System architecture of a mobile message transport system

Abstract

Many scenarios of beyond 3G mobile communications describe the integration of various access technologies into one system. Being always best connected under certain optimization criteria will be a crucial point for network operators and mobile users and requires network changes of mobile devices at runtime, the so-called vertical handovers. For those, bandwidth fluctuations up to the order of one or two magnitudes, e. g., when changing from an IEEE 802.11 to a GPRS System, have to be expected and applications have to cope with them in an user friendly way. Multi-modality and flexible data representations exploiting weights and semantic of transmitted data as means for making applications resource adaptive are currently under investigation. On top of that, device and system-wide adaptation control instances are needed to solve cross-layer and inter-application issues. This requires a rethinking of the classical communication paradigm of OSI-like protocol layering. With this article, an overview on adaptation in communications is presented and an experimental framework providing system support for application adaptation and adaptation control is introduced as part of that discussion.

QoS-Predictions Service: Infrastructural Support for Proactive QoS- and Context-Aware Mobile Services (Position Paper)

“…his location, time, and some physical characteristics of the user's environment and user's personal preferences, based on which the system must adapt. There exists some research in the context-awareness domain on including networksrelated context information at the service infrastructure level [9]; however, there is no solution for the reliable network-related context information acquisition. For example, the publication of [10] provides a framework for network-aware applications and indicates that an application-level monitoring is one of the methods for application to be network-aware.…”