Coupling transparency and visibility: a translucent, middleware approach for positioning system integration and management (PoSIM)

The diffusion of wireless terminals with multiple communication interfaces and the proliferation of heterogeneous positioning techniques opens new possibilities for Location Based Services (LBSs), even if potentially complicating their development. In particular, LBSs can significantly benefit from middleware supports to uniformly access the set of positioning systems available at their wireless clients and to dynamically choose the most suitable one depending on application/execution context, also by fusing concurrent positioning data from multiple sources. The paper presents our PoSIM middleware for the integrated and synergic access/control of heterogeneous positioning systems in a highly flexible way. PoSIM provides LBSs with two differentiated levels of visibility for positioning management: a transparent way based on high-level context-based policies, and a fully-aware access to advanced functions/configurations, mediated and uniformed by the middleware independently of the underlying positioning solution. In particular, the paper mainly concentrates on the description of the PoSIM architecture and of its API, by pointing out our primary design and implementation choices.