Percorrer por autor "Merca, Francisco"
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- Cost/Revenue Optimisation of Multi-Service Cellular Planning for City Centre E-UMTSPublication . Velez, Fernando J.; Anastácio, Nuno; Merca, Francisco; Cabral, Orlando Manuel BritoAn overview of All-IP Enhanced Universal Mobile Telecommunication System, E-UMTS, service needs in the business city centre, BCC, scenario is first presented. Then, E-UMTS traffic generation and activity models are described and characterised. System level simulations are carried out and the enhanced performance is demonstrated based in a single quality parameter, which simultaneously accounts for call blocking and handover failure probabilities. End-to-end delays do not present a limitation. By considering a grade of service of 1% for the quality parameter, and different hypothesis for costs and prices, an optimum coverage distance is obtained around ~200-425 m, which maximises the supported throughput per km2. However, results for the profit in percentage indicates that coverage distances in the range 395-425 m should be used in BCC.
- 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.
- Service characterization for cost/benefit optimization of enhanced UMTSPublication . Velez, Fernando J.; Cabral, Orlando Manuel Brito; Merca, Francisco; Vassiliou, VasosIn this paper an all-IP Enhanced-Universal Mobile Telecommunications System (E-UMTS) is considered, where enhancements include link level behavior, high-speed downlink packet access (HSDPA) channel, resource management, Diffserv architecture, and Radio Resource Management schemes. An overview of E-UMTS deployment scenarios and service needs is presented based on the views of relevant players. Deployment and mobility scenarios are considered, including expected population density and usage of service mix for three environments, namely offices, urban/vehicular, and business city center. In addition, based on population and service penetration values, E-UMTS traffic generation and activity models are described and characterized. Based on these scenarios and characterizations, system level simulations are carried out and the enhanced service quality performance is demonstrated, including blocking probability, handover failure probability and end-to-enddelay in each deployment scenario. By using system level simulations, services and environmental conditions can be mapped into deployment strategies (and supported system capacity) whose evaluation is essential prior to field trials and real implementation. On the one hand, costs depend on the prices of the spectrum, equipment, operation and maintenance, as well as on the number of cells which, in turn, depends on the cell radius. On the other, revenues depend on the price per MB and on the supported throughput. As the goal of operators and service providers is to maximize the profit, the profit in percentage was obtained for the three considered scenarios. Its optimum values are found for cell radii around 31, 257, and 310 m for offices, vehicular and business city center scenarios, respectively.