Seasonal Variations of Polarization Diversity Gain in a Vegetated Area considering High Elevation Angles and a Nomadic User

Kvičera, Milan; Pechač, Pavel

doi:10.1155/2015/194626

Cited by 11 publications

(11 citation statements)

References 12 publications

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“…For these purposes, a remote controlled airship carrying a Tx instantly pointing toward Rx was utilized. The measurement system transmitted left-handed circularly polarized (LHCP) and right-handed circularly polarized continuous wave signals, which were received by a custommade sensitive Rx with a high sampling rate of 10 kHz [15]. Here, however, it is suff cient to address only one copolarized channel, namely, LHCP, and, to be consistent with Section IV, vertical polarization will be considered by both the modif ed PO and MST models.…”

Section: Experimental Validationmentioning

confidence: 99%

“…So far, this resulted, for example, in the characterization of a single-tree scattering pattern by means of computationally demanding f nite-difference time domain [11], canopy volume being f lled with point source scatterers [12] or [13], highfrequency measurement campaigns [14], or measurements of specif c attenuation for different types of trees or seasons [15]- [17].…”

Section: Introductionmentioning

confidence: 99%

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A New Model for Scattering From Tree Canopies Based on Physical Optics and Multiple Scattering Theory

Kvičera

Fontán

Israel

et al. 2017

IEEE Trans. Antennas Propagat.

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Section: Experimental Validationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A New Model for Scattering From Tree Canopies Based on Physical Optics and Multiple Scattering Theory

Kvičera

Fontán

Israel

et al. 2017

IEEE Trans. Antennas Propagat.

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“…The trials were taken in July 2015 at Fleming Square in Prague, Czech Republic, and the same measurement setup as in [19] was utilized. This means that a 3D positioner attached to the UAV enabled instant pointing of the transmit (Tx) antennas towards the receiver (Rx) based on the corresponding GPS coordinates which, for Rx were 50 • 6 16.97 N and 14 • 23 31.62 E in the WGS84 coordinates.…”

Section: Experimental Data Validationmentioning

confidence: 99%

A New Propagation Channel Synthesizer for UAVs in the Presence of Tree Canopies

2017

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Abstract:Following the increasing popularity of unmanned aerial vehicles (UAVs) for remote sensing applications, the reliable operation under a number of various radio wave propagation conditions is required. Assuming common outdoor scenarios, the presence of trees in the vicinity of a UAV or its ground terminal is highly probable. However, such a scenario is very difficult to address from a radio wave propagation point of view. Recently, an approach based on physical optics (PO) and the multiple scattering theory (MST) has been proposed by the authors, which enables fast and straightforward predictions of tree-scattered fields at microwave frequencies. In this paper, this approach is developed further into a generative model capable of providing both the narrowband and wideband synthetic time series of received/transmitted signals which are needed for both UAV communications and remote sensing applications in the presence of scattering from tree canopies. The proposed channel synthesizer is validated using both an artificially-generated scenario and actual experimental dataset.

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“…The first‐order statistics include the probability or cumulative distribution functions (pdf or cdf), whereas the second‐order statistics incorporate parameters such as the autocorrelation function, the level crossing rate (LCR), and the average fade duration (AFD). In this context, there are scarce statistical characterization attempts, mainly in the frame of King and Stavrou, King and Brown et al, Kourogiorgas, and Kvicera and Pechac, for a MIMO, and for a single‐input‐multiple‐output LMS channel, respectively.…”

Section: Introductionmentioning

confidence: 99%

“…Another important issue that should be highlighted is the diversity performance of the LMS channel. There are limited research activities in this framework, eg, Kvicera and Pechac, for high elevation angles in a vegetative environment and for low elevation angles in an urban area. Therefore, it is essential to investigate the potential diversity improvement provided by selecting the best combining technique.…”

Section: Introductionmentioning

confidence: 99%

Statistical characterization of an urban dual‐polarized MIMO LMS channel

Nikolaidis

Moraitis

Kanatas

2018

Satell Commun Network

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This paper presents a thorough statistical characterization of a dual-polarized multiple-input-multiple-output channel, based on a measurement campaign of 2 land mobile satellite link scenarios in urban environments. The received signal is decomposed into its large-scale and small-scale fading parts, which are separately evaluated and characterized. The large-scale fading can be well approximated by the Lognormal distribution, whereas the small-scale fading in line-of-sight condition can be characterized as a Rician channel with a strong direct component and high Kfactors. On the other hand, in nonline-of-sight cases, the fading can be approximated by Nakagami or Rician distribution with low K-factors. The cross-polar discrimination is found between 14.2 and 22.5 dB, whereas the cross-polar isolation is found between 12.8 and 21 dB, respectively. Finally, assessing the diversity performance, applying the maximal ratio combining technique, it is found that the left-hand circular polarized transmission outperforms the right-hand circular polarized transmission, providing gains up to 2.5 dB, especially in nonline-of-sight cases. The low-diversity gains indicate that beamforming would be preferable to be applied in the specific channel.KEYWORDS channel characterization, channel modeling, dual-polarized, multiple-input-multiple-output (MIMO) satellite measurements | INTRODUCTIONIn the years to come, new narrowband satellite communication technologies will allow for direct connection of millions of Internet of Things (IoT) devices in a resource efficient way. The ultimate success of global IoT coverage will depend on the active support of satellite networks providing L-band and S-band services. Satellite technology serves as a key enabler to transform IoT connectivity across industries and geographical borders and has the potential to play a key role in cases where sensors and actuators are distributed over a very wide area as well as in remote areas not served by terrestrial access networks. Indeed, the use of the satellite is found to be of great importance in some applications of IoT, like smart grid, environmental monitoring, and emergency management, because satellite communications have unique merits such as large-scale coverage, superb ability to support emerging communications services, and cost effectiveness for broadcast/multicast connectivity. 1-3 Bringing wide-area connectivity for the IoT by using satellite technology is therefore an attractive solution to complement terrestrial networks, allowing densification and coverage extension in remote areas. 4The proliferation of multiantenna technology and its adoption in terrestrial communication systems provided unprecedented capacity improvement and enhanced spectral efficiency. The applicability of multiple-input-multiple-output (MIMO) techniques is also an appealing solution in satellite communication systems with a very promising outlook. 5,6 Specifically, land mobile satellite (LMS) systems can take advantage of MIMO techniques and achieve substantially in...

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Seasonal Variations of Polarization Diversity Gain in a Vegetated Area considering High Elevation Angles and a Nomadic User

Cited by 11 publications

References 12 publications

A New Model for Scattering From Tree Canopies Based on Physical Optics and Multiple Scattering Theory

A New Model for Scattering From Tree Canopies Based on Physical Optics and Multiple Scattering Theory

A New Propagation Channel Synthesizer for UAVs in the Presence of Tree Canopies

Statistical characterization of an urban dual‐polarized MIMO LMS channel

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