This work addresses the problem of determining whether two multivariate random time series have the same power spectral density

(PSD), which has applications, for instance, in physical-layer security and cognitive radio. Remarkably, existing detectors for this

problem do not usually provide any kind of optimality. Thus, we study here the existence under the Gaussian assumption of optimal

invariant detectors for this problem, proving that the uniformly most powerful invariant test (UMPIT) does not exist. Thus, focusing on

close hypotheses, we show that the locally most powerful invariant test (LMPIT) only exists for univariate time series. In the multivariate

case, we prove that the LMPIT does not exist. However, this proof suggests two LMPIT-inspired detectors, one of which outperforms

previously proposed approaches, as computer simulations show.

%B IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP)
%C Calgary, Canada
%G eng
%0 Journal Article
%J IEEE Trans. Signal Processing
%D 2018
%T Testing equality of multiple power spectral density matrices
%A David Ramírez
%A Daniel Romero
%A Javier Vía
%A R. López-Valcarce
%A Ignacio Santamaría
%K winter
%B IEEE Trans. Signal Processing
%V 66
%P 6268-6280
%8 12/2018
%G eng
%N 23
%R 10.1109/TSP.2018.2875884
%0 Conference Paper
%B International Conference on Availability, Reliability and Security (ARES)
%D 2016
%T Co-creating Security-and-Privacy-by-Design Systems
%A Sauro Vicini
%A Francesco Alberti
%A Nicolás Notario
%A Alberto Crespo
%A Juan Ramón Troncoso-Pastoriza
%A Alberto Sanna
%B International Conference on Availability, Reliability and Security (ARES)
%C Salzburg, Germany
%P 768-775
%8 09/2016
%G eng
%0 Conference Paper
%B IEEE Workshop on Statistical Signal Processing (SSP)
%D 2016
%T Distributed multivariate regression with unknown noise covariance in the presence of outliers: a minimum description length approach
%A R. López-Valcarce
%A Daniel Romero
%A Josep Sala
%A Alba Pagès-Zamora
%K compass
%K wsn
%X We consider the problem of estimating the coefficients in a multivariable linear model by means of a wireless sensor network

which may be affected by anomalous measurements. The noise covariance matrices at the different sensors are assumed

unknown. Treating outlying samples, and their support, as additional nuisance parameters, the Maximum Likelihood

estimate is investigated, with the number of outliers being estimated according to the Minimum Description Length

principle. A distributed implementation based on iterative consensus techniques is then proposed, and it is shown effective

for managing outliers in the data.

%B IEEE Workshop on Statistical Signal Processing (SSP)
%C Palma de Mallorca, Spain
%G eng
%0 Conference Paper
%B ACM Workshop on Information Hiding and Multimedia Security
%D 2016
%T Forensics of high quality and nearly identical JPEG image recompression
%A Cecilia Pasquini
%A Pascal Schoettle
%A Rainer Bohme
%A Giulia Boato
%A Fernando Pérez-González
%B ACM Workshop on Information Hiding and Multimedia Security
%G eng
%0 Journal Article
%J IEEE Transactions on Signal Processing
%D 2016
%T Multiantenna GLR detection of rank-one signals with known power spectral shape under spatially uncorrelated noise
%A Josep Sala
%A Gonzalo Vázquez-Vilar
%A R. López-Valcarce
%A Saeid Sedighi
%A Abbas Taherpour
%K cognitive radio
%K compass
%X We establish the generalized likelihood ratio (GLR) test for a Gaussian signal of known power spectral shape and unknown rank-one spatial signature in additive white Gaussian noise with an unknown diagonal spatial correlation matrix. This is motivated by spectrum sensing problems in dynamic spectrum access (DSA), in which the temporal correlation of the primary signal can be assumed known up to a scaling, and where the noise is due to an uncalibrated receive array. For spatially independent identically distributed (i.i.d.) noise, the corresponding GLR test reduces to a scalar optimization problem, whereas the GLR detector in the general non-i.i.d. case yields a more involved expression, which can be computed via alternating optimization methods. Low signal-to-noise ratio (SNR) approximations to the detectors are given, together with an asymptotic analysis showing the influence on detection performance of the signal power spectrum and SNR distribution across antennas. Under spatial rank-P conditions, we show that the rank-one GLR detectors are consistent with a statistical criterion that maximizes the output energy of a beamformer operating on filtered data. Simulation results support our theoretical findings in that exploiting prior knowledge on the signal power spectrum can result in significant performance improvement.

%B IEEE Transactions on Signal Processing %V 64 %P 6269-6283 %8 12/2016 %G eng %N 23 %& 6269 %R 10.1109/TSP.2016.2601290 %0 Journal Article %J IEEE J. Selected Topics in Signal Processing. Special issue on Signal Processing for Millimeter Wave Wireless Communications %D 2016 %T An overview of signal processing techniques for millimeter wave MIMO systems %A Robert W. Heath Jr. %A Nuria González-Prelcic %A Sundeep Rangan %A Wonil Roh %A Akbar M. Sayeed %K compass %K mmWave %XCommunication at millimeter wave (mmWave) frequencies is defining a new era of wireless communication. The mmWave band offers higher bandwidth communication channels versus those presently used in commercial wireless systems. The applications of mmWave are immense: wireless local and personal area networks in the unlicensed band, 5G cellular systems, not to mention vehicular area networks, ad hoc networks, and wearables. Signal processing is critical for enabling the next generation of mmWave communication. Due to the use of large antenna arrays at the transmitter and receiver, combined with radio frequency and mixed signal power constraints, new multiple-input multiple-output (MIMO) communication signal processing techniques are needed. Because of the wide bandwidths, low complexity transceiver algorithms become important. There are opportunities to exploit techniques like compressed sensing for channel estimation and beamforming. This article provides an overview of signal processing challenges in mmWave wireless systems, with an emphasis on those faced by using MIMO communication at higher carrier frequencies.

%B IEEE J. Selected Topics in Signal Processing. Special issue on Signal Processing for Millimeter Wave Wireless Communications %V 10 %P 436 - 453 %8 04/2016 %G eng %N 3 %R 10.1109/JSTSP.2016.2523924 %0 Conference Paper %B Twelfth International Symposium on Wireless Communication Systems (ISWCS) %D 2015 %T Pushing for higher rates and efficiency in Satcom: the different perspectives within SatNExIV %A Miguel Ángel Vázquez %A Ana Pérez Neira %A Carlos Mosquera %A Bhavani Shankar %A Pol Henarejos %A Athanasios Panagopoulos %A Giovanni Giambene %A Vasilios Siris %A George Polyzos %A Nader Alagha %K satcom %B Twelfth International Symposium on Wireless Communication Systems (ISWCS) %C Brussels %G eng %0 Journal Article %J IEEE Communications Letters %D 2014 %T Active Interference Cancellation for OFDM Spectrum Sculpting: Linear Processing is Optimal %A Schmidt, J.F. %A Daniel Romero %A R. López-Valcarce %K cognitive radio %K compass %K dynacs %XActive interference cancellation (AIC) is a multicarrier spectrum sculpting technique which reduces the power of undesired out-of-band emissions by adequately modulating a subset of reserved cancellation subcarriers. In most schemes online complexity is a concern, and thus cancellation subcarriers have traditionally been constrained to linear combinations of the data subcarriers. Recent AIC designs truly minimizing out-of-band emission shift complexity to the offline design stage, motivating the consideration of more general mappings to improve performance. We show that there is no loss in optimality incurred by constraining these mappings to the set of linear functions.

%B IEEE Communications Letters %V 18 %P 1543-1546 %8 09/2014 %G eng %N 9 %& 1543 %R 10.1109/LCOMM.2014.2338316 %0 Conference Paper %B IEEE Sensor Array and Multichannel Signal Processing Workshop (SAM) %D 2014 %T Antenna competition to boost Active Interference Cancellation in cognitive MIMO-OFDM %A Schmidt, J.F. %A R. López-Valcarce %K cognitive radio %K dynacs %X Active Interference Cancellation (AIC) techniques for OFDM spectrum sculpting have gained interest over the last years, and several extensions to the MIMO case have been recently proposed. However, these designs do not fully exploit the spatial diversity provided by the multiple transmit antennas, as canceler allocation is fixed. This paper proposes a more general mechanism for the allocation of the cancellation subcarriers across antennas in order to better exploit spatial diversity. In particular, we present a novel AIC design for cognitive MIMOOFDM systems, in which transmit antennas compete against each other for a fixed number of cancellation subcarriers. We show that this more general allocation approach results in significant performance improvements with respect to previous designs. %B IEEE Sensor Array and Multichannel Signal Processing Workshop (SAM) %C A Coruña, Spain %G eng %R 10.1109/SAM.2014.6882392 %0 Conference Paper %B Asilomar Conf. on Signals, Systems and Computers %D 2014 %T Channel estimation in millimeter wave MIMO systems with one-bit quantization %A Jianhua Mo %A Phil Schniter %A Nuria González-Prelcic %A Robert W. Heath Jr. %K adaptive signal processing %K compass %K mmWave %B Asilomar Conf. on Signals, Systems and Computers %G eng %R 10.1109/ACSSC.2014.7094595 %0 Conference Paper %B IEEE Workshop on Information Forensics and Security (WIFS) %D 2014 %T Detecting Misreporting Attacks to the Proportional Fair Scheduler %A Schmidt, J.F. %A R. López-Valcarce %K adversarial signal processing %K compass %X

The Proportional Fair Scheduler (PFS) has become

a popular channel-aware resource allocation method in wireless

networks, as it effectively exploits multiuser diversity while

providing fairness to users. PFS decisions on which mobile station

(MS) to schedule next are based on Channel Quality Indicator

(CQI) values. Since CQI values are reported by the MSs to the

scheduler, network performance can be severely degraded if some

malicious MSs report forged information. Previous approaches to

this security issue are based either on modifying PFS, which may

be undesirable in some contexts, or authenticating CQI reports

by periodic transmission of challenges, which increases overhead.

Instead, we propose to detect misreporting attackers, based on the

time correlation features of the wireless channel. Our approach

does not require scheduler modification, and it does not increase

overhead. Simulation results under realistic settings are provided

to show the effectiveness of the proposed test.

%B IEEE Workshop on Information Forensics and Security (WIFS)
%C Atlanta, USA
%8 12/2014
%G eng
%R 10.1109/WIFS.2014.7084310
%0 Conference Paper
%B European Signal Processing Conference (EUSIPCO)
%D 2014
%T Low-Power Active Interference Cancellation for OFDM Spectrum Sculpting
%A Schmidt, J.F.
%A Daniel Romero
%A R. López-Valcarce
%X We present a low-power design for Active Interference

Cancellation (AIC) sculpting of the OFDM spectrum, based

on sparse design concepts. Optimal AIC designs compute

cancellation weights based on contributions from all data subcarriers.

Thus, as the number of subcarriers grows, power

consumption becomes a concern, and suboptimal solutions

that avoid involving all subcarriers are of interest. In this context,

we present novel sparse AIC designs based on a zeronorm

minimization of the matrix defining the cancellation

weights. These designs drastically reduce the number of operations

per symbol, and thus the power consumption, while allowing

to tune the loss with respect the optimal design. They

can be efficiently obtained and significantly outperform usual

thresholding or sparsity-inducing l_1-norm minimization approaches.

%B European Signal Processing Conference (EUSIPCO)
%8 09/2014
%G eng
%U http://www.eurasip.org/Proceedings/Eusipco/Eusipco2014/HTML/papers/1569912103.pdf
%0 Conference Paper
%B IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP)
%D 2014
%T OFDM spectrum sculpting with active interference cancellation: Keeping spectral spurs at bay
%A Schmidt, J.F.
%A R. López-Valcarce
%K cognitive radio
%K dynacs
%B IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP)
%I IEEE
%C Florence, Italy
%P 1-5
%8 05/2014
%G eng
%R 10.1109/ICASSP.2014.6855169
%0 Journal Article
%J IEEE Journal on Emerging and Selected Topics in Circuits and Systems
%D 2013
%T Choose Your Subcarriers Wisely: Active Interference Cancellation for Cognitive OFDM
%A Schmidt, J.F.
%A Costas-Sanz, S.
%A R. López-Valcarce
%K cognitive radio
%K dynacs
%B IEEE Journal on Emerging and Selected Topics in Circuits and Systems
%V 3
%P 615-625
%8 12/2013
%G eng
%N 4
%& 615
%R 10.1109/JETCAS.2013.2280808
%0 Journal Article
%J Engineering Applications of Artificial Intelligence
%D 2013
%T On the design of a novel two-objective harmony search approach for distance- and connectivity-based localization in wireless sensor networks
%A Diana Manjarres
%A Javier Del Ser
%A Sergio Gil-Lopez
%A Massimo Vecchio
%A Itziar Landa-Torres
%A Sancho Salcedo-Sanz
%A R. López-Valcarce
%K dynacs
%K wsn
%B Engineering Applications of Artificial Intelligence
%V 26
%P 669-676
%8 02/2013
%G eng
%N 2
%& 669
%R 10.1016/j.engappai.2012.06.002
%0 Journal Article
%J EURASIP Journal on Advances in Signal Processing
%D 2013
%T Lattice implementation of adaptive channel shortening in multicarrier transmission over IIR channels
%A E. Ben Salem
%A S. Cherif
%A H. Besbes
%A R. López-Valcarce
%B EURASIP Journal on Advances in Signal Processing
%V 2013:174
%8 11/2013
%G eng
%U http://asp.eurasipjournals.com/content/2013/1/174
%R 10.1186/1687-6180-2013-174
%0 Conference Paper
%B European Signal Processing Conf. (EUSIPCO), Marrakech (Morocco)
%D 2013
%T Low Complexity Primary User Protection for Cognitive OFDM
%A Schmidt, J.F.
%A R. López-Valcarce
%K cognitive radio
%K dynacs
%B European Signal Processing Conf. (EUSIPCO), Marrakech (Morocco)
%8 09/2013
%G eng
%0 Journal Article
%J Soft Computing
%D 2013
%T A novel heuristic approach for distance- and connectivity-based multihop node localization in wireless sensor networks
%A Diana Manjarres
%A Javier Del Ser
%A Sergio Gil-Lopez
%A Massimo Vecchio
%A Itziar Landa-Torres
%A R. López-Valcarce
%K dynacs
%K wsn
%B Soft Computing
%V 17
%P 17-28
%8 01/2013
%G eng
%N 1
%& 17
%R 10.1007/s00500-012-0897-2
%0 Conference Paper
%B IEEE Statistical Signal Processing Workshop (SSP 2012)
%D 2012
%T Detection of Gaussian signals in unknown time-varying channels
%A Daniel Romero
%A Javier Vía
%A R. López-Valcarce
%A Ignacio Santamaría
%K cognitive radio
%K dynacs
%K spectrum sensing
%X Detecting the presence of a white Gaussian signal distorted by a noisy time-varying channel is addressed by means of three different detectors. First, the generalized likelihood ratio test (GLRT) is found for the case where the channel has no temporal structure, resulting in the well-known Bartlett’s test. Then it is shown that, under the transformation group given by scaling factors, a locally most powerful invariant test (LMPIT) does not exist. Two alternative approaches are explored in the low signal-to-noise ratio (SNR) regime: the first assigns a prior probability density function (pdf) to the channel (hence modeled as random), whereas the second assumes an underlying basis expansion model (BEM) for the (now deterministic) channel and obtains the maximum likelihood (ML) estimates of the parameters relevant for the detection problem. The performance of these detectors is evaluated via Monte Carlo simulation.

%B IEEE Statistical Signal Processing Workshop (SSP 2012)
%I IEEE
%C Ann Arbor, MI
%8 08/2012
%G eng
%R 10.1109/SSP.2012.6319858
%0 Journal Article
%J IEEE Trans. on Signal Processing
%D 2012
%T Multiantenna GLR detection of rank-one signals with known power spectrum in white noise with unknown spatial correlation
%A Josep Sala
%A Gonzalo Vázquez-Vilar
%A R. López-Valcarce
%K cognitive radio
%K dynacs
%X Multiple-antenna detection of a Gaussian signal with spatial rank one in temporally white Gaussian noise with arbitrary and unknown spatial covariance is considered. This is motivated by spectrum sensing problems in the context of Dynamic Spectrum Access in which several secondary networks coexist but do not cooperate, creating a background of spatially correlated broadband interference. When the temporal correlation of the signal of interest is assumed known up to a scale factor, the corresponding Generalized Likelihood Ratio Test is shown to yield a scalar optimization problem. Closed-form expressions of the test are obtained for the general signal spectrum case in the low signal-to-noise ratio (SNR) regime, as well as for signals with binary-valued power spectrum in arbitrary SNR. The two resulting detectors turn out to be equivalent. An asymptotic approximation to the test distribution for the low-SNR regime is derived, closely matching empirical results from spectrum sensing simulation experiments.

%B IEEE Trans. on Signal Processing
%V 60
%P 3065 - 3078
%8 06/2012
%G eng
%N 6
%R 10.1109/TSP.2012.2189767
%0 Conference Paper
%B IEEE International Conference on Intelligent Systems Design and Applications (ISDA)
%D 2011
%T On the Application of a Hybrid Harmony Search Algorithm to Node Localization in Anchor-based Wireless Sensor Networks
%A Diana Manjarres
%A Javier Del Ser
%A Sergio Gil-Lopez
%A Massimo Vecchio
%A Itziar Landa-Torres
%A R. López-Valcarce
%B IEEE International Conference on Intelligent Systems Design and Applications (ISDA)
%G eng
%0 Journal Article
%J Vehicular Technology, IEEE Transactions on
%D 2011
%T Bit Loading Using Imperfect CSIT for Prediction-Based Resource Allocation in Mobile OFDMA
%A Schmidt, J.F.
%A Cousseau, J.E.
%A Wichman, R.
%A Werner, S.
%K bit loading
%K channel state information in the transmitter
%K CSIT
%K frequency division multiple access
%K imperfect channel prediction information
%K mobile OFDMA
%K mobile radio
%K mobile stations
%K OFDM modulation
%K orthogonal frequency division multiple access
%K prediction error
%K prediction-based resource allocation
%K radio transmitters
%K time-varying channels
%K wireless channel
%B Vehicular Technology, IEEE Transactions on
%V 60
%P 4082 -4088
%8 oct.
%G eng
%R 10.1109/TVT.2011.2165305
%0 Journal Article
%J IEEE Trans. on Signal Processing
%D 2011
%T Detection of Rank-P Signals in Cognitive Radio Networks With Uncalibrated Multiple Antennas
%A David Ramírez
%A Gonzalo Vázquez-Vilar
%A R. López-Valcarce
%A Javier Vía
%A Ignacio Santamaría
%K cognitive radio
%K dynacs
%K spectrum sensing
%X Spectrum sensing is a key component of the Cognitive Radio paradigm. Typically, primary signals have to be detected with uncalibrated receivers at signal-to-noise ratios (SNRs) well below decodability levels. Multiantenna detectors exploit spatial independence of receiver thermal noise to boost detection performance and robustness. We study the problem

of detecting a Gaussian signal with rank-P unknown spatial

covariance matrix in spatially uncorrelated Gaussian noise with

unknown covariance using multiple antennas. The generalized

likelihood ratio test (GLRT) is derived for two scenarios. In the

first one, the noises at all antennas are assumed to have the same (unknown) variance, whereas in the second, a generic diagonal noise covariance matrix is allowed in order to accommodate calibration uncertainties in the different antenna frontends. In the latter case, the GLRT statistic must be obtained numerically, for which an efficient method is presented. Furthermore, for asymptotically low SNR, it is shown that the GLRT does admit a closed form, and the resulting detector performs well in practice. Extensions are presented in order to account for unknown temporal correlation in both signal and noise, as well as frequency-selective channels.

%B IEEE Trans. on Signal Processing
%V 59
%P 3764-3774
%8 08/2012
%G eng
%N 8
%R 10.1109/TSP.2011.2146779
%0 Conference Paper
%B IEEE International Conference on Communications (ICC)
%D 2011
%T A Dirty Paper Scheme for Hierarchical OFDM
%A Scagliola, Michele
%A Fernando Pérez-González
%A Guccione, Pietro
%K dirty paper
%K Hierarchical OFDM
%K watermarking
%B IEEE International Conference on Communications (ICC)
%C Kioto, Japan
%8 June
%G eng
%0 Journal Article
%J IEEE Transactions on Communications
%D 2011
%T Gain-Invariant Dirty Paper Coding for Hierarchical OFDM
%A Scagliola, Michele
%A Fernando Pérez-González
%A Guccione, Pietro
%K dirty paper
%K dynacs
%K Hierarchical OFDM
%K watermarking
%X A novel approach is here presented to superimpose a low-priority data stream on a high-priority data stream for OFDM systems. The main improvement with respect to conventional hierarchical modulation, which is included with the same purpose in various wireless technologies, is that the low-priority data stream can be decoded from the received subcarrier symbols without any previous equalization for multipath fading channels. As a consequence, the expected performance is nearly invariant of the channel estimation method used to equalize the channel. The low-priority stream is inserted adopting a gain-invariant dirty paper coding based on Rational Dither Modulation, which was proposed for data hiding applications. In this paper an analysis of the developed system is presented and several simulations have been carried out using DVB-T system parameters to verify the validity of the proposed approach. The experimental results show the better performance of the proposed method with respect to that of a conventional hierarchical modulation, particularly when the accuracy of the estimated channel response decreases.

%B IEEE Transactions on Communications %V 59 %P 3323-3334 %8 December %G eng %R 10.1109/TCOMM.2011.101011.100544 %0 Journal Article %J Circuits and Systems I: Regular Papers, IEEE Transactions on %D 2011 %T Low-Complexity Channel Prediction Using Approximated Recursive DCT %A Schmidt, J.F. %A Cousseau, J.E. %A Wichman, R. %A Werner, S. %K autoregressive modeling %K autoregressive processes %K basis expansion model %K channel estimator %K computational complexity %K DCT %K discrete cosine transform %K discrete cosine transforms %K Doppler frequencies %K filter bank %K Kalman filters %K low-complexity channel prediction %K OFDM modulation %K OFDM systems %K recursive formulation %K steady-state Kalman filter %K sum-of-sinusoids channel predictors %K time-varying channels %B Circuits and Systems I: Regular Papers, IEEE Transactions on %V 58 %P 2520 -2530 %8 oct. %G eng %R 10.1109/TCSI.2011.2158139 %0 Conference Paper %B IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) %D 2011 %T Multiantenna detection under noise uncertainty and primary user's spatial structure %A David Ramírez %A Gonzalo Vázquez-Vilar %A R. López-Valcarce %A Javier Vía %A Ignacio Santamaría %K cognitive radio %K generalized likelihood ratio test (GLRT) %K spectrum sensing %B IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) %I IEEE %C Prage, Czech Republic %P 2948-2951 %8 May %G eng %0 Journal Article %J IEEE Trans. on Wireless Communications %D 2011 %T Multiantenna Spectrum Sensing Exploiting Spectral a priori Information %A Gonzalo Vázquez-Vilar %A R. López-Valcarce %A Josep Sala %K cognitive radio %K dynacs %K spectrum sensing %B IEEE Trans. on Wireless Communications %V 10 %P 4345 - 4355 %8 12/2011 %G eng %N 12 %R 10.1109/TWC.2011.101211.110665 %0 Conference Paper %B Information Sciences and Systems (CISS), 2011 45th Annual Conference on %D 2011 %T Prediction based resource allocation in OFDMA %A Schmidt, J.F. %A Cousseau, J.E. %A Wichman, R. %A Werner, S. %K empirical characterization %K frequency division multiple access %K low-complexity channel predictor %K mobile radio %K mobile stations %K mobile wireless channels %K OFDM modulation %K OFDMA downlink %K orthogonal frequency division multiple access downlink %K perfect channel state information %K prediction error characterization %K prediction-based RA strategies %K prediction-based resource allocation algorithm %K wireless channels %B Information Sciences and Systems (CISS), 2011 45th Annual Conference on %P 1 -4 %8 march %G eng %R 10.1109/CISS.2011.5766224 %0 Conference Paper %B European Wireless %D 2010 %T A finite interval constant modulus criterion for multicarrier channel shortening %A E. Ben Salem %A R. López-Valcarce %A H. Besbes %A S. Cherif %B European Wireless %C Lucca, Italy %G eng %0 Journal Article %J Digital Investigation %D 2010 %T Leaving Timing Channel Fingerprints in Hidden Service Log Files %A Bilal Shebaro %A Fernando Pérez-González %A Jedidiah R. Crandall %K data-hiding %K fingerprints %K hidden services %K timestamps %K timing channel %K tor network %K watermarking %B Digital Investigation %G eng %0 Conference Paper %B Digital Forensic Research Workshop Annual Conference (DFRWS) %D 2010 %T Leaving Timing Channel Fingerprints in Hidden Service Log Files %A Bilal Shebaro %A Fernando Pérez-González %A Jedidiah R. Crandall %K data hiding %K fingerprints %K hidden services %K timestamps %K timing channel %K tor network %K watermarking %B Digital Forensic Research Workshop Annual Conference (DFRWS) %C Portland, Oregon %8 August %G eng %0 Conference Paper %B IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) %D 2010 %T Multiantenna spectrum sensing: detection of spatial correlation among time-series with unknown spectra %A David Ramírez %A Javier Vía %A Ignacio Santamaría %A R. López-Valcarce %A L. L. Scharf %K cognitive radio %K coherence spectrum %K generalized likelihood ratio test %K Hadamard ratio %K multiple-channel signal detection %B IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) %C Dallas, TX %G eng %0 Conference Paper %B International Workshop on Cognitive Information Processing (CIP) %D 2010 %T Multiantenna spectrum sensing for Cognitive Radio: overcoming noise uncertainty %A R. López-Valcarce %A Gonzalo Vázquez-Vilar %A Josep Sala %B International Workshop on Cognitive Information Processing (CIP) %C Elba Island, Italy %G eng %0 Conference Paper %B IEEE International Workshop on Information Forensics and Security (WIFS) %D 2009 %T AN EXTENDED ANALYSIS OF DISCRETE FOURIER TRANFORM - RATIONAL DITHER MODULATION FOR NON-WHITE HOSTS %A Scagliola, Michele %A Fernando Pérez-González %A Guccione, Pietro %K data hiding %K dither modulation %K filtering %K non-white Gaussian hosts %K watermarking %B IEEE International Workshop on Information Forensics and Security (WIFS) %I IEEE %C London, U.K. %8 December %G eng %0 Journal Article %J EURASIP Journal on Information Security %D 2009 %T High-rate data-hiding robust to linear filtering for colored hosts %A Scagliola, Michele %A Fernando Pérez-González %A Guccione, Pietro %K data-hiding %K rational dither modulation %K watermarking %B EURASIP Journal on Information Security %G eng %0 Conference Paper %B European Signal Processing Conference (EUSIPCO) %D 2008 %T Lattice implementation of Sum-squared Auto-correlation Minimization (SAM) channel shortener %A E. Ben Salem %A R. López-Valcarce %A S. Cherif %A H. Besbes %K Blind Adaptation %K Lattice %K SAM %B European Signal Processing Conference (EUSIPCO) %C Lausanne, Switzerland %8 August %G eng %0 Journal Article %J IEEE Transactions on Signal Processing %D 2008 %T Non-Data-Aided Symbol Rate Estimation of Linearly Modulated Signals %A C. Mosquera %A Sandro Scalise %A R. López-Valcarce %B IEEE Transactions on Signal Processing %8 February %G eng %0 Book Section %D 2007 %T Digital Satellite Communications %A Sandro Scalise %A L. Castanet %A M. Luglio %A Neri, Massimo %A Marcos Álvarez-Díaz %A J. Bito %A M. Bousquet %A I. Frigyes %A P. Horvath %A Axel Jahn %A M. Krejcarek %A J. Lemorton %A S. Morosi %A M. A. Vázquez-Castro %I Springer %C New York %P - %8 April %G eng %& Satellite Channel Impairments %0 Book Section %D 2007 %T Digital Satellite Communications %A C. Mosquera %A M. L. Boucheret %A M. Bousquet %A S. Cioni %A Wilfried Gappmair %A R. Pedone %A Sandro Scalise %A P. Skoutaridis %A M. Villanti %I Springer %G eng %& Parameter Estimation and Synchronization %0 Book Section %D 2007 %T Digital Satellite Communications %A R. Pedone %A G. Albertazzi %A P.T. Mathiopoulos %A C. Mosquera %A N. Sagias %A M. Villanti %I Springer %G eng %& Theoretical Background %0 Book Section %D 2007 %T Digital Satellite Communications %A A. A. Rontogiannis %A Marcos Álvarez-Díaz %A M. Casadei %A V. Dalakas %A A. Duverdier %A F. J. González-Serrano %A M. Iubatti %A T. Javornik %A L. Lapierre %A Neri, Massimo %A P. Salmi %I Springer %C New York %P - %8 April %G eng %& Distortion Countermeasures %0 Conference Paper %B Signal Processing Advances in Wireless Communications, 2007. SPAWC 2007. IEEE 8th Workshop on %D 2007 %T Fast-fading channel estimator using DCT and simplified kalman filter %A Schmidt, J.F. %A Cousseau, J.E. %A Wichman, R. %A Gregorio, F.H. %K band-pass filters %K basis function approximations %K channel coefficient %K channel Doppler spectrum %K channel estimation %K channel estimator %K channel variations %K decoupled parameters %K discrete cosine transform %K discrete cosine transforms %K Doppler effect %K fading channels %K fast-fading channel %K Kalman filter %K Kalman filters %K low complexity estimator %K narrow-band filters %K passband filters %K training symbols %B Signal Processing Advances in Wireless Communications, 2007. SPAWC 2007. IEEE 8th Workshop on %P 1 -5 %8 june %G eng %R 10.1109/SPAWC.2007.4401355 %0 Conference Paper %B International Workshop on Satellite and Space Communications (IWSSC) %D 2007 %T Satellite Communications: Research Trends and Open Issues %A Alessandro Vanelli-Coralli %A Giovanni Emanuele Corazza %A G.K. Karagiannidis %A P.T. Mathiopoulos %A D.S. Michalopoulos %A C. Mosquera %A S. Papaharalabos %A Sandro Scalise %K satellite communications %B International Workshop on Satellite and Space Communications (IWSSC) %G eng %0 Conference Paper %B International Workshop on Multimedia Content Representation, Classification and Security %D 2006 %T A novel model for the print-and-capture channel in 2D bar codes %A Alberto Malvido %A Fernando Pérez-González %A Armando Cousiño %E Bilge Gunsel %E Anil K. Jain %E A. Murat Tekalp %E Bülent Sankur %K bar-codes %K visible-encryption %B International Workshop on Multimedia Content Representation, Classification and Security %S Lecture Notes in Computer Science %I Springer-Verlag Heidelberg %C Istambul, Turkey %V 4105 %P 627-634 %8 September %G eng %0 Conference Paper %B International Workshop on Signal Processing for Space Communications (SPSC) %D 2006 %T Symbol-Rate Estimation for DVB-S2 Broadcasting %A C. Mosquera %A Sandro Scalise %A R. López-Valcarce %K DVB %K symbol rate %K synchronization %B International Workshop on Signal Processing for Space Communications (SPSC) %G eng %0 Conference Paper %B Vehicular Technology Conference (VTC) %D 2004 %T Performance of Coding and Synchronization Schemes for a DVB-S Based Air-Interface in the Railway Environment %A Sandro Scalise %A Giorgio Sciascia %A Marcos Álvarez-Díaz %A Harald Ernst %A Rodolfo Mura %K Digital Communications %K DVB-S %K satellite communications %B Vehicular Technology Conference (VTC) %C Milano, Italy %V 1 %P 347-351 %8 May 17-19 %G eng %0 Conference Paper %B IST Mobile & Wireless Communications Summit %D 2003 %T Characterization of the Railroad Satellite Channel within the FIFTH Project %A Sandro Scalise %A Marcos Álvarez-Díaz %A Giorgio Sciascia %A Rodolfo Mura %K Digital Communications %K satellite communications %B IST Mobile & Wireless Communications Summit %C Aveiro, Portugal %8 June 15-18 %G eng %0 Conference Paper %B Baiona Workshop on Signal Processing in Communications %D 2003 %T DVB-S Air Interface over Railroad Satellite Channel: Performance and Extensions %A Marcos Álvarez-Díaz %A Sandro Scalise %A Giorgio Sciascia %A Rodolfo Mura %A Paolo Conforto %A Harald Ernst %K Digital Communications %K DVB-S %K satellite communications %B Baiona Workshop on Signal Processing in Communications %C Baiona, Spain %8 September 8-10 %G eng %0 Conference Paper %B International Conference on Advanced Satellite Mobile Systems (ASMS) %D 2003 %T Link Design for Satellite Based Services in the Fast Train Environment %A Sandro Scalise %A Paolo Conforto %A Marcos Álvarez-Díaz %A Giorgio Sciascia %A Rodolfo Mura %A Harald Ernst %K Digital Communications %K satellite communications %B International Conference on Advanced Satellite Mobile Systems (ASMS) %C ESRIN, Frascati, Italy %8 July 10-11 %G eng %0 Conference Paper %B AIAA International Communications Satellite Systems Conference (ICSSC) %D 2003 %T Link Performance for Mobile Satellite Based Services in Ku-Band %A Giorgio Sciascia %A Sandro Scalise %A Harald Ernst %A Marcos Álvarez-Díaz %A Matthias Holzbock %A Rodolfo Mura %K Digital Communications %K satellite communications %B AIAA International Communications Satellite Systems Conference (ICSSC) %C Yokohama, Japan %8 April 15-19 %G eng %0 Conference Paper %B International Workshop on Signal Processing for Space Communications (SPSC) %D 2003 %T Performance of DVB-S Air-Interface over Land Mobile Satellite Channel at Ku-Band for Fast Trains %A Marcos Álvarez-Díaz %A Sandro Scalise %A Giorgio Sciascia %A Rodolfo Mura %A Paolo Conforto %A Vincenzo Schena %A Harald Ernst %K Digital Communications %K DVB-S %K satellite communications %B International Workshop on Signal Processing for Space Communications (SPSC) %C Catania, Italia %8 September 24-26 %G eng %0 Conference Paper %B IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) %D 2002 %T Spectral characterization of feedback linear periodically time-varying systems %A C. Mosquera %A Sandro Scalise %A G. Taricco %K burst %K inversion %K LPTV %K PLL %B IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) %G eng %0 Journal Article %J International Journal of Acoustics and Vibration %D 2001 %T Adaptive IIR Filters for Active Noise Control %A C. Mosquera %A J.A. Gómez %A Fernando Pérez-González %A M. Sobreira %A E. Alexandre %K ANC %K IIR %K SPR %B International Journal of Acoustics and Vibration %V 6 %P 3-10 %G eng %0 Conference Paper %B IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) %D 2001 %T Blind equalization of nonlinear channels from second order statistics using precoding and channel diversity %A R. López-Valcarce %A Xuejie Song %A Soura Dasgupta %K Digital Communications %K equalization %K nonlinear channels %B IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) %C Salt Lake City, UT, USA %V 4 %P 2073–2076 %G eng %0 Conference Paper %B International Workshop on Digital Signal Processing Techniques for Space Communications (DSP) %D 2001 %T Time-transfer performance in burst-mode communication systems %A C. Mosquera %A Sandro Scalise %A G. Taricco %A D. Giunta %K burst %K PLL %K synchronization %B International Workshop on Digital Signal Processing Techniques for Space Communications (DSP) %G eng %0 Journal Article %J IEEE Journal on Selected Areas in Communications %D 2001 %T Time-transfer performance in burst-mode communication systems %A C. Mosquera %A Sandro Scalise %A G. Taricco %A G. Garofalo %A D. Giunta %K burst %K PLL %K synchronization %B IEEE Journal on Selected Areas in Communications %V 19 %P 2310-2319 %8 dec %G eng %0 Conference Paper %B IEEE International Conference on Image Processing (ICIP) %D 2001 %T Turbo Coding for Sample-Level Watermarking in the DCT Domain %A Félix Balado %A Fernando Pérez-González %A Sandro Scalise %K data-hiding %K watermarking %B IEEE International Conference on Image Processing (ICIP) %C Thessaloniki, Greece %P 1003–1006 %8 October %G eng %0 Conference Paper %B International Congress on Sound and Vibration %D 1999 %T IIR adaptive filters for active noise control %A C. Mosquera %A J.A. Gómez %A Fernando Pérez-González %A M. Sobreira %K ANC %K IIR %K SPR %B International Congress on Sound and Vibration %C Copenhagen, Denmark %G eng %0 Conference Paper %B Audio Engineering Society Convention (AES Convention) %D 1998 %T Testing a Flexible Time-Frequency Mapping for High Frequencies in TARCO (Tonal Adaptive Resolution COdec) %A Alejandro Casal %A Carlos Serantes %A Nuria González-Prelcic %A Antonio S. Pena %B Audio Engineering Society Convention (AES Convention) %C Amsterdam, The Netherlands %8 May %G eng %0 Conference Paper %B IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) %D 1997 %T A Fast Noise-Scaling Algorithm for Uniform Quantization in Audio Coding Schemes %A Carlos Serantes %A Antonio S. Pena %A Nuria González-Prelcic %B IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) %C Munich, Germany %8 May %G eng %0 Conference Paper %B IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) %D 1997 %T A Flexible Tiling of the Time Axis for Adaptive Wavelet Packet Audio Decompositions %A Nuria González-Prelcic %A Antonio S. Pena %A Carlos Serantes %B IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) %C Munich, Germany %8 May %G eng %0 Conference Paper %B Audio Engineering Society Convention (AES Convention) %D 1997 %T New Improvements in ARCO %A Antonio S. Pena %A Nuria González-Prelcic %A Carlos Serantes %B Audio Engineering Society Convention (AES Convention) %C Munich, Germany %8 March %G eng %0 Conference Paper %B Audio Engineering Society Convention (AES Convention) %D 1996 %T ARCO (Adaptive Resolution COdec): A Hybrid Approach to Perceptual Audio Coding %A Antonio S. Pena %A Carlos Serantes %A Nuria González-Prelcic %B Audio Engineering Society Convention (AES Convention) %C Copenhagen, Denmark %8 May %G eng