The PoSIM Project

The heterogeneity among the available positioning systems, together with the fact that current wireless clients tend to simultaneously host several wireless technologies useful for positioning (e.g., terminals with Wi-Fi and/or Bluetooth connectivity and/or equipped with GPS), motivate the need for novel middleware solutions capable of integrating the available positioning techniques, of controlling them in a synergic way, and of dynamically selecting the most suitable solution depending on context.

We propose our original Positioning System Integration and Management (PoSIM) middleware for the efficient and flexible integrated management of different positioning systems. PoSIM focuses on three aspects:

1. it is capable of integrating positioning systems at service provisioning time in a plug-in fashion, by exploiting their possibly synergic capabilities and by actively controlling their features.
2. it allows positioning systems to flexibly expose their capabilities and location data, respectively defined as features and info, at runtime and without requiring any static knowledge of positioning-specific data/functions.
3. it can perform location data fusion depending on applicable context, e.g., application-specific requirements about accuracy or client requirements about device battery consumption.

PoSIM enables differentiated visibility levels to flexibly answer all possible application requirements stemming from different LBS deployment scenarios and application domains.

• PoSIM enables LBSs (Location Based Services) to access and control the whole set of available location providers in a transparent way at a high level of abstraction: LBSs can simply specify the behavior positioning systems must comply with via declarative policies; PoSIM is in charge of actually and transparently enforcing the selected policies.
• PoSIM allows LBSs to have full visibility of the characteristics of the underlying positioning systems via a PoSIM-mediated simplified access to them. In this case, PoSIM provides LBSs with a uniformed API, independently of the specific positioning solution, that permits to access/configure heterogeneous location providers homogeneously and aggregately.