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MIMO (Multiple-Input-Multiple-Output) is a promising structure for wireless communication. While virtual MIMO structure has been proposed for distributed and cooperative wireless networks, this proposed structure has also put additional energy consumption where energy stands in the important position. At the same time, we have observed that this-problem-caused low energy nodes' mibehavior will degrade...
In Rayleigh fading environments, a MIMO channel matrix can be considered as a random matrix. Theory of Wishart matrix, which is a correlation matrix of the random matrix, has been developed by A. T. James. Later, distributions of eigenvalues of Wishart matrix have been applied to derive MIMO channel capacity, where the average power of the random matrix are uniform. In BSCMIMO, however, the average...
This paper investigates the capacity of multiple-input multiple-output (MIMO) antenna arrays in different on-body area network channels. The two belt-head and belt-chest channels are compared, where, belt, refers to the transmitter's location, while the second part refers to the receiver location. The on-body channel model is constructed by using the Rice factor, the path loss, the shadowing deviation...
In this contribution we propose a geometry-based generic model to characterize a propagation channel in a keyhole environment. The channel considered is dispersive in delay, direction of departure, direction of arrival, and Doppler frequency. Based on the model, we derive the analytical expressions of the marginal and conditional dispersion of the channel, the correlation matrix and the power spectral...
Direct sequence code division multiple access (DSCDMA) is mainly an interference limited channel. When several users are accessed in a common channel and since signature sequences assigned to users are not perfectly orthogonal, so interference is introduced in each user's desired signal. Several interference cancellation methods were proposed to reduce multi-access interference. In this paper, we...
A stochastic 2times2 MIMO wideband channel modelling method is presented. This channel model uses tapped delay lines (TDL) to model the subchannels and a single channel spatial correlation matrix to introduce the statistical dependence. This model represents a novel simplification with respect to other wideband MIMO models. The channel models obtained from this method are accurate and computationally...
A new scheme consisting of a combination of transmit diversity, spatial multiplexing and beamformer is presented for the spatial correlated channels. The proposed scheme exploits the benefits of combining transmit diversity and spatial multiplexing to provide diversity and multiplexing gain. Based on channel's correlation matrix, a robust beamformer is designed. Simulation results show that the robust...
Given a contraint on the total amount of feedback overhead, we investigate the allocation of feedback bits (i.e. codebook sizes) among users in a limited feedback Zero Forcing Beamforming-based MU-MIMO scheme where users have the opportunity to adapt their codebooks as a function of their own channel statistics. We consider both single-polarized and dual- polarized scenarios. Using upper bounds on...
Among all blind channel estimation problems, subspace-based algorithms are attractive due to its fast- converging nature. It primarily exploits the orthogonality structure of the noise and signal subspaces by applying a signal-noise space decomposition to the correlation matrix of the received signal. In practice, the correlation matrix is unknown and must be estimated through time averaging over...
Spatial correlation is one of the impairments in multiple- input multiple-output (MIMO) wireless communication systems. Capacity increases promised by MIMO systems mostly depend on the spatial correlation properties of the radio channels. This letter investigates the connection between these properties and the channel capacity. An analytical formula is derived for the fading correlation function of...
Subspace-based blind channel estimation primarily exploits the orthogonality structure of the noise and signal subspaces by applying a signal-noise space decomposition to the correlation matrix of the received signal. In practice, the correlation matrix is unknown and must be estimated through time averaging over multiple symbol blocks. To this end, the wireless channel must be time-invariant over...
In the simulation of multiple-input multiple-output (MIMO) radio systems, accurate channel models are needed. Channel models have to be approximated to reach reasonable complexity of practical radio channel simulators, but the approximation should not cause too high error in the simulation. The error of the MIMO correlation matrix can be measured via different metrics such as correlation matrix distance...
Kronecker-separable MIMO channels, especially for larger MIMO configurations, are found more often in system simulations than in reality and some good physical explanations for the latter are available. This paper treats testing Kronecker-separability from a statistical perspective. The point raised is that for larger configurations the dimensions of the full correlation matrix become too large (equal...
Greedy interference avoidance provides distributed algorithms for CDMA codeword optimization. These algorithms are based on the implicit assumption that active users have access to the correlation matrix of the the received signal, which should be made available to users through a feedback channel. As a consequence the performance of greedy interference avoidance algorithms will be limited by the...
Spatial correlation is one of the impairments practical multiple-input multiple-output (MIMO) wireless communication systems have to be coped with. Capacity increases promised by MIMO systems mostly depend on the spatial correlation properties of the radio channels. This paper investigates the connection between these properties and the channel capacity. By investigating the channel capacity using...
In the following, we present a novel wideband multiple-input, multiple-output (MIMO) channel model, which we refer to as the structured model. The model is based on the eigenvalue decomposition (EVD) of the wideband channel correlation matrix. It does not assume the scatterers at the receiver fade independently of those at the transmitter. It also models correlation between delay bins in the power...
The space-time wireless communications systems will use the advantages of the MIMO (multiple input multiple output) channels. Precedent studies have focused less attention on the eigen/capacity analysis with correlated channels under different frequencies for indoor environments. The results derived from a frequency measurement campaign performed between 2 and 4 GHz, show frequency band dependence...
The determination of full double-directional parameters of the mobile channel has received considerable attention these last years, one of the main applications being the optimization of MIMO systems. Dedicated high-resolution parameter estimation techniques usually need the prior knowledge of the number of paths (or sources), a wrong estimation leading to erroneous results of the channel parameters...
Current researches on multiple-input multiple-output (MIMO) channel treat it as a kind of Gaussian channel. Without considering the spatial-temporal correlation, considerable deviation exists in output. This paper presents a novel spatial-temporal correlation model (STCM) for MIMO channel modeling. We adopt a correlation matrix to model the spatial correlation at the base and use wave superposition...
In this contribution, we derive a probability distribution suitable for characterizing bi-azimuth (azimuth of arrival and azimuth of departure) direction dispersion of individual path components in the response of the propagation channel. This distribution belongs to the family of generalized von-Mises-Fisher distributions. The elements in this family maximize the entropy under the constraint that...
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