The main issue addressed in this paper is the definition of a model that allows the prediction of the future positions that mobile users will reach inside a building. The building has a stationary LAN cellular network whose cells are small enough to represent a sufficient approximation of mobile users? positions. Mobile users can move inside the building following predeclared routes or in a free manner. The stationary network provides the infrastructure for tracking the mobile users and for delivering several kinds of services to them. An effective delivery of these services should be impossible without the knowledge provided from the predictive model herein described.