Abstmct : This article proposes to investigate the notions of nerwork addresses, directory numbers, and terminal and user identities. The development of personal mobility (i.e. UPT), and of terminal mobility (provided by mobile networks), has created the need to assess the use of these different concepts and identify their current limitations. UMTS/FPLMTS is required to support UP"; thus, the coupling of terminal mobility, UMTSlFPLMTS user mobility and UPT needs to be investigated. Requirements imposed on UMTS/FPLMTS are presented and their impact on addressing mobile terminals and identifying users are discussed. Associated scenarios to take into account this coupling are described. Their assessment will require detailed further study.

n e goal of this paper is to discuss which mobility services need to be offered to FPLMTS/UMTS users. In facr, personal mobility ne& depend on user types and mobility patterns. To define mobility services for FPLMTS/UMTS users, two approaches are possible: the first one is the personal communicator, a small terminal combining n multitude of applications and services that allows you to make and receive calls everywhere; the second one concerns the Universal Personal Telecommunication service which enables urers , to access telecommunication services on the bmis of a unique personal network tramparent UPT number accross multiple networks at any terminal. 7hese two approaches are discussed here from the user point of view.