Research Interests:
Research Interests:
Research Interests: Pharmacology, Bioinformatics, Evolutionary Biology, Pathology, Oncology, and 21 moreRadiology, Pharmacy, Informatics, Genomics, Phylogenetics, Computational Biology, Biotechnology, Cancer, Biomarkers, Biology, Proteomics, Biomedical informatics, Medicine, Bioscience, Phylogeny, Scientific, Microarray, Clinical Medicine, Biological, Genetic modification, and Evidence Based
Research Interests: Pharmacology, Bioinformatics, Evolutionary Biology, Pathology, Oncology, and 21 moreRadiology, Pharmacy, Informatics, Genomics, Phylogenetics, Computational Biology, Biotechnology, Cancer, Biomarkers, Biology, Proteomics, Biomedical informatics, Medicine, Bioscience, Phylogeny, Scientific, Microarray, Clinical Medicine, Biological, Genetic modification, and Evidence Based
Research Interests:
ABSTRACT
Research Interests:
Research Interests:
It is well known that terrestrial analogue TV services are being replaced by digital services. Nevertheless it does not exist many studies about DVB-T signal propagation in MATV networks. Therefore, in this paper a specific DVB-T measure... more
It is well known that terrestrial analogue TV services are being replaced by digital services. Nevertheless it does not exist many studies about DVB-T signal propagation in MATV networks. Therefore, in this paper a specific DVB-T measure procedure to apply to these networks is described. We have also carried out an experimental MATV characterization according to that measure procedure. I. INTRODUCCIÓN En la actualidad, los servicios de difusión de televisión analógica están comenzando a ser sustituidos por los de difusión de televisión digital, siendo el 1 de enero del año 2012 la fecha prevista para que finalicen completamente las emisiones de televisión analógica. Sin embargo, existen escasos estudios acerca de la degradación que producen las MATV sobre esta señal digital (DVB-T). Con el objetivo de cubrir esa deficiencia se han diseñado un sistema y un procedimiento de medidas.
Wind turbines can cause degradation to the existing transmission systems, especially in the analogue television terrestrial broadcasting and radar services. The main effects of the interference are caused by the reflected signals in the... more
Wind turbines can cause degradation to the existing transmission systems, especially in the analogue television terrestrial broadcasting and radar services. The main effects of the interference are caused by the reflected signals in the support tower and in the rotating blades of the wind turbines. Empirical trials are necessary in order to adequately characterize the influence on the quality of the transmitted services, and to determine the parameters involved. The existing techniques to evaluate this influence are cost prohibitive or do not offer the required accuracy. In this paper, a low cost technique for evaluating the reflected signals from wind turbines is proposed, based on the analysis of the channel impulse response of the digital terrestrial television services. The results show that this technique provides accurate and reliable results.
Research Interests:
Research Interests:
Research Interests:
Research Interests:
ABSTRACT
Research Interests:
Emerging radio broadcasting digital systems in the Medium Wave (MW) band require accurate field strength prediction models for network planning. Near Vertical Incidence Sky-wave (NVIS) propagation provides wide coverage areas with only... more
Emerging radio broadcasting digital systems in the Medium Wave (MW) band require accurate field strength prediction models for network planning. Near Vertical Incidence Sky-wave (NVIS) propagation provides wide coverage areas with only one transmitter but extremely high time variability. This time variability is statistically characterized for the first time in this paper, by means of the Maximum Likelihood Estimator that has been applied to data recorded during an extensive measurement campaign in static reception. The difference between the median value and the 1%-of-the-time lowest value has also been calculated. Statistics show a Log Normal behavior and that almost 10 dB should be added to the predicted median value in order to ensure the coverage during 99% of the time.
ABSTRACT In this paper, we propose a novel method to validate channel estimations based on two different analysis that compare the similarity between the real signal measurements and the values obtained after processing the theoretical... more
ABSTRACT In this paper, we propose a novel method to validate channel estimations based on two different analysis that compare the similarity between the real signal measurements and the values obtained after processing the theoretical transmitted signal through the estimated channel. The merit of this technique is its simplicity, its flexibility and the possibility to identificate with one parameter the quality of our estimation. The performance is evaluated over a real Gaussian channel, and the method shows its efficiency for this type of channels.
Research Interests:
... stated on the appropriate standard. DVB-T and T-DAB coverage is defined on the basis of 100 x 100 meter geo-graphic squares, so the spatial variation should be studied over such distances [17]. Obviously, in a medium to ...
Research Interests:
This paper analyzes the reception of terrestrial digital audio broadcasting (T-DAB) signals at L-band in mobile channels, where multipath fading, Doppler spread and noise effects degrade the received signal. Receiver power levels and DAB... more
This paper analyzes the reception of terrestrial digital audio broadcasting (T-DAB) signals at L-band in mobile channels, where multipath fading, Doppler spread and noise effects degrade the received signal. Receiver power levels and DAB base-band parameters have been recorded in order to study real performance of DAB signals in mobile propagation channels, with different vehicle speeds and with different multipath
Research Interests:
ABSTRACT This paper presents the field trials carried out in Bilbao (Spain) for testing the feasibility of Cloud Transmission reception in mobile urban environments. The Cloud Transmission System (Cloud-Txn) is a new way of broadcasting... more
ABSTRACT This paper presents the field trials carried out in Bilbao (Spain) for testing the feasibility of Cloud Transmission reception in mobile urban environments. The Cloud Transmission System (Cloud-Txn) is a new way of broadcasting or point to multipoint transmission system, designed for a flexible use of the spectrum, robustness against noise, multipath and capability to provide fixed or mobile reception while using low transmission power. Therefore this paper analyzes the system performance of the proposed signal structure based on the first measurements in the field so as to determine the coverage area of those kinds of services. Additionally, first approach of the required signal to noise ratio for a correct reception in mobile urban environments will be calculated. The results will provide reference results that can be used for planning purposes in this kind of scenarios.
Research Interests:
Research Interests:
The Lee Method, recommended by ITU-R and CEPT for separation short-term and long-term component spatial variations of the field strength, was solved by Lee assuming Rayleigh distributed variations. In this paper, the method is adapted for... more
The Lee Method, recommended by ITU-R and CEPT for separation short-term and long-term component spatial variations of the field strength, was solved by Lee assuming Rayleigh distributed variations. In this paper, the method is adapted for the specific propagation conditions of ground wave at MW band, using empirical data from DRM field trials. The results complete those obtained by Lee
Research Interests:
This paper suggests an architecture design for a single frequency network (SFN) planning software. These software tools will be very useful during the planning stages in order to optimize the network design and implementation process. The... more
This paper suggests an architecture design for a single frequency network (SFN) planning software. These software tools will be very useful during the planning stages in order to optimize the network design and implementation process. The new digital broadcasting services DVB-T (digital terrestrial video broadcasting) and T-DAB (digital terrestrial audio broadcasting) have already been tested in many countries over the
Research Interests:
The digital broadcasting systems (DRM and HD radio/ IBOC) developed in the last decade have renewed the interest for the MW band. The planning requirements of the digital services require more accurate channel models and a significant... more
The digital broadcasting systems (DRM and HD radio/ IBOC) developed in the last decade have renewed the interest for the MW band. The planning requirements of the digital services require more accurate channel models and a significant improvement in the coverage estimation algorithms. The variability of the local median values (sigmaL) is a key parameter in the estimation process of
Research Interests:
The recent digital broadcasting services developed for the MF and HF bands require the accurate definition of the measurement conditions to be applied both in the planning of future field trials and in the analysis of the signal... more
The recent digital broadcasting services developed for the MF and HF bands require the accurate definition of the measurement conditions to be applied both in the planning of future field trials and in the analysis of the signal variability. This paper describes the outcomes of the necessary distance between adjacent measuring points of field trials, which must be uncorrelated samples.
Research Interests:
ABSTRACT This paper presents a statistical characterization of the skywave interference conditions for DRM (Digital Radio Mondiale) local services in the 26 MHz band. This work is the first step to analyze the feasibility of a world... more
ABSTRACT This paper presents a statistical characterization of the skywave interference conditions for DRM (Digital Radio Mondiale) local services in the 26 MHz band. This work is the first step to analyze the feasibility of a world frequency planning for local services in this band and is focused on regular ionospheric propagation. The analysis has been based on two parameters: Maximum Usable Frequency (MUF) and field strength received level. Values of these parameters were obtained by means of two prediction tools, both of them referenced by the ITU and developed by the NTIA/ITS: REC533 and VOACAP. Simulations were carried out defining combinations of a wide range of Sun Spot Number (SSN) values characterizing a complete solar cycle, 12 months per year and 24 hours per day. This first study has focused on Europe and was done for 20790 circuits after establishing 5 representative transmitters and taking this continent as the reception area. From the resultant database, cumulative distribution functions, as well as other significant statistics, were computed and analyzed for both parameters. The obtained results show the ionospheric conditions that give raise to interfering signals between DRM local services and establish when their propagation is critical.
ABSTRACT This paper analyzes the field strength location variability in the Medium Wave band. Field data from an experimental transmission and statistical inference techniques are used in the study. Several reception scenarios are... more
ABSTRACT This paper analyzes the field strength location variability in the Medium Wave band. Field data from an experimental transmission and statistical inference techniques are used in the study. Several reception scenarios are considered, attending to the main causes of the field strength fluctuations. The paper exposes results for the statistical characterization of both large scale variations and local variability, and useful values for coverage area estimations are given. A proper characterization of the location variability is necessary for the accurate system planning of the new digital radio services at this frequency band.
Research Interests:
ABSTRACT The renewed interest in the use of the Medium Wave band for broadcasting purposes makes it necessary to evaluate if the prediction methods used for network planning of the analogue services are accurate enough for the new digital... more
ABSTRACT The renewed interest in the use of the Medium Wave band for broadcasting purposes makes it necessary to evaluate if the prediction methods used for network planning of the analogue services are accurate enough for the new digital transmissions. The Millington method, included in the ITU-R Rec. P.368-9, is a semi-empirical method that considers non-homogeneous terrain paths composed of sections with different lengths and conductivity values. The aim of this study is to empirically analyze the accuracy of the Millington prediction method in the specific case of land-sea-land propagation paths. Furthermore, a method for minimizing the effect of conductivity inaccuracies in the field strength predicted values is proposed.
This paper describes the first results of an extensive measurement campaign for evaluating the potential impact of scattered signals from wind turbines to terrestrial DTV reception quality in the UHF band. The field trial carried out in... more
This paper describes the first results of an extensive measurement campaign for evaluating the potential impact of scattered signals from wind turbines to terrestrial DTV reception quality in the UHF band. The field trial carried out in Northern of Spain has two main objectives: the empirical characterization of the scattered signals from the wind turbines, and the assessment of the potential impact of these scattered signals to the reception quality of the terrestrial DTV systems. This paper includes preliminary results relating to the second objective. Some empirical threshold carrier-to-noise ratios in the area of influence of a wind farm are presented in order to verify whether scattered signals from wind turbines could affect the threshold carrier-to-noise ratio required for quasi-error-free reception in the DVB-T system.
Research Interests:
ABSTRACT This paper analyzes the impact produced by the use of distributed MISO diversity techniques on the network planning for mobile broadcasting services, compared with the rest of variables considered in the design of these networks.... more
ABSTRACT This paper analyzes the impact produced by the use of distributed MISO diversity techniques on the network planning for mobile broadcasting services, compared with the rest of variables considered in the design of these networks. In order to do that, we have evaluated the results obtained from the simulation of a wide variety of real cases of study, where different deployment topologies and different types of service scenarios have been considered. For all the cases analyzed, the results show evidence that the use of distributed MISO techniques does not provide a significant improvement in the coverage and a low impact compared to the rest of variables considered in the network design.
ABSTRACT DVB-T2 is the second generation terrestrial broadcast system developed within the DVB consortium. Based on multi-carrier transmission OFDM, DVB-T2 introduces many innovative tools offering high flexibility to broadcasters. Among... more
ABSTRACT DVB-T2 is the second generation terrestrial broadcast system developed within the DVB consortium. Based on multi-carrier transmission OFDM, DVB-T2 introduces many innovative tools offering high flexibility to broadcasters. Among many other new techniques DVB-T2 defines an optional Time-Frequency-Slicing (TFS) profile. In TFS slices of a PLP are sent over multiple and non necessarily adjacent RF frequency channels. This technique provides a gain associated to propagation diversity, as well as an intrinsic multiplexation gain. Following a software defined radio approach this paper presents a flexible DVB-T2 Time Frequency Slicing evaluation framework built to study the practical performance of DVB-T2 Time Frequency Slicing configurations under realistic channel scenarios. The paper focuses on the diversity gain associated to propagation diversity.
This paper presents an analysis of the ground wave propagation in the 26 MHz band based on a comparison between measured and predicted field strength values. To do this, a set of empirical data obtained from a measurement campaign of a... more
This paper presents an analysis of the ground wave propagation in the 26 MHz band based on a comparison between measured and predicted field strength values. To do this, a set of empirical data obtained from a measurement campaign of a DRM experimental local service was used. Simulated field strength values were calculated applying two different models that account for