@article {1024, title = {Full-duplex mmWave MIMO with finite-resolution phase shifters}, journal = {IEEE Trans. Wireless Communications}, volume = {21}, year = {2022}, month = {11/2022}, pages = {8979-8994}, abstract = {
Enabling simultaneous transmission and reception on the same carrier frequency, i.e., full-duplex (FD) communication, critically requires that the self-interference (SI) be sufficiently suppressed. We investigate the design of precoders and combiners for an FD millimeter wave point-to-point bidirectional link, where dense antenna arrays provide an opportunity for SI suppression via beamforming cancellation. In practice the precoders and combiners are usually implemented in a hybrid digital/analog fashion with a reduced number of radio frequency (RF) chains, and it becomes necessary to overcome a number of limitations imposed by this structure. We focus on a hybrid architecture with a phase shifter-based fully-connected analog stage, assuming finite-resolution phase shifters. To avoid analog-to-digital converter saturation at the receiver, the proposed design aims at cancelling SI at the analog combiner output. Although accurate SI suppression is difficult with low-resolution phase shifters, our design is able to provide reasonable performance, significantly improving upon previous approaches, and allowing to efficiently exploit the availability of RF chains to partially compensate for coarse phase quantization effects.
}, keywords = {full-duplex, mmWave, rodin}, issn = {1536-1276}, doi = {10.1109/TWC.2022.3171664}, author = {R. L{\'o}pez-Valcarce and M. Mart{\'\i}nez-Cotelo} } @conference {996, title = {Analog beamforming for full-duplex mmWave communication with low-resolution phase shifters}, booktitle = {IEEE International Conference on Communications (ICC)}, year = {2021}, month = {06/2021}, address = {Montreal, Canada (Virtual event)}, abstract = {
Full-Duplex (FD) communication has been the object of recent attention, particularly in sub-6 GHz bands. By enabling in-band simultaneous transmission and reception, these techniques present great potential in terms of spectral efficiency, latency, and medium access flexibility, and their extension to millimeter wave (mmWave) bands can be expected to benefit similarly. The dense antenna arrays available in mmWave offer a large number of degrees of freedom which could be exploited towards self-interference (SI) mitigation in FD. However, analog beamforming architectures based on practical phase shifters make this task quite challenging due to the lack of amplitude
control and finite phase resolution. In this context, we consider a single-stream bidirectional point-to-point mmWave FD link, and develop a new analog beamforming design requiring a single radio frequency chain in each direction, explicitly taking into account such hardware-related constraints. Simulation results show that the proposed scheme significantly outperforms previous methods for practical phase shifter resolution values of a few bits.
}, keywords = {full-duplex, mmWave, rodin}, author = {R. L{\'o}pez-Valcarce and M. Mart{\'\i}nez-Cotelo} } @conference {989, title = {Full-Duplex mmWave Communication with Hybrid Precoding and Combining}, booktitle = {European Signal Processing Conference (EUSIPCO)}, year = {2020}, month = {08/2020}, address = {Amsterdam (Netherlands)}, abstract = {
We investigate the design of hybrid precoders and combiners for a millimeter wave (mmWave) point-to-point bidirectional link in which both nodes transmit and receive simultaneously and on the same carrier frequency. In such full-duplex configuration, mitigation of self-interference (SI) becomes critical. Large antenna arrays provide an opportunity for spatial SI suppression in mmWave. We assume a phase-shifter based, fully connected architecture for the analog part of the precoder and combiner. The proposed design, which aims at cancelling SI in the analog domain to avoid frontend saturation, significantly improves on the performance of previous approaches.
}, keywords = {full-duplex, mmWave, rodin, winter}, author = {R. L{\'o}pez-Valcarce and M. Mart{\'\i}nez-Cotelo} } @conference {991, title = {Robustness analysis of beamforming based designs for mmWave Full-Duplex Amplify-and-Forward relays}, booktitle = {2020 14th International Conference on Signal Processing and Communication Systems (ICSPCS)}, year = {2020}, month = {12/2020}, abstract = {
We consider the robust design of a millimeter wave MIMO two-hop system in which source, relay and destination are
equipped with large antenna arrays. The relay implements the amplify-and-forward protocol and operates in full-duplex mode,
thus being subjected to self-interference (SI). Imperfect channel state information (CSI) is assumed in all involved links, including
the SI channel, with a deterministic isotropic bounded model on CSI errors. The proposed robust design seeks to maximize
the worst-case spectral efficiency, accommodates both digital and phase shifter-based analog beamforming, and is computationally
simple; moreover, it does not require knowledge of the size of the CSI uncertainty regions.
}, keywords = {full-duplex, mmWave, rodin}, author = {R. L{\'o}pez-Valcarce and M. Mart{\'\i}nez-Cotelo} }