Two approaches for an adaptive multimedia transfer service for mobile environments

Abstract

Mobile environments are characterized by varying locations and network access points of end users, by varying levels of network QoS and often also by limited connectivity and reliability. These aspects have to be considered specifically for distributed multimedia applications, typically involving large amounts of data and specific QoS requirements. This article presents concepts and experiences concerning adaptive services for asynchronous multimedia transmission in mobile environments. We describe two different approaches to solve the problems of adaptation to variable network QoS using generic mechanisms. The first approach takes advantage of a mobile queuing service and is based on our former work on a support platform for mobile computing (see Schill and Kümmel. Mobile Computing Special Issue of Distributed Systems Engineering Journal 1995; 128–41; Schill et al. Proceedings of IMC 96 Workshop on Information Visualization and Mobile Computing. Zentrum für graphische Datenverarbeitung, February 1996). The second approach uses the mobile agent paradigm in the context of an application partitioning model to gain flexibility and maintainability (see Schill et al. In: Papaioannou, Minar, editors, Proceedings. Mobile Agents in the Context of Competition and Cooperation (MAC3), a workshop at Autonomous Agents '99, 1999. p. 34–41.). Both approaches exploit software-based conversion to adapt multimedia data according to bandwidth availability. Decoupling of communication peers with automatic notifications about communication actions helps to address disconnection problems.