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.

VL - 156
ER -
TY - JOUR
T1 - Wideband full-duplex MIMO relays with blind adaptive self-interference cancellation
JF - Signal Processing
Y1 - 2017
A1 - Emilio Antonio-Rodríguez
A1 - Stefan Werner
A1 - R. López-Valcarce
A1 - Taneli Riihonen
A1 - Risto Wichman
KW - adaptive signal processing
KW - compass
KW - full duplex
KW - winter
AB - 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.

VL - 130
ER -
TY - CONF
T1 - Subspace-constrained SINR optimization in MIMO full-duplex relays under limited dynamic range
T2 - IEEE 16th Int. Workshop on Signal Processing Advances in Wireless Communications (SPAWC)
Y1 - 2015
A1 - Emilio Antonio-Rodríguez
A1 - R. López-Valcarce
A1 - Taneli Riihonen
A1 - Stefan Werner
A1 - Risto Wichman
KW - adaptive signal processing
KW - compass
KW - full duplex
AB - 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.

JF - IEEE 16th Int. Workshop on Signal Processing Advances in Wireless Communications (SPAWC)
PB - IEEE
CY - Stockholm, Sweden
ER -
TY - CONF
T1 - SINR Optimization in Wideband Full-Duplex MIMO Relays under Limited Dynamic Range
T2 - IEEE Sensor Array and Multichannel Signal Processing Workshop (SAM)
Y1 - 2014
A1 - Emilio Antonio-Rodríguez
A1 - R. López-Valcarce
A1 - Taneli Riihonen
A1 - Stefan Werner
A1 - Risto Wichman
KW - adaptive signal processing
KW - compass
KW - full duplex
JF - IEEE Sensor Array and Multichannel Signal Processing Workshop (SAM)
CY - A Coruña, Spain
ER -
TY - CONF
T1 - Adaptive Self-interference Cancellation in Wideband Full-Duplex Decode-and-Forward MIMO Relays
T2 - IEEE 14th Int. Workshop on Signal Processing Advances in Wireless Communications (SPAWC)
Y1 - 2013
A1 - Emilio Antonio-Rodríguez
A1 - R. López-Valcarce
A1 - Taneli Riihonen
A1 - Stefan Werner
A1 - Risto Wichman
KW - adaptive signal processing
KW - dynacs
KW - full duplex
JF - IEEE 14th Int. Workshop on Signal Processing Advances in Wireless Communications (SPAWC)
CY - Darmstadt, Germany
ER -
TY - CONF
T1 - Autocorrelation-based adaptation rule for feedback equalization in Wideband Full-Duplex Amplify-and-Forward MIMO relays
T2 - Int. Conf. Acoust., Speech, Signal Process. (ICASSP)
Y1 - 2013
A1 - Emilio Antonio-Rodríguez
A1 - R. López-Valcarce
A1 - Taneli Riihonen
A1 - Stefan Werner
A1 - Risto Wichman
KW - adaptive signal processing
KW - dynacs
KW - full duplex
AB - Simultaneous reception and transmission in the same frequency, so-called full-duplex operation, causes an infinite feedback loop in an amplify-and-forward relay. The unwanted echoes may result in oscillation at the relay, making it unstable, and distorting the spectrum. This paper presents an adaptive MIMO filtering method for full-duplex amplify-and-forward relays that aims at solving the joint problem of self-interference mitigation and equalization of the source-relay channel. The scheme exploits knowledge of the autocorrelation of the transmitted signal as the only side information while allowing the relay, in the best case, to implement precoding as if there was not any self-interference or frequency selectivity in the source-relay channel. Finally, the proposed adaptation algorithm is investigated by determining its stationary points and by performing simulations in a MIMO-OFDM framework.

JF - Int. Conf. Acoust., Speech, Signal Process. (ICASSP)
ER -
TY - CONF
T1 - Cancelling self-interference in full-duplex relays without Angle-of-Arrival information
T2 - Int. Conf. Acoust., Speech, Signal Process. (ICASSP)
Y1 - 2013
A1 - Emilio Antonio-Rodríguez
A1 - R. López-Valcarce
KW - adaptive signal processing
KW - dynacs
KW - full duplex
AB - With full-duplex relays, simultaneous reception and transmission in

the same frequency produce self-interference distortion and relay oscillation,

hampering reception at the receiver end unless properly

mitigated. Previous adaptive methods for self-interference cancellation

using multiple receive antennas require knowledge of the direction

of arrival of the source signal. We present a novel architecture

and adaptive scheme for Amplify-and-Forward relays allowing cancellation

without such knowledge. The temporal filter is updated

under the property restoral paradigm in order to match the power

spectrum of the retransmitted signal to that of the source signal.

JF - Int. Conf. Acoust., Speech, Signal Process. (ICASSP)
ER -
TY - JOUR
T1 - An Adaptive Feedback Canceller for Full-Duplex Relays Based on Spectrum Shaping
JF - IEEE J. Selected Areas in Communications
Y1 - 2012
A1 - R. López-Valcarce
A1 - Emilio Antonio-Rodríguez
A1 - C. Mosquera
A1 - Fernando Pérez-González
KW - adaptive signal processing
KW - dynacs
KW - full duplex
AB - Although full-duplex relaying schemes are appealing in order to improve spectral efficiency, simultaneous reception and transmission in the same frequency results in selfinterference,

distorting the retransmitted signal and making the relay prone to oscillation. Current feedback cancellation techniques by means of adaptive filters are hampered by the fact that the useful and interference signals are highly correlated. We present a new adaptive algorithm which effectively and blindly

restores the spectral shape of the desired signal. In contrast

with previous schemes, the novel adaptive feedback canceller has low complexity, does not introduce additional delay in the relay station, and partly compensates for multipath propagation.

VL - 30
IS - 8
ER -
TY - CONF
T1 - Adaptive self-interference suppression for full-duplex relays with multiple receive antennas
T2 - IEEE 13th Int. Workshop on Signal Processing Advances in Wireless Communications (SPAWC 2012)
Y1 - 2012
A1 - Emilio Antonio-Rodríguez
A1 - R. López-Valcarce
KW - adaptive signal processing
KW - dynacs
KW - full duplex
AB - In full-duplex relays, simultaneous reception and transmission

in the same frequency results in self-interference which distorts the retransmitted signal and makes the relay prone to oscillation. We present an adaptive feedback canceller for multiple-input single-output (MISO) relays, efficiently combining spatial and temporal processing. The receive array is adaptively steered towards the minimum variance distortionless response (MVDR), whereas the temporal filter update is based on a novel low-complexity spectrum shaping scheme which avoids introducing additional delay in the relay station.

JF - IEEE 13th Int. Workshop on Signal Processing Advances in Wireless Communications (SPAWC 2012)
PB - IEEE
CY - Çesme, Turkey
ER -