Papers by Bartolomeu Uchôa-Filho
IEEE Transactions on Vehicular Technology, Oct 1, 2019
arXiv (Cornell University), Jan 12, 2010
Anais do XL Simpósio Brasileiro de Telecomunicações e Processamento de Sinais
Anais do XXII Simpósio Brasileiro de Telecomunicações
Anais do XXII Simpósio Brasileiro de Telecomunicações
Sensors, 2022
Intelligent Reflecting Surfaces (IRSs) are emerging as an effective technology capable of improvi... more Intelligent Reflecting Surfaces (IRSs) are emerging as an effective technology capable of improving the spectral and energy efficiency of future wireless networks. The proposed scenario consists of a multi-antenna base station and a single-antenna user that is assisted by an IRS. The large number of reflecting elements at the IRS and its passive operation represent an important challenge in the acquisition of the instantaneous channel state information (I-CSI) of all links as it adds a very high overhead to the system and requires equipping the IRS with radio-frequency chains. To overcome this problem, a new approach is proposed in order to optimize beamforming at the BS and the phase shifts at the IRS without considering any knowledge of I-CSI but while only exploring the statistical channel state information (S-CSI). We aim at maximizing the user-achievable rate subject to a maximum transmit power constraint. To achieve this goal, we propose a new two-phase framework. In the first...
IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 2020
Anais do XXXIX Simpósio Brasileiro de Telecomunicações e Processamento de Sinais, 2021
Anais do XXXIX Simpósio Brasileiro de Telecomunicações e Processamento de Sinais, 2021
IEEE Wireless Communications Letters, 2020
This letter considers the communication between a multiple antenna Base Station (BS) and a single... more This letter considers the communication between a multiple antenna Base Station (BS) and a single antenna user, assisted by an Intelligent Reflecting Surface (IRS). Due to the large number of elements at the IRS, acquiring Channel State Information (CSI) requires many radio-frequency chains and considerable training overhead, what is limiting in practice. We aim to optimize the beamforming at the BS and IRS without CSI, by minimizing the transmit power, subject to a minimum signal-to-noise ratio (SNR). To solve this problem, a new method based on the Particle Swarm Optimization (PSO) technique is proposed. Results show that the new solution achieves similar performance as that of the optimal beamforming with CSI.
Anais de XXIX Simpósio Brasileiro de Telecomunicações, 2011
Anais de XXIX Simpósio Brasileiro de Telecomunicações, 2011
Anais de VII International Telecommunications Symposium, 2010
IEEE Wireless Communications Letters, 2019
Journal of Communication and Information Systems, 2003
Journal of Communication and Information Systems, 2005
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Papers by Bartolomeu Uchôa-Filho