M. Simunek

Czech Technical University in Prague, Praha, Praha, Czech Republic

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Publications (7)5.35 Total impact

  • Michal Simunek, Pavel Pechac, Fernando P. Fontan
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    ABSTRACT: Space diversity techniques provide an effective way to mitigate the deep fades in received power in a scattering environment. Space diversity influence on narrowband UAV links, which are unique due to the elevation angle and mutual position of a moving transmitter in homogeneous environment and static receiver in scattering environment, is analyzed in a wooded area using a remotely controlled airship at 2 GHz. The experimental link forms a 1x4 SIMO configuration with influence quantified by values of diversity gain and subsequent comparison with Rayleigh fading series. The mutual antenna distance and elevation angle influence is also studied as the difference between the wooded area and an open field or urban environment.
    International Journal of Antennas and Propagation 06/2013; 2013. · 0.68 Impact Factor
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    ABSTRACT: In this paper we analyze the fading statistics of the link between a remotely controlled flying platform or an Unmanned Aerial Vehicle (UAV) and a ground receive station in an urban area. This link has a very specific geometry which is somewhere in between that of the purely terrestrial case (e.g., a macro-cell) and that of the land mobile satellite (LMS) systems. We have performed a model-based statistical analysis using unique experimental data, and following well-known models for LMS and terrestrial links with the conclusion that the Loo [1] (Rice+log-normal) model is the most suitable starting point for developing the wanted model; then several modifications have been introduced achieve a better match. Finally, we developed a narrowband time-series generator capable of reproducing the observed signal dynamics.
    IEEE Transactions on Antennas and Propagation 01/2013; 61(7):3850-3858. · 2.33 Impact Factor
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    ABSTRACT: In this communication we quantify the carrier-to-noise ratio, CNR, gains achieved using space diversity in a link reproducing the propagation conditions between a surveillance aerial vehicle, manned or unmanned, and a ground control station in an urban area at low elevation angles, in the 1-4 deg. range. The receiver is assumed to be at street level, i.e., it undergoes strong blockage effects. Such link differs from others, e.g., satellite or terrestrial, thus requiring an ad-hoc analysis including comprehensive measurements. Here, we describe a continuous wave, CW, measurement campaign where we used a four-channel receiver, i.e., we analyzed a 1 × 4 SIMO configuration. First, the correlation between branches was studied and then, we went on to verify the incremental CNR gains achieved by increasing the number of diversity branches. We also paid attention to the influence of the elevation angle within the limited elevation range considered. Moreover, for reference, we present a comparison with the theoretical diversity gains corresponding to four uncorrelated Rayleigh fading channels. In this study three usual combining strategies were also assessed: selection, SC, equal-gain, EGC, and maximal ratio, MRC.
    IEEE Transactions on Antennas and Propagation 01/2013; 61(12):6255-6260. · 2.33 Impact Factor
  • M. Simunek, P. Pechac, F. Perez-Fontan
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    ABSTRACT: In this paper we analyze the possible use of diversity methods for a link between an UAV and a ground control station in an urban area. We describe a measurement campaign which reproduces the UAV link using a four channel receiver. The whole system can be classified as SIMO 1×4. We briefly introduce diversity methods which can be used to improve the link performance. Finally we present the results of a comparison of all the methods, and an analysis of elevation angles, the influence of location on diversity gain, a distribution analysis and an analysis of the number of channels are performed. The conditions for diversity techniques are favorable and all three methods enhance link performance. The diversity gain is not significantly dependent on the elevation angle or on the location of the receiver.
    Antennas and Propagation (EUCAP), 2012 6th European Conference on; 01/2012
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    Michal Simunek, Pavel Pechac, Fernando P Fontan
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    ABSTRACT: In this paper we analyze the link between an UAV and a ground control station in an urban area. This link shows a unique geometry which is somewhere in between the purely terrestrial (e.g., a macro-cell channel) and the land mobile satellite case (LMS). We describe a measurement campaign which reproduces the UAV link conditions and shows how the excess loss is mainly dependent on the elevation angle and fairly independent of the distance. Finally, we propose a simple physical model for predicting the excess loss based on a combination of diffracted and reflected components. Results from this model are in good agreement with the measurements.
    01/2011; 20.
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    ABSTRACT: The aim of this paper is to describe tree attenuation measurements at 2 GHz in four different locations inside vegetation, and at three different positions for a single tree shadowing. The purpose of this measurement campaign was to use a 9-meter long remote-controlled airship as a pseudo-satellite. The transmitting station was located on the airship as a payload and receiving station inside or nearby the vegetation. Subsequently, the received signal strength was measured at each position as a function of elevation angles ranging from 25 to 90 degrees. Measurements taken in an open field were used as a reference. The measured data are still being processed, however, the initial results are shown. The results for locations inside the vegetation and the single tree are compared as well.
    Antennas and Propagation (EuCAP), 2010 Proceedings of the Fourth European Conference on; 05/2010
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    ABSTRACT: This paper presents preliminary results obtained from an extensive measurement campaign aimed at building penetration loss. We have concentrated on three different factors affecting this loss — the elevation, the frequency and the floor number of the investigated building. Results for two different measurement sites at 2.0 GHz and 5.0 GHz inside an old brick three-storey office building located in Prague are provided together with a brief description of the measurement system used during the measurement campaign.
    Antennas and Propagation (EuCAP), 2010 Proceedings of the Fourth European Conference on; 05/2010

Publication Stats

6 Citations
5.35 Total Impact Points

Institutions

  • 2010–2013
    • Czech Technical University in Prague
      • Department of Electromagnetic Field
      Praha, Praha, Czech Republic
  • 2011
    • University of Vigo
      Vigo, Galicia, Spain