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Entradas recentes
Evaluation of Radio Access Protocols for V2X in 6G Scenario-Based Models
2024-06-06 - Orrillo, Héctor Ascama; Silva, Mário Marques da; Sabino, André
The expansion of mobile connectivity with the arrival of 6G paves the way for the new
Internet of Verticals (6G-IoV), benefiting autonomous driving. This article highlights the importance
of vehicle-to-everything (V2X) and vehicle-to-vehicle (V2V) communication in improving road
safety. Current technologies such as IEEE 802.11p and LTE-V2X are being improved, while new
radio access technologies promise more reliable, lower-latency communications. Moreover, 3GPP is
developing NR-V2X to improve the performance of communications between vehicles, while IEEE
proposes the 802.11bd protocol, aiming for the greater interoperability and detection of
transmissions between vehicles. Both new protocols are being developed and improved to make
autonomous driving more efficient. This study analyzes and compares the performance of the
protocols mentioned, namely 802.11p, 802.11bd, LTE-V2X, and NR-V2X. The contribution of this
study is to identify the most suitable protocol that meets the requirements of V2V communications
in autonomous driving. The relevance of V2V communication has driven intense research in the
scientific community. Among the various applications of V2V communication are Cooperative
Awareness, V2V Unicast Exchange, and V2V Decentralized Environmental Notification, among
others. To this end, the performance of the Link Layer of these protocols is evaluated and compared.
Based on the analysis of the results, it can be concluded that NR-V2X outperforms IEEE 802.11bd in
terms of transmission latency (L) and data rate (DR). In terms of the packet error rate (PER), it is
shown that both LTE-V2X and NR-V2X exhibit a lower PER compared to IEEE protocols, especially
as the distance between the vehicles increases. This advantage becomes even more significant in
scenarios with greater congestion and network interference.
Dissertação sobre a renovação da cidade de Lisboa (1755-56)
2024-06-05 - Maia, Manuel da; Santos, Maria Helena Ribeiro dos (coord.)
Este trabalho revela-nos novos “pais da urbanística moderna” e confirma as interpretações
que fazem retroceder o seu início ao século XVIII. Apesar de “a Baixa de Lisboa” ser reconhecida
como um dos paradigmas da beleza urbana, pelo contrário, o exacto e muito consistente
processo da sua concepção por parte de engenheiros militares portugueses, não o
é tanto. Contudo, as instruções e procedimentos para a reconstrução de Lisboa que Manuel
da Maia deixou escritos na sua Dissertação, constituem um extraordinário e original corpo
teórico, germinal para a disciplina de projecto urbano.
The Evolution of 5G Communications within the Scope of the Fourth Industrial Revolution
2022-05-10 - Marques da Silva, Mário; Orrillo Ascama, Héctor
The Fourth Industrial Revolution is a consequence of the latest digital transformation and consists of the replacement of human beings by robots. It is associated with the massive use of robots, artificial intelligence, big data, the Internet of Things (IoT), quantum computing or or 3D printing. Digital transformation and environmental transformation are transformation, since the former allows for a more efficient use of resources, which tends to of resources, which tends to reduce the carbono footprint, and enables the generation of renewable generation. The Fifth Generation of Cellular Communications (5G) is disruptive, as it consists of a paradigm shift a paradigm shift from previous generations. 5G Communications make a strong contribution to the implementation of the Fourth Industrial Industrial Revolution in a wide range of areas, such as autonomous vehicles, smart cities, smart smart cities, smart industries and agriculture, remote surgery, etc. While 5G communications aim to implement some of the requirements of the Fourth Industrial Industrial Revolution, the Sixth Generation of Cellular Communications (6G), scheduled for 2030, aims to complement this implementation in a more profound way.