Browsing 2010/4 by Title
Now showing items 1-20 of 39
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Advanced Fuzzy Logic Based Admission Control for UMTS System
(Společnost pro radioelektronické inženýrství, 2010-12)The capacity of CDMA (Code Division Multiple Access) systems is interference limited. Therefore radio resources management (RRM) functions are used. They are responsible for supplying optimum coverage, ensuring efficient ... -
Analysis and Design of Wideband Low Noise Amplifier with Digital Control
(Společnost pro radioelektronické inženýrství, 2010-12)The design issues in designing low noise amplifier (LNA) for Software-Defined-Radio (SDR) are reviewed. An inductor-less wideband low noise amplifier aiming at low frequency band (0.2-2GHz) for Software-Defined-Radio is ... -
Behavioral Modeling of a C-Band Ring Hybrid Coupler Using Artificial Neural Networks
(Společnost pro radioelektronické inženýrství, 2010-12)Artificial Neural Networks (ANNs) gained importance on the RF microwave (MW) design area and behavioral modeling of MW components in the past few decades. This paper presents a cost effective neural network (NN) approach ... -
Broadband Approximations for Doubly Curved Reflector Antenna
(Společnost pro radioelektronické inženýrství, 2010-12)The broadband approximations for shaped-beam doubly curved reflector antennas with primary feed (rectangular horn) producing uniform amplitude and phase aperture distribution are derived and analyzed. They are very valuable ... -
Compensation-based Game for Spectrum Sharing in the Gaussian Interference Channel
(Společnost pro radioelektronické inženýrství, 2010-12)This paper considers an optimization problem of sum-rate in the Gaussian frequency-selective channel. We construct a competitive game with an asymptotically optimal compensation to approximate the optimization problem of ... -
Continental Fog Attenuation Empirical Relationship from Measured Visibility Data
(Společnost pro radioelektronické inženýrství, 2010-12)Free Space Optics (FSO) has the great potential for future communication applications. However, weather influenced reduced availability had been the main cause for its restricted growth. Among different weather influences ... -
Controlling the Short-Range Propagation Environment Using Active Frequency Selective Surfaces
(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 ... -
Design of Polymer Wavelength Splitter 1310 nm/1550 nm Based on Multimode Interferences
(Společnost pro radioelektronické inženýrství, 2010-12)We report about design of 1x2 1310/1550 nm optical wavelength division multiplexer based on polymer waveguides. The polymer splitter was designed by using RSoft software based on beam propagation method. Epoxy novolak resin ... -
Distributed Multi-Commodity Network Flow Algorithm for Energy Optimal Routing in Wireless Sensor Networks.
(Společnost pro radioelektronické inženýrství, 2010-12)This work proposes a distributed algorithm for energy optimal routing in a wireless sensor network. The routing problem is described as a mathematical problem by the minimum-cost multi-commodity network flow problem. Due ... -
DVCCs Based High Input Impedance Voltage-Mode First-Order Filters Employing Grounded Capacitor and Resistor
(Společnost pro radioelektronické inženýrství, 2010-12)A voltage-mode high input impedance first-order highpass, lowpass and allpass filters using two differential voltage current conveyors (DVCCs), one grounded capacitor and one grounded resistor is presented. The highpass, ... -
The Effects of Interference Suppression by a Reconfigurable Structure at DSSS-DPSK Receiver
(Společnost pro radioelektronické inženýrství, 2010-12)In this paper we show the performances of DSSS-DPSK receiver where the interference rejection circuit is reconfigurable and is using ξ-structure. The results will be shown for the case of packet, as well as for the continuous ... -
An Efficient Filter Banks Based Multicarrier System in Cognitive Radio Networks (invited paper)
(Společnost pro radioelektronické inženýrství, 2010-12)In cognitive radio techniques, OFDM is usually regarded as the physical layer candidate. However, the weaknesses of the OFDM technique, i.e., using plain FFT for spectral analysis , decreased bandwidth efficiency due to ... -
Electronically Tunable Current-Mode Quadrature Oscillator Using Single MCDTA
(Společnost pro radioelektronické inženýrství, 2010-12)This paper presents a modified current differencing transconductance amlpifier (MCDTA) and the MCDTA based quadrature oscillator. The oscillator is current-mode and provides current output from high output impedance ... -
An Energy Efficient MAC Protocol for QoS Provisioning in Cognitive Radio Ad Hoc Networks
(Společnost pro radioelektronické inženýrství, 2010-12)The explosive growth in the use of real-time applications on mobile devices has resulted in new challenges to the design of medium access control (MAC) protocols for ad hoc networks. In this paper, we propose an energy ... -
Estimation of the Radio Channel Parameters using the SAGE Algorithm
(Společnost pro radioelektronické inženýrství, 2010-12)This paper presents the problem of estimating the parameters of a given number of superimposed signals, as is the case of the received signal in wireless communications. Based on the description of the received signal in ... -
Guest Editorial: Cognitive Radio Communications and Software Defined Radio
(Společnost pro radioelektronické inženýrství, 2010-12) -
Impact of Noise Power Uncertainty on the Performance of Wideband Spectrum Segmentation
(Společnost pro radioelektronické inženýrství, 2010-12)The objective of this work is to investigate the impact of noise uncertainty on the performance of a wideband spectrum segmentation technique. We define metrics to quantify the degradation due to noise uncertainty and ... -
Improvement of RF Vector Modulator Performance by Feed-forward Based Calibration
(Společnost pro radioelektronické inženýrství, 2010-12)RF Vector Modulator enables independent control of a narrowband RF signal amplitude and phase. Unfortunately practical realization of an analog vector modulator suffers from misbalances and imperfections in the I and Q ... -
Influence of Sea Surface Roughness on the Electromagnetic Wave Propagation in the Duct Environment
(Společnost pro radioelektronické inženýrství, 2010-12)This paper deals with a study of the influence of sea surface roughness on the electromagnetic wave propagation in the duct environment. The problem of electromagnetic wave propagation is modeled by using the parabolic ... -
Investigating the Behavior of Compact Composite Descriptors in Early Fusion, Late Fusion and Distributed Image Retrieval
(Společnost pro radioelektronické inženýrství, 2010-12)In Content-Based Image Retrieval (CBIR) systems, the visual content of the images is mapped into a new space named the feature space. The features that are chosen must be discriminative and sufficient for the description ...