Unidade de Investigação - CIIC - Computer Science and Communication Research Centre
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Browsing Unidade de Investigação - CIIC - Computer Science and Communication Research Centre by Field of Science and Technology (FOS) "Engenharia e Tecnologia::Engenharia Civil"
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- 802.21-MPA-IMS ArchitecturePublication . Rodrigues, Carlos Miguel de Jesus; Rabadão, Carlos; Pereira, AntónioMobility has become a keyword nowadays with the evolution of mobile devices market and proliferation of realtime services. IP Multimedia Subsystem (IMS) is a single, standardized service framework that supports voice, video, data and messaging services, but does not provide seamless mobility for packet based sessions. This paper purposes an IMS architecture with IEEE 802.21 and media-independent pre-authentication (MPA) integrated. IEEE 802.21 can enable this seamless mobility in IMS and, additionally, MPA provides a secure handover optimization scheme, reducing, as a consequence, handover latency. The main goal of this architecture is to provide seamless and secure handovers between different access technologies in an IMS-based environment.
- Wireless Networks Interoperability - Wifi Wimax HandoverPublication . Silva, Hugues Mickael Carreira da; Figueiredo, Luís Filipe Calado Carvalho de; Rabadão, Carlos; Pereira, AntónioThe mobility with quality of service in wireless networks is a reality ever closer. The need for mobility while communicating becomes more and more necessary. Technologies for wireless networks with interoperability develops the concept of "communications anytime anywhere". Interoperability uses the handover to ensure the mobility of a mobile terminal through various communication infrastructures, supported by different technologies of wireless networks. Maintain the connection between base stations and mobile terminal is the key of the customer's satisfaction, with the guarantee of continuity of services and applications running, moving between different cells, using the technology of wireless communications to provide better coverage in the position where is. The aim of this study is to examine how the mobility between different access technologies in wireless networks can be optimized and what their behavior in scenarios of interoperability. To examine the quality of the service of mobility, we analyze the time required for the handover and the existing loss of packages, the latter being a very important factor to satisfy the user.