Abdulla A. Abouda

Effect of Mutual Coupling on Capacity of MIMO Wireless Channels in High SNR Scenario

Theoretical results on the effect of antenna mutual coupling (MC) on capacity of multiple-input multiple-output (MIMO) wireless channels are presented in this paper with particular emphasis on the case of high signal to noise ratio (SNR) scenario. Two cases are considered, 1- channel capacity variations due to MC effect on correlation properties and target average receive SNR and 2- channel capacity variations due to MC effect on correlation properties at fixed average receive SNR. It is shown that the effect of MC on MIMO channel capacity can be positive or negative depending on the propagation environment spatial correlation properties and the characteristics of the transmitter and receiver MC matrices. Conditions where MC has positive and negative effects on MIMO channel capacity in the two considered cases are identified. Numerical results for half wavelength dipole antenna supporting the theoretical observations are presented.

Effect of Antenna Array Geometry and Ula Azimuthal Orientation on MIMO Channel Properties in Urban City Street Grid

Propagation environment and antenna array configuration have significant effect on spatial correlation properties of multiple- input multiple-output (MIMO) wireless communications channels. In this paper the effect of different antenna array geometries on MIMO channel properties is investigated in urban city street grid propagation environment. Four antenna array geometries with the same number of antenna elements and fixed inter-element spacing are considered, namely, uniform linear array (ULA), uniform circular array (UCA), uniform rectangular array (URA) and uniform cubic array (UCuA). The effect of ULA orientation in azimuthal plane on MIMO channel ergodic capacity is also investigated. Varying orientation angle from 0 to π at the two communication ends is considered. The investigation is carried out based on three dimensional (3D) spatial multi-ray realistic propagation channel model covering different propagation types. It is shown that the antenna array geometry have significant impact on MIMO channel properties. Under different propagation scenarios the ULA shows superiority to the other considered geometries in terms of the ergodic channel capacity and number of spatial parallel channels. However, this superiority depends largely on the array azimuthal orientation.

Spatial Smoothing Effect on Kronecker Mimo Channel Model in Urban Microcells

In this paper, the effect of spatial smoothing on performance of widely used stochastic narrowband multiple-input multiple-output (MIMO) radio channel model, namely the Kronecker model, is investigated based on data measured in urban microcellular environment at 5.3 GHz carrier frequency. Results from non-line of sight (NLOS) and line of sight (LOS) traveling routes are analyzed. It is noticed that in NLOS traveling route spatial smoothing improves the accuracy of the large eigenvalues of the channel correlation matrix and significantly enhances the applicability of the Kronecker structure. Under LOS condition both the Kronecker model and its smoothed version fail to render the eigenvalues of the measured channel correlation matrix but spatial smoothing slightly improves the applicability of the Kronecker structure.

Performance of Stochastic Kronecker MIMO Radio Channel Model in Urban Microcells

In this paper, the performance of the widely used stochastic Kronecker multiple-input multiple-output (MIMO) radio channel model is investigated based on non-line of sight (NLOS) measured data in urban microcellular environment at 5.3 GHz carrier frequency. The channel transfer matrices rendered by the Kronecker model are compared to the measured ones in terms of the distribution of the channel coefficients and the distribution of the eigenvalues of the channel correlation matrix. Furthermore, the channel capacity and the symbol error rate performance achievable over the measured and modeled channels are also compared. Good agreement in terms of symbol error rate performance is found while 4.16% error in the median channel capacity at 20 dB signal to noise ratio (SNR) is observed

Impact of Antenna Array Geometry on MIMO Channel Eigenvalues

Spatial correlation properties of MIMO channel highly depend on the propagation environment and the antenna array geometry. In this paper the impact of different antenna array geometries on MIMO channel eigenvalues is investigated in realistic microcellular propagation environment under different scenarios. Four different antenna array geometries are considered, namely, uniform linear array, uniform circular array, uniform rectangular array and uniform cubic array. All the considered geometries have same number of elements and fixed inter-element spacing. The uniform linear array geometry shows superiority to the other considered geometries

Reducing Impact of Phase Noise on Accuracy of Measured MIMO Channel Capacity

Despite the fact that time-division multiplexed switching (TDMS)-based multiple-input-multiple-output (MIMO) wireless channel sounders are cost effective implementation techniques, they may result in significant measurement errors due to phase noise (PN) in the local oscillators. In this letter, the impact of PN on the accuracy of measured MIMO channel capacity is studied by considering its effect on both the spatial multiplexing gain and on the power gain. We show that in case of a low rank physical channel matrix the impact of PN is more pronounced on the spatial multiplexing gain than on the power gain. Based on that, we propose an eigenvalue filtering (EVF) technique to improve the accuracy of measured channel capacity.

Effect of Mutual Coupling on BER Performance of Alamouti Scheme

This work presents a study on the effect of mutual coupling on the performance of Alamouti scheme by studying the bit error rate (BER) performance under different propagation scenarios and for different coupling cases. We show that the presence of mutual coupling may have positive or negative impact on the achieved power gain depending on the correlation properties of the propagation environment in absence of the coupling effect and on the mutual coupling matrix