This book constitutes the refereed proceedings of the 11th International Conference on Telecommunications, ICT 2004, held in Fortaleza, Brazil in August 2004.
The 188 revised full papers presented were carefully reviewed and selected from 430 submissions. The papers are organized in topical sections on multimedia services, antennas, transmission technologies and wireless networks, communication theory, telecommunication pricing and billing, network performance and telecommunication services, active network and mobile agents, optical photonic techniques, optical networks, ad-hoc networks, signal processing, network performance and MPLS, traffic engineering, SIP, Qos and switches, network operation management, mobility and broadband wireless, cellular system evolution, personal communication, satellites, mobility management, network reliability, ATM and Web services, security, switching and routing, next generation systems, wireless access, Internet, etc.

With the rapid growth of new wireless devices and applications over the past decade, the demand for wireless radio spectrum is increasing relentlessly. The development of cognitive radio networking provides a framework for making the best possible use of limited spectrum resources, and it is revolutionising the telecommunications industry. This book presents the fundamentals of designing, implementing, and deploying cognitive radio communication and networking systems.