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004
Publications

2019

A Comprehensive Study On Enterprise Wi-Fi Access Points Power Consumption

Authors
Silva, P; Almeida, NT; Campos, R;

Publication
IEEE Access

Abstract

2019

Energy Consumption Management for Dense Wi-Fi Networks

Authors
Silva, P; Almeida, NT; Campos, R;

Publication
IFIP Wireless Days

Abstract
Wi-Fi networks lack energy consumption management mechanisms. In particular, during nighttime periods, the energy waste may be significant, since all Access Points (APs) are kept switched on even though there is minimum or null traffic demand. The fact that more than 80% of all wireless traffic is originated or terminated indoor, and served by Wi-Fi, has led the scientific community to look into energy saving mechanisms for Wi-Fi networks. State of the art solutions address the problem by switching APs on and off based on manually inserted schedules or by analyzing real-time traffic demand. The first are vendor specific; the second may induce frequent station (STA) handoffs, which has an impact on network performance. The lack of implementability of solutions is also a shortcoming in most works.We propose an algorithm, named Energy Consumption Management Algorithm (ECMA), that learns the daytime and nighttime periods of the Wi-Fi network. ECMA was designed having in mind its implementability over legacy Wi-Fi equipment. At daytime, the radio interfaces of the AP (2.4 GHz and 5 GHz) are switched on and off automatically, according to the traffic demand. At nighttime, clusters of APs, covering the same area, are formed, leaving one AP always switched on for basic coverage and the redundant APs swichted off to maximize energy savings, while avoiding coverage and performance hampering. Simulation results show energy savings of up to 50% are possible using the ECMA algorithm. © 2019 IEEE.

2014

RFID alarm system and trajectory correction in paralympic athletics races

Authors
Almeida, NT; Pinheiro, V;

Publication
CONFERENCE ON ELECTRONICS, TELECOMMUNICATIONS AND COMPUTERS - CETC 2013

Abstract
In this paper is presented the work relative to the design of an aid system, for athletes with special needs in terms of vision. The system is based on Radio Frequency Identification (RFID) technology and serves to help visually impaired athletes. Relatively to Paralympic athletics competitions, the main goal is the elimination of current guide runners. The system is prepared to give a stereo audio alert, when a runner deviates from his lane central area. The paper presents the main components, namely, the RFID infrastructure and the mobile parts. Tests to tags, infrastructure setting and positioning functions are also presented. (C) 2014 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND License (http://creativecommons.org/licenses/by-nc-nd/3.0/).

2012

RF-based Stent-Graft Endoleakage Monitoring System

Authors
Cristina Cunha Oliveira; Nuno Teixeira Almeida; José Machado da Silva

Publication
URSI 2012 - XXVII Simposium Nacional de la Unión Científica Internacional de Radio, Elche, Alicante, Spain

Abstract

2009

Linux software and Bluetooth: a formula to improve accessibility by using Interactive Voice Response systems

Authors
Nuno Teixeira de Almeida; Emanuel Ribeiro

Publication
DSAI 2009 - The International Conference on Software Development for Enhancing Accessibility and Fighting Info-exclusion, Lisboa, Portugal

Abstract

Supervised
thesis

2017

IEEE 802.11ax Networks: Study and Assessment of New Techniques for the MAC Layer

Author
Paulo Alexandre Baptista Ferreira da Silva

Institution
UP-FEUP

2016

IPBRICK APP Mobile para Android e iOS

Author
Nuno Miguel Batista Pinto

Institution
UP-FEUP

2015

Localization Technology in Special Contexts: a collaborative anti-lost application

Author
Ivo Jorge Magalhães Rocha

Institution
UP-FEUP

2015

Suporte e Análise de Avarias em Redes de Telecomunicações

Author
Nuno Jorge da Fonseca Fernandes

Institution
UP-FEUP