An Open and Modular Approach for a Context Distribution System

The rapid growth of wireless and cellular networks, and the high availability of small communication devices such as PDAs, brings us faster than ever to the point where Context Aware Services (CASs) are becoming a commodity. In order to allow fast and efficient development, deployment, and management of such services, a global system that allows the services to gain access to the context information should be created, maintained, and managed. In this paper, we study the requirements from such a context distribution system. We deal both with the architectural decisions regarding the definition of context items and the way context information becomes available to the CASs, and the algorithmic aspects of disseminating this information. We demonstrate the advantages of the architecture and the proposed information dissemination algorithms by conducting a simulation study under realistic practical assumptions. Our results indicate that a modular approach in which context information is provided in many network locations by brokers through an open simple API is both powerful enough to provide the needed context information, and simple enough to be easily implemented. 1