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Details

  • Name

    Francisco Manuel Ribeiro
  • Role

    Researcher
  • Since

    19th November 2019
003
Publications

2025

Human Activity Recognition with a Reconfigurable Intelligent Surface for Wi-Fi 6E

Authors
Paulino, N; Oliveira, M; Ribeiro, F; Outeiro, L; Pessoa, LM;

Publication
2025 Joint European Conference on Networks and Communications & 6G Summit (EuCNC/6G Summit)

Abstract

2025

Design and Implementation of Scalable 6.5 GHz Reconfigurable Intelligent Surface for Wi-Fi 6E

Authors
Paulino, N; Ribeiro, M; Outeiro, L; Lopes, A; Inácio, S; Pessoa, M;

Publication
EuCAP 2025 - 19th European Conference on Antennas and Propagation

Abstract
Wi-Fi 6E will enable dense communications with low latency and high throughput, meeting the demands of ever growing network traffic and supporting emergent services such as ultra HD or multi-video streaming, and augmented or virtual reality. However, the 6 GHz band suffers from higher path loss and signal attenuation, and poor performance in NLoS conditions. Reconfigurable Intelligent Surfaces (RISs) can address these challenges by providing low-cost directional communications with increased spectral and energy efficiency. However, RIS designs for the WiFi-6E range are under-explored in literature. We present the implementation of an 8x8 RIS tuned for 6.5 GHz designed for scalability. We characterize the response of the unit cell, and evaluate the RIS in an anechoic chamber, measuring the far field radiation patterns for several digital beamsteering configurations in a horizontal plane, demonstrating effective signal steering. © 2025 European Association on Antennas and Propagation.

2024

SpecRF-Posture: Exploring Specular Reflections for Human Posture Recognition

Authors
Oliveira, M; Ribeiro, FM; Paulino, N; Yurduseven, O; Pessoa, LM;

Publication
2024 IEEE INTERNATIONAL MEDITERRANEAN CONFERENCE ON COMMUNICATIONS AND NETWORKING, MEDITCOM 2024

Abstract
This paper presents SpecRF-Posture, a novel low-cost approach for accurate Human Posture Recognition (HPR) using Radio Frequency (RF) signals. SpecRF-Posture leverages S21 parameters within the WiFi-6E frequency range for classification. We obtain a dataset of S21 parameters for different postures by performing beamscanning through mechanical rotation of a horn transmitter aimed at a reflective surface that illuminates the space of interest. We determine the S21 parameters of the signals that are then reflected back from the space onto an omni-directional receiver. Thus for each posture we attain the S21 parameters of each possible illumination direction of the space. Experimental results demonstrate that SpecRF-Posture achieves an accuracy of 99.17% in posture classification, highlighting its effectiveness. Additionally, an RF dataset was acquired using a software package for automatic data acquisition within the WiFi-6E frequency range, and both the dataset and the software package have been made publicly available.

2024

Realistic Model Parameter Optimization: Shadow Robot Dexterous Hand Use-Case

Authors
Correia, T; Ribeiro, FM; Pinto, VH;

Publication
OPTIMIZATION, LEARNING ALGORITHMS AND APPLICATIONS, PT II, OL2A 2023

Abstract
The notable expansion of technologies related to automated processes has been observed in recent years, largely driven by the significant advantages they provide across diverse industries. Concurrently, there has been a rise in simulation technologies aimed at replicating these complex systems. Nevertheless, in order to fully leverage the potential of these technologies, it is crucial to ensure the highest possible resemblance of simulations to real-world scenarios. In brief, this work consists of the development of a data acquisition and processing pipeline allowing a posterior search for the optimal physical parameters in MuJoCo simulator to obtain a more accurate simulation of a dexterous robotic hand. In the end, a Random Search optimization algorithm was used to validate this same pipeline.

2023

FLOOR - Forklift Laser OmnidirectiOnal Robot

Authors
Pinto, VH; Ribeiro, FM; Brito, T; Pereira, AI; Lima, J; Costa, P;

Publication
2023 IEEE INTERNATIONAL CONFERENCE ON AUTONOMOUS ROBOT SYSTEMS AND COMPETITIONS, ICARSC

Abstract
The robot presented in this paper was developed with the main focus on participating in robotic competitions. Therefore, the subsystems here presented were developed taking into account performance criteria instead of simplicity. Nonetheless, this paper also presents background knowledge in some basic concepts regarding robot localization, navigation, color identification and control, all of which are key for a more competitive robot.