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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 ... -
Performance Analysis of Multiradio Transmitter with Polar or Cartesian Architectures Associated with High Efficiency Switched-Mode Power Amplifiers (invited paper)
(Společnost pro radioelektronické inženýrství, 2010-12)This paper deals with wireless multi-radio transmitter architectures operating in the frequency band of 800 MHz – 6 GHz. As a consequence of the constant evolution in the communication systems, mobile transmitters must be ... -
On the Effect of Channel Impairments on VANETs Performance
(Společnost pro radioelektronické inženýrství, 2010-12)The primary means of studying the performance of vehicular ad hoc networks (VANETs) are computer simulations. Nowadays, the development of analytical models and the use of hybrid simulations that combine analytical modeling ... -
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 ... -
Modular Filter Structures Using Current Feedback Operational Amplifiers
(Společnost pro radioelektronické inženýrství, 2010-12)The concept of the wave filtering is followed in the derivation of high-order filter topologies by employing Current Feedback Operational Amplifiers as active blocks. For this purpose, the wave equivalent of an appropriate ... -
LMS Based Adaptive Channel Estimation for LTE Uplink
(Společnost pro radioelektronické inženýrství, 2010-12)In this paper, a variable step size based least mean squares (LMS) channel estimation (CE) algorithm is presented for a single carrier frequency division multiple access(SC-FDMA) system under the umbrella of the long term ... -
Key Information Retrieval in Hyperspectral Imagery through Spatial-Spectral Data Fusion
(Společnost pro radioelektronické inženýrství, 2010-12)Hyperspectral (HS) imaging is measuring the radiance of materials within each pixel area at a large number of contiguous spectral wavelength bands. The key spatial information such as small targets and border lines are ... -
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 ... -
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 ... -
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 ... -
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 ... -
Guest Editorial: Cognitive Radio Communications and Software Defined Radio
(Společnost pro radioelektronické inženýrství, 2010-12) -
Sensing Task Allocation for Heterogeneous Channels in Cooperative Spectrum Sensing
(Společnost pro radioelektronické inženýrství, 2010-12)In the traditional centralized cooperative spectrum sensing, all secondary users sense the same channel. But, for a given channel, there exists detection performance diversity among all the users, due to the different ... -
Optimum Detection Location-Based Cooperative Spectrum Sensing in Cognitive Radio
(Společnost pro radioelektronické inženýrství, 2010-12)Cognitive radio arises as a hot research issue in wireless communications recently, attributed to its capability of enhancing spectral efficiency and catering for the growing demand for bandwidth. As a good embodiment of ... -
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, ... -
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 ... -
Performance of Pilot Aided Channel Estimation Technique in 2D Spreading Based Systems
(Společnost pro radioelektronické inženýrství, 2010-12)It has recently been observed that the combination of the OFDM (Orthogonal Frequency Division Multiplex) and the CDMA (Code Division Multiple Access) can achieve notably lower BER (Bit Error Rate) performance in comparison ... -
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 ... -
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 ... -
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 ...