real-time services in IP-based wireless heterogeneous networks

Wireless networking evolves towards IP-based heterogeneous networks, providing
ubiquitous connections among users and resources. To maintain continuous user
connectivity, cellular systems, wireless LANs and Internet will need to be
interconnected. This leads to the development of IP-based heterogeneous
networks. The challenge resides in the interconnection of the different systems
in order to support user applications such as real-time and non real-time
services.
In this context, mobility, signalling for different applications and security
are crucial issues. In this Ph.D., the three former aspects are related: the
impact of security protocols, of mobility protocols and signalling protocols on
the Quality of Service (QoS) performances will be evaluated in an IP based
heterogeneous environment where users are roaming within one system and from
one system to another. Mobile stations may roam from WLAN to cellular networks
without any interruption of the connection and of the ongoing session. This
involves that the latency introduced by security, signalling and mobility
procedures in the vertical handover should be small enough so that user does
not notice the handover. This is a challenge when the user is using real-time
services that are time-stringent applications. In this Ph.D. the real-time
applications considered are voice applications, especially Voice over IP.
The support of real-time applications is a crucial issue in IP-based
heterogeneous networks and it has received the highest attention within this
Ph. D. project. At present, the main expected outcome of the Ph. D. project is
formulation, analysis and solution to the problem of the support of real-time
services, such as Voice over IP.
Regarding timeliness of the research: real time interactive services over IP
based networks is one of the most discussed issues in the present time. The
findings and solutions proposed in this research are of immediate relevance.
They would also provide important guidelines for future wireless systems.