[pt] Sistemas de celulares de múltiplas camadas (hierarquizados) são úteis para acomodar densidade alta de tráfego mantendo a qualidade de serviço. Estes sistemas procuram agregar as vantagens dos sistemas micro e macrocelulares que são respectivamente: o aumento da capacidade do sistema e a carga de sinalização da rede. Neste trabalho são analisados aspectos de projeto e desempenho de estruturas hierarquizadas como: compartilhamento do espectro entre as camadas de micro- células e macro-células bem como o desempenho de diferentes estratégias de handoff entre essas camadas. Um outro objetivo do trabalho foi o desenvolvimento de uma ferramenta simples de simulação capaz de testar as diversas estratégias de handoff e o desempenho do sistema para diferentes soluções para a distribuição dos recursos de rádio entre camadas. / [en] Multilayer cell systems are useful to accommodate high traffic densities while still satisfying the QoS requirements. These systems combine the advantages of microcellular and macrocellular systems which are: the increase of system capacity and the reduction of the number of handoffs, hence decreasing the signaling load. This work address design aspects such as spectrum sharing between the macrocell and microcell layers and the performance of different handoff strategies considering both layers. Another goal of this work was the development of a simple, but realistic, simulation tool which will allow obtaining the radio resources management results here presented.

Capacitive crosstalk noise can affect the delay of a switching signal or induce a glitch on a static signal causing timing violations or chip failure. Crosstalk noise depends on coupling parasitics, driver strength, signal timing characteristics, and signal transition patterns. Layout level crosstalk analysis techniques are generally pessimistic and computationally expensive for large designs due to lack of design flexibility at lower-levels of design hierarchy. The architectural decisions such as type of interconnect architecture, number of storage and execution units, network of communicating units, data bus width, etc., have a major impact on the quality of design attributes such as area, speed, power, and noise. To address all these concerns, we propose a high-level synthesis framework to optimize for worst-case crosstalk patterns on coupled nets, a floorplan driven high-level synthesis framework to minimize coupling capacitance, and an on-chip technique to dynamically detect and eliminate worst-case crosstalk pattern on bus-based macro-cell designs. Due to Miller coupling effect, the switching activity pattern on adjacent nets may increase the effective capacitance seen by a victim net and thereby it may cause a worst-case signal delay on the victim net. However, signal activity pattern on coupled nets are dependent on data correlations which in turn depend on resource sharing. The resource sharing in turn depends on scheduling, allocation, and binding during high-level synthesis flow. Therefore, we propose a Simulated Annealing (SA) based design space exploration of HLS design subspace, bus line re-ordering, and encoding subspaces to optimize for worst-case crosstalk pattern in bus-based macro-cell designs. We demonstrate that the proposed framework will aid layout level techniques in eliminating false positive violations. We also propose an SA based algorithm to explore floorplan and HLS subspaces to optimize coupling capacitances in bus-based macro-cell designs. We have integrated an RTL floorplanner in HLS flow to estimate coupling capacitances between bus lines. Crosstalk analysis using Cadence Celtic shows that the designs generated by the proposed framework results in less number of crosstalk violations compared to designs generated through traditional ASIC design flow. We also propose an on-chip crosstalk detection and elimination technique that dynamically detects and eliminates worst-case crosstalk pattern with minimum area penalty compared to other layout level techniques reported in the literature.

[pt] Este trabalho descreve uma ferramenta de simulação esenvolvida para analisar o gerenciamento dos recursos de rádio e parâmetros de QoS (Quality of Service) dos sistemas móveis celulares. Pela natureza de um sistema real de telefonia celular, é extremamente difícil que as variáveis de saída de um simulador sejam derivadas de um conjunto real de funções. Isso se deve à grande quantidade de parâmetros que devem ser considerados no comportamento da mobilidade, nas condições de tráfego, nas características geográficas e morfológicas da região, na modelagem complexa do canal rádio propagação móvel, entre outras. Visando a desenvolver uma ferramenta de simulação próxima da realidade, adotam-se modelos de propagação, de mobilidade e de tráfego que sejam satisfatoriamente adequados ao caso real. A contribuição deste trabalho é oferecer uma ferramenta de simulação flexível, aqui adequada ao sistema norte-americano TDMA (IS-136), que possibilite ao usuário, além de analisar a capacidade do sistema,também avaliar novos algoritmos de controle de potência, novas estratégias de handoff, novos esquemas de alocação de canal e modelos de propagação. A ferramenta será validada seguindo o processo de um projeto real de telefonia celular e ao final, será aplicada a um sistema celular com sobreposição macro-células/micro-células, analisando-se algumas estratégias de handoff dedicadas a esses sistemas. / [en] This work describes a simulation tool, which was developed to analyze the radio resources and QoS (Quality of Service) parameters in mobile systems. Because of the complex characteristics of an actual cellular network, it is extremely difficult having the outputs of the simulator being derived from a real set of functions, due to the large amount of parameters that have to be considered such as the mobility behavior, the traffic conditions, the geographic and morphologic characteristics of the region, the complex modeling of mobile radio propagation channel, and so on. In order to develop a simulation tool as near as possible to the reality, models that are satisfactorily adequate to the real case have been considered. So, propagation, mobility and traffic models were adapted from the IS-136 American system. The contribution of this work is to offer a flexible simulation tool that allows the user, in addition to analyzing the capacity of the system, to evaluate new algorithms of power control, handoff strategies, channel allocation schemes and propagation models. The tool will be validated following the process of a real project of cellular telephony and at the end, it will be applied to a cellular system with overlapped macro- cells/micro-cells, and some handoff strategies dedicated to those systems will be analyzed.