Buffering principles for mobile multimedia over IP

Abstract

This thesis suggests a test-bed for reviewing queue algorithms suitable for IP based mobile multimedia services. Subjective performance quality obtained in the test-bed was analysed using a network performance monitor tool. In order to evaluate possible services for use in the test-bed, a comprehensive survey was conducted. The survey revealed that a variety of categorization methods for electronic services exist. However, none of them were targeted at mobile multimedia services. Based on the different methods a framework of six service classes were proposed. Together, these classes provide a useful and easy-to-navigate overview of both existing and future mobile services. Most services on the Internet use TCP for end-to-end message transfer. It is reasonable to expect services in IP based mobile systems to use this protocol as well. TCP offers reliable connection management and is known as an extremely trustworthy protocol when used on wired links. Running TCP over wireless links is another story, though. Selected documents and reports that discuss TCP in wireless environments are evaluated, and proposed solutions are commented. Two queuing algorithms were implemented in a router. Streaming video from a server on the Internet was routed to a host inside the selected test-bed. Run through Microsoft Media Player, the perceived quality of picture and sound was described. This description was then matched to a captured data flow from the same streaming session. The comparison did not reveal strict relations between subjective experience and objective measurements. Possible explanations for this are discussed at the end of the thesis document.