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- Hybrid WiMAX and Wi-Fi networks for the support of b-Learning and TelemedicinePublication . Costa, Rui; Velez, Fernando José; Robalo, Daniel Luís Silveira; Marques, Marco; Comissário, Cláudio; Riscado, José; Cavaleiro, Victor; Sebastião, Pedro; Rodrigues, Antóniohis paper addresses the deployment of hybrid WiMAX and Wi-Fi networks for the support of always best connected telemedicine and health sciences education applications. The available services include a LMS (Learning Management System) and several structured functionalities for b-Learning. For the support of these services, fixed and wireless LANs have been deployed, as well as an experimental point-to-multipoint IEEE 802.16-2004 network covering part of the city of Covilhã. The FCS (Health Sciences Faculty) Campus as well as the tutorial rooms of the Faculty spread at the different Hospitals of the region of Beira Interior, Portugal, are benefiting from WLAN coverage, whose backhaul is supported by WiMAX point-to-point links with relays. Field trials results were compared with the ones arising from the WiMAX radio links design, and very similar results were achieved. Service quality was guaranteed by adjusting QoS parameters.
- Design and Implementation of IEEE 802.16 Radio Links with RelaysPublication . Marques, Marco; Ambrósio, João; Reis, Carlos; Gouveia, David; Robalo, Daniel; Velez, Fernando José; Costa, Rui; Riscado, JoséThis paper addresses aspects of design and planning of a Wireless network WiMAX (IEEE 802.16) to establish a point-to-point, PTP, link from the Health Sciences Faculty of University of Beira Interior (FCS/UBI) to Hospital Sousa Martins (Guarda), and also presents a field trial where we tested point-to-point links with pre-WiMAX equipment. The design of the link had into consideration the carrier to noise ratio, C/N, and the minimum carrier to noise ratio with fading, C/Nmin_fad. The use of two relays is needed to guarantee LoS conditions. The use of BreezeNET B equipment from Alvarion was assumed. From the dimensioning process, it was verified that with γ = 2, for the second clause, the three types of modulations can be used. Field trials results were compared with the theoretical model, and very similar conclusions were achieved.
- Design and Installation of Pre-Wimax Radio Links And RelaysPublication . Velez, Fernando José; Costa, Rui; Robalo, Daniel Luís Silveira; Marques, Marco; Comissário, Cláudio; Riscado, José; Cavaleiro, VictorThis paper addresses aspects of design for WiMAX wireless networks to establish a point-to-point, PTP, link with Alvarion BreezeNET B equipment, from the Health Sciences Faculty of University of Beira Interior to Hospital Amato Lusitano (in Castelo Branco, Portugal), and also presents the respective field trial with pre-WiMAX PTP equipment. The design of the link with relays had into consideration the carrier to noise ratio, and the minimum carrier to noise ratio with fading. Field trials results agree with the ones extracted from the dimensioning process. The small differences registered can be explained by the small beam width of the antennas and therefore to imperfect orientation during the field trials. The actual installation of the three hop link was successfully achieved, followed by a tune up of the tilt of the antennas, by the choice of the best QoS parameters and of the turbo-mode for the equipment, which allowed for obtaining higher values of the throughput.
- Concepção e Planeamento de Redes sem Fios IEEE 802.16Publication . Carvalho, Vitor; Santos, Dany; Marcos, Rui; Costa, Rui; Velez, Fernando J.; Sebastião, Pedro; Rodrigues, António; Riscado, José; Romão, José; Cavaleiro, VictorEsta comunicação aborda aspectos de projecto e planeamento celular duma rede sem fios WiMax (IEEE 802.16) para interligar ponto-a-ponto a Faculdade de Ciências da Saúde da Universidade da Beira Interior (FCS/UBI) ao Hospital Amato Lusitana (Castelo Branco), uma rede ponto-multiponto para ligar a FCS/UBI/Hospital Pêro da Covilhã a toda a área urbana do centro da cidade da Covilhã e uma rede móvel celular dedicada aos serviços públicos de emergência e de segurança, abrangendo toda a região da Beira-Interior, fazendo-se a avaliação detalhada da existência de linha de vista no concelho da Covilhã. Efectuou-se o planeamento tendo em conta aspectos relacionados com a relação portadora-ruído, C/N, e a relação portadora-interferência, concluindo-se ser necessário usar sectorização e considerar sobreposição de micro-células à estrutura macro-celular (cell overlay). Utilizaram-se ferramentas GIS para auxiliar no processo de determinação das posições para as estações de base e da respectiva área com linha de vista, de forma a assegurar um expoente de propagação baixo. Dos resultados para a ligação ponto-a-ponto Covilhã-Gardunha-Castelo Branco, conclui-se que é possível assegurar comunicação com qualidade a 3.5 GHz, mas a 5.8 GHz, como a distância máxima para a qual C/N<(C/N)min é de 25 km, é necessário aumentar o ganho de pelo menos uma das antenas para assegurar a qualidade da ligação.