Abstract:
A location system comprises a communication terminal for transmitting a location request specifying a target mobile terminal and a type of location information, and a location network. In response to the location request, the location network produces current location information of the target mobile terminal if the type of location information of the received request specifies current location information and transmits the current location information to the communication terminal and stores the last known location information in a memory as last known location information of the target mobile terminal. If the type of location information specifies last known location information, stored last known location information of the target mobile terminal is copied from the memory and transmitted to the communication terminal if the location request is verified by a privacy check and if the stored information is reusable.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to location systems for providing information services to clients as to the location of mobile user equipment (UE) terminals according to the 3GPP (Third Generation Partnership Program) Technical Specification 23.271 v. 5.3.0, “Functional stage 2 description of LCS”, pages 33-62, June 2002. More specifically, the present invention is concerned with the reuse of last known location information. 
     2. Description of the Related Art 
     The location information of a mobile UE terminal is usually sensitive to the privacy of the mobile user and often crucial when the user is in a critical situation. To protect mobile users from illegal access to their private location information, the mobile communications network is provided with a sophisticated privacy protection mechanism which imposes various restrictions on location requests according to privacy profiles (time and place) specified by the mobile users. The privacy protection mechanism provides two types of verification on a location request according to decision capability that varies with a point in the network where the location request is being served. The first type of verification is performed on a client terminal when the network receives a location request from this terminal, known as client check. The second type of verification is a permission granted to the location request after location information of a UE terminal has been obtained if the place and time interval specified by the privacy profile of the UE terminal user are satisfied, known as privacy check. 
     Mobile network providers, on the other hand, are required to provide location service in addition to their basic mobile communications service. Specifically, the location service involves several network nodes exchanging special messages with one another for the position calculation of a target UE and exchanging messages with a target UE terminal over wireless link. 
     The 3GPP location information system, as specified in the 3GPP standard, is basically made up of client terminal, GMLC (Gateway Mobile Location Center), SGSN/MSC (Serving General packet radio service Support Node/Mobile Services switching Center), local wireless network known as RAN (Radio Access Network) and UE (User Equipment) terminal connected to the RAN via wireless link. HLR/HSS (Home Location Register/Home Subscriber Server) is connected to the GMLC as a database for holding the identity of the RAN to which UE terminals are connected. Registered client terminals are given exclusive right to access UE terminals. 
     The 3GPP standard provides two modes of operation for requesting location information, i.e., the mobile terminated location request (MT-LR) and the mobile originated location request (MO-LR). In the MT-LR mode, the client terminal can either request the current location of a target UE or the current or last known location of this terminal. The last known location information is used as a location report instead of the current location information when the network has failed in locating the target UE for some reason if the last known location information is usable. 
     More specifically, when the network receives a location request for a target UE, the SGSN/MSC responsible for the management of the target UE is also responsible for the privacy protection of the UE terminal. According to the privacy protection of the MT-LR mode as specified by the 3GPP standard, UE mobile users register their privacy profile (e.g., the identifiers of those clients allowed to request their location) in the SGSN/MSC of their home network. In response to a location request, the SGSN/MSC performs a privacy check by verifying it against the registered privacy profile of the target UE and determines whether or not the location request is granted. If the privacy profile of a UE terminal further specifies that a notification/verification request be sent to the UE terminal, the UE terminal is given a notification that it is being targeted or verifies the location request and returns a verification result to the client terminal. When the location request is acceptable, the SGSN/MSC proceeds with a location estimation process in collaboration with the associated RAN to determine the current location of the target UE. If the SGSN/MSC fails to acquire current location information of a target UE, a copy of the stored last known location information of the target UE is transmitted to the client terminal if this information is currently still usable, or significant. 
     In the MO-LR mode, the mobile UE terminal exclusively requests its own current location from the network. In this mode, a failure in location measurement will result in the transmission of an error report to the requesting mobile UE terminal. Last known location information is not reused at all for transmission instead of the error report. 
     However, a number of shortcomings exist in the prior art location system. 
     First, the flow of traffic through the location network and the amount of location measurement calculations increase in proportion to location requests from client and mobile terminals. Further, part of the location network is shared in common by a mobile communication network. Therefore, when the location network experiences heavy traffic loads, it is likely that mobile communication traffic is adversely affected, which could lead to an extra burden on mobile network providers. 
     Second, in the MT-LR mode of operation, privacy check is performed by the SGSN/MSC. If reusable last known location information of a UE terminal is available in the GMLC, for example, the SGSN/MSC would perform privacy check for the UE terminal. However, no mechanism is provided for the GMLC to request the SGSN/MSC to perform privacy check. As a result, privacy protection of last known location information is only ensured when this private information is maintained in the GMLC. 
     Third, the reusability of last known location information depends exclusively on whether or not an SGSN/MSC is holding the last known location information, and the criteria of usability depends on specific details of an SGSN/MSC which may differ among different SGSN/MSCs. Therefore, it is likely that requesting client terminals may receive worthless last known location information. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the present invention to provide a location system that reduces location traffic loads and measurement calculation loads and concomitant elimination of an extra network cost. 
     It is a further object of the present invention to provide a location system capable of utilizing last known location information of a mobile terminal for both MT-LR (mobile terminated location request) and MO-LR (mobile originated location request) modes of operation, regardless of whether an SGSN/MSC has failed in obtaining current location information of a target mobile UE (user equipment) terminal. 
     It is a still further object of the present invention to provide a location system capable of providing privacy protection of target UE terminals when their last known location information are reused. 
     It is a still further object of the present invention to provide a location system capable of establishing reusability criteria for last known location information according to requests from client terminals as well as from UE terminals indicating an age parameter of their last known location information. 
     According to a first aspect of the present invention, there is provided a location system for locating a plurality of mobile terminals. The system comprises a communication terminal for transmitting a location request specifying a target mobile terminal and a type of location information, and a location network. The location network is responsive to the location request from the communication terminal for producing current location information of the target mobile terminal if the type of location information of the received request specifies current location information and transmitting the current location information to the communication terminal and storing the last known location information in a memory as last known location information of the target mobile terminal, and copying stored last known location information of the target mobile terminal from the memory if the type of location information specifies last known location information and transmitting the copied information to the communication terminal. 
     The network performs a reusability test on the stored last known location information and transmits the last known location information if the reusability test indicates a favorable result and transmits the current location information if the reusability test indicates an unfavorable result. 
     According to a second aspect, the present invention provides a location method comprising the steps of transmitting a location request from a communication terminal, the request specifying a target mobile terminal and a type of location information, receiving the location request at a location network, producing current location information of the target mobile terminal and transmitting the current location information from the location network to the communication terminal if the type of location information of the received request specifies current location information, storing the current location information in a memory as last known location information of the target mobile terminal, and copying the stored last known location information of the target mobile terminal from the memory if the type of location information specifies last known location information and transmitting the copied information from the location network to the communication terminal. 
     According to a third aspect, the present invention provides a method of operating a gateway with a location network. The method comprises the steps of receiving a location request from a communication terminal, said request specifying a target mobile terminal and a type of location information, acquiring current location information of the target mobile terminal from said location network and transmitting the current location information to said communication terminal if the type of location information of the received request specifies current location information, storing the current location information in a memory as last known location information of the target mobile terminal, and transmitting a copy of the stored last known location information of the target mobile terminal to said communication terminal if said type of location information specifies last known location information. 
     According to a fourth aspect, the present invention provides a communication terminal which comprises a transmit means for transmitting a location request to a location system in which last known location information of mobile terminals are stored, the location request specifying a target mobile terminal and a type of last known location information, and receive means for receiving from the location system a copy of current location information of the target mobile terminal if the type specifies current location information or a copy of last known location information of the target mobile terminal if the type specifies last known location information. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will be described in detail further with reference to the following drawings, in which: 
         FIG. 1  is a block diagram of a location system of the present invention; 
         FIGS. 2A and 2B  are block diagrams useful for describing a first network configuration of the present invention; 
         FIG. 3  is a block diagram useful for describing a second network configuration of the present invention; 
         FIG. 4  is a block diagram useful for describing a third network configuration of the present invention; 
         FIG. 5  is a block diagram useful for describing a fourth network configuration of the present invention; 
         FIG. 6  is a block diagram useful for describing a fifth network configuration of the present invention; 
         FIGS. 7A and 7B  are block diagrams useful for describing a sixth network configuration of the present invention; 
         FIGS. 8A and 8B  are block diagrams useful for describing a seventh network configuration of the present invention; 
         FIGS. 9A and 9B  are block diagrams useful for describing an eighth network configuration of the present invention; 
         FIGS. 10A and 10B  are block diagrams useful for describing a ninth network configuration of the present invention; 
         FIGS. 11A and 11B  are block diagrams useful for describing a tenth network configuration of the present invention; 
         FIGS. 12A to 12E  are flowcharts of the operation of a local GMLC which maintains the privacy information of its home UE terminals, and  FIG. 12F  is a flowchart of a local GMLC which does not maintain the privacy information of its home UE terminals; 
         FIG. 13  is a flowchart of the operation of a SGSN/MSC of the present invention; 
         FIG. 14  is a flowchart of the operation of a mobile terminal of the present invention; 
         FIGS. 15A ,  15 B and  15 C are sequence diagrams associated with the first network mode of operation of the present invention; 
         FIG. 16  is a sequence diagram associated with the second network mode of operation; 
         FIG. 17  is a sequence diagram associated with the third network mode of operation; 
         FIG. 18  is a sequence diagram associated with the fourth network mode of operation; 
         FIG. 19  is a sequence diagram associated with the fifth network mode of the present invention; 
         FIG. 20  is a sequence diagram associated with the sixth network mode of the present invention; 
         FIG. 21  is a sequence diagram associated with the seventh network mode of the present invention; 
         FIG. 22  is a sequence diagram associated with the eighth network mode of the present invention; 
         FIG. 23  is a sequence diagram associated with the ninth network mode of the present invention; and 
         FIG. 24  is a sequence diagram associated with the tenth network mode of the present invention. 
     
    
    
     GENERAL DESCRIPTION 
     Referring now to  FIG. 1 , there is shown a location system of a mobile multi-network in which the present invention is incorporated. The location system is comprised of a plurality of client terminals  101 ,  111 ,  121  connected via landline links to a location network and a mobile UE terminal  105  wirelessly connected the location network. 
     The location network is formed by a plurality of GMLCs (Gateway Mobile Location Centers)  102 ,  112 ,  122  to which client terminals  101 ,  111 ,  121  are respectively connected to send their location requests to and receive location reports from the associated GMLCs. GMLCs  102 ,  112 ,  122  are connected to SGSN/MSCs (Serving General packet radio service Support Node/Mobile service Switching Centers)  103 ,  113  and  123 , respectively, and mutually connected to one another. SGSN/MSCs  103 ,  113 ,  123  are respectively connected to RANs (Radio Access Networks)  104 ,  114 ,  124 . Further associated with the GMLCs  102 ,  112 ,  122  are HLR/HSSs (Home Location Register/Home Subscriber Server)  106 ,  116  and  125 . Privacy profile registers (PPR)  107 ,  117 ,  127  are also connected to the GMLCs  102 ,  112 ,  122 , respectively. 
     The network nodes which are directly connected to each other, such as GMLC, HLR/HSS, SGSN/MSC, RAN, PPR, form a group known as a home network for mobile UE (user equipment) terminals. For example, a UE terminal  105  is connected as a home UE terminal via a wireless link to the RAN  104 . 
     As shown in  FIG. 1 , the client terminal transmits a location request message  150  having a number of fields containing a message type, a source address (client&#39;s identifier), a destination address (phone number of target mobile UE terminal), a location information type and a reusability criteria. The location information type field specifies a type of location information (C=current, L=last known, C/L=current or last known, or L/C=last known or current). The “current or last known” type indicates that the current location information is given priority over the last known location information if both information are available, and the “last known or current” type of location information indicates that the last known location information is given priority over the current location information if both information are available. Current location information may be a default setting. If the requesting user desires a previous location of a target UE terminal, the information-type field of the message is set equal to L. If the requesting user desires a previous location of a target UE terminal, but allows current location information if the previous location is not available nor reusable, the message contains an information-type field set equal to L/C. The information-type field of the message may be set equal to C/L if the user allows last known location information if current location information is not available. The reusability criteria field of the location request message specifies the accuracy of last known location information (allowable distance error) and the allowable age of last known information. The reusability criteria will be used by the location network to make a decision as to whether stored last known location information of a UE terminal can be reused. 
     Each mobile terminal is also capable of transmitting a location request which specifies its own mobile terminal and contains a type of location information. 
     The location network stores last known location information of the mobile terminals. The location network is responsive to a location request from the communication terminal, either from client terminal or mobile terminal, for producing current location information of a target mobile terminal specified by the request and transmitting it to the communication terminal if the type of location information of the received request is current location information, and transmitting a copy of the stored last known location information of the target mobile terminal to the communication terminal if the type of location information is last known location information. 
     The location network is responsive to a location request from the client terminal for performing privacy check on the location request prior to the transmission of said last known location information to the communication terminal. The location network performs reusability check on the stored last known location information according to the privacy profile of the target mobile terminal or client terminal. 
     Identification data of the SGSN/MSCs  103 ,  113 ,  123  are maintained in the associated HLR/HSSs  106 ,  116 ,  126 . The privacy profile of UE terminal  105  is stored in the GMLC of the home network, (i.e., GMLC  102 ). 
     NETWORK CONFIGURATIONS 
     The present invention provides a number of network configurations depending on the location of the requesting communication terminal (client or mobile), the location of the target UE terminal  105  as well as the location of network nodes where privacy profiles and location reports are maintained. 
     First Network Configuration 
     The first network configuration is shown in  FIGS. 2A and 2B . The client terminal  101  is the requesting terminal, and the target UE  105  is currently establishing its link to home network A. 
     In  FIG. 2A , the privacy profile and location information of the target UE are maintained in the home GMLC  102 . The client terminal  101  includes a transmit means  1011  for transmitting a location request to the home GMLC  102  and a receive means  1012  for receiving location information from the GMLC  102 . GMLC  102  includes a memory  1021  for storing the privacy profile and last known location information of UE  105 , and a client/privacy check means  1022 . In response to the location request from the client terminal  101 , the client/privacy check means  1022  performs a client check on the requesting terminal. 
     If the client terminal fails to pass the client check, the client/privacy check means  1022  formulates an error message and sends it from a report transmit means  1026  to the requesting terminal  101 . If the client terminal is verified, the client/privacy check means  1022  proceeds to reference the privacy profile of the target UE stored in the memory  1021  and performs a first privacy check on the location request. If the location request fails to pass the first privacy check, an error message is supplied from the check means  1022  to the report transmit means  1026  and transmitted to the client terminal. If the location request is verified by the first privacy check, the check means  1022  determines which type of location information the request specifies. 
     If the location request specifies type C or C/L, the client/privacy check means  1022  instructs a notification/verification means  1024  to transmit a location request to the SGSN/MSC  103  to perform a location estimation process with the RAN  104  to determine the location of the target UE  105 . A location report is then returned from the SGSN/MSC  103  to a second privacy check means  1025 . In response to the location report, the second privacy check means  1025  proceeds to perform a second privacy check. 
     If the location request specifies type L or L/C, the client/privacy check means  1022  instructs a reusability check means  1023  to make a search through the memory  1021  for last known location information that meets the “age and place” requirements of the client&#39;s request. If the requested last known location information of the target UE is not stored in the memory  1021 , the reusability check means  1023  generates an error message and transmits it to the client terminal  101  from the report transmit means  1026 . 
     If the requested last known location information is stored in the memory  1021 , the reusability check means  1023  instructs the notification/verification means  1024  to check the UE&#39;s privacy profile to see if notification/verification process must be performed. If this is the case, the notification/verification means  1024  acquires the identity of this SGSN/MSC  103  from the home HLR/HSS  106  of the target UE  105  and transmits a notification/verification message to SGSN/MSC  103  to request it to send a notification to the UE  105  for indicating that a location request is being terminated or a verification message to it to request it to verify the client terminal. In the former case, the SGSN/MSC  103  proceeds to request the second privacy check means to perform a second privacy check on the last known location information. In the latter case, the target UE returns a verification report to the SGSN/MSC  103 , which repeats the report to the second privacy check means  1025  to perform a second privacy check if the location request is verified by the target UE. 
     The second privacy check involves verifying the location request against the privacy profile of the target UE stored in the memory  1021  and determining whether the current or UE&#39;s last known location information can be sent to the client terminal. If the location request is not verified by the second privacy check, an error message is sent from the report transmit means  1026  to the client terminal. If the location request is verified by the second privacy check, the report transmit means  1026  transmits the location information contained in the location report from the SGSN/MSC  103  or a copy of the UE&#39;s last known location information stored in the memory  1021 . 
     In a MO-LR mode of operation, the mobile UE terminal  105  includes a control unit  1051  for transmitting a location request via a wireless interface  1053  to the RAN  104  for requesting the location information of its own terminal from the SGSN/MSC  103 . The location request is of the same format as used in transmitting a location request from the client terminal. SGSN/MSC  103  formulates and transmits a location report containing current or last known location information of the UE terminal, depending on the type of location information specified by the location request message. The location report is transferred via the RAN  104  to the UE terminal  105  and received and stored in a memory  1052  and then displayed. 
     In  FIG. 2B , the privacy profile and location information of the target UE are maintained in the SGSN/MSC  103 . GMLC  102  includes a client check means  1027  and a report transmit means  1026 . Client check means  1027  performs a client check on the location request from the client terminal  101 . If the client check means  1027  does not verify the client terminal  101 , it sends an error message to the client terminal from the report transmit means  1026 . Otherwise, the client check means  1027  acquires the identity of SGSN/MSC  103  from HLR/HSS  106  and sends a privacy check request to the SGSN/MSC  103 . 
     SGSN/MSC  103  includes a first privacy check means  1032 , which receives the privacy check request and performs a first privacy check using the privacy profile of the target UE stored in a memory  1031 . If the location request is verified, the first privacy check means  1032  determines which of the location information type the verified request specifies. 
     If the location request specifies type C or C/L, the first client check means  1032  instructs a notification/verification means  1034  to transmit a location request to the RAN  104  to perform a location estimation process to determine the location of the target UE  105 . A location report is then returned from the RAN  104  to a second privacy check means  1035 . In response to the location report, the second privacy check means  1035  proceeds to perform a second privacy check. 
     If the location request specifies type L or L/C, the first privacy check means  1032  instructs a reusability check means  1033  to make a search through the memory  1031  for last known location information that meets the “age and place” requirements of the client&#39;s request. If the requested last known location information of the target UE is not stored in the memory  1031 , the reusability check means  1033  generates an error message and transmits it from the report transmit means  1036  to the client terminal  101 . If the requested last known location information is stored in the memory  1031 , the reusability check means  1033  instructs the notification/verification means  1034  to check the UE&#39;s privacy profile to see if notification/verification process must be performed. If this is the case, the notification/verification means  1034  transmits a notification to the UE  105  from the RAN  104  for indicating that a location request is being terminated or a verification message to request it to verify the client terminal. In the former case, the notification/verification means  1034  instructs the second privacy check means  1035  to perform a second privacy check on the last known location information. In the latter case, the second privacy check means  1035  receives a verification report from the target UE and proceeds to perform a second privacy check if the client terminal is verified by the target UE. 
     The second privacy check involves verifying the location request against the privacy profile of the target UE stored in the memory  1031  and determining whether the current or UE&#39;s last known location information can be sent to the client terminal. If the location request is verified by the second privacy check, the report transmit means  1036  transmits to the GMLC  102  the location information contained in the location report from the RAN  104  or a copy of the UE&#39;s last known location information stored in the memory  1031 . 
     Second Network Configuration 
     According to the second network configuration shown in  FIG. 3 , the client terminal  111  is the requesting terminal and the target UE terminal  105  is currently establishing its link to the home network A. The privacy profile and location report of the target UE terminal  105  are maintained in the home GMLC  102  similar to that shown in  FIG. 2A . 
     Client terminal  111  includes a transmit means  1111  for transmitting a location request to the home GMLC  112  and a receive means  1112  for receiving a location report from the GMLC  112 . GMLC  112  includes a request transfer means  1121  which identifies the GMLC  102  as a node that maintains the privacy profile and location information of the target UE  105  by acquiring its node identifier from the home HLR/HSS  106  of the target UE. GMLC  112  includes a report transfer means  1122  for repeating a location report from the GMLC  102  to the client terminal  111 . 
     GMLC  102  is of identical configuration to that shown in  FIG. 2A . GMLC  102  operates on the location request from the GMLC  112  in a manner identical to its operation on the location request directly received from the client terminal  101  of  FIG. 2A . Therefore, the description of GMLC  102  is omitted for simplicity. 
     Third Network Configuration 
     According to the third network configuration shown in  FIG. 4 , client terminal  111  is the requesting terminal and the target UE terminal  105  is currently visiting the external network C. The privacy profile and location report of the target UE terminal  105  are maintained in the home GMLC  102  similar to that shown in  FIG. 3 . 
     Client terminal  111  sends a location request from transmit means  1111  to the home GMLC  112  and receives a location report by receive means  1112  from the GMLC  112 . Similar to  FIG. 3 , the request transfer means  1121  repeats the received location request to the GMLC  102  and the report transfer means  1122  repeats a location report from the GMLC  102  to the client terminal  111 . In the GMLC  102 , memory  1021  maintains the privacy profile and last known location information of the target UE  105 . GMLC  102  is of the same configuration as in  FIG. 3 . The operation of GMLC  102  is the same as that of  FIG. 3  except that its notification/verification means  1024  sends notification/verification and location request messages to the GMLC  122  of the visited network C and its second privacy check means  1025  receives verification and location reports from the GMLC  122 . 
     GMLC  122  includes a message transfer means  1221  for repeating the message from the GMLC  102  to the SGSN/MSC  123  of the visited network C and a report transfer means  1222  for repeating verification and location reports from the SGSN/MSC  123  to the GMLC  102 . 
     Fourth Network Configuration 
     According to the fourth network configuration shown in  FIG. 5 , the client terminal  101  is the requesting terminal and the target UE terminal  105  is currently visiting the external network B. The privacy profile and location report of the target UE  105  are maintained in the home GMLC  102 . 
     The location network of this configuration is similar to that of  FIG. 2A  with the exception that its notification/verification means  1024  sends notification/verification and location request messages to the GMLC  112  of the visited network B and its second privacy check means  1025  receives verification and location reports from the GMLC  112 . 
     GMLC  112  includes a message transfer means  1121  for repeating the message from the GMLC  102  to the SGSN/MSC  113  of the visited network B and a report transfer means  1122  for repeating verification and location reports from the SGSN/MSC  113  to the GMLC  102 . 
     Fifth Network Configuration 
     According to the fifth network configuration shown in  FIG. 6 , the client terminal  111  is the requesting terminal and the target UE terminal  105  is currently visiting the external network B. The privacy profile and location report of the target UE terminal  105  are maintained in the home GMLC  102 . 
     The location network of this configuration is similar to that of  FIG. 4  with the exception that the GMLC  112  of the visited network B includes a transfer means  1123  and the notification/verification means  1024  of GMLC  102  sends notification/verification and location request messages to the transfer means  1123  for repeating it to the SGSN/MSC  113  of the visited network B. The second privacy check means  1025  of GMLC  102  receives verification and location reports from the SGSN/MSC  113  via the transfer means  1123  of GMLC  112 . 
     Sixth Network Configuration 
     The sixth network configuration is shown in  FIGS. 7A and 7B  in which the client terminal  101  is the requesting terminal and the target UE terminal  105  is currently establishing its link to the home network A. In  FIG. 7A , the privacy profile and location information of the target UE terminal  105  are both maintained in the PPR  107 . 
     In  FIG. 7A , the GMLC  102  includes a client check means  1027  to perform a client check on the location request from the client terminal  101 . If the request is verified, the client check means  1027  transmits an authorization request to the PPR  107  for authorizing it to perform a number of checks including a first privacy check, an information type check and a reusability test. PPR  107  includes a memory  1061  for storing privacy profiles and location information of mobile terminals and a first privacy check means  1072  which receives the authorization request from the GMLC  102  to perform a first privacy check using the privacy profile stored in the memory  1071 . If the request is verified by the first privacy check, the location information type of the request is examined. 
     If the client is requesting current location information, the first privacy check means  1072  instructs the notification/verification means  1024  to determine if notification/verification is required. Notification/verification means  1024  acquires the identifier of SGSN/MSC  103  from the HLR/HSS  106  and sends a location request (and a notification/verification message if required) to the identified SGSN/MSC to obtain location information of the target UE (with or without a verification report). The obtained location information is supplied to a privacy check request means  1028  of the GMLC  102 . In response, the privacy check request means  1028  transmits an authorization request to a second privacy check means  1075  of the PPR to authorize it to perform a second privacy check using the UE&#39;s privacy profile stored in the memory  1071 . If the request for the current location information is verified by the second privacy check, the second privacy check means  1075  permits the privacy check request means  1028  of GMLC  102  to transmit the current location information which has been received from the SGSN/MSC  103  to the client terminal  101  via the report transmit means  1026 . 
     If the client terminal  101  is requesting last known location information of the target UE, the privacy check means  1072  of the PPR allows the reusability check means  1073  to perform a reusability test on the “age and place” data of the location request to determine whether the requested last known location information is available in the memory  1071 . If this is the case, the reusability check means  1073  transmits information to the notification/verification means  1024 , indicating whether or not notification/verification is required. If notification/verification is required, the notification/verification means  1024  transmits a notification/verification message to the SGSN/MSC  103 . Privacy check request means  1028  responds to a verification report from the SGSN/MSC  103  by checking it to see if second privacy check should proceed. If so, it sends an authorization request to a second privacy check means  1075  of PPR  107  to authorize it to perform a second privacy check by using the privacy profile of the target UE and returns a privacy check report to the GMLC  102  from report transmit means  1076 . If the second privacy check verifies the request, the report transmit means  1076  transmits a copy of the last known location information of the target UE from the memory  1071  to the GMLC  102 , which is repeated by the report transmit means  1026  to the client terminal  101 . 
     If any of the results of the two privacy checks and the reusability check is unfavorable, an error report will be transmitted from the report transmit means  1076  to the GMLC  102  and repeated by the report transmit means  1026  to the client terminal  101 . 
     In  FIG. 7B , the privacy profile and location report of the target UE terminal  105  are respectively maintained by the PPR  107  and the GMLC  102 . Client check means  1027  performs a client check on the received location request. If the request is verified, the client check means  1027  transmits an authorization request to the PPR  107  to authorize it to perform a first privacy check. PPR  107  includes a privacy check means  1077  which references the privacy profile of the UE terminal  105  and performs a privacy check using the referenced privacy profile. If the request is not verified, the privacy check means  1077  transmits an error message to the GMLC  102  from report transmit means  1076  to the client terminal  101 . If the request is verified, the privacy check means  1077  requests the client check means  1027  of the GMLC to examine the type of location information of the location request. 
     If the client is requesting current location information, the client check means  1027  of the GMLC instructs the notification/verification means  1024  to acquire the identifier of the SGSN/MSC  103  from the HLR/HSS  106  and transmits a location request to the SGSN/MSC  103 . Location information obtained by the SGSN/MSC  103  is transmitted to the privacy check request means  1028 . If notification/verification by the UE terminal is required, a notification/verification message is sent with the location request and a verification report will be received by the privacy check request means  1028 . In response to the location information, the privacy check request means  1028  sends an authorization request to the privacy check means  1077  of the PPR to authorize it to perform a second privacy check. If the request is verified by the second privacy check, the privacy check means  1077  allows the privacy check request means to transmit the received current location information to the client terminal  101  via the report transmit means  1026 . 
     If the client terminal  101  is requesting last known location information of the target UE, the client check means  1027  of the GMLC allows the reusability check means  1023  to perform a reusability test on the “age and place” data of the location request to determine whether the requested last known location information is available in the memory  1021 . If this is the case, the reusability check means  1023  instructs the notification/verification means  1024  to check to see notification/verification is required. If notification/verification is required, the notification/verification means  1024  transmits a notification/verification message to the SGSN/MSC  103  to receive a verification report. Privacy check request means  1028  responds to the verification report by checking it to see if second privacy check should proceed. If so, it sends an authorization request to the privacy check means  1077  to authorize it to perform a second privacy check by using the privacy profile of the target UE and returns a privacy check report to the GMLC  102 . If the request is verified by the second privacy check means  1077 , the report transmit means  1026  is directed to transmit a copy of the last known location information of the target UE from the memory  1021  to the GMLC  102  to the client terminal  101 . 
     Seventh Network Configuration 
     The seventh network configuration is shown in  FIGS. 8A and 8B  in which the client terminal  111  is the requesting terminal and the target UE terminal  105  is currently establishing its link to the home network A. 
     In  FIG. 8A , the privacy profile and location information of the target UE terminal  105  are both maintained in the PPR  107 . Client terminal  111  includes a transmit means  1111  for transmitting a location request to the home GMLC  112  and a receive means  1112  for receiving a location report from the GMLC  112 . GMLC  112  includes a request transfer means  1121  which identifies the GMLC  102  as a node that maintains the privacy profile and location information of the target UE  105  by acquiring its node identifier from the home HLR/HSS  106  of the target UE. GMLC  112  includes a report transfer means  1122  for repeating a location report from the GMLC  102  to the client terminal  111 . 
     GMLC  102  and PPR  107  are of identical configuration to that shown in  FIG. 7A  and hence they operate in the same manner as that of  FIG. 7A  on the location request repeated by the GMLC  112 . 
     In  FIG. 8B , the privacy profile and location information of the target UE terminal  105  are respectively maintained in the GMLC  102  and PPR  107 . 
     Similar to  FIG. 8A , the client terminal  111  transmits a location request to the home GMLC  112  and receives a location report from the GMLC  112 . GMLC  102  and PPR  107  are of identical configuration to that shown in  FIG. 7B  and hence they operate in the same manner as that of  FIG. 7B  on the location request repeated by the GMLC  112 . 
     Eighth Network Configuration 
     The eighth network configuration is shown in  FIGS. 9A and 9B  in which the client terminal  111  is the requesting terminal and the target UE terminal  105  is currently visiting the external network C. 
     In  FIG. 9A , the privacy profile and location information of the target UE terminal  105  are both maintained in the PPR  107 . Client terminal  111  transmits a location request to the home GMLC  112  and receives a location report from the GMLC  112 . GMLC  112  includes request transfer means  1121  which identifies the GMLC  102  as a node that maintains the privacy profile and location information of the target UE  105  by acquiring its node identifier from the home HLR/HSS  106  of the target UE. GMLC  112  includes report transfer means  1122  for repeating a location report from the GMLC  102  to the client terminal  111 . 
     Since the target UE is visiting the network C, the notification/verification means  1024  acquires the identifiers of GMLC  122  and SGSN/MSC  123  from the HLR/HSS  106  when instructed from the PPR  107  and sends a location request and notification/verification message to the SGSN/MSC  123  via the message transfer means  1221  of GMLC  122  and receives a location report and verification report via the report transfer means  1222  of GMLC  122 . 
     In  FIG. 9B , the privacy profile and location information of the target UE terminal  105  are respectively maintained in the GMLC  102  and PPR  107 . 
     The operation of  FIG. 9B  is similar to  FIG. 8B  with the exception that location report and verification report are obtained from the SGSN/MSC  123  via the GMLC  122 . 
     Ninth Network Configuration 
     The ninth network configuration is shown in  FIGS. 10A and 10B  in which the client terminal  101  is the requesting terminal and the target UE terminal  105  is currently visiting the external network B. 
     In  FIG. 10A , the privacy profile and location information of the target UE terminal  105  are both maintained in the PPR  107 . Client terminal  101  transmits a location request to the home GMLC  102  and receives a location report from the GMLC  102 . Since the target UE is visiting the network B, the notification/verification means  1024  of GMLC  102  acquires the identifiers of GMLC  112  and SGSN/MSC  113  from the HLR/HSS  106  when instructed from the PPR  107  and sends a location request and notification/verification message to the SGSN/MSC  113  via the message transfer means  1123  of GMLC  112  and receives a location report and verification report via the report transfer means  1124  of GMLC  112 . 
     In  FIG. 10B , the privacy profile and location information of the target UE terminal  105  are respectively maintained in the GMLC  102  and PPR  107 . 
     The operation of  FIG. 10B  is similar to  FIG. 8B  with the exception that location report and verification report are obtained from the SGSN/MSC  113  via the GMLC  112 . 
     Tenth Network Configuration 
     The ninth network configuration is shown in  FIGS. 11A and 11B  in which the client terminal  111  is the requesting terminal and the target UE terminal  105  is currently visiting the external network B. 
     In  FIG. 11A , the privacy profile and location information of the target UE terminal  105  are both maintained in the PPR  107 . Client terminal  111  transmits a location request to the home GMLC  112  which repeats the request to the GMLC  102  after acquiring its identifier from the HLR/HSS  106 . Client terminal  111  receives a location report from the GMLC  102  via the home GMLC  112 . Since the target UE is visiting the network B, the notification/verification means  1024  of GMLC  102  acquires the identifiers of GMLC  112  and SGSN/MSC  113  from the HLR/HSS  106  when instructed from the PPR  107  and sends a location request and notification/verification message to the SGSN/MSC  113  via the message transfer means  1123  of GMLC  112  and receives a location report and verification report via the report transfer means  1124  of GMLC  112 . 
     In  FIG. 11B , the privacy profile and location information of the target UE terminal  105  are respectively maintained in the GMLC  102  and PPR  107 . 
     The operation of  FIG. 11B  is similar to  FIG. 8B  with the exception that location report and verification report are obtained from the SGSN/MSC  113  via the GMLC  112 . 
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     The MT-LR operation of a local GMLC proceeds according to flowcharts shown in  FIGS. 12A to 12E  if the GMLC holds the privacy information of its home UE terminals. 
     In  FIG. 12A , when the local GMLC receives a message from a client terminal or from the network, the routine starts with decision step  201  to examine the type and source of the message to determine whether the message is a location request from a client terminal, a location request repeated from other GMLC, or the message contains an SGSN/MSC identifier from an HLR/HSS. If the message is a location request from client terminal, flow proceeds to step  202  to perform a client check to verify the requesting client terminal for agreement with the privacy profile of the target UE maintained in the local GMLC. If the location request is not verified at step  202 , an error message is transmitted to the requesting terminal (step  223 ) and the routine is terminated. 
     If the requesting client is verified (step  202 ) or the received message is a location request from other GMLC (step  201 ), flow proceeds to step  204  to determine whether the local GMLC is the home GMLC of the target UE. If this is the case, flow proceeds to decision step  205  to check to see if a PPR (Privacy Profile Register) is connected to the GMLC. 
     If no PPR is connected to the local GMLC, a first privacy check is performed on the location request for agreement with the privacy profile of the target UE terminal (step  206 ) to determine if the location request is acceptable (step  207 ). 
     The first privacy profile of a UE terminal may include grant/reject indication of whether or not the client terminal is acceptable, or whether or not the requested accuracy of location information is acceptable, or whether or not the requested age of last known location information is acceptable. The first privacy profile may further include an indication of whether the UE terminal user is desirous of notification from the client terminal or verification by the UE terminal as a criteria for the acceptance of a location request. If a UE user desires notification from the requester, the UE user will receive a notification from the network indicating that the UE terminal is being the target of a location request. If a UE user desires verification, the user will receive a verification message from the network indicating whether the current location request should be accepted or not. The UE terminal responds to the verification message with a verification report. 
     If first privacy check step  207  determines that the received location request is not acceptable, flow proceeds to step  223  to transmit an error message to the requesting terminal. If the location request is acceptable, flow proceeds to step  208  to perform a check on the type of location information contained in the received location request to determine which of the parameters (C, L, C/L and L/C) is specified in the request (step  209 ). If the type of location information specifies last known (L) or “last known or current (L/C) location information” (indicating that the client user desires last known location information but satisfies with it if current location information is not available), flow proceeds to step  210  to perform a check on the last known location information for reusability. If the requested “age and place” requirements of the location request meet the privacy profile of the target UE, a further check is made as to whether last known location information that fulfills the requirements is stored in memory (step  211 ). 
     If such last known location information is available, flow proceeds to step  212  to check to see if the privacy profile of the target UE indicates that notification to or verification by the target UE is required. If this is the case, flow proceeds to step  213  to send an enquiry message to an HLR/HSS for requesting the identifier of a SGSN/MSC responsible for the target UE terminal. If no response is received from the HLR/HSS, an error message is sent to the client terminal (step  223 ). When a response message is received from the HLR/HSS (step  214 ), the GMLC proceeds to step  215  to examine its contents and transmits a notification/verification message to the identified SGSN/MSC if the response message contains only SGSN/MSC identifier. If the response message from the HLR/HSS contains the identifier of a GMLC in addition to an SGSN/MSC identifier, the GMLC sends the notification/verification message to the identified GMLC. If the privacy profile of the target UE requires only notification (step  216 ), flow proceeds to step  218 . Otherwise, flow proceeds to step  217  to check to see if a verification report from the UE terminal indicates that the requesting client terminal is verified. If the decision is negative at step  217 , flow proceeds to step  223  to send an error message to the requesting terminal. If the decision at step  217  is affirmative, flow proceeds to step  218  to determine if the GMLC is connected to a PPR. 
     If no PPR is connected to the GMLC (step  218 ), flow proceeds to step  219  to perform a second privacy check on the current or last known location information to determine whether its time of location estimation and its estimated location agree with allowed “time-zone and area” parameters of the UE&#39;s privacy profile (step  220 ). If the result of the second privacy check is unfavorable (step  220 ), an error message is transmitted to the client terminal (step  223 ). Otherwise, the location information is processed according to the UE&#39;s privacy profile if the accuracy of the location information is higher than the allowed accuracy (step  221 ). At step  222 , the location information (current or last known) is transmitted to the client terminal. If the location information is current and a copy of the current location information is stored in memory as last known location information. 
     If no notification/verification is required by the UE terminal, the decision at step  212  is negative and flow proceeds to step  219  to perform second privacy check, skipping steps  214  through  218 . 
     If current (C or C/L) location information is specified in the received location request (step  209 ) or last known location information is not available (step  211 ), flow proceeds to step  231  ( FIG. 12B ) to transmit an enquiry message to the home HLR/HSS for requesting the identifier of a SGSN/MSC responsible for the target UE terminal. When the requested identifier is received (step  232 ), flow proceeds to step  233  to check to see if the privacy profile of the target UE indicates that notification/verification is required. If not, a location request is sent to the home or external SGSN/MSC depending on the current location of the target UE to obtain its current location information. When the requested current location information is received (step  235 ), flow returns to step  218 . If there is no response, an error message is transmitted to the requesting terminal (step  223 ). If the decision at step  233  is affirmative, flow proceeds to step  236  to transmit a location request and notification/verification request message to the home or external SGSN/MSC depending on the current location of the target UE for receiving a response (step  237 ). If the current location information of the target UE and a verification report is received, flow proceeds from step  237  to step  217 . If no response is received, flow proceeds from step  237  to step  223  to send an error message to the client terminal. 
     If the decision at step  204  indicates that the local GMLC is not the home GMLC of the target UE, flow proceeds to step  241  ( FIG. 12C ) to send an enquiry message to the external HLR/HSS, which is the home HLR/HSS of the external target UE, to obtain the identifier of an appropriate GMLC. When the identifier of the appropriate GMLC is obtained, a location request is transmitted to the identified GMLC to obtain the location information of the target UE. If the location information is received successfully, flow proceeds to step  222  to repeat the received location information to the requesting terminal. If no response is returned, an error message is sent to the requesting terminal (step  223 ). 
     If the decision at step  201  indicates that a message such as notification/verification message, verification report, location request, or location report is received from other GMLC, flow proceeds from step  201  to step  251  ( FIG. 12D ) to repeat the received message to downstream node identified by a SGSN/MSC (or plus GMLC) identifier contained in the message. 
     If a PPR is connected to the local GMLC, the decision at step  205  is affirmative and flow proceeds to step  224  to send an authorization request (for privacy check with or without a location-info-type check) to the PPR to obtain a report. The PPR performs a first privacy check on the location request and additionally an information-type check with an attendant reusability test on stored location information of the target UE if the PPR maintains location information of mobile terminals. At step  225 , the GMLC receives a report from the PPR indicating a result of the first privacy check and a result of the reusability test. Step  225  analyzes the received report. If the result of the first privacy check is favorable and no reusability test is performed (a), flow proceeds to step  208 . Otherwise, flow proceeds to step  223  to send an error message to the requesting terminal. If the results of the first privacy check and reusability test are both favorable (b), flow proceeds to decision step  212 . If the result of the first privacy check is favorable, but the result of the reusability test is unfavorable (c), flow proceeds to step  231  ( FIG. 12B ). 
     If the decision at step  218  is affirmative, flow proceeds to step  261  ( FIG. 12E ) to send a request to the PPR for requesting it to perform a second privacy check. At step  262 , a report indicating a result of the second privacy check is received from the requested PPR and the result is analyzed. If the result indicates a favorable decision, flow proceeds from step  262  to step  222  to transmit the location information of the target UE to the requesting terminal. If the report from the PPR indicates an error at step  262 , flow proceeds to step  223  to send an error message to the requesting terminal or GMLC. 
     If the privacy information of home UE terminals is not maintained in the local GMLC, the MT-LR operation of the GMLC proceeds according to the flowchart of  FIG. 12F  and the home SGSN/MSC of target UE terminal operates according to the flowchart of  FIG. 13 . 
     In  FIG. 12F , the routine starts with step  271  to check the type and source of a message when it arrives on the local GMLC. If the message is a location request from a client terminal, flow proceeds to step  272  to perform a client check. If the client terminal is verified (step  273 ), flow proceeds to step  274  to check to see if the local GMLC is the home GMLC of the target UE. If so, flow proceeds to step  231  ( FIG. 12B ). Otherwise, flow proceeds to step  241  ( FIG. 12C ). If the message is a location request from other GMLC, steps  272 ,  273  are skipped and step  274  is executed. If the message contains a node identifier, flow proceeds from step  271  to step  251  to repeat the message downstream. 
     The MT-LR operation of the SGSN/MSC of the present invention will be described below with reference to the flowchart of  FIG. 13 . 
     The routine of a SGSN/MSC begins with the reception of a message either from a GMLC or a mobile UE terminal (step  300 ). If the location request is transmitted from a GMLC and the SGSN/MSC maintains location reports and private profiles of UE terminals (step  301 ), flow proceeds to step  302  to perform a privacy check for agreement with the first privacy profile of the target UE. If the request is acceptable, flow proceeds to step  304  to check the location information type of the request. If the request is not acceptable (step  303 ), an error message is returned to the requesting GMLC (step  315 ). 
     If the location reports and private profiles of UE terminals are not maintained by the SGSN/MSC, flow proceeds to step  331  to transmit a location request to the RAN and repeats a location report from the RAN to the requesting GMLC (step  332 ). 
     If the decision at step  300  indicates that the location request is transmitted from a UE terminal, flow proceeds to step  304 , skipping steps  302  and  303 . 
     If the location request specifies last known location information of the target UE (step  304 ), a reusability test is provided (steps  306 ,  307 ). If the result of the reusability test at step  307  is unfavorable, flow proceeds to step  308  to transmit a location request to the associated RAN to obtain the current location information of the target UE (steps  308 ,  309 ). If no response is received, an error message is transmitted to the requesting source (step  315 ). 
     If the decision at step  307  or  309  is affirmative, flow proceeds to step  310 . If the location request has been received from a GMLC, flow proceeds to step  311  to perform a privacy check for agreement with a second privacy profile of the target UE terminal (step  312 ). If the result of the privacy check is unfavorable, an error message is returned to the requesting source (step  315 ). Otherwise, flow advances to step  313  to process the location information according to the privacy profile if the accuracy of the location information (either current or last known) is higher than the allowed accuracy. The processed location information is then transmitted to the requesting source (step  314 ). If the location request has been received from a UE terminal, flow proceeds from step  310  to step  314  to transmit the location information to the requesting UE terminal. 
     If the SGSN/MSC receives a notification/verification message from a GMLC (step  300 ), flow proceeds to step  320  to check to see if notification or verification is requested. If notification is requested, flow proceeds to step  321  to send a notification message to the target UE and terminates the routine. If verification by the target UE is requested, flow proceeds to step  322  to send a verification message to the target UE. In response, the target UE checks the requesting terminal and sends a verification report to the SGSN/MSC. This report is repeated by the SGSN/MSC to the requesting GMLC (step  323 ). 
     The MO-LR operation of the mobile UE terminal of the present invention proceeds according to a flowchart shown in  FIG. 14 . 
     The routine of a mobile UE terminal starts with step  401  when the user of the UE enters a request to the terminal for requesting a location information of its own terminal. The entered request data specifies one of the types of location information as described above. At step  402 , the UE terminal checks the entered type of location information and determines which type is specified (step  403 ). If the last known location information is requested, flow proceeds to step  404  to determine whether past location information is stored in the memory  1052  ( FIG. 2A ) of the UE terminal. If the decision is affirmative at step  404 , flow proceeds to step  405  to check the stored last known location information for reusability (step  406 ). If the stored information satisfies the privacy profile of the UE terminal, the stored location information is determined to be reusable and the stored information is read (step  407 ) and displayed on a map (step  411 ). If the decision at step  403  indicates that the entered request specifies current location of the UE terminal or if the decision at step  404  or  406  is negative, flow proceeds to step  408  to transmit a location request to a SGSN/MSC via a RAN. The location request is processed in the SGSN/MSC and location information is transmitted from the SGSN/MSC and received by the UE terminal at step  409 . Depending on the type of location information specified in the transmitted location request message, the location information received from the SGSN/MSC is either last known or current location information of the requesting UE terminal. The memory of the UE terminal is updated with the received location information at step  410  and the received information is displayed (step  411 ). 
     NETWORK MODES OF OPERATION 
     The present invention operates in first to tenth network modes corresponding respectively to the first to tenth network configurations discussed previously. The following is a description of the network modes of operation using the flowcharts just described above. 
     First Network Mode 
       FIG. 15A  is a sequence diagram illustrating a location network operating in MT-LR mode in which the client terminal  101  is the requesting terminal and the mobile terminal  105  is the target UE which is currently staying in the home network A. The home GMLC  102  of target UE maintains its privacy profile and location report. Client terminal  101  initially transmits a location request (event  501 ) to the home GMLC  102 . In response, the GMLC  102  performs a client check (event  502 ), a privacy check (event  503 ) and a location information type check (event  504 ) by executing steps  200  through  211  of  FIG. 12A . If the location request specifies current location information of the target UE and notification/verification is not required, steps  231  through  235  are executed by sending a location request to the SGSN/MSC  103  using its identifier acquired from HLR/HSS  106  (events  505 ,  506 ,  507 ). 
     If the location request specifies last known location information of the target UE and the stored information is reusable (step  211 ), and notification/verification is required (step  212 ), steps  213  through  215  are executed by sending a notification/verification request to the SGSN/MSC  103  using its identifier obtained from HLR/HSS  106  (events  505 ,  506 ,  507 ). 
     SGSN/MSC  103  executes steps  300 ,  320 - 323  in response to the notification/verification message (event  507 ) from the GMLC  102  or executes steps  300 ,  301 ,  331 ,  332  in response to the location request from the GMLC  102  (event  508 ) and transmits a location report or a verification report (event  509 ) to the GMLC  102 . If verification report is received, the GMLC  102  checks to see if the target UE has verified the request (step  217 ). If the request is verified, the GMLC  102  performs a second privacy check (event  510 ) on the current or last known location information by executing steps  219  to  221  and transmits location information to the client terminal  101  (event  511 ). 
       FIG. 15B  is a sequence diagram illustrating a location network operating in the MT-LR mode in which the client terminal  101  is the requesting terminal, the mobile terminal  105  is the target UE establishing its wireless link to the home network A, and the home SGSN/MSC  103  of target UE maintains its privacy profile and location report. Client terminal  101  transmits a location request (event  601 ) to the home GMLC  102 . In response, the GMLC  102  executes steps  271 ˜ 273  ( FIG. 12F ) to perform a client check (event  602 ). Being the home GMLC of the target UE, the GMLC  102  makes an affirmative decision at step  274  and executes steps  231 ,  232  ( FIG. 12B ) to acquire the identifier of SGSN/MSC  103  (events  603 ,  604 ) from HLR/HSS  106  and sends a location request to the SGSN/MSC  103  (event  605 ). 
     In response to the location request from GMLC  102 , the SGSN/MSC  103  executes steps  300 ˜ 307  to perform a first privacy check and information type check (events  606 ,  607 ) and executes steps  308 ,  309  to perform location estimation process (event  608 ) to obtain a location report. Second privacy check is performed (event  609 ) by the SGSN/MSC  103  by executing steps  310 ˜ 313 . The location report is then transmitted (step  314 ) to the GMLC  102  (event  610 ), which receives this location report (step  235 ,  FIG. 12B ) and repeats it to the client terminal  101  (step  222 ,  FIG. 12A , event  611 ). 
     In  FIG. 15C , the location network operates in MO-LR mode in which the UE terminal  105  transmits a location request to the SGSN/MSC  103  (event  701 ). SGSN/MSC  103  responds to this request by executing steps  300 ,  304  and  305  ( FIG. 13 ) to perform an information type check (event  702 ). If the current location is specified in the location request, the SGSN/MSC  103  sends a location request to the RAN  104  (steps  308 ,  309 ,  310 ,  314 ) to provide a location estimation process (event  703 ). If last known location is specified in the location request, the SGSN/MSC  103  performs a reusability test (steps  306 ,  307 ) and sends a location report (event  704 ) to the UE terminal (steps  310 ,  314 ). 
     Second Network Mode 
       FIG. 16  is a sequence diagram illustrating a location network operating in the MT-LR mode in which the client terminal  111  is the requesting terminal, the mobile terminal  105  is the target UE which is currently staying in its home network A, and the home GMLC  102  of target UE  105  maintains its privacy profile and location report. Client terminal  111  initially transmits a location request (event  801 ) to the home GMLC  112 . In response, the GMLC  112  executes steps  201 ˜ 203  ( FIG. 12A ) to perform a client check (event  802 ). Since the privacy information of the target UE is not available, the GMLC  112  passes through steps  204 ,  205  and executes steps  241  and  242  ( FIG. 12C ) to acquire the identifier of GMLC  102  (events  803 ,  804 ) from the home HLR/HSS  106  of the target UE  105  and sends a location request to the GMLC  102  (event  805 ). 
     In response to the location request from GMLC  112 , the GMLC  102  passes through steps  201 ,  204  and executes steps  206 ˜ 211  to perform a first privacy check and information type check (events  806 ,  807 ) and executes steps  212 ˜ 215  to obtain the identifier of SGSN/MSC  103  from HLR/HSS  106  (events  808 ,  809 ) and transmit a notification/verification message or a location request (event  810 ) to the SGSN/MSC  103 . SGSN/MSC  103  performs its routine (event  811 ) and returns a location report or a verification report to the GMLC  102  (event  812 ). In response, the GMLC  102  executes steps  216 ˜ 218  and then performs a second privacy check on the received location information (steps  219 ,  220 ,  221 , event  813 ). The location report is then transmitted (step  222 , event  814 ) to the requesting GMLC  112 , which receives this location report (step  242 ,  FIG. 12C ) and repeats it to the client terminal  111  (step  222 ,  FIG. 12A , event  815 ). 
     Third Network Mode 
       FIG. 17  is a sequence diagram illustrating a location network operating in the MT-LR mode in which the client terminal  111  is the requesting terminal, the mobile terminal  105  is the target UE which is currently visiting the external network C, and the home GMLC  102  of target UE  105  maintains its privacy profile and location report. Client terminal  111  initially transmits a location request  901  to the home GMLC  112 . In response, the GMLC  112  executes steps  201 ˜ 203  ( FIG. 12A ) to perform a client check  902 . Since the privacy information of the target UE is not available, the GMLC  112  passes through steps  204 ,  205  and executes steps  241  and  242  ( FIG. 12C ) to acquire the identifier of GMLC  102  (events  903 ,  904 ) from the home HLR/HSS  106  of the target UE  105  and sends a location request  905  to the GMLC  102 . 
     In response to the location request from GMLC  112 , the GMLC  102  passes through steps  201 ,  204  and executes steps  206 ˜ 211  to perform a first privacy check  906  and information type check  907  and executes steps  212 ˜ 215  to obtain the identifiers of SGSN/MSC  123  and GMLC  122  from HLR/HSS  106  (events  908 ,  909 ). On receiving these identifiers, the GMLC  102  executes step  215  and transmits a notification/verification request or a location request  910  to the GMLC  122 . Each of these requests contains the identifiers of SGSN/MSC  123  and GMLC  122 . In response to the request message from the GMLC  102 , the GMLC  122  passes through step  201  to step  251  ( FIG. 12D ) to repeat the received request message to the SGSN/MSC  123 . SGSN/MSC  123  performs its routine  911  and returns a location report or a verification report  912  to the GMLC  112 , which repeats it to the GMLC  102  (step  252 ,  FIG. 12D ). 
     GMLC  102  executes steps  216 ˜ 218  for verification and then performs a second privacy check  913  on the received location information (steps  219 ,  220 ,  221 ). The location report  914  is then transmitted (step  222 ) to the requesting GMLC  112 , which repeats this location report  915  (steps  242 ,  222 ) to the client terminal  111 . 
     Fourth Network Mode 
       FIG. 18  is a sequence diagram illustrating a location network operating in the MT-LR mode in which the client terminal  101  is the requesting terminal, the mobile terminal  105  is the target UE which is currently visiting the external network B, and the home GMLC  102  of target UE  105  maintains its privacy profile and location report. Client terminal  101  initially transmits a location request  1001  to the home GMLC  102 . In response, the GMLC  102  executes steps  200  through  211  ( FIG. 12A ) to perform a client check (event  1002 ), a privacy check  1003  and an information type check  1004 . Since the target UE is visiting the network of SGSN/MSC  113 , the GMLC  102  acquires the identifiers of SGSN/MSC  113  and GMLC  112  (events  1005 ,  1006 ) from HLR/HSS  106  when its has executed steps  212  and  213 , and sends a notification/verification or location request message (each containing the acquired node identifiers) to the GMLC  112  (event  1007 ). GMLC  112  executes steps  201 ,  251  ( FIG. 12D ) to repeat the received request message to the SGSN/MSC  113 . 
     SGSN/MSC  113  executes steps  300 ,  320 ˜ 323  of  FIG. 13  in response to the notification/verification message from the GMLC  112  or executes steps  300 ,  321 ˜ 332  in response to the location request  1008  from the GMLC  112  and sends a location report or a verification report  1009  to the GMLC  112 . GMLC  112  executes step  252  ( FIG. 12D ) to repeat the received report message to the GMLC  102 . 
     If verification report is received, the GMLC  102  checks to see if the target UE has verified the request (step  217 ). If the request is verified, the GMLC  102  performs a second privacy check  1010  on the current or last known location information by executing steps  219  to  221  and transmits location information  1011  to the client terminal  101 . 
     Fifth Network Mode 
       FIG. 19  is a sequence diagram illustrating a location network operating in the MT-LR mode in which the client terminal  111  is the requesting terminal, the mobile terminal  105  is the target UE which is currently visiting the external network B, and the home GMLC  102  of target UE  105  maintains its privacy profile and location report. Client terminal  111  initially transmits a location request  1101  to the home GMLC  112 . In response, the GMLC  112  executes steps  201 ˜ 203  ( FIG. 12A ) to perform a client check  1102 . Since the privacy information of the target UE is not available, the GMLC  112  passes through steps  204 ,  205  and executes steps  241  and  242  ( FIG. 12C ) to acquire the identifier of GMLC  102  (events  1103 ,  1104 ) from the home HLR/HSS  106  of the target UE  105  and sends a location request  1105  to the GMLC  102 . 
     In response to the location request from GMLC  112 , the GMLC  102  passes through steps  201 ,  204  and executes steps  206 ˜ 211  to perform a first privacy check  1106  and information type check  1107  and executes steps  212 ˜ 215  to obtain the identifiers of SGSN/MSC  113  and GMLC  112  from HLR/HSS  106  (events  1108 ,  1109 ). On receiving these identifiers, the GMLC  102  executes step  215  and transmits a notification/verification request or a location request  1110  to the GMLC  112 . Each of these requests contains the identifiers of SGSN/MSC  113  and GMLC  112 . In response to the request message from the GMLC  102 , the GMLC  112  passes through step  201  to step  251  ( FIG. 12D ) to repeat the received request message to the SGSN/MSC  113 . SGSN/MSC  113  performs notification/verification or location estimation routine  1111  and returns a location report or a verification report  1112  to the GMLC  112 , which repeats the report to the GMLC  102  (step  252 ,  FIG. 12D ). 
     GMLC  102  executes steps  216 ˜ 218  for verification and then performs a second privacy check  1113  on the received location information (steps  219 ,  220 ,  221 ). If the privacy check result is favorable, the location report  1114  is transmitted from the GMLC  102  (step  222 ) to the requesting GMLC  112 , which repeats this location report  1115  to the client terminal  111  (steps  242 ,  222 ). 
     Sixth Network Mode 
       FIG. 20  is a sequence diagram illustrating a location network operating in the MT-LR mode in which the client terminal  101  is the requesting terminal and the mobile terminal  105  is the target UE which is staying in the home network A. The PPR  107  is connected to the GMLC  102 . The privacy profile and location report of target UE  105  are maintained in the PPR  107 . Client terminal  101  initially transmits a location request  1201  to the home GMLC  102 . In response, the GMLC  102  performs a client check  1202  (steps  202 ˜ 203 ) and sends an authorization request  1203  to the PPR  107  (steps  204 ,  224 ). PPR  107  performs a first privacy check  1204  and a location information type check  1205  and returns a report message  1206 . Alternatively, information type check  1207  may be provided by the GMLC  102 . 
     GMLC  102  analyzes the received report message  1206  (step  225 ) and executes steps  212  and  213  to send an enquiry message  1208  to HLR/HSS  106  to acquire the identifier  1209  of SGSN/MSC  103  and transmits a notification/verification message or a location request message  1210  to the SGSN/MSC  103 . 
     SGSN/MSC  103  performs a notification/verification process or location estimation process  1211  and returns a location report or verification report message  1212  to the GMLC  102 . 
     In response to the report message, the GMLC  102  sends an authorization request  1213  to the PPR  107  (steps  216 ,  217 ,  218 ,  261 ) to authorize it to perform a second privacy check  1214  and then analyzes a privacy check report  1215  from the PPR  107 , indicating a result of the second privacy check (step  262 ). If the result of the privacy check is favorable, the GMLC  102  repeats the location information  1216  received from the SGSN/MSC  103  to the client terminal  101 . 
     Seventh Network Mode 
       FIG. 21  is a sequence diagram illustrating a location network operating in MT-LR mode in which the client terminal  111  is the requesting terminal and the mobile terminal  105  is the target UE which is located in the home network A. The privacy profile and location report of target UE  105  are maintained in the PPR  107  connected to the GMLC  102 . Client terminal  111  initially transmits a location request  1301  to the home GMLC  112 . In response, the GMLC  112  performs a client check  1302  (steps  202 ˜ 203 ) and transmits an enquiry message  1303  to the HLR/HSS  106  to acquire the identifier  1304  of the home GMLC  102  of the target UE. Using the acquired identifier, the GMLC  112  sends a location request  1305  to the GMLC  102 . GMLC  102  responds to the location request by transmitting an authorization request  1306  to the PPR  107 . PPR  107  performs a first privacy check  1307  and an information type check  1308  and returns a report message  1309  to the GMLC  102 . 
     GMLC  102  analyzes the received report (step  225 ) and executes steps  212  and  213  to acquire the identifier of SGSN/MSC  103  from HLR/HSS  106  (events  1310 ,  1311 ) and transmits a notification/verification message or a location request message  1312  to the SGSN/MSC  103 . 
     SGSN/MSC  103  performs a notification/verification process or location estimation process  1313  and returns a location report or verification report message  1314  to the GMLC  102 . 
     In response to the report message  1314 , the GMLC  102  sends an authorization request  1315  to the PPR  107  (steps  216 ,  217 ,  218 ,  261 ) to authorize it to perform a second privacy check  1316  and analyzes a privacy check report  1317  from the PPR  107  (step  262 ). If the result of the privacy check is favorable, the GMLC  102  sends the location information  1319  received from the SGSN/MSC  103  to the client terminal  101 . 
     Eighth Network Mode 
       FIG. 22  is a sequence diagram illustrating a location network operating in the MT-LR mode in which the client terminal  111  is the requesting terminal and the mobile terminal  105  is the target UE which is visiting the external network C. The privacy profile and location report of target UE  105  are maintained in the PPR  107  connected to the GMLC  102 . Client terminal  111  transmits a location request  1401  to the home GMLC  112 . In response, the GMLC  112  performs a client check  1402  and transmits an enquiry message  1403  to the HLR/HSS  106  to acquire the identifier  1404  of the home GMLC  102  of the target UE. Using the acquired identifier, the GMLC  112  sends a location request  1405  to the GMLC  102 . GMLC  102  responds to the location request by transmitting an authorization request  1406  to the PPR  107 . PPR  107  performs a first privacy check  1407  and an information type check  1408  and returns a report message  1409  to the GMLC  102 . 
     GMLC  102  acquires the identifiers of SGSN/MSC  123  and GMLC  122  from HLR/HSS  106  (events  1410 ,  1411 ) and transmits a notification/verification message or a location request message  1412  to the SGSN/MSC  123  via the GMLC  122 . 
     SGSN/MSC  123  performs a notification/verification process or location estimation process  1413  and returns a location report or verification report message  1414  to the GMLC  102  via the GMLC  122 . In response to the report message  1414 , the GMLC  102  sends an authorization request  1415  to the PPR  107  to authorize it to perform a second privacy check  1416  and analyzes a privacy check report  1417  from the PPR  107 . If the result of the privacy check is favorable, the GMLC  102  sends the location information  1418  received from the SGSN/MSC  123  to the GMLC  112 , which sends location information  1419  to the client terminal  111 . 
     Ninth Network Mode 
       FIG. 23  is a sequence diagram illustrating a location network operating in the MT-LR mode in which the client terminal  101  is the requesting terminal and the target UE  105  is visiting the external network B. The privacy profile and location report of the target UE are maintained in the PPR  107  connected to the GMLC  102 . Client terminal  101  transmits a location request  1501  to the home GMLC  102 . In response, the GMLC  102  performs a client check  1502  and transmits an authorization request  1503  to the PPR  107 . PPR  107  performs a first privacy check  1504  and an information type check  1505  and returns a report message  1506  to the GMLC  102 . 
     GMLC  102  acquires the identifiers of SGSN/MSC  113  and GMLC  112  from HLR/HSS  106  (events  1507 ,  1508 ) and transmits a notification/verification message or a location request message  1509  to the SGSN/MSC  113  via the GMLC  112 . 
     SGSN/MSC  113  performs a notification/verification process or location estimation process  1510  and returns a location report or verification report message  1511  to the GMLC  102  via the GMLC  112 . In response to the report message  1511 , the GMLC  102  sends an authorization request  1512  to the PPR  107  to authorize it to perform a second privacy check  1513  and analyzes a privacy check report  1514  from the PPR  107 . If the result of the privacy check is favorable, the GMLC  102  sends location information  1515  received from the SGSN/MSC  113  to the client terminal  101 . 
     Tenth Network Mode 
       FIG. 24  is a sequence diagram illustrating a location network operating in MT-LR mode in which the client terminal  111  is the requesting terminal and the target UE  105  is visiting the external network B. The privacy profile and location report of target UE  105  are maintained in the PPR  107  connected to the GMLC  102 . Client terminal  111  transmits a location request  1601  to the home GMLC  112 . In response, the GMLC  112  performs a client check  1602  and transmits an enquiry message  1603  to the HLR/HSS  106  to acquire the identifier  1604  of the home GMLC  102  of the target UE. Using the acquired identifier, the GMLC  112  sends a location request  1605  to the GMLC  102 . GMLC  102  responds to the location request by transmitting an authorization request  1606  to the PPR  107 . PPR  107  performs a first privacy check  1607  and an information type check  1608  and returns a report message  1609  to the GMLC  102 . 
     GMLC  102  acquires the identifiers of SGSN/MSC  113  and GMLC  112  from HLR/HSS  106  (events  1610 ,  1611 ) and transmits a notification/verification message or a location request message  1612  to the SGSN/MSC  113  via the GMLC  112 . 
     SGSN/MSC  113  performs a notification/verification process or location estimation process  1613  and returns a location report or verification report message  1614  to the GMLC  102  via the GMLC  112 . 
     In response to the report message  1614 , the GMLC  102  sends an authorization request  1615  to the PPR  107  to authorize it to perform a second privacy check  1616  and analyzes a privacy check report  1617  from the PPR  107 . If the result of the privacy check is favorable, the GMLC  102  sends the location report  1618  received from the SGSN/MSC  113  to the GMLC  112  which transmits the location information  1619  to the client terminal  111 .