Encontrados 14 documentos, a visualizar página 1 de 2
V2X Messaging with CoAP and EdgeX for Probabilistic Risk-Aware Coordination in ...
Mendes, Bruno; Araújo, Marco; Goes, Adriano; Corujo, Daniel; Oliveira, Arnaldo S. R.This article presents a standards-based architecture for V2X communication using CoAP and EdgeX Foundry. By mapping ETSI ITS messages to CoAP, the system enables efficient risk alerting at the edge. An inference module illustrates the architecture's extensibility, and the simulation confirms responsiveness and scalability under mixed traffic conditions.
Study of the Impact of Cooperative Maneuvers Among Different Types of Vehicles ...
Mendes, Bruno; Goes, Adriano; Araújo, Marco; Corujo, Daniel; Oliveira, Arnaldo S. R.The automotive sector has seen a significant increase in autonomous mobility expenditures throughout the past decade through private-sector investments made by original equipment manufacturers and public research via universities and institutes. However, despite the significant funds invested in enabling technologies, the world is not much closer to self-driving vehicles on its main roads. One of the reasons fo...
A Survey on Over-The-Air Linearization Methods for MIMO Systems
Jordão, Marina; Caldeirinha, Rafael; Oliveira, Arnaldo S. R.; Carvalho, Nuno BorgesTransmitter antenna arrays are typically coupled to several RF chains, which imposes stringent requirements on the linearization of each power amplifier (PA) present in the system. For this and other reasons discussed in this work, Over-the-air (OTA) linearization methods are considered to linearize transmitter antenna arrays in 5G scenarios. However, several factors need to be considered when applying OTA line...
Active reflection coefficients characterization system for multiple input multi...
Jordão, Marina; Belo, Daniel; Caldeirinha, Rafael F. S.; Oliveira, Arnaldo S. R.; Carvalho, Nuno B.The main objective of this study is to present a characterization system that can be used to measure the active reflection coefficient of each port of the multiple input multiple output (MIMO) antennas, when the main beam is steered to an intended direction. Since MIMO systems are composed of antennas with several elements and each antenna element is connected to a power amplifier, an active component, the beam...
RF-dc Converter Optimization using MIMO Antennas and OTA Multi-Sine Calibration...
Jordão, Marina; Belo, Daniel; Caldeirinha, Rafael; Oliveira, Arnaldo S. R.; Carvalho, Nuno Borges deIn this paper, the optimization of the power transmitted from several non-collocated antennas to an RF-dc converter circuit is performed using an Over-The-Air (OTA) multi-sine feedback method. An experimental system is tested in an indoor environment and the OTA multi-sine calibration method is applied to produce constructive interference at the RF-dc converter location. It is shown that its overall performance...
When backscatter communication meets vehicular networks: boosting crosswalk awa...
Pereira, Felisberto; Sampaio, Hugo; Chaves, Ricardo; Correia, Ricardo; Luís, Miguel; Sargento, Susana; Jordão, Marina; Almeida, Luís; Senna, CarlosThe 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 ...
Enforcing Replica Determinism in the Road Side Units of Fault-Tolerant Vehicula...
Almeida, João; Ferreira, Joaquim; Oliveira, Arnaldo S. R.; Pedreiras, Paulo; Fonseca, JoséThis paper presents a strategy to enforce replica determinism in the road-side units (RSUs) of wireless vehicular networks. An active replication scheme is used to enhance fault-tolerant behaviour in these RSU nodes, which are responsible for handling channel access and admission control policies in real-time vehicular communications protocols. The proposed solution guarantees consistency among all RSU replicas...
FPGA-based all-digital multi-protocol RFID reader
Santos, João Borges dos; Oliveira, Arnaldo S. R.No abstract available.
Hardware co-processor for the OReK real-time executive
Ferreira, Carlos Miguel; Oliveira, Arnaldo S. R.Este artigo discute os benefícios em utilizar um co-processador, para melhorar o determinismo e desempenho de um executivo de tempo-real. O co-processador proposto foi modelado numa linguagem de descrição de hardware(VHDL) e implementado num circuito reconfigurável (FPGA - Field Programmable Gate Array). Tem a capacidade de gerir (escalonamento, preempção e execução) várias tarefas tanto periódicas como aperiód...
Towards a new baseband processing architecture for next generation software-def...
Silva, Nelson; Oliveira, Arnaldo S. R.; Carvalho, Nuno Borges deA necessidade de melhores rádios, dotados de maior flexibilidade e que facilitem o projecto e verificação levaram a uma mudança de paradigma a favor do Rádio Configurável por Software (SDR). Por outro lado, a implementação de redes sem fio de próxima geração (NGWN) através de SDR irá requerer unidades de processamento com uma eficiência energética muito superior à actualmente permitida. Neste artigo apresentamo...