KR100799572B1 - Extended proxy-call session control function block in next generation network based on IP Multimedia Subsystem and mobility management method using the same - Google Patents

Abstract

The present invention relates to an extended proxy call session control function block and a mobility management method using the same in an IMS-based next generation network. The method includes an extension for a mobile terminal to perform a proxy call session control function and manage mobility of a mobile terminal. Sending a registration request message for the S-CSCF block to an Extended Proxy-Call Session Control Function (hereinafter, P-CSCF +) block; Storing, by the P-CSCF + block, location information of the mobile terminal, and transmitting the registration request message to the S-CSCF block; And performing registration by the S-CSCF block with respect to the mobile terminal based on the received registration request message. According to the present invention, it is possible to easily provide a location management function for a mobile terminal in the next generation network based on IMS without introducing an additional protocol.

Description

Extended proxy-call session control function block in next generation network based on IP Multimedia Subsystem and mobility management method using the same}

1 is an IMS-based next generation network structure basically assumed in the present invention.

2 is a block diagram illustrating a configuration of an extended proxy call session control function block according to an embodiment of the present invention.

3 is a block diagram for achieving location management using the P-CSCF + block according to the present invention in the existing IMS-based next-generation network.

4 to 6 illustrate a mobility management method of a mobile terminal according to an embodiment of the present invention.

7 illustrates a method in which a counterpart terminal performs packet transmission or session establishment for a mobile terminal according to an embodiment of the present invention.

The present invention complements the low-level mobility management function basically provided by IMS in the next generation network based on IP Multimedia Subsystem (IMS), thereby enabling an efficient mobility management support without introducing additional mobility management technology. It is about the procedure.

Next-generation networks are wired and wireless integrated, and are being developed under the names NGN (Next Generation Network) and B3G (Beyond 3rd Generation) in the wired and wireless fields, respectively. Next-generation networks have different characteristics from existing wired / wireless networks. Its main features are as follows. First, next-generation networks are based on IP-based core networks. Second, various access networks including new access networks as well as existing wired / wireless networks are connected through the IP-based core network, and users are provided with seamless services through these various access networks. In such a different network environment, an efficient mobility management technology for seamless service to a user is regarded as one of the core technologies in the next generation network.

Another feature of the next generation network is that the IP-based network operates using IP-based call control protocols such as IMS, rather than conventional No7-based signaling. IMS is standardized in 3GPP as the basic protocol for call control in IP-based next generation networks. IMS is basically based on the Session Initiation Protocol (SIP) developed by the Internet Engineering Task Force (IETF) and is the most powerful protocol for call control in next generation networks. IMS basically provides the personal mobility provided by SIP and provides a low level of terminal mobility.

One of the technologies under consideration for mobility management in next-generation networks is the Mobile IP standardized by the IETF. Mobile IP supports mobility at the network layer by adding a mobile IP protocol to a terminal and adding an agent (eg, Home Agent, Foreign Agent) to support mobility in a network. However, the mobile IP may be a burden on the operator because it requires the addition of new protocols and agents to the terminal and network for mobility management. In particular, there is a problem that inefficiency due to duplication of functions may occur when other layers such as IMS already support some of mobility management functions.

An object of the present invention is to provide an extended proxy call session control function block and an mobility management method using the same, which efficiently manage mobility in the next generation network based on IMS without introducing additional mobility management protocol.

In order to achieve the above technical problem, the mobility management method in an IMS-based next generation network according to the present invention includes an extended proxy control function in which a mobile station performs a proxy call session control function and manages mobility of a mobile terminal. Call Session Control Function (P-CSCF +) block to transmit a registration request message for a Serving Call Session Control Function (S-CSCF) block; Storing, by the P-CSCF + block, location information of the mobile terminal, and transmitting the registration request message to the S-CSCF block; And performing registration by the S-CSCF block with respect to the mobile terminal based on the received registration request message.

In order to achieve the above technical problem, the mobility management method in an IMS-based next-generation network according to the present invention includes an extended proxy control function for performing a proxy call session control function and managing mobility of the mobile terminal after the mobile terminal moves. Obtaining information of an Extended Proxy-Call Session Control Function (hereinafter, P-CSCF +) block; And registering, by the mobile terminal, the changed location information with the P-CSCF + block.

According to another aspect of the present invention, there is provided a mobility management method in an IMS-based next-generation network according to the present invention, in which an extended proxy control for performing a proxy call session control function and managing mobility of a mobile terminal after the mobile terminal moves. Obtaining information of an Extended Proxy-Call Session Control Function (hereinafter, P-CSCF +) block; And when the mobile terminal detects a change in the P-CSCF + block based on the obtained information, transmits a registration request message to a serving call session control function block to the P-CSCF + block. It includes a step.

In order to achieve the above technical problem, a mobility management method in an IMS-based next generation network according to the present invention includes an interrogating-call session control function (hereinafter referred to as I-CSCF) in a home network of a mobile terminal. A serving call session control function (S-CSCF) block and a home subscriber server (S-CSCF) block in which a block is queried from a counterpart terminal for the location of the mobile terminal and manages the mobile terminal. Querying the location of the mobile terminal; Location of the mobile terminal to the Extended Proxy-Call Session Control Function (P-CSCF +) block in which the S-CSCF block and the HSS perform mobility management and proxy call session control functions of the mobile terminal. Querying; Transmitting, by the P-CSCF + block, the location information of the mobile terminal to the counterpart terminal; And communicating by the counterpart terminal with the mobile terminal based on the location information.

In order to achieve the above technical problem, an extended proxy call session control function block in an IMS-based next generation network according to the present invention includes a P-CSCF unit performing a proxy call session function; A location manager for managing mobility for the mobile terminal; And a location database in which location information of the mobile terminal obtained by the location manager is stored. Preferably, the location manager performs location information acquisition, location information registration, location information update and packet forwarding of the mobile terminal. Preferably, the location manager stores the location information of the mobile terminal in the location database when the mobile terminal makes a registration request for a serving call session control function block or the mobile terminal has a location change. Preferably, the location manager, in response to the query of the serving call session control function block, provides the location information of the mobile terminal to the counterpart terminal to initiate communication with the mobile terminal.

Hereinafter, a method and an apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

The present invention is basically used for call control in the next generation network and expands its functionality in terms of mobility management, which provides a low level of mobility, thereby providing an efficient mobility management structure and procedure in the next generation network without introducing an additional mobility management protocol. Its purpose is to.

1 is an IMS-based next generation network structure basically assumed in the present invention. In FIG. 1, the location of a proxy-call session control function (hereinafter, P-CSCF) block may vary depending on an operator, but in the present invention, a typical IP-CAN (IP-Connectivity Access Network) GPRS (General) Referring to FIG. 1, it is assumed that each IP-CAN has one P-CSCF block. That is, although one P-CSCF block may support multiple IP-CANs or multiple P-CSCF blocks may support one IP-CAN, this may be equally supported through simple modification of the method proposed by the present invention. .

Reference numeral 100 represents an IP based core network.

Reference numeral 101 is a serving call session control function (Serving-CSCF: S-CSCF) block that provides an IMS service. The S-CSCF block is a server that controls a user's session mainly in a home subscriber server (HSS), and then downloads and stores the user's subscriber information, and plays a role as a proxy server and a user agent. . In addition, it provides the user with information related to the service resource along with the interaction with the service platform to provide the service.

Reference numeral 102 denotes an interrogating-CSCF block (hereinafter referred to as I-CSCF) block for mediation between a P-CSCF block and an S-CSCF block. The I-CSCF block is the first point of access to the user's home network, and there may be several in one network domain. The main role of the I-CSCF block is briefly described as follows. The I-CSCF block receives an address of the S-CSCF block that performs SIP registration of user equipment such as a mobile terminal from the HSS and allocates an S-CSCF block to be in charge of actual registration. In addition, the SIP message received from the other network is routed to the S-CSCF block.

Reference numeral 103 is a home subscriber server, and manages user information.

Reference numerals 111, 112, and 113 denote an IP-based access network.

Reference numerals 121, 122, and 123 denote P-CSCF blocks for supporting IMS located in IP-CAN-1 111, IP-CAN-2 112, and IP-CAN-3 113, respectively. The P-CSCF block is the first point of the user's access to the IP multimedia network and exists in the same domain as the Gateway GPRS Support Node (GGSN). The address of the P-CSCF block is delivered to the user device by PDP context activation using the "Local CSCF Discovery" mechanism. The main role of the P-CSCF block is briefly described as follows. The SIP registration request message received from the user equipment is transferred to the I-CSCF block by referring to the home domain of the user equipment. In addition, the SIP message received from the user equipment is delivered to the S-CSCF block using the address of the S-CSCF block received through the registration procedure. In addition, the user equipment requests or responds to the SIP message.

Reference numeral 131 denotes a mobile terminal provided with a service through one or more IP-CAN.

In FIG. 1, IP-CAN-1 111, IP-CAN-2 112, and IP-CAN-3 113 having various wired / wireless access technologies are connected through an IP-based core network 100. . In order to support the IMS service, the S-CSCF block 101 is implemented in the IP-based core network 100, and the P-CSCF blocks 121-123 are implemented in each IP-CAN 111-113, and the I-CSCF block is implemented. 102 is implemented for interworking between the P-CSCF blocks 121 to 123 and the S-CSCF block 101. The HSS 103 is implemented in the IP based core network 100 as a main database for managing subscriber information.

The registration procedure for the IMS service can be briefly described as follows. First, the mobile terminal 131 having obtained the IP connectivity through the IP-CAN-1 111 discovers the P-CSCF block 121 through the P-CSCF discovery procedure for IMS registration. Request registration to the S-CSCF block 101 in its home network through the CSCF block 121. The P-CSCF block 121 delivers this registration request message to the I-CSCF block 102 of the home network, and the I-CSCF block 102 sends the registration request to the S-CSCF block 101 which will serve the mobile terminal. Pass the message. The S-CSCF block 102 performs registration for the mobile terminal using a registration request message in the mobile terminal. In addition, the S-CSCF block 101 interworks with the HSS 103 for authentication of the subscriber in this registration process.

As shown in FIG. 1, the next generation network based on IMS basically has a simple level of mobility management capability. Therefore, it will be able to use for location management in next generation network. However, the current IMS specification does not support mobility management as a function block for call processing, and the current IMS specification does not cover the case where a mobile terminal moves between different P-CSCFs. There is a problem to use as a location management technology for the next generation based network.

Accordingly, the present invention provides a general mobility management function in an IMS-based network by introducing an extended P-CSCF (P-CSCF +) as shown in FIG. 2 to solve the above two problems.

FIG. 2 is a block diagram illustrating a configuration of an extended proxy-call session control function (hereinafter referred to as P-CSCF +) block according to an embodiment of the present invention. Referring to FIG. 2, the P-CSCF + block 200 according to the present embodiment includes an existing Existing P-CSCF (P-CSCF) block 201, a location manager 202, and a location database. data base) 203. That is, the P-CSCF + block 200 according to the present embodiment adds the location manager 202 and the location database 203 to the existing P-CSCF block 201 that performs the aforementioned proxy call session control function. will be.

The P-CSCF unit 201 performs the same proxy call session control function as that of the existing P-CSCF block. Since the functions of the existing P-CSCF block have already been described, they will be omitted below. The location manager 202 manages mobility for mobile terminals in the same P-CSCF + area. The location information of the mobile terminal transmitted through the location manager 202 is managed using the location database 203. That is, the location database 203 stores location information about the mobile terminal in a single P-CSCF + region. The present invention does not consider a specific protocol for the database associated with the location manager 202. That is, various protocols can be used for this function. For example, existing technologies such as mobile IP may be used, in which case additional work for interworking with IMS is required. In addition, the location management function provided in the existing S-CSCF block may be implemented by being distributed to each P-CSCF block. In addition, new protocols may be defined for this function.

3 is a configuration diagram for achieving location management using the P-CSCF + block 200 according to the present invention in the existing IMS-based next-generation network.

Reference numeral 300 denotes a core network based on IP. Reference numeral 301 is a serving call session control function (Serving-CSCF: S-CSCF) block that provides an IMS service, and reference numeral 302 is a relay call session control function (B) for mediation between a P-CSCF block and an S-CSCF block. Interrogating-CSCF: I-CSCF) block.

Reference numeral 303 denotes an HSS for managing user information, respectively.

Reference numerals 311, 312, and 313 denote IP-based access networks.

Reference numerals 321, 322, and 323 are located at IP-CAN-1 311, IP-CAN-2 312, and IP-CAN-3 313, respectively, and are located in addition to the basic P-CSCF functions. Represents a P-CSCF + block that provides functionality for management.

Reference numeral 331 denotes a mobile terminal provided with a service through one or more IP-CAN.

Referring to Figure 3 describes the location management procedure using the IMS service as follows. First, the mobile terminal 331 obtaining IP connectivity through the IP-CAN-1 311 discovers the P-CSCF + block 321 through the P-CSCF discovery procedure for IMS registration, and then the P-CSCF + block 321. It requests a registration to the S-CSCF block 301 in its home network through. The P-CSCF + block 321 forwards this registration request message to the I-CSCF block 302 of the home network, and the I-CSCF block 302 sends the S-CSCF block 301 to service the mobile terminal 331. Pass this registration request message. The S-CSCF block 301 registers the mobile terminal 331 using the registration request message of the mobile terminal 331. In addition, the S-CSCF block 301 interworkes with the HSS 303 for authentication of a subscriber in this registration process.

After the IMS registration, if the mobile station moves within the service area of the P-CSCF + block (i.e., a change of subnet occurs, movement-1), the mobile station changes location information indicating its current location. Register the information in the P-CSCF + block. Here, the example of the location information may be an IP address of the mobile terminal, but is not necessarily limited thereto. This procedure is repeated whenever the subnet of the mobile terminal changes. However, since this movement is a movement within a single P-CSCF +, re-registration for S-CSCF is not performed. If the mobile station moves to another P-CSCF + region (movement-2), the IMS registration procedure is performed as defined in the existing IMS. Subsequently, when moving in the same P-CSCF region (movement-1), as described above, only location registration for the P-CSCF + block is performed. Through this process, the structure proposed in the present invention provides a general mobility management function.

4 illustrates a location registration procedure of a mobile terminal according to an embodiment of the present invention and illustrates a location registration procedure when the mobile terminal is powered on or starts an IMS service. Referring to FIG. 4, the MT 480 represents a mobile terminal, and the AR 482 represents an access router providing a wired / wireless interface at a network end. Referring to FIG. 2, the procedure of FIG. 4 will be described.

In step S400, the MT 480 secures the connectivity for transmitting and receiving IP packets through the IP connectivity with the AR 482 and the P-CSCF + block to support IMS registration for the mobile terminal through the P-CSCF discovery procedure. 484) obtain information.

In step S405, the MT 480 requests registration of the S-CSCF in the P-CSCF + block 484 using the information obtained in the step S400.

In step S410, the location manager 202 of the P-CSCF + block 484 stores the location information of the MT 480 in the location database 203, and the P-CSCF unit 201 of the P-CSCF + block 484. ) Transmits the registration request message of the MT 480 to the I-CSCF block 486 of the home network.

In step S415, the I-CSCF block 486 forwards this registration request message to the S-CSCF block / HSS 488 in charge of the IMS service for the mobile terminal.

In step S420, the S-CSCF block / HSS 488 performs authentication for the mobile terminal through the authentication process and records the relevant information in its database, and if the registration is successfully performed, the ACK for this registration 200 OK corresponding to the I-CSCF block 486 is transmitted.

In step S425, the I-CSCF block 486 sends 200 OK to the P-CSCF + block 484.

In step S430, the P-CSCF + block 484 finally transmits 200 OK to the MT 480.

5 illustrates a location registration procedure of a mobile terminal according to another embodiment of the present invention, and illustrates a location registration procedure when a mobile station changes a subnet within the same P-CSCF + region. Referring to FIG. 5, the MT 580 represents a mobile terminal, and the AR 582 represents an access router providing a wired / wireless interface at a network end. Referring to FIG. 2, the procedure of FIG. 5 will be described.

In step S500, the MT 580, which has moved in the same P-CSCF + region, secures connectivity for transmitting and receiving IP packets through IP connectivity with the AR 582. At this time, it is assumed that information of the P-CSCF + block 584 in service can be obtained through this IP connectivity setting procedure as described in FIG. 4. However, in this case, since the MT 580 has moved within the same P-CSCF + region, there is no change of the P-CSCF + block.

In step S505, the MT 580 registers the changed location information in the P-CSCF + block 584. Here, as an example of the location information, an IP address is mentioned as mentioned above.

In step S510, the location manager 202 of the P-CSCF + block 584 stores the changed location information of the MT 580 in the location database 203. On the other hand, authentication for the mobile terminal for movement in the same P-CSCF + may be omitted using existing records of the P-CSCF +.

6 illustrates a location registration procedure of a mobile terminal according to another embodiment of the present invention, and illustrates a location registration procedure when the mobile terminal moves between P-CSCF + regions. Referring to FIG. 6, the MT 680 represents a mobile terminal, and the AR 682 represents an access router providing a wired / wireless interface at a network end. Referring to FIG. 2, the procedure of FIG. 6 will be described.

In step S600, the MT 680, which has moved between the P-CSCF + regions, secures connectivity for transmitting and receiving IP packets through the IP connectivity setting with the AR 682, and the IMS for the mobile terminal through the P-CSCF discovery procedure. Obtain information about the P-CSCF + block 684 that will support registration. Since the MT 680 can obtain the information of the P-CSCF + block 684 in service through the IP connectivity setting procedure, the MT 680 detects that the P-CSCF + block serving itself has been changed.

In step S605, the MT 680 requests registration of the S-CSCF in the P-CSCF + block 684 using the information obtained in step S400.

In step S610, the location manager 202 of the P-CSCF + block 684 stores the location information of the MT 680 in the location database 203 and the P-CSCF unit 201 of the P-CSCF + block 684. The MT 680 forwards the registration request message to the I-CSCF block 686 of the home network.

In step S615, the I-CSCF block 686 forwards this registration request message to the S-CSCF block / HSS 688 in charge of the IMS service for the mobile terminal.

In step S620, the S-CSCF block / HSS 688 performs authentication for the mobile terminal through the authentication process and records the relevant information in its database, and if the registration is successful, ACK for this registration 200 OK corresponding to the I-CSCF block 686 is transmitted.

In step S625, the I-CSCF block 686 transmits 200 OK to the P-CSCF + block 684.

In step S630, the P-CSCF + block 684 finally transmits 200 OK to the MT 680.

7 illustrates a procedure in which a correspondent terminal performs packet transmission or session establishment for a mobile terminal according to an embodiment of the present invention. In this case, the fixed terminal and the mobile terminal can be used as the counterpart terminal. Referring to FIG. 7, the MT 780 represents a mobile terminal, and the AR 782 represents an access router providing a wired / wireless interface at a network end. In addition, the CT 790 indicates the counterpart terminal to which to forward the packet to the MT (780). Referring to FIG. 2, the procedure of FIG. 7 will be described.

In step S700, the CT 790 queries the I-CSCF block 788 in the home network of the MT 780 for the location of the MT 780.

In step S705, the I-CSCF block 788 queries the S-CSCF block / HSS 788 managing the MT 780 for the location of the MT 780.

In step S710, the S-CSCF block / HSS 786 queries the P-CSCF + block 784, which is currently serving the MT 780, to locate the MT 780 to determine the exact location of the MT 780. do.

In step S715, in response to the query, the P-CSCF + block 784 provides the CT 790 with information about the current location of the MT 780 stored in the location database 203. Here, an example of the information on the current position may be the IP address of the CT 790.

In operation S720, the CT 790 sets up a session with the MT 780 based on the received location information to start communication.

The invention can also be embodied as computer readable code on a computer readable recording medium. Computer-readable recording media include all kinds of recording devices that store data that can be read by a computer system. Examples of computer-readable recording media include ROM, RAM, CD-ROM, magnetic tape, floppy disks, optical data storage devices, and the like, which are also implemented in the form of carrier waves (for example, transmission over the Internet). Include. The computer readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion. In addition, functional programs, codes, and code segments for implementing the present invention can be easily inferred by programmers in the art to which the present invention belongs.

Such a method and apparatus of the present invention have been described with reference to the embodiments shown in the drawings for clarity, but these are merely exemplary, and various modifications and equivalent other embodiments are possible to those skilled in the art. Will understand. Therefore, the true technical protection scope of the present invention will be defined by the appended claims.

The present invention has the following advantages over the existing FMIPv6 by having the structure and procedure as described above. First, the present invention can easily provide a location management function for a mobile terminal without introducing an additional protocol for location management by using the registration procedure of IMS basically provided in the next generation network based on IMS. Second, since the present invention does not introduce additional mobility management technology, it is possible to prevent redundancy with the mobility management function in the existing IMS due to the introduction of additional protocols, and thus, it is possible to simply implement the protocol stack of the terminal and network elements.

Claims (9)

The mobile terminal performs a proxy call session control function and serves a serving call session control function (Serving-Call) to an extended proxy control function (P-CSCF +) block that manages mobility of the mobile terminal. Session Control Function: Hereinafter, transmitting a registration request message for the S-CSCF) block; Storing, by the P-CSCF + block, location information of the mobile terminal, and transmitting the registration request message to the S-CSCF block; And And registering, by the S-CSCF block, the mobile terminal based on the received registration request message. After the mobile terminal moves, obtaining information of an extended proxy-call session control function (hereinafter referred to as P-CSCF +) block that performs a proxy call session control function and manages mobility of the mobile terminal; And And registering, by the mobile terminal, the changed location information with the P-CSCF + block. After the mobile terminal moves, obtaining information of an extended proxy-call session control function (hereinafter referred to as P-CSCF +) block that performs a proxy call session control function and manages mobility of the mobile terminal; And On the basis of the obtained information, if the mobile terminal detects a change in the P-CSCF + block, it transmits a registration request message to a Serving Call Session Control Function block to the P-CSCF + block. A mobility management method in an IMS-based next generation network, characterized in that it comprises a step. Serving call session control for interrogating-call session control function (hereinafter referred to as I-CSCF) block in the home network of a mobile terminal inquiring about the position of the mobile terminal from a counterpart terminal and managing the mobile terminal Querying a location of the mobile terminal to a serving (S-CSCF) block and a home subscriber server (HSS); Location of the mobile terminal to the Extended Proxy-Call Session Control Function (P-CSCF +) block in which the S-CSCF block and the HSS perform mobility management and proxy call session control functions of the mobile terminal. Querying; Transmitting, by the P-CSCF + block, the location information of the mobile terminal to the counterpart terminal; And And the counterpart terminal communicating with the mobile terminal based on the location information. A P-CSCF unit performing a proxy call session control function; A location manager for managing mobility for the mobile terminal; And Extended proxy call session control function block in an IMS-based next generation network, characterized in that it comprises a location database that stores the location information of the mobile terminal obtained by the location manager. The method of claim 5, wherein the location manager Extended proxy call session control function block in an IMS-based next-generation network, characterized in that the mobile station acquires location information, registers location information, updates location information, and forwards packets. The method of claim 5, wherein the location manager In the IMS-based next generation network, when the mobile terminal requests registration for a serving call session control function block or the mobile terminal changes its location, the mobile terminal stores location information of the mobile terminal in the location database. Proxy call session control function block. The method of claim 5, wherein the location manager In response to a query of a serving call session control function block, providing location information of the mobile terminal to a counterpart terminal to initiate communication with the mobile terminal. A computer-readable recording medium containing a program for executing the method according to any one of claims 1 to 4.

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