then, the beamformer tries to produce the optimum weight for each element with respect to the reference element in the array. This technique is called beamformig. MVDR is one of the most important...
In ideal cases, assumptions are made that the direction of the desired signal is accurately known and there are no array position errors. But in practice, some errors of DOA estimation and array geometries will bring the uncertainty of steering vector of the desired signal. Then, investigation is needed to solve the beamforming problem when steering vector error is uncertain. In this paper, we propose...
In order to solve the problem that most of the directions-of-arrival (DOA) algorithms are based on the prior knowledge of source number and the estimation error of source number leads to the degradation of DOA algorithm performance, a conformal array DOA algorithm with unknown source number is proposed. This method is realized by introducing the pseudo expected signal. The optimum weight deduced by...
The performance of adaptive beamforming degrades in presence of signal model mismatches. In particular, when the desired signal is present in training snapshots, the adaptive beamforming is quite sensitive to desired signal steering vector mismatch. Therefore, a robust adaptive beamforming for actual system is proposed based on the reconstruction of interference covariance matrix and mismatched steering...
This paper presents the theoretical capacity performance of different linear multi-user MIMO (MU-MIMO) pre-coding algorithms for a millimeter wave communication system using hybrid beam-forming. Hybrid beam-forming uses both RF and digital beam-forming and is a practical way to achieve the required array gains when the high bandwidths available at millimeter wave frequencies are utilized. The performances...
Traditional approaches for interference suppression will enjoy the added benefits when more domains are involved in antenna array. However, the information from range domain and its collaboration with other domains are rarely explored, and their potentials in improvement of radar performance are under-estimated. In this paper, we introduce the concept of polarization sensitive frequency diverse array...
Robust adaptive beamforming algorithms with fully automatic diagonal level computation are desired but scarce in the literature. We note that the an imaginary-valued diagonal loading level well approximates but differs from its real-valued counterpart in terms of output signal-to-interference-plus-noise ratio (SINR), and an estimate of the optimal diagonal loading level can be found by the highest...
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