Patent ID: 8090347

Claim:
A method for detecting the presence of fraudulent Subscriber Identity Modules in a network for cellular communications the method comprising the steps of: (a) at a Service Node, receiving a registration request by a first User Equipment comprising a Subscriber Identity Module for defining an identity of a subscriber; (b) determining whether the subscriber is already registered with the same identity in the Service Node, (c) if the subscriber is already registered with the same identity in the Service Node, retrieving status information on at least a second User Equipment associated with the already registered subscriber for determining whether said at least second User Equipment is different than the first User Equipment, by: determining whether the already registered subscriber is in idle mode; in response to determining that the already registered subscriber is in idle mode, issuing a Global Paging from said Service Node directed to the User Equipments served by said Service Node and checking whether at least two Paging Responses are received by the Service Node in response to said Global Paging, the second User Equipment determined not to be the first User Equipment should at least two Paging Responses be received, (d) disabling any subscription of the subscriber associated with said identity if said at least second User Equipment is determined to be different than the first User Equipment, (e) de-registering the subscriber, (f) sending a Purge Mobile Application Part Message to a Home Location Register associated with said subscriber for purging said first User Equipment and (g) issuing an alarm report to operator personnel.