Adaptive Wireless Multimedia Communications with Context-Awareness Using Ontology-Based Models

The increasing popularity of ubiquitous, interconnected computing devices such as laptops, PDAs, and 3G mobile phones is fostering the emergence of environments where people access their personal information, corporate data and public resources "anytime" and "anywhere". Context, an important concept that can be any information regarding the situation and environment, is often exploited by human beings for communications and actions. Context-aware services have been proposed in the computing field to adapt system behaviors based on the retrieved context data. Although different context-aware systems have been presented in literature, this paper moves one step further by building an adaptive wireless multimedia system with context-awareness using ontology-based models. The proposed system can adapt its behaviors according to the changes of various context data. First, it chooses the appropriate video content based on the retrieved static context data such as user\´s profile, location, time, and weather forecast. Then, dynamic media adaption is performed to greatly improve the video quality perceived by the end user by adapting to various context data such as varying wireless channel quality, available energy of the end equipment, network congestion and application Quality of Services (QoS). To verify the effectiveness of proposed system, a test bench and its experimental results are also described.