Browsing by Issue Date, starting with "2006-09"
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- Enhanced UMTS Cellular Planning for Multiple Traffic Classes in Offices ScenariosPublication . Cabral, Orlando Manuel Brito; Velez, Fernando J.; Hadjipollas, George; Stylianou, Marinos; Antoniou, Josephine; Vassiliou, Vasilis; Pitsillides, AndreasIt is shown that enhanced UMTS is an affordable solution for providing the required network quality and to reduce infrastructure investments in offices scenarios. System capacity results are obtained by using a system level simulator which considers traffic characterisation parameters and services usage in detail, among other. Results for the most profitable cell radius are obtained via an optimisation procedure based in economic aspects. A higher number of pico cells (with a smaller radius, around 30-32 m) can be installed in the future, when costs of deploying and maintaining the network decreases, allowing for supporting higher system capacity, and reducing prices. Our approach is based in a detailed services analysis, which represents a worst case situation relatively to the total services approach, because the later does not discriminate results for the different traffic classes. The impact of call blocking, handover failure, end-to-end delay, and delay variation are taken into account.
- QoS Metrics for Cross-Layer Design and Network Planning for B3G SystemsPublication . Anastácio, Nuno; Merca, Francisco; Cabral, Orlando Manuel Brito; Velez, Fernando J.After 3G mobile and wireless systems take-up, the research community is now directing its interest towards unified ways of looking at system design, optimization, and quality of service (QoS) issues to satisfy the requirements of next generation multi-service mobile and wireless IP-based networks. Their implementation requires the development of IP QoS architecture and mechanisms encompassing the various layer of the OSI Model to cope with the new requirements. This work identifies the requirements on latency (link radio), latency (end-to-end), bit error rate, data rates, and traffic characterisation for mobile multimedia network beyond 3G. Characterisation parameters were identified and values were suggested for their range of variation, in the context of cross-layer design.
- Frei Casimiro Wyszynzki: Peregrinação e ProfeciaPublication . Rosa, José Maria Silva«É preciso passar». A essência do profetismo encontra-se toda na categoria da relação. «Vir de» e «ser para»: «vir de» de Alguém que proccde de mais longe e que envia; e «ser para» como uma flecha que visa o alvo. Foi assim o Frei Casimiro Wyszynski, na Polónia e em Balsamão.
- Modelling and Simulation of Multi-Rate Multi-Service Traffic in the Presence of MobilityPublication . Juarez, Jesus M.; Paulo, Rui R.; San Jose, Eva; Velez, Fernando J.A multi-service traffic model is proposed, and its validation is achieved by using event-based simulation results. In the single-service case, theoretical and experimental results for ON-OFF blocking probability are close to each other, and there is an almost perfect concordance between theoretical and simulation values when the average sojourn time in cells is equal to the average holding time. In the multi-service case, the behaviour is not exactly the same but a coherent behaviour is achieved for an average traffic per user up to 0.10 Erl.
- Modelling of Multi-rate Multi-service Traffic in the Presence of MobilityPublication . Juárez, Jesús M.; Paulo, Rui R.; San José, Eva Reguera; Velez, Fernando JoséA multi-service traffic model is presented, and its validation is achieved in a vehicular scenario by using event-based simulation results. In the single-service case, theoretical and experimental results for ON-OFF blocking probability are close to each other, and there is an almost perfect concordance between theoretical and simulation values when the average sojourn time in cells is equal to the average holding time. The challenges presented by the multi-service case are identified, and a question related with a possible correspondence between blocking/handover failure probabilities and ON-OFF blocking probability are presented.