@article {871, title = {CDMA-based Acoustic Local Positioning System for Portable Devices with Multipath Cancellation}, journal = {Digital Signal Processing}, volume = {62}, year = {2017}, month = {03/2017}, pages = {38-51}, abstract = {
This paper presents an acoustic local positioning system (ALPS) suitable for indoor positioning
of portable devices such as smartphones or tablets, based on the transmission of high frequency
CDMA-coded signals from a fixed network of beacons. The main novelty of the proposed ALPS is
its capability to mitigate the effects of multipath propagation by performing an accurate estimation
of the Line-of-Sight Time-of-Flights (LOS-TOF) through the Matching Pursuit algorithm. Signal
detection, multipath cancellation and positioning estimation all take place within the portable device,
which provides a graphical representation of the updated position in less than a second. The
performance of the Matching Pursuit algorithm is analyzed in a real scenario and the results show
that the proposed method is capable to retrieve the multipath-free System Availability under strong
multipath conditions with SNR levels as low as 0 dB.
}, keywords = {compass, wsn}, issn = {1051-2004}, doi = {10.1016/j.dsp.2016.11.001}, author = {Fernando J. Alvarez and Teodoro Aguilera and R. L{\'o}pez-Valcarce} } @article {880, title = {FER Estimation in a Memoryless BSC with Variable Frame Length and Unreliable ACK/NAK Feedback}, journal = {IEEE Transactions on Wireless Communications}, volume = {16}, year = {2017}, month = {06/2017}, pages = {3661 - 3673}, abstract = {
We consider the problem of estimating the frame error rate (FER) of a given memoryless binary symmetric channel by observing the success or failure of transmitted packets. Whereas FER estimation is relatively straightforward if all observations correspond to packets with equal length, the problem becomes considerably more complex when this is not the case. We develop FER estimators when
transmissions of different lengths are observed, together with the Cramer-Rao Lower Bound (CRLB). Although the main focus is on Maximum Likelihood (ML) estimation, we also obtain low complexity schemes performing close to optimal in some scenarios. In a second stage, we consider the case in which FER estimation is performed at a node different from the receiver, and incorporate the impairment of unreliable observations by considering noisy ACK/NAK feedback links. The impact of unreliable feedback is analyzed by means of the corresponding CRLB. In this setting, the ML estimator is obtained by applying the Expectation-Maximization algorithm to jointly estimate the error probabilities of the data and feedback links. Simulation results illustrate the benefits of the proposed estimators.
}, keywords = {adaptive signal processing, compass, Cram{\'e}r-Rao bound (CRB), frame error rate, myrada, winter}, doi = {10.1109/TWC.2017.2686845}, author = {Alberto Rico-Alvari{\~n}o and R. L{\'o}pez-Valcarce and Carlos Mosquera and Robert W. Heath Jr.} } @conference {877, title = {Filter design for delay-based anonymous communications}, booktitle = {IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP)}, year = {2017}, keywords = {adversarial signal processing, compass, Multimedia security, winter}, author = {Simon Oya and Fernando P{\'e}rez-Gonz{\'a}lez and Carmela Troncoso} } @article {878, title = {Learning Power Spectrum Maps from Quantized Power Measurements}, journal = {IEEE Transactions on Signal Processing}, volume = {65}, year = {2017}, month = {05/2017}, pages = {2547-2560}, abstract = {
Using power measurements collected by a network of low-cost sensors, power spectral density (PSD) maps are con-
structed to capture the distribution of RF power across space and frequency. Linearly compressed and quantized power measure-
ments enable wideband sensing at affordable implementation complexity using a small number of bits. Strengths of data- and model-
driven approaches are combined to develop estimators capable of incorporating multiple forms of spectral and propagation prior
information while fitting the rapid variations of shadow fading across space. To this end, novel nonparametric and semiparametric
formulations are investigated. It is shown that the desired PSD maps can be obtained using support vector machine-type solvers.
In addition to batch approaches, an online algorithm attuned to real-time operation is developed. Numerical tests assess the performance of the novel algorithms.\ 
}, keywords = {cognitive radio, compass, compressed sensing, spectrum sensing, winter, wsn}, doi = {10.1109/TSP.2017.2666775}, author = {Daniel Romero and Seung-Jun Kim and Georgios Giannakis and R. L{\'o}pez-Valcarce} } @conference {883, title = {Secure Genomic Susceptibility Testing based on Lattice Encryption}, booktitle = {IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP)}, year = {2017}, publisher = {IEEE}, organization = {IEEE}, address = {New Orleans, USA}, keywords = {adversarial signal processing, compass, Genomic Privacy, homomorphic encryption, Lattice-Based Cryptography, Privacy Protection}, author = {Juan Ram{\'o}n Troncoso-Pastoriza and Alberto Pedrouzo-Ulloa and Fernando P{\'e}rez-Gonz{\'a}lez} } @conference {924, title = {Time-domain channel estimation for wideband millimeter wave systems with hybrid architecture}, booktitle = { IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP)}, year = {2017}, month = {03/2017}, pages = {6193-6197}, abstract = {

Millimeter wave (mm Wave) systems will likely employ large antennas at both the transmitter and receiver for directional beamforming. Hybrid analog/digital MIMO architectures have been proposed previously for leveraging both array gain and multiplexing gain, while reducing the power consumption in analog-to-digital converters. Channel knowledge is needed to design the hybrid precoders/combiners, which is difficult to obtain due to the large antenna arrays and the frequency selective nature of the channel. In this paper, we propose a sparse recovery based time-domain channel estimation technique for hybrid architecture based frequency selective mmWave systems. The proposed compressed sensing channel estimation algorithm is shown to provide good estimation error performance, while requiring small training overhead. The simulation results show that using multiple RF chains at the receiver and the transmitter further reduces the training overhead.

}, keywords = {compass, mmWave, myrada}, author = {Kiran Venugopal and Ahmed Alkhateeb and Robert W. Heath Jr. and Nuria Gonz{\'a}lez-Prelcic} } @article {838, title = {Wideband full-duplex MIMO relays with blind adaptive self-interference cancellation}, journal = {Signal Processing}, volume = {130}, year = {2017}, month = {01/2017}, pages = {74-85}, chapter = {74}, abstract = {
We develop adaptive self-interference cancellation algorithms for both filter-and-forward and decode-and-forward
multiple-input multiple-output relays. The algorithms are blind in the sense that they only exploit the spectral properties
of the transmitted signal to identify the self-interference channel, while dealing with frequency-selective channels and
arbitrary signal spectra. Our approach is non-intrusive in the sense that the algorithms can successfully identify, track,
and cancel the self-interference distortion while the relay is operating in its normal mode. We study the stationary
points of the algorithms and analyze under which conditions they achieve perfect cancellation of the self-interference.
Simulation results show that the algorithms provide residual self-interference levels below the noise floor by using
the time samples of only a few OFDM symbols.
}, keywords = {adaptive signal processing, compass, full duplex, winter}, issn = {0165-1684}, doi = {10.1016/j.sigpro.2016.06.010}, author = {Emilio Antonio-Rodr{\'\i}guez and Stefan Werner and R. L{\'o}pez-Valcarce and Taneli Riihonen and Risto Wichman} } @conference {841, title = {Advanced Signal Processing Techniques for Fixed and Mobile Satellite Communications}, booktitle = {8th Advanced Satellite Multimedia Systems Conference 14th Signal Processing for Space Communications Workshop}, year = {2016}, month = {09/2016}, keywords = {compass, full duplex, satcom}, author = {Pol Henarejos and Ana P{\'e}rez-Neira and Nicol{\`o} Mazzali and Carlos Mosquera} } @conference {857, title = {Array thinnig for antenna selection in millimeter wave MIMO systems}, booktitle = {IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP)}, year = {2016}, month = {2016}, keywords = {compass, mmWave}, author = {C. Rusu and Nuria Gonz{\'a}lez-Prelcic and R. W. Heath Jr} } @conference {840, title = {Bandwidth Allocation in Partial Duplex Relaying}, booktitle = {The 17th IEEE International workshop on Signal Processing advances in Wireless Communications (SPAWC)}, year = {2016}, month = {07/2016}, address = {Edinburgh, UK}, keywords = {compass, full duplex, relay}, author = {Carlos Mosquera and R. L{\'o}pez-Valcarce} } @article {825, title = {Compressive Covariance Sensing: Structure-Based Compressive Sensing Beyond Sparsity}, journal = {IEEE Signal Processing Magazine}, volume = {33}, year = {2016}, month = {01/2016}, pages = {78--93}, abstract = {
Compressed sensing deals with the reconstruction of signals
from sub-Nyquist samples by exploiting the sparsity of their
projections onto known subspaces. In contrast, the present
article is concerned with the reconstruction of second-order
statistics, such as covariance and power spectrum, even in
the absence of sparsity priors. The framework described here
leverages the statistical structure of random processes to
enable signal compression and offers an alternative perspective
at sparsity-agnostic inference. Capitalizing on parsimonious
representations, we illustrate how compression and reconstruction
tasks can be addressed in popular applications such
as power spectrum estimation, incoherent imaging, direction
of arrival estimation, frequency estimation, and wideband
spectrum sensing.
}, keywords = {compass, compressed sensing}, author = {Daniel Romero and Dyonisius D Ariananda and Zhi Tian and Geert Leus} } @conference {846, title = {Design of data-injection adversarial attacks against spatial field detectors}, booktitle = {IEEE Workshop on Statistical Signal Processing (SSP)}, year = {2016}, month = {06/2016}, address = {Palma de Mallorca, Spain}, abstract = {

Data-injection attacks on spatial field detection corrupt a subset of measurements to cause erroneous decisions. We consider a centralized decision scheme exploiting spatial field smoothness to overcome lack of knowledge on system parameters such as noise variance. We obtain closed-form expressions for system performance and investigate strategies for an intruder injecting false data in a fraction of the sensors in order to reduce the probability of detection. The problem of determining the most vulnerable subset of sensors is also analyzed.

}, keywords = {adversarial signal processing, compass, wsn}, author = {R. L{\'o}pez-Valcarce and Daniel Romero} } @article {837, title = {Design of pool mixes against profiling attacks in real conditions}, journal = {IEEE/ACM Transactions on Networking}, volume = {24}, year = {2016}, month = {12/2016}, pages = {3662-3675}, keywords = {adversarial signal processing, compass}, doi = {10.1109/TNET.2016.2547391}, author = {Simon Oya and Fernando P{\'e}rez-Gonz{\'a}lez and Carmela Troncoso} } @article {850, title = {Designing incoherent frames through convex techniques for optimized compressed sensing}, journal = {IEEE Transactions on Signal Processing}, volume = {64}, year = {2016}, month = {May/2016}, pages = {2334-2344}, chapter = {2334}, keywords = {compass, compressed sensing}, author = {Cristian Rusu and Nuria Gonz{\'a}lez-Prelcic} } @conference {845, title = {Distributed multivariate regression with unknown noise covariance in the presence of outliers: a minimum description length approach}, booktitle = {IEEE Workshop on Statistical Signal Processing (SSP)}, year = {2016}, address = {Palma de Mallorca, Spain}, abstract = {
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.
}, keywords = {compass, wsn}, author = {R. L{\'o}pez-Valcarce and Daniel Romero and Josep Sala and Alba Pag{\`e}s-Zamora} } @conference {860, title = {Estimating millimeter wave channels using out-of-band measurements}, booktitle = {Information Theory and Applications Workshop (ITA}, year = {2016}, month = {January, 2016}, keywords = {compass, mmWave}, author = {Anum Ali and Nuria Gonz{\'a}lez-Prelcic and R.W. Heath Jr.} } @article {855, title = {Fast orthonormal sparsifying transforms based on Householder reflectors}, journal = {IEEE Transactions on Signal Processing}, volume = {64}, year = {2016}, month = {12/2016}, pages = {6589-6599}, keywords = {compass, compressed sensing}, doi = {10.1109/TSP.2016.2612168}, author = {C. Rusu and Nuria Gonz{\'a}lez-Prelcic and R.W. Heath Jr.} } @conference {925, title = {Frequency selective multiuser hybrid precoding for mmWave systems with imperfect channel knowledge}, booktitle = {Asilomar Conf. on Signals, Systems and Computers}, year = {2016}, month = {11/2016}, keywords = {compass, mmWave}, doi = {10.1109/ACSSC.2016.7869044}, author = {Jose P. Gonzalez-Coma and Nuria Gonz{\'a}lez-Prelcic and Luis Castedo and Robert W. Heath Jr.} } @conference {843, title = {Full-duplex operation in two-way broadcast service for maritime applications}, booktitle = {8th Advanced Satellite Multimedia Systems Conference and 14th Signal Processing for Space Communications Workshop}, year = {2016}, month = {09/2016}, keywords = {compass, full duplex, satcom}, author = {Tom{\'a}s Ram{\'\i}rez and Carlos Mosquera} } @conference {870, title = {Hybrid precoders and combiners for mmWave MIMO systems with per-antenna power constraints}, booktitle = { IEEE Global Telecommunications Conf. (GLOBECOM)}, year = {2016}, abstract = {
This paper considers the design of hybrid precoders
and combiners for mmWave MIMO systems with per-antenna
power constraints and the additional limitations introduced by
the phase-shifting network in the analog processing stage. Previous
hybrid designs were obtained using a total power constraint,
but in practical implementations per-antenna constraints are
more realistic, specially at mmWave, given the large number of
power amplifiers used in the transmit array. Assuming perfect
channel knowledge, we obtain first an approximation to the alldigital
solution for the precoder and the combiner given the
per-antenna constraints. Then, we develop a new method for the
design of the hybrid precoder and combiner which attempts to
match such all-digital approximation. Simulation results show
the effectiveness of the proposed approach, which performs close
to the all-digital solution.
}, keywords = {compass, mmWave}, author = {R. L{\'o}pez-Valcarce and Nuria Gonz{\'a}lez-Prelcic and Cristian Rusu and R. W. Heath, Jr} } @conference {881, title = {Image denoising in the encrypted domain}, booktitle = {IEEE International Workshop on Information Forensics and Security (WIFS)}, year = {2016}, month = {12/2016}, publisher = {IEEE}, organization = {IEEE}, address = {Abu Dhabi, UAE}, keywords = {compass, homomorphic processing, Image Denoising, Image Encryption, lattice cryptography}, author = {Alberto Pedrouzo-Ulloa and Juan Ram{\'o}n Troncoso-Pastoriza and Fernando P{\'e}rez-Gonz{\'a}lez} } @conference {842, title = {The impact of feeder link interference in multiple gateway multibeam satellite systems}, booktitle = {8th Advanced Satellite Multimedia Systems Conference 14th Signal Processing for Space Communications Workshop}, year = {2016}, month = {09/2016}, keywords = {compass, satcom}, author = {Vahid Joroughi and Carlos Mosquera} } @conference {844, title = {Link adaptation in mobile satellite links: field trials results}, booktitle = {8th Advanced Satellite Multimedia Systems Conference and 14th Signal Processing for Space Communications Workshop}, year = {2016}, month = {09/2016}, keywords = {compass, satcom}, author = {Anxo Tato and Carlos Mosquera and Iago G{\'o}mez} } @article {828, title = {Link adaptation in mobile satellite links: schemes for different degrees of CSI knowledge}, journal = {International Journal of Satellite Communications and Networking}, volume = {34}, year = {2016}, month = {09/2016}, pages = {679-694}, keywords = {compass, satcom}, author = {Alberto Rico-Alvari{\~n}o and Jesus Arnau and Carlos Mosquera} } @article {926, title = {Low complexity hybrid precoding strategies for millimeter wave communication systems}, journal = {IEEE Trans. Wireless Communications}, volume = {15}, year = {2016}, month = {12/2016}, pages = {8380 - 8393}, abstract = {

Millimeter communication systems use large antenna arrays to provide good average received power and to take advantage of multi-stream MIMO communication. Unfortunately, due to power consumption in the analog front-end, it is impractical to perform beamforming and fully digital precoding at baseband. Hybrid precoding/combining architectures have been proposed to overcome this limitation. The hybrid structure splits the MIMO processing between the digital and analog domains, while keeping the performance close to that of the fully digital solution. In this paper, we introduce and analyze several algorithms that efficiently design hybrid precoders and combiners starting from the known optimum digital precoder/combiner, which can be computed when perfect channel state information is available. We propose several low complexity solutions which provide different trade-offs between performance and complexity. We show that the proposed iterative solutions perform better in terms of spectral efficiency and/or are faster than previous methods in the literature. All of them provide designs which perform close to the known optimal digital solution. Finally, we study the effects of quantizing the analog component of the hybrid design and show that even with coarse quantization, the average rate performance is good.

}, keywords = {compass, mmWave}, doi = {10.1109/TWC.2016.2614495}, author = {Cristian Rusu and Roi M{\'e}ndez-Rial and Nuria Gonz{\'a}lez-Prelcic and Robert W. Heath Jr.} } @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 {847, title = {Online EM-based distributed estimation in sensor networks with faulty nodes}, booktitle = {European Signal Processing Conference (EUSIPCO)}, year = {2016}, month = {09/2016}, address = {Budapest, Hungary}, abstract = {
This paper focuses on the problem of the distributed estimation of a parameter vector based on noisy observations regularly acquired by the nodes of a wireless sensor network and assuming that some of the nodes have faulty sensors. We propose two online schemes, both centralized and distributed, based on the Expectation-Maximization (EM) algorithm. These algorithms are able to identify and disregard the faulty nodes, and provide a refined estimate of the parameters each time instant after a new set of observations is acquired. Simulation results demonstrate that the centralized versions of the proposed online algorithms attain the same estimation error as the centralized batch EM, whereas the distributed versions come very close to matching the batch EM.
}, keywords = {compass, wsn}, author = {Pere Gimenez-Febrer and Alba Pag{\`e}s-Zamora and R. L{\'o}pez-Valcarce} } @article {929, title = {An overview of signal processing techniques for millimeter wave MIMO systems}, journal = {IEEE J. Selected Topics in Signal Processing. Special issue on Signal Processing for Millimeter Wave Wireless Communications}, volume = {10}, year = {2016}, month = {04/2016}, pages = {436 - 453}, abstract = {

Communication 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.

}, keywords = {compass, mmWave}, doi = {10.1109/JSTSP.2016.2523924}, author = {Robert W. Heath Jr. and Nuria Gonz{\'a}lez-Prelcic and Sundeep Rangan and Wonil Roh and Akbar M. Sayeed} } @conference {859, title = {Radar aided mmWave beam alignment in V2I communications supporting antenna diversity}, booktitle = {Information Theory and Applications Workshop (ITA}, year = {2016}, month = {January, 2016}, keywords = {compass, mmWave}, author = {Nuria Gonz{\'a}lez-Prelcic and R. M{\'e}ndez-Rial and R.W. Heath Jr.} } @conference {858, title = {Robust analog precoding designs for millimeter wave MIMO transceivers}, booktitle = {20th International ITG Workshop on Smart Antennas (WSA)}, year = {2016}, month = {March, 2016}, keywords = {compass, mmWave}, author = {Pengfei Xia and Robert Heath and Nuria Gonz{\'a}lez-Prelcic} } @article {927, title = {Robust analog precoding designs for millimeter wave MIMO transceivers with frequency and time division duplexing}, journal = {IEEE Trans. Communications}, volume = {64}, year = {2016}, month = {11/2016}, pages = {4622 - 4634}, abstract = {

Millimeter wave (mmWave) communication provides high data rates thanks to large arrays at the transmitter and receiver, coupled with large bandwidth channels. Exploiting the arrays is challenging due to the need to configure precoding at the transmitter based on the large frequency selective channel. In this paper, we exploit the power iteration principle and propose a robust analog precoding training algorithm that can be applied in both frequency division duplex transmission systems and time division duplex transmission systems with or without RF calibration. We further analyze the convergence of the proposed algorithm and show how it converges to the singular value decomposition optimality exponentially. We propose null space projection on top of the power iteration to form multiple orthogonal beams at the transmitter and receiver. Strongest tap selection with proper energy pruning is used to collect as much precoding gain as possible from a frequency selective fading channel. The exponential effective SINR mapping performance is evaluated and demonstrates that the overall approach works smoothly. Numerical simulation results demonstrate algorithm robustness and the algorithm works not only for the simplified mmWave directional channels, but also for more general rich scattering channels.

}, keywords = {compass, mmWave}, doi = {10.1109/TCOMM.2016.2604312}, author = {Pengfei Xia and Robert W. Heath Jr. and Nuria Gonz{\'a}lez-Prelcic} } @article {853, title = {Security in automotive radar and vehicular networks}, journal = {Microwave Journal}, year = {2016}, keywords = {compass, mmWave}, author = {E. R. Yeh and J. Choi and Nuria Gonz{\'a}lez-Prelcic and C. Bhat and R. W. Heath Jr.} } @conference {856, title = {The use of unit norm tight measurement matrices for one-bit compressed sensing}, booktitle = {IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP)}, year = {2016}, month = {2016}, abstract = {

In this paper we analyze the mean squared error (MSE) for one-bit compressed sensing schemes based on measurement matrices that correspond to unit norm tight frames. We show that, as in the unquantized case, sensing with unit norm tight frames improves the MSE in the reconstruction of sparse vectors from one-bit measurements using l1\ and thresholding algorithms. From our analytical and experimental results we conclude that when implementing one-bit compressed sensing schemes with fixed measurement matrices unit norm tight frames are the measurements of choice

}, keywords = {compass, compressed sensing}, author = {C. Rusu and Nuria Gonz{\'a}lez-Prelcic and R. W. Heath Jr.} } @conference {839, title = {Wideband self-interference cancellation for better spectrum use}, booktitle = {IEEE WoWMoM 2016 Workshop on Fifth Generation Wireless}, year = {2016}, month = {06/2016}, keywords = {adaptive signal processing, compass, full duplex}, author = {Carlos Mosquera} } @conference {863, title = {Adaptive hybrid precoding and combining in mmWave multiuser MIMO systems based on compressed covariance estimation}, booktitle = {IEEE International Workshop on Computational Advances in Multi-Sensor Adaptive Processing (CAMSAP)}, year = {2015}, month = {December, 2015}, keywords = {compass, mmWave}, author = {R. M{\'e}ndez-Rial and Nuria Gonz{\'a}lez-Prelcic and R. W. Heath Jr.} } @conference {861, title = {Adaptive one-bit compressive sensing with application to low-precision receivers at mmWave}, booktitle = {IEEE Global Telecommunications Conf. (GLOBECOM), }, year = {2015}, month = {December, 2015}, keywords = {compass, mmWave}, author = {C. Rusu and R. M{\'e}ndez-Rial and Nuria Gonz{\'a}lez-Prelcic and R. W. Heath, Jr} } @conference {815, title = {Attack detectors for data aggregation in clustered sensor networks}, booktitle = {European Signal Processing Conf. (EUSIPCO)}, year = {2015}, month = {accepted}, pages = {2098-2102}, publisher = {EURASIP}, organization = {EURASIP}, address = {Nice, France}, abstract = {
Among many security threats to sensor networks, compromised sensing is particularly challenging due to the fact that it cannot be addressed by standard authentication approaches. We consider a clustered scenario for data aggregation in which an attacker injects a disturbance in sensor readings. Casting the problem in an estimation framework, we systematically apply the Generalized Likelihood Ratio approach to derive attack detectors. The analysis under different attacks reveals that detectors based on similarity of means across
clusters are suboptimal, with Bartlett{\textquoteright}s test for homoscedasticity constituting a good candidate when lacking a priori knowledge of the variance of the underlying distribution.
}, keywords = {adversarial signal processing, compass, wsn}, author = {R. L{\'o}pez-Valcarce and Daniel Romero} } @conference {816, title = {An attack on antenna subset modulation for millimeter-wave communication}, booktitle = {IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP)}, year = {2015}, month = {04/2015}, pages = {2914-2918}, publisher = {IEEE}, organization = {IEEE}, address = {Brisbane, Australia}, abstract = {

Antenna subset modulation (ASM) is a physical layer security technique that is well suited for millimeter wave communication systems. The key idea is to vary the radiation pattern at the symbol rate by selecting one from a subset of patterns with a similar main lobe and different side lobes. This paper shows that ASM is not robust to an eavesdropper that makes multiple simultaneous measurements at multiple angles. The measurements are combined and used to formulate an estimation problem to undo the effects of the side lobe randomization. Simulations show the performance of the estimation algorithms and how the eavesdropper can effectively recover the information if the signal-to-noise ratio exceeds a certain threshold. Using fewer active radio frequency chains makes it harder for the attacker to recover the transmit symbol, at the expense of more grating lobes.

}, keywords = {adversarial signal processing, compass, mmWave}, author = {Cristian Rusu and Nuria Gonz{\'a}lez-Prelcic and Robert W. Heath Jr.} } @conference {804, title = {Blind Satellite Inter-Gateway Interference Mitigation}, booktitle = {IEEE International Conference on Communications (ICC)}, year = {2015}, month = {2015}, keywords = {compass, satcom}, author = {J. Arnau and C. Mosquera} } @article {770, title = {Compression Limits for Random Vectors with Linearly Parameterized Second-Order Statistics}, journal = {IEEE Trans. Information Theory}, volume = {61}, year = {2015}, month = {03/2015}, pages = {1410-1425}, chapter = {1410}, abstract = {
The class of complex random vectors whose covariance
matrix is linearly parameterized by a basis of Hermitian
Toeplitz (HT) matrices is considered, and the maximum
compression ratios that preserve all second-order information
are derived {\textemdash} the statistics of the uncompressed vector must
be recoverable from a set of linearly compressed observations.
This kind of vectors arises naturally when sampling widesense
stationary random processes and features a number of
applications in signal and array processing.
Explicit guidelines to design optimal and nearly optimal
schemes operating both in a periodic and non-periodic fashion
are provided by considering two of the most common linear
compression schemes, which we classify as dense or sparse. It
is seen that the maximum compression ratios depend on the
structure of the HT subspace containing the covariance matrix of
the uncompressed observations. Compression patterns attaining
these maximum ratios are found for the case without structure as
well as for the cases with circulant or banded structure. Universal
samplers are also proposed to compress unknown HT subspaces.
}, keywords = {compass, compressed sensing}, doi = {10.1109/TIT.2015.2394784}, author = {Daniel Romero and R. L{\'o}pez-Valcarce and Geert Leus} } @article {769, title = {Cram{\'e}r-Rao Bounds for SNR Estimation of Oversampled Linearly Modulated Signals}, journal = {IEEE Trans. Signal Processing}, volume = {63}, year = {2015}, month = {04/2015}, pages = {1675-1683}, chapter = {1675}, abstract = {
Most Signal-to-noise ratio (SNR) estimators use the
receiver matched filter output sampled at the symbol rate, an
approach which does not preserve all information in the analog
waveform due to aliasing. Thus, it is relevant to ask whether
avoiding aliasing could improve SNR estimation. To this end, we
compute the corresponding data-aided (DA) and non-data-aided
(NDA) Cram{\'e}r-Rao bounds (CRBs). We adopt a novel dual filter
framework, which is shown to be information-preserving under
suitable conditions and considerably simplifies the analysis. It is
shown that the CRB can be substantially reduced by exploiting
any available excess bandwidth, depending on the modulation
scheme, the SNR range, and the estimator (DA or NDA) type.
}, keywords = {adaptive signal processing, compass, Cram{\'e}r-Rao bound (CRB), dynacs, oversampling, Signal-to-noise ratio (SNR)}, doi = {10.1109/TSP.2015.2396013}, author = {R. L{\'o}pez-Valcarce and J. Villares and J. Riba and W. Gappmair and C. Mosquera} } @conference {818, title = {Dictionary-free Hybrid Precoders and Combiners for mmWave MIMO Systems}, booktitle = {IEEE Int. Workshop on Signal Processing Advances in Wireless Communications (SPAWC)}, year = {2015}, month = {06/2015}, publisher = {IEEE}, organization = {IEEE}, address = {Stockholm, Sweden}, keywords = {compass, mmWave}, author = {Roi M{\'e}ndez-Rial and Cristian Rusu and Nuria Gonz{\'a}lez-Prelcic and Robert W. Heath Jr.} } @conference {812, title = {Distributed AoA-based Source Positioning in NLOS with Sensor Networks}, booktitle = {IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP)}, year = {2015}, month = {04/2015}, publisher = {IEEE}, organization = {IEEE}, address = {Brisbane, Australia}, abstract = {
This paper focuses on the problem of positioning a source using angle-of-arrival measurements taken by a wireless sensor network in which some of the nodes experience non-line-of-sight (NLOS) propagation conditions. In order to mitigate the errors induced by the nodes in NLOS, we derive an algorithm that combines the expectation-maximization algorithm with a weighted least-squares estimation of the source position so that the nodes in NLOS are eventually identified and discarded. Moreover, a distributed version of this algorithm based on a diffusion strategy that iteratively refines the position estimate while driving the network to a consensus is presented.
}, keywords = {compass, wsn}, author = {Pere Gimenez-Febrer and Alba Pag{\`e}s-Zamora and Silvana Silva Pereira and R. L{\'o}pez-Valcarce} } @conference {811, title = {Distributed TLS Estimation under Random Data Faults}, booktitle = {IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP)}, year = {2015}, month = {04/2015}, publisher = {IEEE}, organization = {IEEE}, address = {Brisbane, Australia}, abstract = {
This paper addresses the problem of distributed estimation of a parameter vector in the presence of noisy input and output data as well as data faults, performed by a wireless sensor network in which only local interactions among the nodes are allowed. In the presence of unreliable observations, standard estimators become biased and perform poorly in low signal-to-noise ratios. We propose two different distributed approaches based on the Expectation-Maximization algorithm: in the first one the regressors are estimated at each iteration,
whereas the second one does not require explicit regressor estimation. Numerical results show that the proposed methods approach the performance of a clairvoyant scheme with knowledge of the random data faults.
}, keywords = {compass, wsn}, author = {Silvana Silva Pereira and Alba Pag{\`e}s-Zamora and R. L{\'o}pez-Valcarce} } @mastersthesis {798, title = {Estimation, Detection, and Learning for Dynamic Spectrum Access}, volume = {Ph.D.}, year = {2015}, month = {05/2015}, school = {University of Vigo}, type = {Ph.D. Thesis}, address = {Vigo, Spain}, keywords = {cognitive radio, compass, dynacs, wsn}, author = {Daniel Romero} } @article {796, title = {Forensic detection of processing operator chains: recovering the history of filtered JPEG images}, journal = {IEEE Transactions on Information Forensics and Security}, year = {2015}, keywords = {compass, forensics}, doi = {10.1109/TIFS.2015.2424195}, author = {Valentina Conotter and Pedro Comesa{\~n}a and Fernando P{\'e}rez-Gonz{\'a}lez} } @conference {806, title = {Frequency Reuse in Dual Satellite Settings: an Initial Evaluation of Full Duplex Operation}, booktitle = {IEEE International Conference on Communications (ICC)}, year = {2015}, keywords = {compass, full duplex, satcom}, author = {D. Marti{\~n}{\'a}n-Otero and C. Mosquera} } @article {767, title = {A Greedy Topology Design to Accelerate Consensus in Broadcast Wireless Sensor Networks}, journal = {Information Processing Letters}, volume = {115}, year = {2015}, month = {03/2015}, pages = {408-413}, chapter = {408}, abstract = {

We present techniques to improve convergence speed of distributed average consensus algorithms in wireless sensor networks by means of topology design. A broadcast network is assumed, so that only the transmit power of each node can be independently controlled, rather than each individual link. Starting with a maximally connected configuration in which all nodes transmit at full power, the proposed methods successively reduce the transmit power of a chosen node in order to remove one and only one link; nodes are greedily selected either in order to yield fastest convergence at each step, or if they have the largest degree in the network. These greedy schemes provide a good complexity-performance tradeoff with respect to full-blown global search methods. As a side benefit, improving the convergence speed also results in savings in energy consumption with respect to the maximally connected setting.

}, keywords = {compass, wsn}, doi = {10.1016/j.ipl.2014.11.009}, author = {Massimo Vecchio and R. L{\'o}pez-Valcarce} } @article {756, title = {Improving Area Coverage of Wireless Sensor Networks Via Controllable Mobile Nodes: a Greedy Approach}, journal = {Journal of Network and Computer Applications}, volume = {48}, year = {2015}, month = {02/2015}, pages = {1-13}, abstract = {
Reliable wide-area monitoring with Wireless Sensor Networks (WSNs) remains a problem of
interest: simply deploying more nodes to cover wider areas is generally not a viable solution, due to
deployment and maintenance costs and the increase in radio interference. One possible solution
gaining popularity is based on the use of a reduced number of mobile nodes with controllable
trajectories in the monitored field. In this framework, we present a distributed technique for iteratively
computing the trajectories of the mobile nodes in a greedy fashion. The static sensor nodes actively
assist the mobile nodes in this task by means of a bidding protocol, thus participating towards the goal
of maximizing the area coverage of the monitored field. The performance of the proposed technique is
evaluated on various simulation scenarios with different number of mobile and static nodes in terms of
achieved coverage and mean time to achieve X\% coverage. Comparison with previous state-of-the-art
techniques reveals the effectiveness and stability of the proposed method.
}, keywords = {compass, wsn}, doi = {10.1016/j.jnca.2014.10.007}, author = {Massimo Vecchio and R. L{\'o}pez-Valcarce} } @conference {819, title = {Low Complexity Hybrid Sparse Precoding and Combining in Millimeter Wave MIMO Systems}, booktitle = {IEEE Int. Conference on Communications (ICC)}, year = {2015}, month = {06/2015}, publisher = {IEEE}, organization = {IEEE}, address = {London, UK}, keywords = {compass, mmWave}, author = {Cristian Rusu and Roi M{\'e}ndez-Rial and Nuria Gonz{\'a}lez-Prelcic and Robert W. Heath Jr.} } @conference {862, title = {Low Resolution Adaptive Compressed Sensing for mmWave MIMO receivers}, booktitle = {Asilomar Conf. on Signals, Systems, and Computers}, year = {2015}, month = {November, 2015}, keywords = {compass, mmWave}, author = {C. Rusu and Nuria Gonz{\'a}lez-Prelcic and R.W. Heath Jr.} } @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 {807, title = {Robust Adaptive Coding and Modulation Scheme for the Mobile Satellite Forward Link}, booktitle = {IEEE International Workshop on Signal Processing Advances in Wireless Communications, SPAWC}, year = {2015}, keywords = {compass, satcom}, author = {Alberto Rico-Alvari{\~n}o and Anxo Tato and Carlos Mosquera} } @conference {810, title = {Spectrum Cartography using quantized observations}, booktitle = {IEEE Int. Conference on Acoustics, Speech and Signal Processing (ICASSP)}, year = {2015}, month = {04/2015}, publisher = {IEEE}, organization = {IEEE}, address = {Brisbane, Australia}, abstract = {
This work proposes a spectrum cartography algorithm used for learning the power spectrum distribution over a wide frequency band across a given geographic area. Motivated by low-complexity sensing hardware and stringent communication constraints, compressed and quantized measurements are considered. Setting out from a nonparametric regression framework, it is shown that a sensible approach leads to a support vector machine formulation. The simulated tests verify that accurate spectrum maps can be constructed using a simple sensing architecture with significant savings in the feedback.
}, keywords = {cognitive radio, compass, compressed sensing, spectrum sensing}, author = {Daniel Romero and Seung-Jun Kim and R. L{\'o}pez-Valcarce and Georgios Giannakis} } @conference {808, title = {Subspace-constrained SINR optimization in MIMO full-duplex relays under limited dynamic range}, booktitle = {IEEE 16th Int. Workshop on Signal Processing Advances in Wireless Communications (SPAWC)}, year = {2015}, month = {06/2015}, publisher = {IEEE}, organization = {IEEE}, address = {Stockholm, Sweden}, abstract = {
We propose a method for maximizing the signal-to-interference-plus-noise ratio (SINR) in a wideband full-duplex MIMO regenerative relay that accounts limited dynamic range of the receiver and transmitter impairments. Transmit and receive filters are designed at the relay, by means of an alternating minimization algorithm, to minimize the interference at the decoder input in the destination node. We impose channel shortening and subspace constraints to ensure that the received signal at the destination is not compromised. Simulation results show that the presented method significantly outperforms other constrained approaches.
}, keywords = {adaptive signal processing, compass, full duplex}, author = {Emilio Antonio-Rodr{\'\i}guez and R. L{\'o}pez-Valcarce and Taneli Riihonen and Stefan Werner and Risto Wichman} } @conference {797, title = {An SVD Approach to Forensic Image Resampling Detection}, booktitle = {EUSIPCO}, year = {2015}, month = {09/2015}, pages = {2112-2116}, abstract = {
This paper describes a new strategy for image resampling detection whenever the applied resampling factor is larger than one. Delving into the linear dependencies induced in an image after the application of an upsampling operation, we show that interpolated images belong to a subspace defined by the interpolation kernel. Within this framework, by computing the SVD of a given image block and a measure of its degree of saturated pixels per row/column, we derive a simple detector capable of discriminating between upsampled images and genuine images. Furthermore, the proposed detector shows remarkable results with blocks of small size and outperforms state-of-the-art methods.
}, keywords = {compass, digital image forensics, resampling detection, SVD, tampering detection}, author = {David V{\'a}zquez-Pad{\'\i}n and Pedro Comesa{\~n}a and Fernando P{\'e}rez-Gonz{\'a}lez} } @article {748, title = {Active Interference Cancellation for OFDM Spectrum Sculpting: Linear Processing is Optimal}, journal = {IEEE Communications Letters}, volume = {18}, year = {2014}, month = {09/2014}, pages = {1543-1546}, chapter = {1543}, abstract = {

Active 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.

}, keywords = {cognitive radio, compass, dynacs, spectrum shaping}, doi = {10.1109/LCOMM.2014.2338316}, author = {Schmidt, J.F. and Daniel Romero and R. L{\'o}pez-Valcarce} } @conference {758, title = {A Benford-Fourier JPEG compression detector}, booktitle = {IEEE International Conference on Image Processing (ICIP)}, year = {2014}, address = {Paris, France}, keywords = {compass, forensics}, doi = {10.1109/ICIP.2014.7026077}, author = {Cecilia Pasquini and Fernando P{\'e}rez-Gonz{\'a}lez and Giulia Boato} } @conference {771, title = {Channel estimation in millimeter wave MIMO systems with one-bit quantization}, booktitle = {Asilomar Conf. on Signals, Systems and Computers}, year = {2014}, keywords = {adaptive signal processing, compass, mmWave}, doi = {10.1109/ACSSC.2014.7094595}, author = {Jianhua Mo and Phil Schniter and Nuria Gonz{\'a}lez-Prelcic and Robert W. Heath Jr.} } @conference {765, title = {Circular Sparse Rulers Based On Co-prime Sampling For Compressive Power Spectrum Estimation}, booktitle = {IEEE Global Communications Conference}, year = {2014}, month = {12/2014}, publisher = {IEEE}, organization = {IEEE}, address = {Austin, TX}, keywords = {cognitive radio, compass, compressed sensing}, doi = {10.1109/GLOCOM.2014.7037272}, author = {Nuria Gonz{\'a}lez-Prelcic and M. E. Dom{\'\i}ngez-Jim{\'e}nez} } @conference {753, title = {Detecting Misreporting Attacks to the Proportional Fair Scheduler}, booktitle = {IEEE Workshop on Information Forensics and Security (WIFS)}, year = {2014}, month = {12/2014}, address = {Atlanta, USA}, abstract = {
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.
}, keywords = {adversarial signal processing, compass}, doi = {10.1109/WIFS.2014.7084310}, author = {Schmidt, J.F. and R. L{\'o}pez-Valcarce} } @conference {747, title = {Do dummies pay off? Limits of dummy traffic protection in anonymous communications}, booktitle = {Privacy Enhancing Technologies Symposium}, year = {2014}, keywords = {anonymous communications, compass, disclosure attacks, dummies}, author = {Simon Oya and Carmela Troncoso and Fernando P{\'e}rez-Gonz{\'a}lez} } @conference {726, title = {FER prediction with variable codeword length}, booktitle = {ICASSP2014 - Signal Processing for Communications and Networking (ICASSP2014 - SPCOM)}, year = {2014}, address = {Florence, Italy}, abstract = {

Frame error rate (FER) prediction in wireless communication systems is an important tool with applications to system level simulations and link adaptation, among others. Although in realistic communication scenarios it is expected to have codewords of different lengths, previous work on FER prediction marginally treated the dependency of the FER on the codeword length. In this paper, we present a method to estimate the FER using codewords of different length. We derive a low complexity FER estimator for frames of different length transmitted over a binary symmetric channel of unknown error probability. We extend this technique to coded systems by the use of effective SNR FER predictors. The proposed estimation scheme is shown to outperform other simpler estimation methods.

}, keywords = {adaptive signal processing, compass, dynacs, Effective SNR, FER prediction, PHY abstraction}, doi = {10.1109/ICASSP.2014.6853935}, author = {Alberto Rico-Alvari{\~n}o and Robert W. Heath Jr. and Carlos Mosquera} } @conference {733, title = {How to Implement Doubly-Stochastic Matrices for Consensus-Based Distributed Algorithms}, booktitle = {IEEE Sensor Array and Multichannel Signal Processing Workshop (SAM)}, year = {2014}, address = {A Coru{\~n}a, Spain}, abstract = {
Doubly-stochastic matrices are usually required by
consensus-based distributed algorithms. We propose a simple
and efficient protocol and present some guidelines for implementing
doubly-stochastic combination matrices even in noisy,
asynchronous and changing topology scenarios. The proposed
ideas are validated with the deployment of a wireless sensor
network, in which nodes run a distributed algorithm for robust
estimation in the presence of nodes with faulty sensors.
}, keywords = {compass, dynacs, wsn}, doi = {10.1109/SAM.2014.6882409}, author = {S. Valc{\'a}rcel-Macua and C. Moreno-Le{\'o}n and J. S. Romero and Silvana Silva Pereira and Javier Zazo and Alba Pag{\`e}s-Zamora and R. L{\'o}pez-Valcarce and S. Zazo} } @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 {755, title = {The optimal attack to histogram-based forensic detectors is simple(x)}, booktitle = {IEEE International Workshop on Information Forensics and Security (WIFS)}, year = {2014}, month = {12/2014}, pages = {137-142}, address = {Atlanta, GA}, keywords = {compass, Multimedia security}, author = {Pedro Comesa{\~n}a and Fernando P{\'e}rez-Gonz{\'a}lez} } @conference {732, title = {SINR Optimization in Wideband Full-Duplex MIMO Relays under Limited Dynamic Range}, booktitle = {IEEE Sensor Array and Multichannel Signal Processing Workshop (SAM)}, year = {2014}, address = {A Coru{\~n}a, Spain}, keywords = {adaptive signal processing, compass, full duplex}, doi = {10.1109/SAM.2014.6882369}, author = {Emilio Antonio-Rodr{\'\i}guez and R. L{\'o}pez-Valcarce and Taneli Riihonen and Stefan Werner and Risto Wichman} }