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  • Challenges in resource-constrained IoT devices: energy and communication as critical success factors for future IoT deployment
    Publication . Pereira, Felisberto; Correia, Ricardo; Pinho, Pedro; Lopes, Sérgio I.; Carvalho, Nuno Borges
    Internet of Things (IoT) has been developing to become a free exchange of useful information between multiple real-world devices. Already spread all over the world in the most varied forms and applications, IoT devices need to overcome a series of challenges to respond to the new requirements and demands. The main focus of this manuscript is to establish good practices for the design of IoT devices (i.e., smart devices) with a focus on two main design challenges: power and connectivity. It groups IoT devices in passive, semi-passive, and active, giving details on multiple research topics. Backscatter communication, Wireless Power Transfer (WPT), Energy Harvesting (EH), chipless devices, Simultaneous Wireless Information and Power Transfer (SWIPT), and Wake-Up Radio (WUR) are some examples of the technologies that will be explored in this work.
  • Small size antennas mountable on mettalic gas cylinders
    Publication . Pereira, Felisberto; Carvalho, Nuno; Pinho, Pedro
    This paper presents a solution to integrate a metallic gas cylinder in an Internet of Things (IoT) network. The work briefly explains the different attempts made, then focusing on describing the final solution. The discussion has in account the simulated and measured results. The final result is a small antenna (dimensions lower than 90mm x 35mm) capable of taking advantage of the metallic surface of the gas cylinder without compromising its input impedance.
  • When backscatter communication meets vehicular networks: boosting crosswalk awareness
    Publication . Pereira, Felisberto; Sampaio, Hugo; Chaves, Ricardo; Correia, Ricardo; Luís, Miguel; Sargento, Susana; Jordão, Marina; Almeida, Luís; Senna, Carlos; Oliveira, Arnaldo S. R.; Carvalho, Nuno Borges
    The research of safety applications in vehicular networks has been a popular research topic in an effort to reduce the number of road victims. Advances on vehicular communications are facilitating information sharing through real time communications, critical for the development of driving assistance systems. However, the communication by itself is not enough to reach the most desired target as we need to know which safety-related information should be disseminated. In this work, we bring passive sensors and backscatter communication to the vehicular network world. The idea is to increase the driver (or vehicle) awareness regarding the presence of pedestrians in a crosswalk. Passive sensors and backscatter communication technologies are used for the pedestrians’ detection phase, while the vehicular network is used during the dissemination of the detection information to surrounding vehicles. The proposed solution was validated through end-to-end experimentation, with real hardware and in a real crosswalk with real pedestrians and vehicles, demonstrating its applicability.
  • Antenna design for ultra-compact Bluetooth devices
    Publication . Pereira, Felisberto; Pinho, Pedro; Gonçalves, Ricardo; Carvalho, Nuno; Lobato, João; Lopes, Sérgio I.
    This paper presents a solution for an ultra-compact antenna for small Bluetooth devices. The work considers the battery and the electronic components influence in the antenna design process for a real device, i.e. a Bluetooth tracker. Three different models for representing the battery and the main electronic components are studied: (i) a simple model that represents both battery and components by a ground plane; (ii) a model that represents the battery realistically and the components by a ground plane and (iii) a model that represents realistically both battery and components.