Preventing roaming of a home subscriber in a visited network restricted for roaming

#This application is the U.S. national phase of International Application No. PCT/EP2009/054795, filed 22 Apr. 2009, which designated the U.S., the entire contents of which is hereby incorporated by reference.

#The present invention relates to roaming restrictions. More specifically, the present invention relates to the prevention of roaming where a visited operator's network allows subscriber roaming via Local Number Server and without having roaming agreements with the subscriber's operator.

#Subscribers of mobile network operators are allowed or not to roam in a specific area depending on roaming agreements with other operators and, in particular, depending on information stored in the subscriber profile.

#The features, objects and advantages of the invention will become apparent by reading this description in conjunction with the accompanying drawings, in which:

#FIG. 1 shows a simplified view of two exemplary GSM architectures wherein a mobile subscriber with a user terminal equipped with a GSM SIM connects with a VLR of a GSM network and the VLR communicates with a HLR to carry out an update location procedure. In particular, the VLR may be provided in a stand-alone configuration or combined with a Mobile Switching Centre (hereinafter MSC), combination which is generally referred to as an MSC/VLR. Also in particular, the HLR may be provided as a monolithic entity or as a distributed entity including a number of HLR front-ends (hereinafter HLR-FE) and a HLR back-end (hereinafter HLR-BE) acting as a centralized common database accessible to every HLR-FE.

#FIG. 2 shows a simplified view of two exemplary GPRS architectures wherein a mobile subscriber with a user terminal equipped with a GPRS SIM connects with a SGSN of a GPRS network and the SGSN communicates with a HLR to carry out an update location procedure. In particular, the HLR may be provided as a monolithic entity or as a distributed entity including a number of HLR front-ends (hereinafter HLR-FE) and a HLR back-end (hereinafter HLR-BE) acting as a centralized common database accessible to every HLR-FE.

#The following describes currently preferred embodiments of means and method for preventing roaming of a home subscriber in a visited network with roaming restrictions.

#FIG. 5 illustrates a first embodiment of the invention whereby an authentication billing or charging is applied for providing authentication data for a home subscriber roaming in a visited network, namely a ‘roaming subscriber’. Under this embodiment, as switching on the user equipment 1 of the roaming subscriber, an Update Location procedure is started during a step S-105 towards network entities such as antenna and Base Station of the visited network, which are not illustrated in FIG. 5 for the sake of simplicity, and the Update Location is forwarded thereof towards a VSE 15 of the visited network where the home subscriber is roaming.

#The VSE receiving the Update Location, as conventionally accepted by mobile communication systems, firstly requires an authentication of the roaming subscriber and, to this end, submits during a step S-110 an authentication data request for the roaming subscriber towards an HLS 25 holding subscription data for the roaming subscriber in the home network of said roaming subscriber.