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Large-scale antenna systems provide a promising way to increase spectral and energy efficiency with a very large number of antennas at the base station serving many tens of users simultaneously. However, to a large extent, the theoretical performance relies on some fundamental assumptions of the radio environment, which need to be validated in realistic propagation scenarios. In this study we focus...
We study and analyze coverage region for MIMO amplify-and-forward (AF) relay network. We consider the network geometry in which L relays are placed uniformly around the source, and assume that there is no direct link between source and destination. We analyze desired transmission rate with the purpose of maximizing coverage region. Using Monte Carlo simulations the impact of number of transceiver...
Compact structure of the large-scale antenna array and low power angular spread (PAS) in vertical dimension improve the fading correlation of wireless channel dramatically in full-dimension multiple input multiple output (FD-MIMO) systems. Whereby beamforming (BF) can fully exploit the quasi-static spatial correlation to reduce dependence on the instantaneous channel state information at the transmitter...
Intruder detection method by using time variant Multiple Input Multiple Output (MIMO) channels was proposed (MIMO sensor). It was verified that the antenna height and element spacing suitable for the MIMO sensor by the measurement. It was also shown that 2 × 2 MIMO sensor obtains the higher detection performance compared to 1 × 4 SIMO sensor. However, we conducted only the measurement when considering...
For 3D MEMO precoding systems over spatially correlated channel, a novel limited feedback method is proposed by utilizing the nature of the spatial correlation and clustering of the subchannel of transmitting and receiving antenna pair. In this method, due to the co-phased and spatial-correlated characteristics of the vertical channel for 2D antenna array, each vertical antenna is assumed to have...
When distributed MIMO antenna systems are deployed in underground tunnels, the optimal separation between antennas depends on achieving a suitable balance between the fading correlation and path loss observed at the receiver. Here, we formulate the task of finding the optimal separation as an optimization problem and propose a genetic algorithm to solve for it.
In this paper, a beamforming and cell searching method is proposed for a mobile station (MS) with antenna array to compensate the high attenuation in a millimeter wave (mm-wave) OFDM-based cellular systems. A cell searching and direction-of-arrival (DoA) estimation method is proposed for a multipath environment, even with the existence of the symbol timing offsets (STOs) and carrier frequency offsets...
The performance of transmit beamforming (BF) systems in terms of the spatial correlation coefficient and channel gain variance (CGV) are analyzed over Rayleigh fading channels. We derive bit error rate (BER) of distributed BF (DBF) systems as a function of CGV of distributed channel links. As for clustered BF (CBF), we express its BER as the explicit function of the correlation coefficient. Based...
To improve the performances of a communication link, both in terms of capacity and bit error rate, MIMO technique is a solution which has been widely studied. However, in road or railway tunnels, the waves are guided by the structure and the angular spread of the rays, both at the transmitting side and at the receiving side, is rather small. Nevertheless, improvement of the capacity based on the Shannon...
In this paper, an adaptive antenna arrays processing based on Sample Matrix Inversion (SMI) algorithm with a novel training scheme is presented. The training scheme used is known as distributed training scheme [1]. The scheme uses distributed placement of the training symbols throughout the packet. The channel estimation, along with this particular training scheme, is designed to track intermittent...
Massive multiple-input multiple-output (MIMO) is a breakthrough communication technique for providing high spectral efficiency. The idea is to deploy a very large number of antennas at each base station and to use multiuser MIMO transmission to serve a smaller number of users. In this paper, the viability of using distributed antennas for massive MIMO on the uplink is investigated for a particular...
In most research of PN code acquisition performance of antenna array, the signal DOA is regarded as a constant. But in practice, the signal DOA always spreads to a certain extent, which affects PN code acquisition performance. In this paper, the angle extension is introduced into the direct-sequence spread-spectrum array signal model, and PN code acquisition performance is analyzed through CFAR algorithm...
In this paper a method for the accurate and fast determination of direction of arrival (DOA) of impinging electromagnetic signal radiated from stochastic sources in the far-field is proposed. The method is based on neural models using MLP (Multi-Layer Perceptron) artificial neural network. To illustrate the applicability of the proposed method, two MLP models for one-dimensional (1D) DOA estimation...
In this paper, we propose a modified unitary multiple signal classification (MUSIC) algorithm for a two-port composite right/left handed (CRLH) leaky-wave antenna (LWA). The algorithm requires only real-valued operations to estimate direction of arrival (DoA) of the received signals, which will simplify future hardware implementation. The CRLH LWA consists of a cascade of metamaterial unit cells,...
Doppler radar-based fall detection has been attractive due to its low cost and high detection performance. However, fall detection based on Doppler signatures is affected by the spatial variance due to the multipath and non-line-of-sight (NLOS) effects, which has been one of the key issues for detection performance in current Doppler radar-based systems. Moreover, the drawbacks of Doppler radar are...
It is well known that compact arrays introduce spatial channel correlation, antenna coupling, superdirectivity and noise correlation. While these effects have been thoroughly investigated for point to point MIMO, only isolated results are available on the effect of such phenomena on performance of relaying systems. This paper tries to fill part of this void. Specifically we study the impact of lossless...
Using large number of antennas at base station (BS) to formulate a multi-user multiple-input multiple-output (MU-MIMO) system, i.e., the massive MIMO, has attracted more and more attention recently, due to the high spectrum and energy efficiency it has. When there is correlation and mutual coupling, Rusek et al. showed that the channel may lose asymptotic orthogonality as the number of antennas increases...
In this paper, we propose a novel type of Impulse Radio Ultra-Wideband (IR-UWB) beamforming structure that we named a chirp beamformer. It represents an alternative to the well-known correlation beamforming paradigm. The chirp beamformer uses a chirp pulse as a symbol waveform. In comparison with a correlation beamformer, the chirp beamformer requires considerably lower timing resolution in cases...
A procedure for effective secret key sharing from wireless channel estimation is presented. The feasibility of the bit sequence achieved after a proper decorrelation process is demonstrated by means of standard RNGs tests.
Recently, new technologies have made it possible to produce synthetic aperture radar (SAR) based microwave images in real-time by using different microwave imaging arrays. However, depending on the imaging array construction the data of interest may be corrupted by mutual coupling and poor isolation. SAR images created from this data have an increased level of artifacts. This paper presents a method...
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