Subsystems for future access networks

Current evolution and tendencies of Telecom Networks in general and more specifically optical Metro and Access Networks and their convergence are reported. Based on this evolution, a set of research lines are foreseen regarding subsystems and devices as: high speed optical sources, modulators and receivers, for the next generation of Passive Optical Networks. The ICT project EURO-FOS is achieving European level cooperative research among academia and industry, enabling future telecommunication networks

The Design of a System Architecture for Mobile Multimedia Computers

This chapter discusses the system architecture of a portable computer, called Mobile Digital Companion, which provides support for handling multimedia applications energy efficiently. Because battery life is limited and battery weight is an important factor for the size and the weight of the Mobile Digital Companion, energy management plays a crucial role in the architecture. As the Companion must remain usable in a variety of environments, it has to be flexible and adaptable to various operating conditions. The Mobile Digital Companion has an unconventional architecture that saves energy by using system decomposition at different levels of the architecture and exploits locality of reference with dedicated, optimised modules. The approach is based on dedicated functionality and the extensive use of energy reduction techniques at all levels of system design. The system has an architecture with a general-purpose processor accompanied by a set of heterogeneous autonomous programmable modules, each providing an energy efficient implementation of dedicated tasks. A reconfigurable internal communication network switch exploits locality of reference and eliminates wasteful data copies

Simulation

In this paper, performance analysis of the Wireless and Wired computer networks through simulation has been attempted using OPNET as simulating tool. For wired networks, the performance parameters like delay and throughput have been investigated with varying transmission links and load balancers. The load-balancing has been analyzed through parameters like analysis of traffic sent and traffic received. While in wireless networks the metrics like delay, retransmission attempts and throughput have been estimated with varying physical characteristic and buffer size. From the obtained results, it is gathered that performance of the wired networks is good if high speed Ethernet links like 1000 Base X and server-load balancing policy are used whereas the performance of Wireless LAN can be improved by fine tuning and properly choosing the WLAN parameters. For the tested simulation scenarios the performance is observed to be better with wireless networks using infra-red type physical characteristics and higher buffer size (1024Kb