Creating always-best-connected multimedia applications for the 4:th generation wireless systems

Sammanfattning: This thesis describes an application-layer framework for managing network connectivity in the 4th-generation wireless systems, which will consist of overlapping heterogeneous networks. If multiple access networks are present, users will have a choice to access the Internet through the “best” available network. The main problem today is that different wireless networks are not particularly integrated and users are in most cases forced to manually interact with the system when switching between networks. The work presented in this thesis addresses this challenge and describes a framework for managing IP mobility while considering competing connection speeds and pricing models. By using an application-layer mobility scheme, called the Resilient Mobile Socket (RMS), the thesis shows how applications can manage handovers and seamlessly migrate data streams between different networks. Moreover, by using a method called Competition based Soft Handovers (CSHM), the thesis demonstrates how handovers can be automatically triggered to the network currently offering the least packet losses and end-to-end delay. Finally, the thesis proposes bandwidth broker to manage network connectivity and share bandwidth effectively between multiple media within an application. As a proof of concept several prototypes have been built into the commercial e-meeting application Marratech Pro. The thesis presents real-life results from exploratory experiments using these prototypes.