@conference {1060, title = {Multibeam Compact Dual Reflectarray Antenna for High-Throughput Satellites in Ka-Band}, booktitle = {18th European Conference on Antennas and Propagation}, year = {2024}, author = {Daniel Mart{\'\i}nez-de-Rioja and Eduardo Mart{\'\i}nez-de-Rioja and Y Rodr{\'\i}guez-Vaqueiro and A Pino and Carlos Mosquera and Jos{\'e} A. Encinar and Giovanni Toso} } @article {995, title = {Mask-Compliant Orthogonal Precoding for Spectrally Efficient OFDM}, journal = {IEEE Transactions on Communications}, volume = {69}, year = {2021}, month = {03/2021}, pages = {1990-2001}, abstract = {
Orthogonal precoding constitutes a powerful technique to reduce spectrum sidelobes of multicarrier signals. This reduction is bought at the cost of introducing precoder redundancy, which results in some throughput loss and additional precoding/decoding complexity. When the goal is to meet some spectral emission mask constraints, it is desirable to avoid unnecessary sidelobe suppression in order to keep precoder redundancy at a minimum. In this context, we introduce a general framework under which we develop a novel Lagrange multiplier-based mask-compliant orthogonal precoder design targeting minimal redundancy. We also adapt to this framework two previously proposed
designs based on spectral notches and minimum out-of-band emission, respectively, to explicitly incorporate mask constraints. Simulation results are provided to show the effectiveness of the proposed designs under different practical masks for multicarrier wireless systems.
}, keywords = {rodin, spectrum shaping, winter}, doi = {10.1109/TCOMM.2020.3041351}, author = {Ravinder Kumar and Khawar Hussain and R. L{\'o}pez-Valcarce} } @conference {1003, title = {Memory Tricks: Improving Active Interference Cancellation for Out-of-Band power reduction in OFDM}, booktitle = {IEEE Int. Workshop Signal Process. Adv. Wireless Commun. (SPAWC)}, year = {2021}, address = {Lucca, Italy (Virtual event)}, abstract = {

Although active interference cancellation (AIC) is an appealing approach to reduce out-of-band radiation (OBR) in multicarrier systems without distorting data subcarriers, it usually requires a large number of reserved subcarriers to be effective. Introducing memory in AIC precoding may help alleviate this drawback in exchange for some increase in computational complexity. We propose a novel memory AIC precoder which, in contrast to previous schemes, minimizes OBR within a user-selectable frequency region and allows for controlling spectral overshoot.

}, keywords = {rodin, spectrum shaping}, author = {Khawar Hussain and R. L{\'o}pez-Valcarce} } @article {1018, title = {Multiquadratic rings and oblivious linear function evaluation}, journal = {TEMat monogr{\'a}ficos}, volume = {2}, year = {2021}, pages = {83-86}, issn = {2660-6003}, url = {https://temat.es/monograficos/article/view/vol2-p83}, author = {Alberto Pedrouzo-Ulloa} } @conference {998, title = {Multiquadratic Rings and Walsh-Hadamard Transforms for Oblivious Linear Function Evaluation}, booktitle = {IEEE International Workshop on Information Forensics and Security (WIFS)}, year = {2020}, publisher = {IEEE}, organization = {IEEE}, author = {Alberto Pedrouzo-Ulloa and Juan Ram{\'o}n Troncoso-Pastoriza and Nicolas Gama and Mariya Georgieva and Fernando P{\'e}rez-Gonz{\'a}lez} } @article {948, title = {Maximally stationary window design for overlap-add based random vibration synthesis}, journal = {Mechanical Systems and Signal Processing}, volume = {122}, year = {2019}, month = {05/2019}, pages = {642-657}, abstract = {
The accurate synthesis of realistic waveforms conforming to certain speci ca-
tions is a fundamental step in random vibration testing. Since real-time imple-
mentation of digital signal processing systems for random vibration and noise
synthesis necessarily operates frame by frame, the overlap-add (OLA) method,
by which frames are windowed and overlapped, is widely used in practice to
avoid artifacts at frame boundaries. When a wide-sense stationary random
signal is desired, however, the OLA method presents a shortcoming, because
the inherent periodicity of the frame-by-frame process unavoidably produces a
cyclostationary signal, i.e., its statistics present an undesired periodic behav-
ior. We analyze the impact of the window coecients in the cyclostationarity
properties of the synthetic process, and then present algorithms for window de-
sign with the goal of maximizing a measure of its stationarity, considering both
second- and fourth-order statistical properties. The proposed designs are shown
to signi cantly improve the stationarity properties when compared to commonly
used windows.
}, keywords = {random vibration}, doi = {10.1016/j.ymssp.2018.12.038}, author = {Dami{\'a}n Gonz{\'a}lez and R. L{\'o}pez-Valcarce} } @article {947, title = {MMSE filter design for Full-Duplex filter-and-forward MIMO relays under limited dynamic range}, journal = {Signal Processing}, volume = {156}, year = {2019}, month = {03/2019}, pages = {208-219}, abstract = {
We study the problem of optimizing the end-to-end performance of a full-duplex filter-and-forward MIMO relay link, consisting
of a source, a relay, and a destination node, by employing linear filtering at each node. The system model accounts for multipath
propagation and self-interference at the relay, as well as transmitter impairments and limited dynamic range at every node. The
design accommodates signals with arbitrary spectra and includes the direct link between the source and destination nodes. Under
the minimum mean square error criterion, the resulting non-convex problem is approximated by a sequence of convex problems
and solved by means of an alternating minimization method. Linear constraints allocate some of the degrees of freedom in the relay
to guarantee a sufficiently small residual self-interference. Simulations quantify the impact of degrees of freedom, the dynamic
range, and the balance between direct and relay paths on the link performance.
}, keywords = {adaptive signal processing, full-duplex, winter}, doi = {doi.org/10.1016/j.sigpro.2018.11.001}, author = {Emilio Antonio-Rodr{\'\i}guez and Stefan Werner and R. L{\'o}pez-Valcarce and Risto Wichman} } @conference {937, title = {Message-Splitting for Interference Cancellation in Multibeam Satellite Systems}, booktitle = {9th Advanced Satellite Multimedia Systems Conference (ASMS) and 15th Signal Processing for Space Communications Workshop (SPSC)}, year = {2018}, address = { Berlin, Germany}, author = {Tom{\'a}s Ram{\'\i}rez and Carlos Mosquera and M{\`a}rius Caus and Adriano Pastore and M{\`o}nica Navarro and Nele Noels} } @conference {1042, title = {Millimeter Wave Receiver Comparison Under Energy vs Spectral Efficiency Trade-off}, booktitle = {European Wireless 2017; 23th European Wireless Conference}, year = {2017}, pages = {1{\textendash}7}, author = {Abbas, W B and Gomez-Cuba, F and Zorzi, M} } @article {866, title = {Multiantenna GLR detection of rank-one signals with known power spectral shape under spatially uncorrelated noise}, journal = {IEEE Transactions on Signal Processing}, volume = {64}, year = {2016}, month = {12/2016}, pages = {6269-6283}, chapter = {6269}, abstract = {

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.

}, keywords = {cognitive radio, compass}, issn = {1053-587X}, doi = {10.1109/TSP.2016.2601290}, author = {Josep Sala and Gonzalo V{\'a}zquez-Vilar and R. L{\'o}pez-Valcarce and Saeid Sedighi and Abbas Taherpour} } @conference {1038, title = {A Microeconomic Approach to Data Trading in User Provided Networks}, booktitle = {IEEE Globecom Workshops}, year = {2015}, pages = {1{\textendash}7}, author = {Lorenzo, B and Gomez-Cuba, F and Garcia-Rois, J and Gonzalez-Castano, F J and Burguillo, J C} } @inbook {805, title = {Multibeam Joint Detection}, booktitle = {Cooperative and Cognitive Satellite Systems}, year = {2015}, publisher = {Elsevier}, organization = {Elsevier}, keywords = {satcom}, author = {J. Arnau and R. de Lamare and C. Mosquera} } @conference {809, title = {Multipath cancellation in broadband acoustic local positioning systems}, booktitle = {IEEE 9th International Symposium on Intelligent Signal Processing (WISP)}, year = {2015}, month = {05/2015}, publisher = {IEEE}, organization = {IEEE}, address = {Siena, Italy}, abstract = {

This work proposes a novel method to estimate the Line-of-Sight Time-of-Flights (LOS-TOFs) in a broadband acoustic local positioning system (ALPS) with strong multipath interference. The proposed method is based on the Matching Pursuit channel estimation algorithm that provides a low complexity approximation to the Maximum Likelihood solution for sparse channels. A multichannel version of this algorithm has been implemented to estimate a minimum of three coefficients in the channel responses of a particular ALPS, composed of four beacons that perform the simultaneous emission of BPSK modulated 255-bit Kasami codes. A statistical analysis of performance has been carried out by using a set of test signals synthetically generated to simulate different positions and reflection coefficients of the environment. The results of this analysis show the enhanced capability of the proposed method to estimate the LOS-TOFs under strong multipath interference, with respect to that of a classical system based on correlation + thresholding.

}, keywords = {compass, wsn}, doi = {10.1109/WISP.2015.7139174}, author = {Fernando J. Alvarez and R. L{\'o}pez-Valcarce} } @conference {777, title = {Multivariate Lattices for Encrypted Image Processing}, booktitle = {IEEE International Conference on Acoustics, Speech and Signal Processing}, year = {2015}, month = {04/2015}, publisher = {IEEE}, organization = {IEEE}, address = {Brisbane, Australia}, keywords = {homomorphic encryption, lattice cryptography, SPED}, author = {Alberto Pedrouzo-Ulloa and Juan Ram{\'o}n Troncoso-Pastoriza and Fernando P{\'e}rez-Gonz{\'a}lez} } @article {766, title = {MIMO precoding and combining solutions for millimeter wave systems}, journal = {IEEE Communications Magazine}, volume = {52}, year = {2014}, month = {12/2014}, pages = {122-131}, abstract = {

Millimeter-wave communication is one way to alleviate the spectrum gridlock at lower frequencies while simultaneously providing high-bandwidth communication channels. MmWave makes use of MIMO through large antenna arrays at both the base station and the mobile station to provide sufficient received signal power. This article explains how beamforming and precoding are different in MIMO mmWave systems than in their lower-frequency counterparts, due to different hardware constraints and channel characteristics. Two potential architectures are reviewed: hybrid analog/digital precoding/combining and combining with low-resolution analog- to-digital converters. The potential gains and design challenges for these strategies are discussed, and future research directions are highlighted.

}, keywords = {adaptive signal processing, compass, mmWave}, doi = {10.1109/MCOM.2014.6979963}, author = {Ahmed Alkhateeb and Jianhua Mo and Nuria Gonz{\'a}lez-Prelcic and Robert W. Heath Jr.} } @conference {757, title = {Multiple JPEG compression detection by means of Benford-Fourier coefficients}, booktitle = {IEEE International Workshop on Information Forensics and Security (WIFS)}, year = {2014}, month = {12/2014}, address = {Atlanta, GA}, author = {Cecilia Pasquini and Giulia Boato and Fernando P{\'e}rez-Gonz{\'a}lez} } @conference {695, title = {Meet the Family of Statistical Disclosure Attacks}, booktitle = {GlobalSIP}, year = {2013}, month = {12/2013}, author = {Simon Oya and Carmela Troncoso and Fernando P{\'e}rez-Gonz{\'a}lez} } @article {689, title = {MMSE Performance Analysis of Generalized Multibeam Satellite Channels}, journal = {Communications Letters, IEEE}, year = {2013}, pages = {1-4}, keywords = {dynacs, linear minimum mean square error receivers, multibeam satellites, Multiuser detection, return link, satcom}, doi = {10.1109/LCOMM.2013.052013.122658}, author = {Christopoulos, D. and J. Arnau and Chatzinotas, S. and C. Mosquera and Ottersten, B.} } @conference {661, title = {ML Estimation of the Resampling Factor}, booktitle = {IEEE International Workshop on Information Forensics and Security (WIFS)}, year = {2012}, month = {12/2012}, pages = {205-210}, publisher = {IEEE}, organization = {IEEE}, address = {Tenerife, Spain}, abstract = {

In this work, the problem of resampling factor estimation for tampering detection is addressed following the maximum likelihood criterion. By relying on the rounding operation applied after resampling, an approximation of the likelihood function of the quantized resampled signal is obtained. From the underlying statistical model, the maximum likelihood estimate is derived for one-dimensional signals and a piecewise linear interpolation. The performance of the obtained estimator is evaluated, showing that it outperforms state-of-the-art methods.

}, author = {David V{\'a}zquez-Pad{\'\i}n and Pedro Comesa{\~n}a} } @article {648, title = {Multiantenna GLR detection of rank-one signals with known power spectrum in white noise with unknown spatial correlation}, journal = {IEEE Trans. on Signal Processing}, volume = {60}, year = {2012}, month = {06/2012}, pages = {3065 - 3078}, abstract = {
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.
}, keywords = {cognitive radio, dynacs}, doi = {10.1109/TSP.2012.2189767}, author = {Josep Sala and Gonzalo V{\'a}zquez-Vilar and R. L{\'o}pez-Valcarce} } @conference {657, title = {Multimedia operator chain topology and ordering estimation based on detection and information theoretic tools}, booktitle = {International Workshop on Digital-forensics and Watermarking}, year = {2012}, address = {Shanghai, China}, author = {Pedro Comesa{\~n}a and Fernando P{\'e}rez-Gonz{\'a}lez} } @conference {642, title = {Multiuser Detection Performance in Multibeam Satellite Links under Imperfect CSI}, booktitle = {ASILOMAR 2012}, year = {2012}, address = {Pacific Grove, CA}, keywords = {dynacs, satcom}, doi = {10.1109/ACSSC.2012.6489048}, author = {Arnau, Jesus and C. Mosquera} } @conference {5990449, title = {Multiantenna detection of constant-envelope signals in noise of unknown variance}, booktitle = {IEEE Workshop on Signal Processing Advances in Wireless Communications (SPAWC)}, year = {2011}, month = {june}, pages = {446 -450}, abstract = {

Detection of unknown signals with constant modulus (CM) using multiple antennas in additive white Gaussian noise of unknown variance is considered. The channels from the source to each antenna are assumed frequency-flat and unknown. This problem is of interest for spectrum sensing in cognitive radio systems in which primary signals are known to have the CM property. Examples include analog frequency modulated signals such as those transmitted by wireless microphones in the TV bands and Gaussian Minimum Shift Keying modulated signals as in the GSM cellular standard. The proposed detector, derived from a Generalized Likelihood Ratio (GLR) approach, exploits both the CM property and the spatial independence of noise, outperforming the GLR test for Gaussian signals as shown by simulation.

}, keywords = {cognitive radio, multiantenna detection, spectrum sensing}, issn = {1948-3244}, doi = {10.1109/SPAWC.2011.5990449}, author = {Daniel Romero and R. L{\'o}pez-Valcarce} } @conference {RamirezVazquezICASSP11, title = {Multiantenna detection under noise uncertainty and primary user{\textquoteright}s spatial structure}, booktitle = {IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP)}, year = {2011}, month = {May}, pages = {2948-2951}, publisher = {IEEE}, organization = {IEEE}, address = {Prage, Czech Republic}, keywords = {cognitive radio, generalized likelihood ratio test (GLRT), spectrum sensing}, author = {David Ram{\'\i}rez and Gonzalo V{\'a}zquez-Vilar and R. L{\'o}pez-Valcarce and Javier V{\'\i}a and Ignacio Santamar{\'\i}a} } @article {649, title = {Multiantenna Spectrum Sensing Exploiting Spectral a priori Information}, journal = {IEEE Trans. on Wireless Communications}, volume = {10}, year = {2011}, month = {12/2011}, pages = {4345 - 4355}, keywords = {cognitive radio, dynacs, spectrum sensing}, doi = {10.1109/TWC.2011.101211.110665}, author = {Gonzalo V{\'a}zquez-Vilar and R. L{\'o}pez-Valcarce and Josep Sala} } @conference {RamirezValcarceICASSP10, title = {Multiantenna spectrum sensing: detection of spatial correlation among time-series with unknown spectra}, booktitle = {IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP)}, year = {2010}, address = {Dallas, TX}, keywords = {cognitive radio, coherence spectrum, generalized likelihood ratio test, Hadamard ratio, multiple-channel signal detection}, author = {David Ram{\'\i}rez and Javier V{\'\i}a and Ignacio Santamar{\'\i}a and R. L{\'o}pez-Valcarce and L. L. Scharf} } @conference {ValcarceVazquez10, title = {Multiantenna spectrum sensing for Cognitive Radio: overcoming noise uncertainty}, booktitle = {International Workshop on Cognitive Information Processing (CIP)}, year = {2010}, address = {Elba Island, Italy}, author = {R. L{\'o}pez-Valcarce and Gonzalo V{\'a}zquez-Vilar and Josep Sala} } @conference {spieei09, title = {Model-based steganalysis using invariant features}, booktitle = {Media Forensics and Security}, year = {2009}, month = {January}, address = {San Jose, CA, U.S.A.}, keywords = {Invariant features, Model-based, Steganalysis}, author = {Tu-Thach Quach and Fernando P{\'e}rez-Gonz{\'a}lez and Gregory L. Heileman} } @conference {dgonzalez-icip09, title = {Modeling Magnitudes of Gabor Coefficients: The \β-Rayleigh Distribution}, booktitle = {IEEE International Conference on Image Processing (ICIP)}, year = {2009}, month = {November}, publisher = {IEEE}, organization = {IEEE}, address = {Cairo, Egypt}, keywords = {Gabor, generalized Gaussian, Rayleigh, watermarking}, author = {Daniel Gonz{\'a}lez-Jim{\'e}nez and Enrique Argones-R{\'u}a and Fernando P{\'e}rez-Gonz{\'a}lez and Jos{\'e} Luis Alba-Castro} } @conference {ValcarceVazquezAlvarez2009, title = {Multiantenna detection of multicarrier primary signals exploiting spectral a priori information}, booktitle = {International Conference on Cognitive Radio Oriented Wireless Networks and Communications (Crowncom)}, year = {2009}, month = {June 22-24}, address = {Hannover, Germany}, author = {R. L{\'o}pez-Valcarce and Gonzalo V{\'a}zquez-Vilar and Marcos {\'A}lvarez-D{\'\i}az} } @conference {ValcarceMosquera08a, title = {Maximum Likelihood SNR Estimation for Asynchronously Oversampled OFDM Signals}, booktitle = {IEEE International Workshop on Signal Processing Advances in Wireless Communications}, year = {2008}, address = {Recife, Brazil}, keywords = {estimation, ML, OFDM, SNR}, author = {R. L{\'o}pez-Valcarce and C. Mosquera} } @conference {GappmairCNSDSP08, title = {ML and EM Algorithm for non-data-aided SNR Estimation of Linearly Modulated Signals}, booktitle = {International Symposium on Communication Systems, Networks and Signal Processing (CNSDSP)}, year = {2008}, pages = {530-534}, keywords = {EM, ML, SNR estimation}, author = {Wilfried Gappmair and R. L{\'o}pez-Valcarce and C. Mosquera} } @conference {icip07dani, title = {Modeling Gabor coefficients via Generalized Gaussian Distributions for face recognition}, booktitle = {IEEE International Conference on Image Processing (ICIP)}, year = {2007}, month = {September}, pages = {1261-1264}, address = {San Antonio, TX, USA}, keywords = {biometrics, face-recognition}, author = {Daniel Gonz{\'a}lez-Jim{\'e}nez and Fernando P{\'e}rez-Gonz{\'a}lez and Pedro Comesa{\~n}a and Luis P{\'e}rez-Freire and Jos{\'e} Luis Alba-Castro} } @article {uvigo:teq, title = {Minimum delay spread TEQ design in multicarrier systems}, journal = {IEEE Signal Processing Letters}, volume = {11}, number = {8}, year = {2004}, month = {August}, pages = {682{\textendash}685}, keywords = {channel shortener, cyclic prefix, delay spread, Digital Communications, multicarrier communications, time domain equalizer}, doi = {10.1109/LSP.2004.831676}, author = {R. L{\'o}pez-Valcarce} } @conference {uvigo:misconvergence, title = {Misconvergence and stabilization of adaptive IIR lattice filters}, booktitle = {IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP)}, volume = {1}, year = {2000}, pages = {65{\textendash}68}, address = {Istanbul, Turkey}, keywords = {adaptive IIR filters, lattice filters, system identification}, author = {Fernando P{\'e}rez-Gonz{\'a}lez and R. L{\'o}pez-Valcarce} } @conference {uvigo:masterslave, title = {The Master-Slave family of system identification algorithms: theoretical results and new structures}, booktitle = {IFAC World Congress}, volume = {J}, year = {1996}, month = {June}, pages = {185{\textendash}190}, publisher = {IFAC}, organization = {IFAC}, address = {San Francisco, CA, USA}, keywords = {adaptive IIR filters, lattice filters, system identification}, author = {R. L{\'o}pez-Valcarce and Fernando P{\'e}rez-Gonz{\'a}lez} } @article {uvigo:speech-wavelets, title = {A multipulse-like wavelet-based speech coder}, journal = {Applied Signal Processing}, volume = {3}, year = {1996}, pages = {78-87}, author = {Nuria Gonz{\'a}lez-Prelcic and D. Docampo} } @conference {Prelcic95, title = {A Multipulse-like Wavelet-based Speech Coder}, booktitle = {UK Symposium on Applications of Time-Frequency and Time-Scale Methods (TFTS)}, year = {1995}, month = {August}, address = {Warwick, UK}, author = {Nuria Gonz{\'a}lez-Prelcic and D. Docampo} }