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We propose a three-dimensional (3D) polarized MIMO channel model, which takes into account 3D power an-gular spectrum and comprehensive propagation characteristics of electromagnetic waves excited by polarized antennas. Based on the model, we derive a close form expression of the spatial correlation as a function of the physical parameters represen...
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... the case using a slanted polarized dipole array which composes of slanted dipoles. The radiation field patterns of the half-wavelength dipole for vertical and horizontal polarizations and are given by [31] (31) where . For convenience, the field patterns of the half-wavelength dipole with the inclination angle of 0 , 45 , and 90 are shown in Fig. ...
Context 2
... correlation for the configurations with the V/V and slanted polarizations (Fig. 6(a) and (b)). However, it is interesting to note that the 2D channel model provides the cor- relation of zero for the configuration with the V/H polarization (Fig. 6(c)). This is because the 2D model considers antenna pat- tern in azimuth plane only. As shown in Fig. 4, the vertical com- ponents of the dipole with inclination angle of 90 is only equal to zero in the plane . In this case, omission of the ver- tical components of the 2D model makes the orthogonality of polarization between the two antennas at the transmitter and re- ceiver, yielding zero correlation. Therefore, depending on the ...
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Citations
... The electric field components of the LoS path are achieved by projecting the time-varying electric fields of the transmit RPA onto the wavefront of the LoS path [33]. The projection matrix that captures this transformation can be obtained using the vectors u ′ and v ′ , as shown in (7) at the top of the next page. ...
This paper presents, for the first time, the concept of \textit{polarforming} for wireless communications. Polarforming refers to a novel technique that enables dynamic adjustment of antenna polarization using reconfigurable polarized antennas (RPAs). It can fully leverage polarization diversity to improve the performance of wireless communication systems by aligning the effective polarization state of the incoming electromagnetic (EM) wave with the antenna polarization. To better demonstrate the benefits of polarforming, we propose a general RPA-aided system that allows for tunable antenna polarization. A wavefront-based channel model is developed to properly capture depolarization behaviors in both line-of-sight (LoS) and non-line-of-sight (NLoS) channels. Based on this model, we provide a detailed description of transmit and receive polarforming on planes of polarization (PoPs). We also evaluate the performance gains provided by polarforming under stochastic channel conditions. Specifically, we derive a closed-form expression for the relative signal-to-noise ratio (SNR) gain compared to conventional fixed-polarization antenna (FPA) systems and approximate the cumulative distribution function (CDF) for the RPA system. Our analysis reveals that polarforming offers a diversity gain of two, indicating full utilization of polarization diversity for dual-polarized antennas. Furthermore, extensive simulation results validate the effectiveness of polarforming and exhibit substantial improvements over conventional FPA systems. The results also indicate that polarforming not only can combat depolarization effects caused by wireless channels but also can overcome channel correlation when scattering is insufficient.
... T HE growing demand for the services of mobile radio communication systems has fostered a continuous search for novel transmission techniques with high spectral efficiency [1]. In this search, antenna polarization [2], [3] is investigated as an option to double or even triple the channel capacity using, for example, compact antenna arrays [4], [5]. Nonetheless, such an increase in channel capacity can be obtained only if the received signal is co-polarized with the receiving antenna. ...
... for the carrier frequency. 4 The average Doppler shift of the LOS path, υ 0 (t; 0), is shown as a red-solid curve in Fig. 10. The blue-solid curves correspond to the average Doppler shift, υ 1 (t; 0), of the NLOS paths stemming from the first cluster of ROs, i.e., NLOS paths having a mean AAOD equal to π/2. ...
This paper presents a geometrical framework for the polarimetric modeling of mobile fading channels. Such a framework is formulated upon a spherical-wave propagation paradigm that allows to account for two important factors pertaining to wave polarization that are not jointly considered in the state of the art, namely: the anisotropic radiation characteristics of practical antennas, and the variations in time and space of the channel depolarization effects. The joint characterization of these two factors is important, e.g., for the analysis of mobile communication systems that rely on highly dynamic radio links, such as vehicular networks. The channel depolarization function is modeled by a linear transformation in the form of a simple rotation matrix that is transparent to the antenna polarization and to the geometry of the propagation scenario. The effects of multipath depolarization on the average power, the first-order envelope distribution, the average per-path Doppler shift, and the mean Doppler shift of mobile fading channels are analyzed mathematically and numerically. An open geometrical configuration of the propagation scenario is considered for the mathematical analysis, whereas a particular configuration given by a new geometrical street model with reflecting surfaces is adopted for the numerical analysis. The obtained results show that the aforementioned statistical quantities are strongly influenced by the anisotropic antenna pattern characteristics and by the time-space variations of multipath depolarization, demonstrating the importance of incorporating both factors into the modeling of mobile fading channels.
... Indicators like capacity, correlation, and condition number(CN) can be evaluated from channel matrix to assess the cellular communication performance. We used geometric based stochastic channel model (GBSCM) [14]- [16] with correlation among multipolarized antenna for channel matrix computation in our analysis of different polarization order. A MATLAB code for polarized 3D MIMO channel model is developed and executed using Monte Carlo method with 15000 samples to calculate the channel capacity, correlation, and CN of different 4 pol antenna combination. ...
p>This work provided a study of multiple polarization for use in a MIMO system. Currently, only 2 polarization MIMO system model is in use. However, there are multiple antennas in Tx and Rx sides, therefore, increasing the number of polarization equivalent to the number of antennas can improve MIMO channel capacity.
We experimented with different combinations for polarization for 4T4R MIMO system. The 4 suitable polarization obtained is further studied for higher capacity with Transmitter Beam Angular Diversity. Tranmistter Beam Angular Diversity reduce the correlation among non orthogonal polarization channel and improve MIMO system capacity.</p
... In this paper, in order to verify the working of proposed 4 polarization MIMO system, we analyse 4 polarization MIMO system using SCM due to its mathematical simplicity. The equations and details of the 3D SCM, a modified model from previous work [24], is presented in this section. However, we used COST 259 channel model (geometry based stochastic channel model) in section V for simulation and evaluation of proposed OPRA system with the real environment (urban) channel characteristics for comparison with field trial test results. ...
... Earlier SCMs (2D models) are simplified by considering that propagating wave arrives only from azimuth plane [25]- [27], however, it has been found that arrival/departure of wireless signal in both azimuth and elevation plane is significant for cross correlation analysis between polarized antennas in MIMO system [28]- [30], therefore, a 3D SCM considering wave propagation both in azimuth and elevation plane is essential for accurate analysis of multi-polarized MIMO system. Accordingly, a two sphere 3D geometrical SCM [24] is considered in this paper with antenna polarization and channel depolarization for the 4polarization OPRA configuration analysis. In this spherical model a 3D Von Mises Fisher (VMF) directional distribution of scatterers are considered over the sphere to closely emulate the real environment scatterer measurement data to fully create a 3D channel model. ...
... For the simulation and comparison, normalized field pattern of the different schemes (Fig. 3) is considered as Tx antenna pattern. Whereas a simple cross-polarized (V/H) omnidirectional dipole antenna as in [24] is considered for the Rx antenna unit. Also we set d T = 0.5λ, d R = 0.5λ, ϕ Rx = 0 • , θ Rx = 90 • , the mean XP D v = XP D h = 9 dB, and mean CP R = 5 dB. ...
5G communication promises fast and large data stream which requires higher capacity of a cellular wireless network. A higher capacity could be achieved with wider bandwidth and network densification, but they are expensive approaches. Instead, upgrading the wireless network with higher-order Multiple Input Multiple Output (MIMO) antenna system with polarization diversity can inexpensively escalate the peak data rate for higher capacity. We present a 4x4 MIMO cellular network scheme utilizing polarization reuse scheme and using 4 polarization to reform the cellular network from current state of the art of dual polarization 4x4 MIMO scheme. 4 Polarizations (vertical, Horizontal, ±45° slant) is used in 2 orthogonal polarization pair form, with a beam-separation among pair, to intensify polarization diversity and maximize the MIMO network channel capacity. This beam-separated polarization reuse technique minimizes the channel correlation which maximizes the probability of four independent data streams (rank 4). The simulated result of the channel capacity with the proposed scheme achieves a 30% higher capacity compared to the baseline configuration of 3-sector 4x4 MIMO. The field trial of the presented network indicates a higher portion of rank 4, supporting four independent data streams in the rich scattering environment of a cellular network.
... At the mobile side, the effects of orientation on the performance of MIMO systems have received considerable research attention where the handset is often tested using many different orientation angles [8][9][10][11][12][13][14]. In [11], the impact of random handset orientation using Macro-cell and Pico-cell channel models is studied. ...
... In [11], the impact of random handset orientation using Macro-cell and Pico-cell channel models is studied. In [12] and [14], MIMO antenna performance is compared with different polarizations as a function of antenna orientation in terms of capacity. The influence on the throughput performance due to the handset polarization has been presented in [14][15][16][17][18]. ...
... In [12] and [14], MIMO antenna performance is compared with different polarizations as a function of antenna orientation in terms of capacity. The influence on the throughput performance due to the handset polarization has been presented in [14][15][16][17][18]. ...
... Previous works have proved that multipolarized multiple input multiple output (MIMO) outperforms the corresponding unipolarized MIMO in terms of channel capacity in many situations [6]- [8]. Moreover, dual-polarized antenna configurations outperform single polarization in terms of spatial correlation [9]. Due to these advantages, the multipolarized MIMO is considered to be a promising technique for next-generation mobile communication systems. ...
The clustered delay line channel model, in which each cluster consists of a number of rays, is widely used for link-level evaluations in mobile communications. Multiple parameters of each ray, including delay, amplitude, cross polarization ratio (XPR), initial phases of four polarization combinations and the azimuth and elevation angles of arrival and departure, shall be known. These parameters are measured using a channel sounder. The number of rays in every cluster is usually greater than the number of elements in the antenna array of the channel sounder, which represents a challenging issue in multipolarized channel measurements. A new subspace estimation method based on the broadband extended array response of an electromagnetic vector antenna array is proposed to resolve a large number of rays. The interelement spacing of the array can be greater than half the carrier wavelength, which reduces interelement coupling and simplifies the array design, especially for millimeter wave bands. First, the delay of each cluster is estimated using the reference antenna element. Then, the 2D angles of every ray are estimated using the classic rank-deficient multiple signal classification (MUSIC). Lastly, the initial phases, XPR and amplitude of every ray is estimated. Simulation results validate the proposed method.
... More specifically, the X parameter indicates the cross-attenuation between the co-polarized channels (vv, hh) and the cross-polarized channels (hv, vh). XPD is defined as the ratio of the power of co-polarized channels to the power of cross-polarized channels over V and H, expressed as [44] ...
In this treatise, we introduce a novel polarization modulation (PM) scheme, where we capitalize on the reconfigurable polarization antenna design for exploring the polarization domain degrees of freedom, thus boosting the system throughput. More specifically, we invoke the inherent properties of a dual polarized (DP) antenna for transmitting additional information carried by the axial ratio (AR) and tilt angle of elliptic polarization, in addition to the information streams transmitted over its vertical (V) and horizontal (H) components. Furthermore, we propose a special algorithm for generating an improved PM constellation tailored especially for wireless PM modulation. We also provide an analytical framework to compute the average bit error rate (ABER) of the PM system. Furthermore, we characterize both the discrete-input continuous-output memoryless channel (DCMC) capacity and the continuous-input continuous-output memoryless channel (CCMC) capacity as well as the upper and lower bounds of the CCMC capacity. The results show the superiority of our proposed PM system over conventional modulation schemes in terms of both higher throughput and lower BER. In particular, our simulation results indicate that the gain achieved by the proposed Q-dimensional PM scheme spans between 10dB and 20dB compared to the conventional modulation. It is also demonstrated that the PM system attains between 54% and 87.5% improvements in terms of ergodic capacity. Furthermore, we show that this technique can be applied to MIMO systems in a synergistic manner in order to achieve the target data rate target for 5G wireless systems with much less system resources (in terms of bandwidth and the number of antennas) compared to existing MIMO techniques.
... To begin our experimentation, we first characterize the body-induced effects of the drone on the radiation pattern in the elevation and azimuth planes for co-polarized (co-pol) and cross-polarized (x-pol) channels. Understanding the body-induced effects on radiation pattern and XPD can be crucial for researchers in establishing and analyzing models for polarized MIMO channels [25][26][27][28][29][30][31] that take radiation pattern, XPD, and correlation coefficients into consideration. These factors can affect drone-based design decisions such as antenna placement, orientation, and optimal location of a drone in 3D space. ...
... Hence, spatial multiplexing is not possible [33]. On the other hand, the same 0 dB value can indicate a richness of scatterers in the multipath environment, which leads to a low correlation coefficient and high diversity gains [29]. Surprisingly, and to the best of our knowledge, there is no prior work that characterizes polarization mixing and XPD degradation due to the sole effects of the drone body. ...
... Since the orientation and spacing of two co-located receiving antennas can greatly affect the correlation and consequently the capacity of a MIMO system [29], we analyze the cross-correlation coefficient of the received signal at the two receiving branches in all of our six experiments. In doing so, we see how our antenna spacing decision of 2 3 λ compares against what has been studied in literature and provide recommendations on antenna placement and polarization decisions. ...
In the next wave of swarm-based applications, unmanned aerial vehicles (UAVs) need to communicate with peer drones in any direction of a three-dimensional (3D) space. On a given drone and across drones, various antenna positions and orientations are possible.We know that, in free space, high levels of signal loss are expected if the transmitting and receiving antennas are cross polarized. However, increasing the reflective and scattering objects in the channel between a transmitter and receiver can cause the received polarization to become completely independent from the transmitted polarization, making the cross-polarization of antennas insignificant. Usually, these effects are studied in the context of cellular and terrestrial networks and have not been analyzed when those objects are the actual bodies of the communicating drones that can take different relative directions or move at various elevations. In this work, we show that the body of the drone can affect the received power across various antenna orientations and positions and act as a local scatterer that increases channel depolarization, reducing the cross-polarization discrimination (XPD). To investigate these effects, we perform experimentation that is staged in terms of complexity from a controlled environment of an anechoic chamber with and without drone bodies to in-field environments where drone-mounted antennas are in-flight with various orientations and relative positions with the following outcomes: (i.) drone relative direction can significantly impact the XPD values, (ii.) elevation angle is a critical factor in 3D link performance, (iii.) antenna spacing requirements are altered for co-located cross-polarized antennas, and (iv.) cross-polarized antenna setups more than double spectral efficiency. Our results can serve as a guide for accurately simulating and modeling UAV networks and drone swarms.
... In this scenario, we propose interference mitigation strategy by considering the impact of 3D antenna radiation pattern of dipole antenna with different configurations. The 3D radiation pattern of single dipole antenna [9] and two cross-dipole antenna [10], [11] configuration are studied in the literature. Unlike 2D domain geometric setup, the radiation pattern of dipole antenna varies depending on the location of devices. ...
Internet of things (IoT) is one of main paradigms for 5G wireless systems. Due to high connection density, interference from other sources is a key problem in IoT networks. Especially, it is more difficult to find a solution to manage interference in uncoordinated networks than coordinated system. In this work, we consider 3D topology of uncoordinated IoT network and propose interference mitigation scheme with respect to 3D antenna radiation pattern. In 2D topology network, the radiation pattern of dipole antenna can be assumed as onmi-directional. We show the variance of antenna gain on dipole antenna in 3D topology, consider the simultaneous use of three orthogonal dipole antennas, and compare the system performance depending on different antenna configurations. Our simulation results show that proper altitude of IoT devices can extensively improve the system performance.
... So the behavior of the propagation environment plays a significant role in determining the throughput. The 3GPP has provided several standard channel models for modeling the typical use scenarios of MIMO user equipment, including the number of clusters, number of subpaths in each cluster, angles of departure, angles of arrivals, power distribution, and delay, Doppler frequency component, as shown in Fig. 1 [32], [33]. ...
Multiple-input and multiple-output (MIMO) over-the-air (OTA) measurements have helped 4G wireless systems significantly for the communication throughput and to enhance the network stability. However, there remains a potential challenge, which may substantially obstruct the OTA test methodologies being adopted in 5G evaluations. According to the MIMO OTA measurement standards, throughput tests should be conducted in the far-field. As a result, a general system covering all the 4G frequency bands should be larger than 3.6 m, and even tens of meters for 5G. In addition to the cost of the chamber hardware, a sizeable footprint of building space is also required for the test system. Consequently, conducting far-field tests directly incurs excessively high costs in 5G. A compact system with dimensions of 1.9 m for 5G MIMO OTA is proposed in this paper, where a near-field to far-field transformation method is adopted into the current standard MIMO OTA test approach (the radiated two-stage approach), and the throughput in the near field is measured. Compared to existing test systems, the compact solution can achieve a cost reduction by at least an order of magnitude and obtain comparable results as a full-scale certification system.
