Abstract:
Disclosed are a particularly efficient and resource-saving method and device for intercepting at least one user of a communication terminal in a communication network. The invention is characterized in that a central interception and evaluation unit (BAA) receives service data of at least one communication terminal (MS), said received service data is evaluated according to at least one predefined filtering criterion, and at least one evaluation result is forwarded to another network unit (LEA).

Description:
CLAIM FOR PRIORITY  
       [0001]     This application is a national stage of PCT/EP2004/050614 which was published on Dec. 2, 2004 and which claims the benefit of priority to German Application No. 103 23 006.8 filed May 21, 2003.  
       TECHNICAL FIELD OF THE INVENTION  
       [0002]     The invention relates to a method and a device for intercepting at least one user of a communication terminal in a communication network.  
       BACKGROUND OF THE INVENTION  
       [0003]     Service-dependent monitoring of users of a communication terminal among network operators or telecommunication service providers (TSP) and internet service providers (ISP) is being required increasingly by authorities.  
         [0004]     Communication terminals can be mobile radio terminals, fixed network terminals, stationary and mobile computers or similar. Services can be, for example, radio broadcasting, television, multimedia services, multimedia broadcast services, multicast services, etc. Previous solutions, such as, for example, sniffer solutions, for intercepting and searching such services are aimed at analyzing the content of the communication for keywords or, as the case may be, details (information on services). Sniffer solutions are typically used by intelligence services and require large system resources.  
         [0005]     It is known from the publications TS 33.107 and TS 33.108 on interception (monitoring) and TS 22.071 on LCS (Location Services) (see www.etsi.org) that during the interception of data (voice data/short message data/other data) of a mobile radio subscriber to be monitored in a mobile radio communications network by a (generally national) interception center from a switching center (e.g. MSC or SGSN via which data of the subscriber to be monitored is transmitted), in addition to said data, further descriptive data relating to this communication, such as, for example, location information relating to the current or last recorded location of the subscriber is also transmitted to the data center in an “IRI data record”. The location data transferred in the intercept information packet IRI (=interception related information) represents the location information of the mobile radio subscriber in the form of a cell information identity (available to the switching center or requested by the switching center from a home location register (HLR/HSS) of the mobile radio communications network) which indicates in which cell or cell group the mobile radio subscriber was last registered.  
       SUMMARY OF THE INVENTION  
       [0006]     The present invention proposes an efficient method for intercepting services that is economical in its use of resources.  
         [0007]     In one embodiment of the invention, a central interception and evaluation unit in a communication network receives service data of at least one communication terminal and evaluates said service data. The result of the evaluation of the service data can be used (if necessary) to start a time-limited (only for this communication) monitoring operation in other network units.  
         [0008]     One advantage of this invention is that no modifications to the usual signaling between the network units (separate signaling for the interception) are necessary and that only a slight load is placed on the system resources (already available administration interfaces are used for the interception). 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]     The invention will be explained in more detail with reference to the exemplary embodiments illustrated in the figures, in which:  
         [0010]      FIG. 1  shows the interworking of the central interception and evaluation unit with other network units.  
         [0011]      FIG. 2  shows the central interception and evaluation unit. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0012]      FIG. 1  shows a simplified diagram depicting the interworking of the central interception and evaluation unit ZAA with other network units. Such network units can be different interception and information units in communication networks, such as, for example, TSP IE PLMN in a mobile communication network, TSP IE PSTN in a fixed network, VoIP IE or ISP IE on the internet, or IN IE in an intelligent data network. Users of a communication terminal MS participating in a service are intercepted. A service can be a voice service, a multicast, multimedia or message service and/or similar. Intercept orders are activated/deactivated centrally and are submitted by a law enforcement agency LEA via an HI 1  interface. It is also possible that a central interception and evaluation unit ZAA intercepts further network units without an intercept order (preventive intelligence service and/or general data gathering relating to retroactive surveillance operations) and stores the evaluation results and/or delivers them to a law enforcement agency LEA. At the same time data (IMEI) which indicates the multimedia capability, characteristics or other services of a network unit MS to be intercepted can also be registered by an interception and evaluation unit ZAA, stored and if necessary transferred to a law enforcement agency LEA.  
         [0013]     A central interception and evaluation unit ZAA determines the relevant network units TSP IE PLMN, TS PIE PSTN, ISP IE, VoIP IE, IN IE and activates/deactivates the intercept. The intercept includes data on the content of the communication and IRI information with location information LI (if monitoring is taking place in a mobile radio terminal with collection of location information). In the process evaluations are produced from the obtained data by the central interception and evaluation unit ZAA taking into account conditions and statutory regulations. The relevant network units TSP IE PLMN, TSP IE PSTN, ISP IE, VoIP IE, IN IE can also be specified in accordance with a possible judicial authorization.  
         [0014]     Filter criteria are defined in an IRI filter and/or CC (Content of Communication) filter in accordance with conditions and rules of the law enforcement agency LEA and the data obtained evaluated according to the filter criteria. Filter criteria of this kind can include, for example: no location information, without short message (SMS) content, voice services only, electronic messages (emails) only, no prohibited services, no communication with specific call numbers, such as e.g. telephone numbers of politicians, etc. A central interception and evaluation unit ZAA can intercept data relating to specific services, such as e.g. short messages (SMS), voice, data, fax, voice over IP (VoIP), internet, etc. Filters, conditions and rules can be set up, such as, for example, only parts of short messages, no location information, no partner information etc. It may also be necessary to use filters, conditions and rules to restrict the receiving or, as the case may be, retrieval of data and/or evaluation results by network units such as a law enforcement agency LEA. The intercept is then performed in accordance with the filters, conditions and rules. The result of the evaluation is subsequently transferred via the interfaces HI  2  and HI  3  to a law enforcement agency LEA. The central interception and evaluation unit ZAA can combine intercept data relating to different services, such as, for example, with whom the partner of the person under surveillance is communicating. A law enforcement agency LEA can also be allowed active access to all and/or specific data, such as, for example, data relating to a service. The central interception and evaluation unit ZAA can store the intercept data obtained (in this exemplary embodiment, either all or, for example, only charging information can be sent to the interception and evaluation unit ZAA) so that it will be possible to carry out a retroactive monitoring operation/data analysis. The interception and evaluation unit ZAA can also buffer the obtained data when there are transmission problems via the interfaces to a law enforcement agency LEA. Intercept data relating to a user of a communication terminal MS can also be stored in the central interception and evaluation unit ZAA on a longer-term basis for identification purposes so that further information gathering operations can be implemented without further overhead for the telecommunication service providers. By means of a centralized storage of all offered intercept data it would be possible to dispense with the delivery of data to all monitoring intercept equipment TSP IE PLMN, TSP IE PSTN, ISP IE, VOIP IE, IN IE and only relevant data could be read out. Central storage in an interception and evaluation unit ZAA can be performed by the telecommunication service provider, the service provider or by a central authority. The storage period can be defined in statutory legislation. As an option, the intercept units TSP IE PLMN, TSP IE PSTN, ISP IE, VoIP IE, IN IE can be allowed to access the central storage element in a central interception and evaluation unit ZAA. If necessary the interception conditions and regulations can be amended at short notice and possibly for a limited time. In the case of multimedia broadcast and multicast services (MBMS) the available services can also be restricted through the combined evaluation of stored data of the broadcast/multicast services with subscription and location information. For this purpose an additional data transmission by the broadcast/multicast service provider is necessary, detailing when, where and which services are offered. The date and/or time can or, as the case may be, should be included in the transferred data.  
         [0015]      FIG. 2  shows a simplified diagram depicting a central interception and evaluation unit ZAA. Intercept data of further network units TSP IE PLMN, TSP IE PSTN, ISP IE, VoIP IE, IN IE is forwarded via a receiving unit E to a processing unit V. The processing unit V specifies filters in accordance with conditions and rules and produces an evaluation result. Said evaluation result is sent via a transmitting unit S to a law enforcement agency LEA. The obtained intercept data and/or the evaluation result can be stored in a storage element SP to enable retrieval actions or, as the case may be, evaluations to be carried out at a later time. The evaluation result can be sent in an IRI intercept information packet with an extension for the content of the communication to a law enforcement agency LEA. The service data and/or the evaluation result can also be transferred in encrypted form to a law enforcement agency LEA. The encoding can then be performed using a suitable key server. The reception and/or retrieval options of a law enforcement agency LEA can be restricted by means of filters in the central interception and evaluation unit. Said filters are set and activated in accordance with conditions and statutory provisions.  
         [0000]     Abbreviations:  
         [0000]    
       
          AAA Authentication, Authorization and Accounting  
          ADMF Administration Function  
          CC Content of Communication  
          DF Delivery Function  
          E Receiving unit  
          ES European Standard  
          GMSC Gateway MSC  
          HI Handover Interface  
          HLR Home Location Register  
          HSS Home Subscriber Service  
          IE Interception Equipment  
          IIF Internal Interception Function  
          IN Intelligent Network  
          IMS IP Multimedia Subsystem  
          IRI Interception Related Information  
          ISP Internet Service Provider  
          LEA Law Enforcement Agency  
          MF Mediation Function  
          MSC Mobile Switching Center  
          S Transmitting unit  
          SIP Session Initiation Protocol  
          PLMN Public Land Mobile Network  
          PSTN Public Switched Telephone Network  
          TSP Telecommunication Service Provider  
          V Processing unit  
          VLR Visitor Location Register  
          VOIP Voice over IP  
          ZAA Central interception and evaluation unit