Roaming support method and system in UMTS

[Technical Field] The present invention relates to the field of mobile communication. More specifically, the present invention is directed to the handling of connection or connection related parameters when the connection involves more than one network.

Background Techniques Recent or planned network architectures provide various service models for roaming subscribers. When the user is roaming, the subscriber is registered and a control means or control function that handles connection control such as call state control (such as serving CSCF (call state control function) in network architectures based on Release 2000). ) Is still located on the home network. In such a home service model, it is important to pass various kinds of information from the visited network to the home network for proper connection control.

[0003] For example, if the serving control function does not have all the necessary information about, for example, the service class or billing rate, the control function will make a call from a roaming subscriber to another device or user. Such connections may be improperly handled or charged.

[Disclosure of the Invention] The present invention provides a system and a method capable of appropriately handling or handling a connection such as a call even when a subscriber should be attached to a visited network. According to certain features of the present invention, a communication system defined in the claims is provided. According to another feature of the present invention, the method specified in the claim of the method is provided.

[0005] More specifically, the present invention comprises at least one first network element that can be attached to the visited first network, which can be connected to the second network element of the visited first network. This second network element can be directed to a communication method and / or communication system that allows access to a third network element located in the second network. The first network element sends the first message to the second network element so that it either registers with the first network or is connected to the third or fourth network element of the visited first network. The second network element sends a second message to the third network element, which is related to the handling or processing of connections from the first network element to the fourth network element, or of the first network. Yet another network element contains additional information related to the address of yet another network element or an identifier that identifies it, said yet another network element comprises a database consisting of information related to the handling or processing of connections to the fourth network element. Can include or access it. The third network element uses that additional information to handle the connection, process one or more connection-related functions, or access yet another network element, or store additional information. And supply it on demand. The message is particularly preferably sent as a Session Initiation Protocol (SIP) protocol message.

[0006] In general, the present invention preferably transfers service information and / or other information from a visited network to a home network in the case of a home service model in which call control, such as call state control, is handled in the home network. To do. According to a preferred feature of the present invention, the visited network provides a proxy function, such as a proxy call state control function (CSCF), which is a home network, preferably a serving control means or function, such as a serving CSCF. Alternatively, information can be passed to a subscriber serving function or means such as HSS (Home Subscriber Server).

[0007] According to the preferred features of the present invention, problems associated with properly handling or handling the subscriber's connection during roaming are eliminated. For example, the present invention can provide appropriate billing or other call control when a roaming subscriber calls a destination within the visited network, such as the local PSTN (Public Switched Telephone Network). Controls such as proxy functions in the visited network (eg, proxy CSCF) because the home network usually does not know the level of detail information about the local number and / or logical name and / or alias used in the visited network. The means or function is configured to add information about the called local destination according to one embodiment of the invention. For example, the additional information can indicate the billing rate and format of the destination. A proxy server or function can add this information on a call basis, for example, when a visiting subscriber calls through the proxy server to a local destination on the visited network.

[0008] According to another embodiment of the invention, the proxy server or function is a visiting network where a home network serving control function can ask for information about the destination (eg, billing rate, destination format, etc.). You can add pointers to local services or service elements. Instead of adding such a pointer on a call basis, i.e., adding it to each call notification, a pointer to a local service element with that information about the destination in the visited network can also be passed through during the registration phase.

[0009] The structures and methods according to the invention also provide the ability to perform other services such as blocking calls in the home network based on information received from the visited network. For example, when a home network call control function or means receives call blocking information that defines, for example, blocking an international call that is entered and exited by a user or company, for example, a roaming subscriber makes an international call. When requesting a visited network call control function or means to initiate a connection (the visited network call control function or means makes such a request to the home network before establishing such a call. The home network call control function or means (report to the serving control function) requires the visited network control function or means (eg, the visiting network's proxy server) not to establish a connection. It is preferable that the signaling information (message) to be transmitted is secured and authenticated between different networks.

[0010] FIG. 1 shows a mobile terminal, eg, a mobile network element 1 such as a mobile phone, from a home network in which it is registered as a subscriber to another network ( An embodiment of the present invention in a state of roaming to a visited network) is shown. The visited network comprises yet another network element 3, which in this embodiment is a control means or function such as a proxy CSCF (Call State Control Function). This function, or means 3 to perform this function, and other network elements are described, for example, in 3GPP TR23.821 v1.0.0 (eg, accessible via the Internet www.3gpp.org). The boundary between the visited network and the home network is indicated by the dashed line 4. The home network comprises a serving CSCF6 in which subscribers of network element 1 are registered and call state control including, for example, billing is handled.

[0011] When the mobile network element 1 is required to be connected to another network element registered in the visited network, the network element 1 may refer to another network element by, for example, a name, a number, or another identifier. Send the identifying message 2 to proxy element 3. This message is preferably a protocol message. In a preferred embodiment, the protocol message is a SIP (Session Initiation Protocol) word indicating the name and / or number of the called party. This protocol word is a SIP: Invite message.

[0012] The proxy means 3 provides additional service classes, such as payphones, billing information, such as rates, etc., that are mapped to the subscriber identification (eg, name or number) of the subscribers of the visited network. It has or can access a table containing various information. Further, does the proxy means 3 include network or network element related information such as time zone, visiting network or network element service capability, and service interworking information for visiting network and home network collaboration? , Or you can access it. Upon receiving message 2, proxy means 3 uses the identification (name or number) contained in message 2 to look up additional information or parameters stored for the called party, and Send message 5 to the serving function or means 6 of the home network. In addition, information related to the visited network or network element may be included in message 5 in addition to or separately from it.

Message 5 is a protocol word, preferably SIP: Inbyte, which, in this case, is a network, in addition to a name and / or number or other identifier that identifies the party to which the connection should be established. Contains additional parameters or information necessary to properly handle or handle the connection from element 1 to the called party. The name and / or number or other identifier contained in message 5 may be the same information as the information contained in message 2, or may be derived from or from other information. For example, when a call repetition request is sent in message 2, this call repetition request may for example, using a database that stores the last called number, etc., or the name of the party connection should be established in other Can be converted to an identifier of.

[0014] In the example shown here, the additional information included in the message 5 is "service class: payphone" and "billing information: rate". Therefore, service means 6 has sufficient information to properly control, handle or process the call, including properly imposing charges for the connection. This structure ensures proper functioning of the network and relieves control means 6 from the burden of fixed storage of information about all network elements of all other networks that allow roaming of its subscribers. Each network to be visited sends additional information that identifies or characterizes the party or device to which network element 1 wishes to be connected, or additional information related to the visited network or the network elements within it message 5. It may have one or more proxy means 3 that can be added to.

[0015] Therefore, the structure of the communication system shown in FIG. 1 is a visited network on a call-by-call basis such that the parameter of the called person or visited network is directly included in the message 3 transmitted from the network element 3. Service information can be transferred from to the home network. FIG. 2 shows yet another embodiment of the invention in which the proxy means 3 stores a pointer to a local service element 8 of the visited network. This local service element 8 is or comprises a database in which information and / or parameters for the subscribers of the visited network are stored. This information or parameter preferably includes information such as service class, eg payphone, and billing rate, eg business rate or personal rate. In addition, information related to the visited network or network element may be stored in the database of service element 8. This information includes, for example, time zones, service capabilities of visited networks or network elements, and service interworking information for visiting networks and home network collaboration. Such a structure reduces the proxy means 3 from storing and accessing its own database, and thus reduces the storage and processing capacity requirements of the proxy means 3.

[0016] In the case of FIG. 2, when the network element 1 such as the mobile user telephone wishes to be connected to another network element registered in the visited network, for example, a subscriber or a host, the first is As a step, message 2 is sent to proxy means 3 as in the case of FIG. 1, which is an identifier (callee's name and / or number) for identifying the called network element or called person. including. Upon receiving message 2, proxy means 3 responds by sending message 7 to service entity 6 on the home network of network element 1. Like message 2, message 7 is preferably a SIP protocol protocol message, such as SIP: Inbyte Message. However, the proxy means 3 includes, in addition to the callee's name / number, an identifier in message 7, such as a pointer to another network element of the visited network, preferably the local service element 8.

[0017] Separately or in addition, the proxy means 3 may add other information related to the local service element 8 as well as the called number of the visited network or network element. This parameter may be the "key" used when the local service element is queried by means 6. This "key" refers to the actual information about the called number, the visited network and / or the visited network element.

The pointer may be information that identifies the local service element 8, eg, an address sufficient to address the element 8. Local service element 8 includes a database in which the subscriber name or number of the visited network subscriber is mapped to the information or parameters necessary to properly handle or handle the connection to the visited network subscriber. The local service element 8 can also store information specific to the visited network or network element that is accessed from the database using the above "key". After receiving message 7, service means 6 sends message 9 to the local service element 8 identified by the pointer contained in message 7. This message 9 is a request to the local service element 8 requesting that the local service element 8 transmit information about the called party or information related to the visited network or network element. Message 9 may be the question used to determine the price. The message 9 may also include the name and / or number of the called person to identify the called person, and finally the above key. Local service element 8 contains information about the called person to look up its database and respond to message 9 to properly handle the connection to the called person, such as the class of service and billing rate. Message 10 is returned. The message 10 may also include a direct instruction to process the connection. Service means 6 now has sufficient information to properly handle and handle (including billing) the connection between network element 1 and the called party.

In the case of FIG. 2, the transfer of service information from the visited network to the home network first sends message 7 from the visited network to the home network, and then message 9 from the home network to the visited network. Is sent back to access the database of local service element 8, and finally, the call-related information is sent from the visited network to the home network by message 10 in a number of steps. Therefore, the transfer of service information from the visited network to the home network is performed by passing a pointer on a call-by-call basis, that is, the connection between the roaming subscriber of the home network and the subscriber of the visited network. Executed by each call with.

[0020] FIG. 3 shows yet another embodiment in which a pointer to a local service element of the visited network is passed through the registration stage for the transfer of service information from the visited network to the home network. When a subscriber to the home network roams to the visited network and wants to use or activate it by switching on their terminal network element 1, such as a mobile phone or laptop, the network element is " A "register" request is generated, which is sent to the proxy server or function 3 of the visited network. This register request is message 11, SIP: register. The details of SIP are specified, for example, in RFC2543, and this document describes, among other things, "inbyte" and "register" requirements and their handling. The disclosures of this document are included here.

[0021] When the proxy means 3 receives the register (registration) request 11, it sends a message 12 to the home network in response to the register request 11. Message 12 may be "SIP: register" as well. In message 12, in addition to the information identifying the network element 1 to be registered, a pointer to the local service element or database of the visited network as shown in element 8 of FIG. 2 is added. This local service element or database contains information about the network entity or user who has contracted with the visited network, and this information connects to the subscribers of the visited network, as already mentioned with reference to Figures 1 and 2. Includes service class and billing information to build properly. Message 12 is addressed to a home network register that registers such information to access the local service element / database of the visited network. The pointer contained in message 12 may be a local service element such as element 8, an access address of a database, or any other suitable identifier. According to FIG. 3, message 12 is directed to the network element of the home network of network element 1.

The element 13 to which message 12 is directed and the pointer or address to the local service element / database is stored may be the home subscriber server (HSS) 13 of the home network or roaming subscription to the home network. It may be another register that stores location information related to the subscriber, including the person. This register, such as Home Subscriber Server 13, points to the basic subscriber data of network element 1 registered in the visited network in its database and, in connection with it, the local service element or database of the visited network. It remembers a pointer or address, which contains the connection-related information needed to properly handle calls to subscribers on the visited network. After that, when network element 1 requests to be connected to another network element of the visited network, a message such as message 2 (Fig. 2) is sent to proxy dan 3. The proxy means 3 sends a message similar to the message 7 to the service means 6 of the home network. However, in this case, in contrast to message 5 or 7 of FIG. 1 or 2, message 7 contains only a name or number and no additional pointer or address. Service means 6 queries home subscriber server 13 by identifying network element 1 and requesting the transmission of a pointer or address of local service element 8 stored in server 13 in connection with network element 1. .. Server 13 transmits this information to service means 6, as indicated by arrow 14 in FIG. At that time, the service means 6 sends a message 9 to the local service element 8 as shown in FIG. 2, and the local service element 8 responds to the connection-related information such as the service class and the account rate. Returns message 10 containing.

[0023] In another embodiment (not shown), a redirection server is provided in the visited network instead of the proxy means 3. Such a redirection server is described in the SIP specification. In this case, the pointer to S-CSCF6 is stored at the registration stage. When the actual call is set up, Terminal 1 sends an byte message to the redirection server, which in response then returns the S-CSCF address to Terminal 1. The terminal resends the byte message directly to S-CSCF6. In this case, you do not have to expect that billing and other call handling procedures will be performed correctly by S-CSCF6, and that Terminal 1 will send billing information.

[0024] Although the present invention has been described above by primarily referring to embodiments based on the Release 2000 architecture, the present invention is a network architect of different forms such as GPRS-based, UMTS-based, GSM-based networks and the like. It can also be incorporated into the char. Further, although the SIP protocol is preferred, other protocols for forwarding messages such as outgoing or registration messages can also be used. The scope of the present invention is not limited to the preferred embodiments described above, but also includes changes, modifications and omissions of the above-mentioned features.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing a first embodiment of the present invention for transferring service information from a visited network to a home network.

FIG. 2 illustrates yet another embodiment of the present invention in which the transfer of service information from a visited network to a home network is performed on a call basis by transmitting a pointer.

FIG. 3 illustrates another embodiment of the invention that transfers service information from a visited network to a home network so that the pointer is passed through the registration stage.