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We consider the problem of estimating the angular coordinates of closely spaced signal sources using a rectangular antenna array with an arbitrary number of rows and columns. This problem is solved using the superresolution method of the minimum polynomial, which was previously proposed for the one-dimensional case of the angular resolution of signal sources. Two approaches to using this method are proposed, namely, the pseudospectral and the root techniques. The computational complexity is analyzed. A simpler alternative method for developing the resolution polynomial is also proposed in the special case of a two-row (two-column) antenna array for the root approach. The simulation results show the high efficiency of the angular resolution of the signal sources using the proposed methods. [ABSTRACT FROM AUTHOR]

We consider the problem of using the concept of a virtual antenna array in a MIMO radar for estimating the angular location of the target in the presence of signals reflected from the ground surface. The formal criteria of realizability of a virtual antenna array are formulated. Various antenna configurations are analyzed theoretically. The restrictions on the location of the receiving and transmitting antennas of a MIMO radar are established. Using numerical simulation, the influence of the reflected signals on the accuracy of determining the angular location of a target is studied for various antenna configurations. [ABSTRACT FROM AUTHOR]

We propose a new variant of the superresolution method of minimum polynomial of the correlation matrix for estimating the number and angular coordinates of the closely located sources of the signals recorded by the antenna array. The method ensures the direction finding of the sources by determining roots of the denominator of the pseudospectral function (the root method). Special attention is paid to the cases of strongly correlated signal sources and a short sample of the input process when the number of samples is smaller than that of array elements. The efficiencies of the angular superresolution for the root and spectral variants of the method of minimum polynomial, as well as the root MUSIC (MUltiple SIgnal Classification) method are compared. [ABSTRACT FROM AUTHOR]

We consider an adaptive antenna array, which forms a great number of beams for the parallel or successive observation of space and ensures the maximum ratio of the signal power to the mean noise power at the output. An algorithm for adaptive signal processing in the basis of the power vectors is proposed and the regularized estimates of the weight vectors are obtained using the limited number of the input-process samples, which can be both greater and smaller (the case of a short sample) than the number of the elements. The results of simulation of the adaptive signal processing are given, which show the high signal-processing efficiency in the adaptive antenna array. [ABSTRACT FROM AUTHOR]

We consider an adaptive antenna array, which ensures the maximum output ratio of the signal power to the average noise power. Two algorithms for the adaptive processing of the signal in the power-vector basis are proposed. For each algorithm, the regularized estimates of the weight vector are obtained using a limited number of input-process samples, which can be both greater and smaller (the short-sample case) than the number of array elements. The results of simulating the adaptive signal processing, which demonstrate a high signal-processing efficiency in the considered array, are presented. [ABSTRACT FROM AUTHOR]

We consider an adaptive antenna array (AAA) with the maximum signal-to-noise ratio (SNR) at the output. The antenna configuration is assumed to be arbitrary. A rigorous analytical solution for the optimal weight vector of the AAA is obtained if the input process is defined by the noise correlation matrix and the useful-signal vector. On the basis of this solution, the regularized estimate of the weight vector is derived by using a limited number of input noise samples, which can be either greater or smaller than the number of array elements. Computer simulation results of adaptive signal processing indicate small losses in the SNR compared with the optimal SNR value. It is shown that the computing complexity of the proposed estimate is proportional to the number of noise samples, the number of external noise sources, and the squared number of array elements. [ABSTRACT FROM AUTHOR]

We consider multiple-input multiple-output (MIMO) communication systems with adaptive antenna arrays at both ends of the link in which the data transmission is performed via parallel eigenchannels matched to the random spatial channel. The effectiveness of the projection method of space-division multiple access is studied. The method does not require estimation of the arrival directions of signals and is based on orthogonalization of all eigenchannels. Exact analytical expressions are obtained for the bit-error probability during the data transmission via the channel with uncorrelated Rayleigh fading of signals in an MIMO system with an arbitrary number of users and antennas. [ABSTRACT FROM AUTHOR]

We consider multiple-input multiple-output (MIMO) cellular communication systems with antenna arrays at both link ends and data transmission via parallel eigenchannels matched with a random spatial channel. We analyze the effectiveness of the space-division multiple-access (SDMA) method, which does not require estimation of signal-arrival directions and is based on orthogonalization of the parallel channels of all users. We obtained approximate analytical expressions for the mean ratio of the signal power to the noise power and the MIMO system capacity, which are derived for the case of Rayleigh fading of signals. Although the obtained formulas are much simpler than the exact ones, they ensure high accuracy for an arbitrary number of transmitting and receiving antennas and an arbitrary power of transmitter. Our results demonstrate the high effectiveness of the proposed SDMA method. [ABSTRACT FROM AUTHOR]

We consider cellular communication systems with antenna arrays at both link ends, in which the data transmission is performed via parallel eigenchannels under conditions of a scattering medium. To reduce the bit error probability, we propose a method of information transmission based on the use of only part of the eigenchannels with maximum signal-to-noise ratios and ensuring a tradeoff of the data-transmission rate against the bit-error probability. Eigenchannels are separated into energy-strong and energy-weak channels with the help of the threshold technique. Two possible versions of using the proposed method under conditions of a random multipath spatial channel are studied. The results of numerical simulation in the case of Rayleigh fading of signals confirm the high efficiency of the proposed method of information transmission. [ABSTRACT FROM AUTHOR]