Henning Maass

Location-aware mobile applications based on directory services

Location-aware applications are becoming increasingly attractive due to the widespread dissemination of wireless networks and the emergence of small and cheap locating technologies. We developed a location information server that simplifies and speeds up the development of these applications by offering a set of generic location retrieval and notification services to the application. The data model and the access protocols of these services are based on the X.500 directory service and the lightweight directory access protocol LDAP since these are becoming the standard attribute-value-pair retrieval mechanisms for Internet and Intranet environments. This approach establishes a smooth migration path from conventional to location-aware applications. The paper presents the location information server concepts, defines its directory data model and access services, and discusses the implementation options of the location information server.

Directory services for mobility management in private telecommunication networks

The use of standardized directory services (X.500) in comparison with the Groupe Speciale Mobile (GSM) concepts for storing mobility management data in private telecommunication networks (PTNs) is discussed. The functional requirements on the database that are called for by mobility management are defined. Solutions to these requirements based on GSM principles and on X.500 principles are presented. The conclusion is that X.500 seems to be a powerful and flexible platform for mobility management in PTNs. The main advantage is that user dialing numbers are independent of the storage node in which the user data is held, allowing free numbering. There are, however, open issues concerning the consistency and performance characteristics of X.500.<<ETX>>

PLASMADS: Smart mobiles meet intelligent environments

Pervasive connectivity over short-range RF technology will provide mobile devices access to interaction opportunities with people, services and contents, being offered by other nearby mobile devices as wen as by local bot spot infrastructures. Currently the mobile device is dumb and the infrastructure knows everything, or vice versa. Mobile devices sucb as PDAs and smart phones are becoming more and more powerful and bot spots provide more and more services. One of the major problems that have to be solved before real pervasiveness is achieved, is how to enable a specific mobile device to use services offered at a hot spot that bas Just been detected. With the variety of mobile devices, platforms, programming languages, operating systems etc. it is very likely that the mobile and the hot spot do not use the same components, i.e. they are not capable to cooperate. We present a system architecture and middlewarel for pervasive connectivity that is based on open standards such as UPnP and Web Services. Thus, it allows out of the box interaction between mobile devices, services and hot spot infrastructures.

Interworking between mobility supporting networks

This paper addresses the interworking between telecommunication networks to support mobile users. The private network operators point of view is emphasized. By identifying general interworking domains, the main tasks for private mobility management are presented. Solutions are suggested and briefly discussed.