9 documents found, page 1 of 1
Electronic circuits for wireless optical LANs - I
Aguiar, Rui L.; Tavares, António; Cura, José Luis; Vasconcelos, Eduardo de; Alves, Luis Nero; Valadas, Rui; Santos, Dinis M.This is the first of two papers discussing practical issues and results on the implementation of low-cost transceivers for several wireless optical LANs, covering most physical layer elements. Target optical LANs under consideration have bit-rates varying between 4Mbps and 25Mbps, and input photodiode capacitance may vary between 10pF and 50pF. PPM modulation, either in a 4-PPM or 16-PPM format, istypically use...
Electronic circuits for wireless optical LANs - II
Aguiar, Rui L.; Tavares, António; Cura, José Luis; Vasconcelos, Eduardo de; Alves, Luis Nero; Valadas, Rui; Santos, Dinis M.This is the second of two papers discussing practical issues and results on the implementation of low-cost transceivers for several wireless optical LANs, covering most physical layer elements. Target optical LANs under consideration have bit-rates varying between 4Mbps and 25Mbps, and input photodiode capacitance may vary between 10pF and 50pF. PPM modulation, either in a 4-PPM or 16-PPM format, is typically u...
Experiências laboratoriais sobre encaminhamento na Internet
Lopes, Carlos; Ferreira, Paulo; Valadas, RuiThis paper describes a set of laboratory experiments designed to illustrate the main characteristics of the routing protocols used in IP networks.; Este artigo descreve um conjunto de experiências laboratoriais que foram concebidas para ilustrar as características mais importantes dos protocolos de encaminhamento utilizados nas redes IP.
O algoritmo MENTOR para o projecto topológico de redes de telecomunicações
Lemos, Celso; Valadas, RuiThis paper describes the MENTOR algorithm used to optimize telecommunications networks with a mesh topology. A software package based on this algorithm is presented. To illustrate the use of the software package an example of aprivate data network design is given.; Este artigo descreve o algoritmo MENTOR usado para optimização de topologias de redes de telecomunicações sem malha. É apresentado um pacote de...
Demonstrador animado das técnicas de programação de simuladores de eventos disc...
Fernandez, Elizabeth; Valadas, RuiThis paper describes an animated demo that ilustrates the programming techniques for discrete-event simulators. The demo is based on an M/M/1 queuing system and was developed using MATLAB.; Este artigo descreve um demonstrador animado concebido para ilustrar as técnicas de programação de um modelo de simulação de eventos discretos. O demonstrador foi desenvolvido no MATLAB e a ilustração é feita com base num mo...
Análise e planeamento de tráfego em redes DECT
Ruivo, José; Pimentel, J. Miguel; Vale, Henrique; Valadas, Rui; Duarte, A. Manuel de OliveiraThe normalisation of DECT’s technical standards was finished in 1992. At the moment, DECT is already adopted as official cordless technology in 42 countries all over the world and daily used by more than 12 millions persons. However, many other aspects regarding implementation, like traffic behaviour, were left open for future development and/or study. The main objective of this paper is to contribute for the c...
Arquitecturas para redes privadas virtuais em ATM
Carapinha, Jorge; Valadas, RuiThis paper provides an overview of the main strengths of the ATM technology to establish virtual private networks (VPN) over ATM public networks. Three basic models are analysed: VPN based on permanent end-to-end VPCs, VPN based on permanent VCCs and VPN based on switched VCCs.; Este artigo analisa as principais potencialidades da tecnologia ATM para estabelecer e explorar redes privadas virtuais. São...
Estudo e desenvolvimento da subcamada MAC da rede de área local sem fios IEEE80...
Couto, Paula; Valadas, Rui; Duarte, A. M. de OliveiraThe fast evolution of mobile computing equipment and the consequent raising mobility requirements has been the major drive of research in Wireless Local Area Networks. WLANs distinguishes from cabled networks at physical layer and MAC layer. This paper focus aspects of both layers: it presents transmissions technologies and discusses the requirements of a MAC (Medium Access Control) protocol to be used in this ...
Contribuições da Universidade de Aveiro para a especificação da rede de área lo...
Valadas, Rui; Moreira, Adriano; Lomba, Cipriano; Tavares, António; Moreira, Luís; Oliveira, Carlos; Aguiar, Rui; Sousa, Amaro; Duarte, A. M. de OliveiraThis paper introduces the IEEE 802.11 wireless local area network and describes the main contributions given by the University of Aveiro to its specification.; Este artigo introduz a rede de área local não-cablada IEEE 802.11 e descreve as principais contribuições da Universidade de Aveiro para a sua especificação.