Location and Tracking Services for a Meta-UbiComp Environment

Current prototypes of UbiComp environments are bounded to a physical site equipped with a WLAN. However, next generation of UbiComp environments will have to aggregate different physical sites, spread over a wide geographic area, each one equipped with an own WLAN, and interconnected by the internet. The emerging model is a meta-environment that integrates different physical environments. It must provide users with a uniform interaction model independently from the physical site they are in. Clients, active in a site, have to get access only to services available in that site. Moreover, users, who move from one site to another one, must have the possibility of suspending their computations before leaving the site and of resuming them once in the new site. These needs call for advanced location and tracking services. This paper presents a location and tracking service for meta-UbiComp environments. The location function is in charge of determining mobile clients active inside the meta-environment, at every time, in every physical site. Mobile users get access only to services available in the physical site they are in. In addition, users are tracked, and the environment automatically reconfigures itself when they move from one location to another one, or when they definitively leave the environment. This makes the environment able to reliably handle resources and services.