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The uplink in a cellular network where the base station (BS) and an advanced user equipment (UE) that is not the traditional mobile device is investigated. This is proposed as a method of antenna offloading for the typical UE which suffers from size constraints. The Gram-Schmidt (GS) precoding algorithm is used to design novel precoding solutions when the receiver and transmitter can have a large...
One of the research activities in 5G communication systems is the extension of the MIMO processing from the 2D to the 3D plane by exploiting the elevation dimension which gives an additional degree of freedom to meet the high capacity demands. Despite the growing researches concerning 3D space propagation, there are few studies that evaluate the impact of 3D propagation on MIMO performance at the...
Channel correlation between different users can significantly deteriorate the energy and spectral efficiency of massive MIMO systems. As such, it is tempting to separate the highly correlated users in order to reduce intra-cell interference to improve the overall system performance. In this respect, and unlike existing work, we propose an adaptive user grouping algorithm for the downlink of multiuser...
This paper summarizes the influence of many parameters on the keyhole probability of a 2×2 MIMO-OFDM train-to-wayside communications system on a tunnel. These parameters are the separation of the antennas within the array, polarization and the cross-section of the tunnel. Results in terms of capacity and keyhole probability are provided. Measurements were carried out on Metro de Madrid (Spain) on...
The multi-probe anechoic chamber measurement methodology (MPAC) for quantifying the MIMO OTA performances of multiple antennas wireless terminals is described in [1-2-3-4] and is designed for emulating the spatial characteristics of the propagation models defined in [5]. This testing methodology has been currently the only approved by CTIA for measuring radiated performances of MIMO (TM3) wireless...
In this paper a novel low complexity scheme that achieves also reduced feedback overhead is studied for reporting the channel state information in Carrier aggregation MIMO systems. Such systems usually involve a large number of carriers and users, so the calculation and reporting of the required RI/PMI/CQI indexes could result in high computational complexity and feedback overhead. Given that the...
This paper analyzes the performance of full-duplex relaying (FDR) with multiple-antenna amplify-and-forward (AF) relay. The system performance due to practical wireless transmission impairments of spatial fading correlation and imperfect channel state information (CSI) is investigated. To this end, new exact closed-form expressions for the outage probability are derived, where the case of arbitrary,...
In this paper, we analyze multiple-input multiple-output quadrature spatial modulation (QSM-MIMO) systems that operate under imperfect channel information over correlated α-μ fading channels. A simple and closed-form expression for the pairwise error probability (PEP) is provided. Based on the obtained PEP, a closed-form upper bound expression for the average bit error probability (BEP) is obtained...
In the last decade, Nakagami fading shows good performance in matching measurement data under many scenarios, i.e., vehicle-to-vehicle (V2V), mobile-to-mobile (M2M) and indoor. However, little research has been done for generating of spatial-temporal correlated MIMO Nakagami fading. In this paper, we propose a generalized and accurate algorithm to generate Nakagami-m envelope channels with arbitrary...
This paper presents a 3-D statistical channel model of the impulse response with small-scale spatially correlated random coefficients for multi-element transmitter and receiver antenna arrays, derived using the physically-based time cluster - spatial lobe (TCSL) clustering scheme. The small-scale properties of multipath amplitudes are modeled based on 28 GHz outdoor millimeter-wave small-scale local...
This paper presents a comparison of different three dimensional (3D) MIMO Over-The-Air (OTA) multi-probe configurations. Spatial correlation is used as metric to evaluate the setup accuracy, considering different antenna probes emplacements and Elevation Spread (ES). Simulation results are presented in uniform and single cluster channel models for spherical and cylindrical 3D OTA.
In this paper, minimum redundancy multiple-input multiple-output (MR-MIMO) arrays - a class of thinned antenna arrays - are discussed. The concepts of MR-MIMO array design and almost difference sets (ADSs) are introduced, and an analytical method based on ADSs is proposed for MR-MIMO array designs. This method can quickly determine the locations of MR-MIMO arrays and require little computational cost...
This paper presents the results of a dual polarized multiple-input-multiple-output (MIMO) channel measurements, investigating a land mobile satellite (LMS) pedestrian scenario in an urban environment. The channel characterization considers the downlink from a fixed elevated position, emulating a satellite, to a mobile terminal, incorporating line-of-sight (LOS) and non-line-of-sight (NLOS) conditions,...
A geometry-based reference model for Second Order Scattering Fading (SOSF) distributed multiple-input-multiple-output (MIMO) channels is proposed for mobile-to-mobile scenarios. From this model, a spatial correlation function is derived. The time-variant nature of channel statistics is modeled by using a Hidden Markov Model (HMM) based approach. The proposed method enables to implement a generator...
The multiplexing efficiency of 4×4 higher order MIMO with different MIMO topologies under different propagation scenarios in a mobile terminal is presented in this study. The mean effective gain, correlation coefficient and multiplexing efficiency of different MIMO topologies are compared and the impact from the angular spread of the incoming wave is also studied. The results are instructive for the...
This paper presents a wideband miniaturized Vivaldi antenna with two excitation ports to create broadside and omnidirectional radiation patterns. The antenna is based on two Vivaldi monopoles implemented perpendicularly to a conductive ground plane, and oriented in opposite directions of the vertical symmetry axis. By exciting the ports in- and out- of phase, two orthogonal radiating modes can be...
MIMO technology enables high-data rates in wireless devices to allow from speech and video calls up to streaming media and web browsing all over a common platform. MIMO technology needs M antennas both in transmission and reception. Since the space in a wireless device is limited, including M antennas is a challenge. To face such challenge, two MIMO systems are proposed. A first one using a multiband...
The advantages of Multiple Input-Multiple Output (MIMO) wireless communication systems are known for more than a decade. The operational mechanism of a 2 × 2 MIMO system generally reminds either having cross-polarised receiver/transmitter multiport antennas in line-of-sight (LOS), or both co/cross-polarised multiport antennas in non-line-of-sight multipath environments [1]. In contrast to the aforementioned...
This paper investigates the effect of the radius of a Over-The-Air (OTA) multi-probes ring employing half-wavelength dipoles, on the emulated spatial correlation. The Device Under Test (DUT) is considered randomly oriented in the test zone. Based on the correlation error metric, antenna effect on correlation is evaluated for a Clarke's and single cluster scenarios and OTA two-dimensional rings with...
Introduction Multiple-Input-Multiple-Output(MIMO) and Multi-User MIMO (MU-MIMO) systems have been expected to improve the channel capacity over a limited bandwidth of existing networks [1], [2]. The effects on channel capacity of Single-User MIMO (SU-MIMO) systems in urban scenarios have been previously studied [3]. It has been clarified that the larger number of antennas cannot contribute the improvement...
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