Abstract:
The present invention relates to methods, nodes, arrangements and articles of manufacture to automatically identify unknown identities of a target. The method comprises the following steps: positioning indicators indicating presence of a known identity of the target in at least one location are periodically collected; —at least one mobile network is interrogated and lists of identities of users located in defined target areas, each area covering at least one of the collected positioning indicators, are fetched; —a crosscheck between the fetched lists is performed; a single or restricted number of identities that is common to the fetched lists is identified.

Description:
CROSS REFERENCE TO RELATED APPLICATION(S) 
     This application is a 35 U.S.C. §371 National Phase Entry Application from PCT/EP2009/065782, filed Nov. 24, 2009, designating the United States, the disclosure of which is incorporated by reference herein in its entirety. 
     TECHNICAL FIELD 
     The present invention relates to methods, nodes, arrangements and articles of manufacture for automatically identify unknown identities of a target. 
     BACKGROUND 
     Lawful Interception of communications can be made based on knowledge of the identity of a party responsible for transmitting or receiving the communication. For example if a mobile telephone number of a criminal suspect is known, it is possible to intercept or retain electronic communication sent from or received by the criminal suspect&#39;s mobile telephone. In governments around the world, various law enforcement agencies may have the right to authorize this interception in their respective jurisdictions. 
       FIG. 1  is part of the prior art and discloses an Intercept Mediation and Delivery Unit IMDU, also called Intercept Unit. The IMDU is a solution for monitoring of Interception Related Information IRI and Content of Communication CC for the same target. The different parts used for interception are disclosed in current Lawful Interception standards (see 3GPP TS 33.108 and 3GPP TS 33.107—Release 7). A Law Enforcement Monitoring Facility LEMF is connected to three Mediation Functions MF, MF 2  and MF 3  respectively for ADMF, DF 2 , DF 3  i.e. an Administration Function ADMF and two Delivery Functions DF 2  and DF 3 . The Administration Function and the Delivery Functions are each one connected to the LEMF via standardized handover interfaces HI 1 -HI 3 , and connected via interfaces X 1 -X 3  to an Intercepting Control Element ICE in a telecommunication system. Together with the delivery functions, the ADMF is used to hide from ICEs that there might be multiple activations by different Law Enforcement Agencies. Messages REQ sent from LEMF to ADMF via HI 1  and from the ADMF to the network via the X 1 _ 1  interface comprise identities of a target that is to be monitored. The Delivery Function DF 2  receives Intercept Related Information IRI from the network via the X 2  interface. DF 2  is used to distribute the IRI to relevant Law Enforcement Agencies LEAs via the HI 2  interface. The Delivery Function DF 3  receives Content of Communication CC, i.e. speech and data, on X 3  from the ICE. Requests are also sent from the ADMF to the Mediation Function MF 2  in the DF 2  on an interface X 1 _ 2  and to the Mediation Function MF 3  in the DF 3  on an interface X 1 _ 3 . The requests sent on X 1 _ 3  are used for activation of Content of Communication, and to specify detailed handling options for intercepted CC. In Circuit Switching, DF 3  is responsible for call control signaling and bearer transport for an intercepted product. Intercept Related Information IRI, received by DF 2  is triggered by Events that in Circuit Switching domain are either call related or non-call related. In Packet Switching domain the events are session related or session unrelated. Lawful Interception needs specific target information to be activated on a suspect. Law Enforcement Authorities receive the mandate to intercept a certain person usually from a judge. Their first task is to discover the target identities that they can use to activate LI. If the user has a subscription with a telecom operator it is rather straightforward to ask the operator for this information and then activate the interception on the discovered identities. In most cases criminals carry a personal phone which is registered to them and is used solely for legally uncompromising communications, e.g. with family members. The smarter criminals will never compromise themselves on these registered known phones due to their knowledge of Lawful Interception of communications. What they usually do is to get one or more additional secret “identities” by for example using SIMs registered to someone else or buying a prepaid SIM card with a small initial amount which has only to be registered at the first refill. With no known link to the criminal&#39;s name or knowledge of these unknown identities, the authorities are powerless to intercept the illegal conversations. 
     The problem at hand is thus how to discover efficiently additional target identities of a well known person having a known identity and who is a subject of lawful interception due to a judicial warrant. 
     SUMMARY 
     The present invention relates to a problem how to automatically identify unknown identities associated to a known identity of a target that is subject of lawful monitoring due to a judicial warrant, which unknown target identities are necessary to perform Lawful Interception. This problem and others are solved by the invention by mechanisms that make use of geographical positioning features and that make a crosscheck between positioning indicators until a single or a restricted number of target identities in a mobile network are identified. 
     More in detail, by tracing a number of locations where the known identity of the target has been present and collecting from a mobile network all mobile subscribers known to the network to be present in target areas covering these locations, a single or restricted number of subscriber identities can be identified as the only ones present in all areas at collection time. The method comprises the following steps: 
     positioning indicators indicating presence of a known identity of the target in at least one location are periodically collected; 
     at least one mobile network is interrogated and lists of identities of users located in defined target areas, each area covering at least one of the collected positioning indicators, are fetched; 
     a crosscheck between the fetched lists is performed; and 
     a single or restricted number of identities that is common to the fetched lists is identified. 
     In one aspect of the invention a Lawful Interception embodiment is disclosed. Real time data is collected from positioning indicators and lists of identities are fetched from mobile networks. 
     An object of the invention is to enhance the Lawful Interception solution in order to ensure automatic discovering of unknown target identities associated to a well known target identity that is subject of lawful monitoring due to a judicial warrant. 
     Other than with the above-mentioned method, this object and other are achieved by a node to automatically identify unknown identities of a target associated to a known identity thereof, where the node comprises:
         means for periodically collecting positioning indicators indicating presence of a known identity of the target in at least one location,   means for sending a request to monitor users present in a target area covering a collected positioning indicator, and   means for receiving a list of user identities.       

     Furthermore, the above object and others are achieved by an arrangement to automatically identify unknown identities of a target associated to a known identity thereof, where the arrangement comprises:
         means for periodically collecting positioning indicators indicating presence of a known identity of the target in at least one location,   means for interrogating at least one mobile network to fetch lists of identities of users located in at least one target area covering at least one collected positioning indicator,   means for crosschecking between the fetched lists, and   means for identifying a single or restricted number of identities that is common to the fetched lists.       

     The means adopted in the nodes and arrangements of the present invention can be circuits, processors, electronic components, parts or subparts, chips, boards, computer readable program codes, computers, or combinations or groups thereof, and the like. 
     The above object and others are also achieved by an article of manufacture comprising a program storage memory having computer readable program code embodied therein to automatically identify unknown identities of a target associated to a known identity thereof, the program code comprising:
         computer readable program code able to collect positioning indicators indicating presence of a known identity of the target in at least one location,   computer readable program code able to interrogate at least one mobile network to fetch lists of identities of users located in at least one target area covering at least one collected positioning indicator,   computer readable program code able to crosscheck between the fetched lists, and   computer readable program code able to identify a single or restricted number of identities that is common to the fetched lists.       

     An advantage with the invention is that an agency will be able to identify for example additional phone numbers or mobile identities of a suspect in an automatic way when a specific mobile phone number or identity of the individual is known. In these way commonly used techniques, such as using for example anonymous prepaid subscriptions to elude monitoring can be neutralized. 
     The invention will now be described more in detail with the aid of preferred embodiments in connection with the enclosed drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is part of the prior art and discloses a block schematic illustration of an Intercept Mediation and Delivery Unit attached to an Intercepting Control Element. 
         FIG. 2  is a block schematic illustration disclosing a target area within a operator network and the arrangement of units up to the Law Enforcement Agency LEA. 
         FIG. 3  is a block diagram showing the steps taken to automatically discover unknown identities through the Spatial Trigger Functionality “Any phone within the area”. 
         FIG. 4  discloses a signal sequence diagram representing collecting and handling of various data in a Lawful interception environment. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 2  discloses a telecommunication system. The system comprises in this example one Operator Network ON 1 . A target known identity T, i.e. a mobile phone identifier of subject under interception, can be seen in  FIG. 2 . The identity can be for example one of MSISDN, IMEI and IMSI codes commonly associated to a mobile phone subscription. The target is present in a target area TA in this example, having entered it at a certain moment (arrow IN) and going to exit it at a certain subsequent moment (arrow OUT). The Operator Network ON 1  comprises two cell areas C 1  and C 2 . A Mobile Switching Centre MSC controls the cell areas C 1  and C 2 . In the example of the figure the target area TA partially overlaps the two cell areas C 1  and C 2 , and can be defined as a “shape” (a circle, an oval, a polygon, etc.) but it can also be defined to coincide with one cell, for example C 1  or C 2 , or with a group of cells, for example the group resulting from the combination of cell C 1  and cell C 2 . A Lawful Interception unit IMDU (Intercept Mediation and Delivery Unit) is disclosed in  FIG. 2 . This IMDU has similar functionalities as the IMDU discussed in the BACKGROUND ART section of this application, and is operatively connected to a Law Enforcement Agency LEA for reporting information about the subject under interception. This IMDU is sometimes also referred to as LI-IMS (Lawful Intercept Mediation System). 
     Between the IMDU and the MSC is interposed a Gateway Mobile Positioning Centre (GMPC) which is part of a mobile positioning system which provides location based services. More specifically, the GMPC can perform several functions related to the geographical location of cell phones. Of particular interest for the present invention is the functionality “Any phone within an area” through which the GMPC can interrogate the Operator Network ON 1  and retrieve a snapshot of all the subscribers within a given area, for example the target area TA of  FIG. 2 . The general configuration and operation of a GMPC within a mobile positioning system is generally known and will not be described further in detail unless it is necessary for the proper understanding of the present invention. 
     For a better understanding of the invention, a typical although non-limiting scenario is now described by way of example, with reference to  FIG. 3 . The target is under interception via his known identity, e.g. MSISDN. The process of automatically identifying his other unknown identity or identities starts at  501 . The position of the target, i.e. the location of his known identity, regardless his telephone activity, is periodically reported in step S 02 . At each positioning report received, the functionality “Any phone within the area” (S 03 ) is activated to retrieve a list, e.g. a MSISDN list S 04 , of all identities within the target area defined the position of the known identity. 
     It is to be noted that the specific target area can be selected amongst a group of areas (which are predetermined areas corresponding to a shape, a cell or group of cells) as the geographical area comprising the geographical location of the know identity of the target, or it can be identified as the area where the known identity enters, as it is indicated by arrow IN in  FIG. 2 . In other words, triggering criteria such as “Any phone entering an area” can be used as an alternative or in combination with the report of the geographical coordinates of the known identity to identify the target area subjected to scrutiny with the “Any phone within the area” functionality. 
     Over a period of time, more spatial surveys are done based on the position of the target. The process is iterative and every time a new MSISDN list is retrieved, it is compared with the previous one, or with the results deriving from previous comparisons of MSISDN lists (S 05 ). In particular, the lists are crosschecked until a single or a very restricted number of MSISDNs is identified (S 06 ). The criteria for ending the iteration can be based on e.g. the identification of a small number of MSISDN, possibly but not limitatively less than two or three unknown identities to be associated to the known identity, or the iteration can be stopped after the same number of identities repeatedly occurs, for a certain number of times, when comparing the lists, or a combination of these criteria, or analogous ones. 
     A report of the discovered identities, e.g. MSISDN, is delivered in S 07  after which the process stops (S 08 ). 
     A method according to the preferred embodiment of the invention will now be explained together with  FIG. 4 . Signalling points MSC, GMPC, IMDU and LEA have all been shown and briefly explained earlier in  FIG. 2 . The method according to the preferred embodiment comprises the following steps:
         The IMDU sends out  1  signals to activate the monitoring of the known identity of the target.   The IMDU sends out  2  signals to LEA through the Handover Interface to inform that the monitoring of the known identity has been activated.   The target T is in a location and brings the registered/known phone/subscription with him, together with any associated unregistered/unknown phone(s)/subscription(s).   The GMPC sends out  3  periodical positioning reports to the IMDU.   At the first periodical positioning report received by GMPC, the IMDU determines the area where the subscriber is and invokes  4  an “Any phone within the area” request towards the GMPC.   The GMPC sends out  5  a first e.g. MSISDN list which is received by the IMDU and stored as data set baseline A.   The target T moves around bringing the known subscription with him, together with any associated unknown subscription(s).   As the target moves around, the GMPC sends out  6  other periodical positioning reports to the IMDU, and the system continues to invoke other “Any phone within the area” requests  7 . For each new data set B which the GMPC sends out  8  to the IMDU, the system removes those MSISDNs which do not appear in each subsequent set of MSISDNs.       

     Users located within the target area and reported to the IMDU are those users who are present in the area substantially at the same time when a position of the target is reported within that area. 
     Eventually, after this iterative process there will be a single or a restricted number of MSISDNs left. At this point, the IMDU stops  9  invoking GMPC and produces an IRI REPORT  10  towards the LEA including all the unveiled target identity(s) C. 
     As an option, a warrant could be automatically created by IMDU on this newly discovered target identity(s) to facilitate the monitoring. 
     As it has been mentioned above, the present invention makes use of spatial triggers. A spatial trigger is a feature that allows a Location Services (LCS) client to define spatial criteria. The GMPC monitors the criteria and when it is fulfilled the GMPC reports to the LCS client. 
     Within the context of the present invention, the following spatial triggers are used:
         “Any phone within an area”, and   “All phones entering an area”.       

     The use of spatial triggers is related to the concept of target area, which can be a cell-id (i.e. CGI/SAI), a cell-id list or a shape (defined for example as a circle or a polygon or the like). 
     A system that can be used to put the invention into practice is schematically shown in the  FIGS. 1-4 . Enumerated items are shown in the figure as individual elements. In actual implementations of the invention, however, they may be inseparable components of other electronic devices such as a digital computer. Thus, actions described above may be implemented in software that may be embodied in an article of manufacture that includes a program storage medium. The program storage medium includes data signal embodied in one or more of a carrier wave, a computer disk (magnetic, or optical (e.g., CD or DVD, or both), non-volatile memory, tape, a system memory, and a computer hard drive. 
     The systems and methods of the present invention may be implemented for example on any of the Third Generation Partnership Project (3GPP), European Telecommunications Standards Institute (ETSI), American National Standards Institute (ANSI) or other standard telecommunication network architecture. Other examples are the Institute of Electrical and Electronics Engineers (IEEE) or The Internet Engineering Task Force (IETF). 
     The description, for purposes of explanation and not limitation, sets forth specific details, such as particular components, electronic circuitry, techniques, etc., in order to provide an understanding of the present invention. But it will be apparent to one skilled in the art that the present invention may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known methods, devices, and techniques, etc., are omitted so as not to obscure the description with unnecessary detail. Individual function blocks are shown in one or more figures. Those skilled in the art will appreciate that functions may be implemented using discrete components or multi-function hardware. Processing functions may be implemented using a programmed microprocessor or general-purpose computer. The invention is not limited to the above described and in the drawings shown embodiments but can be modified within the scope of the enclosed claims.