Now showing items 1-20 of 23

  • Area Coverage Simulations for Millimeter Point-to-Multipoint Systems Using Building Blockage 

    Ledl, P.; Pechač, Pavel (Společnost pro radioelektronické inženýrství, 2002-12)
    Area coverage simulation results for LMDS or PMP systems in millimeter waveband are presented in this paper. Area coverage simulations were performed according to ITU-R P.1410 model, where Rayleigh statistical distribution ...
  • Broadband Spectrum Survey Measurements for Cognitive Radio Applications 

    Urban, R.; Korinek, T.; Pechač, Pavel (Společnost pro radioelektronické inženýrství, 2012-12)
    It is well known that the existing spectrum licensing system results in a gross under-utilization of the frequency spectrum. Spectrum background measurements – spectrum surveys – provide useful data for spectrum regulation, ...
  • Closed-Form Approximation for Parallel-Plate Waveguide Coefficients 

    Valtr, P.; Pechač, Pavel (Společnost pro radioelektronické inženýrství, 2013-12)
    Simple closed-form formulas for calculating coefficients of modes excited in a parallel-plate waveguide illuminated by a planar wave are presented. The mode-matching technique and Green’s formula are used to arrive at a ...
  • Coexistence of Terrestrial and HAP 3G Networks during Disaster Scenarios 

    Holis, J.; Pechač, Pavel (Společnost pro radioelektronické inženýrství, 2008-12)
    The aim of this paper is to show the possible coexistence of an HAP and a terrestrial component of 3G networks at a single carrier frequency. The main goal is to compare the basic parameters of terrestrial and HAP com-ponent ...
  • Comparative Evaluation of UMTS, WLAN, BWA, MBWA, and UWB Systems 

    Ledl, P.; Pechač, Pavel (Společnost pro radioelektronické inženýrství, 2003-12)
    UMTS, WLAN, BWA and UWB systems are compared in this paper. The comparative analysis covers system capacity, QoS, and radiowave propagation.
  • Controlling the Short-Range Propagation Environment Using Active Frequency Selective Surfaces 

    Subrt, L.; Grace, D.; Pechač, Pavel (Společnost pro radioelektronické inženýrství, 2010-12)
    This paper deals with a new approach to the control of the propagation environment in indoor scenarios using intelligent walls. The intelligent wall is a conventional wall situated inside a building, but equipped with an ...
  • Diffraction Calculations and Measurements in Millimeter Frequency Band 

    Valtr, P.; Pechač, Pavel (Společnost pro radioelektronické inženýrství, 2004-09)
    The paper deals with a study of diffraction on dielectric wedge (building corner) in millimeter frequency band, both theoretically and experimentally, to provide knowledge support for ray tracing/launching calculations of ...
  • Electromagnetic Field in Anechoic and EMC Chambers - Part I - Modelling 

    Mazanek, M.; Klepal, M.; Pechač, Pavel (Společnost pro radioelektronické inženýrství, 2000-04)
    Anechoic and EMC chamber at the CTU in Prague was designed and used for a variety of antenna measurements and EMI testing. Due to different measurement methods (near field, far field, compact range, and EMI measurement) ...
  • Electromagnetic Wave Propagation Modeling Using the Ant Colony Optimization Algorithm 

    Pechač, Pavel (Společnost pro radioelektronické inženýrství, 2002-09)
    The Ant Colony Optimization algorithm - a multi-agent approach to combinatorial optimization problems - is introduced for a simple ray tracing performed on only an ordinary bitmap describing a two-dimensional scenario. ...
  • Empirical Models for Indoor Propagation in CTU Prague Building 

    Pechač, Pavel; Klepal, M. (Společnost pro radioelektronické inženýrství, 2000-04)
    Indoor propagation modelling is demanded for the design and maintenance of indoor wireless services. Empirical modelling seems to be the most efficient approach. Even so there are many studies dealing with empirical models ...
  • Excess Loss Model for Low Elevation Links in Urban Areas for UAVs 

    Simunek, M.; Pechač, Pavel; Fontan, F. P. (Společnost pro radioelektronické inženýrství, 2011-09)
    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 ...
  • First-Order Statistics Prediction for a Propagation Channel of Arbitrary Non-Geostationary Satellite Orbits 

    Kvicera, M.; Pechač, Pavel (Společnost pro radioelektronické inženýrství, 2015-04)
    A method enabling the prediction of first-order statistics of received signal level for arbitrary non-geostationary satellite orbits based on a reference dataset for a wide range of elevation angles is introduced for ...
  • Generalized Propagation Channel Model for 2GHz Low Elevation Links Using a Ray-tracing Method 

    Zeleny, J.; Perez-Fontan, F.; Pechač, Pavel (Společnost pro radioelektronické inženýrství, 2015-12)
    Unmanned Aerial Vehicles (UAV) will increasingly be used for responding to emergencies or for law enforcement in civil surveillance applications. Transferring the enormous amounts of information from UAV-mounted cameras ...
  • Indoor Propagation Measurement for WLAN Systems Operating in 2.45 GHz ISM Band 

    Valek, M.; Zvanovec, S.; Pechač, Pavel (Společnost pro radioelektronické inženýrství, 2002-12)
    For a planning of indoor Wireless LAN systems working in the ISM band, the signal propagation prediction is needed. In this article, the measurement campaign based on two types of measurements at 2.45 GHz is introduced. ...
  • Influence of Antenna Characteristics on Elevation Dependence of Building Penetration Loss for High Elevation Links 

    Kvicera, M.; Pechač, Pavel (Společnost pro radioelektronické inženýrství, 2012-12)
    Building penetration loss models presented in our previous paper [1] were valid for various scenarios, propagation conditions, frequency bands and hemispherical receiving antenna pointing towards zenith. These models had ...
  • A Model for the Detailed Analysis of Radio Links Involving Tree Canopies 

    Perez-Fontan, F.; Kvicera, M.; Pechač, Pavel; Israel, J. (Společnost pro radioelektronické inženýrství, 2016-12)
    Detailed analysis of tree canopy interaction with incident radiowaves has mainly been limited to remote sensing for the purpose of forest classification among many other applications. This represents a monostatic configuration, ...
  • Novel Approach to Indoor Propagation Modeling 

    Pechač, Pavel; Klepal, M.; Novotny, K. (Společnost pro radioelektronické inženýrství, 2000-09)
    An indoor propagation prediction for personal communication systems is demanded for modern wireless services. There are two main general approaches for indoor propagation modeling: empirical and deterministic. Both of them ...
  • Provision of 3G Mobile Services in Sparsely Populated Areas Using High Altitude Platforms 

    Holis, J.; Pechač, Pavel (Společnost pro radioelektronické inženýrství, 2008-04)
    This paper deals with the application of High Altitude Platforms for the provision of third generation mobile services in sparsely-populated areas or in developing countries. It focuses on the behavior of large cells ...
  • Results of Indoor Propagation Measurement Campaign at 1900 MHz 

    Pechač, Pavel; Klepal, M.; Zvanovec, S. (Společnost pro radioelektronické inženýrství, 2001-12)
    For the design of indoor picocellular systems in the frequency band of 1800/2100 MHz, a signal propagation modelling is needed. Empirical and semi-empirical models represent an efficient approach to the coverage prediction. ...
  • Simulation of UMTS Capacity and Quality of Coverage in Urban Macro- and Microcellular Environment 

    Holis, J.; Pechač, Pavel (Společnost pro radioelektronické inženýrství, 2005-12)
    This paper deals with simulations of a radio interface of third generation (3G) mobile systems operating in the WCDMA FDD mode including propagation predictions in macro and microcells. In the radio network planning of 3G ...