KR20100121350A - Mobile communication system supporting multi-pcrf and method thereof - Google Patents

Abstract

PURPOSE: A mobile communications system and a method thereof for supporting a plurality of PCRF(Policy and Charging Rule Functions) in order to efficiently implement a network architecture for supporting an IMS QoS are provided to select the object in which a P-CSCF(Proxy-Call Session Control Function) interworks. CONSTITUTION: A plurality of PCRFs(40, 45) determines a PCC(Policy and Charging Control) rule applied to a call requested from a user terminal. A P- CSCF(50) selects the PCRF about the call. GGSNs(Gateway GPRS Support Nodes) supply a QoS(Quality of Service) service according to the PCC rule determined by the PCRF. The GGSN selects the PCRF that determines the PCC rule to the user terminal.

Description

Mobile Communication System Supporting Multi-PCRF and Method Thereof

The present invention relates to a mobile communication system, and more particularly, to a quality of service (QoS).

In case of call processing supporting QoS, QoS system composed of AF (Application Function or P-CSCF), PCRF (Policy Charging Rule Function), and PCEF (Policy Charging Enforcement Function or GGGSN) has the same information about the same session. Should be According to the 3GPP standard, there are rules for a plurality of PCEFs, but there are no rules for the number of PCRFs. Therefore, when implementing multiple PCRFs, a call processing procedure is required accordingly.

On the other hand, if any one of the plurality of PCRF out of the service (Out of Service), the information of the session of one subscriber is the same AF and GGSN, but in the case of PCRF is transferred to the other PCRF session information. In this case, the SYNC between systems does not match and a solution for this is required.

An object of the present invention is to propose a call processing procedure for using a plurality of PCRFs in a 3G mobile communication system. That is, by allowing the P-CSCF to select a target to be interlocked among a plurality of PCRFs, it is possible to efficiently configure a network for supporting IMS (IP Multimedia Subsystem) QoS.

Another object of the present invention is to enable a normal service provision using another PCRF even when any one PCRF is in an abnormal state in a 3G mobile communication system supporting a plurality of PCRFs.

According to an aspect of the present invention, a plurality of PCRF for determining the PCC rule to be applied to the call requested from the user terminal, and P-CSCF and the PCRF for selecting a PCRF to determine the PCC rule for the call from the plurality of PCRF There is provided a mobile communication system including a GGSN that provides a QoS service to the call according to the PCC rule determined by.

According to another aspect of the present invention, upon receiving a call request from a user terminal, selecting a PCRF to determine a policy and charging control (PCC) rule to be applied to the downlink of the call from a plurality of policy and charging rule functions (PCRF), Sending the service information for the call to the selected PCRF, receiving the PCC rule for the downlink of the call from the PCRF, and receives a call setup response message for the call request, the PCC rule for the uplink of the call To provide a call processing method in a multiple PCRF environment comprising transmitting the service information of the call to the selected PCRF to determine.

The present invention makes it possible to use a plurality of PCRFs in 3G mobile communication systems. Through this, it is possible to efficiently configure a network for supporting IMS (IP Multimedia Subsystem) QoS. In addition, even when any one PCRF is in an abnormal state in a 3G mobile communication system supporting a plurality of PCRFs, it is possible to provide a normal service using another PCRF.

As the invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all transformations, equivalents, and substitutes included in the spirit and scope of the present invention. In the following description of the present invention, if it is determined that the detailed description of the related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In order to facilitate a thorough understanding of the present invention, the same reference numerals are used for the same means regardless of the number of the drawings.

1 is a block diagram of a mobile communication system for call processing using multiple PCRFs according to an embodiment of the present invention. Referring to FIG. 1, a mobile communication system includes user terminals 10 and 15, SGSNs 20 and 25, first and second GGSNs 30 and 35, and a policy and charging rule function (PCRF) 40 and 45. P-CSCF (Proxy-Call Session Control Function) 50.

User equipment (User Equipment) (10, 15) is a terminal that performs a session establishment procedure with the mobile communication system and transmits and receives packet data. The user terminals 10 and 15 may operate only in the PS (Packet Switched) domain or may be a dual mode terminal capable of operating in the CS (Circuit Switched) domain. The user terminals 10 and 15 may include a wireless application protocol, which is a wireless Internet access protocol, a Microsoft Internet Explorer (MIE) based on HTML using an HTTP protocol, a handheld device transport protocol, Packet data is transmitted and received with the mobile communication system using the FTP function.

The Serving GPRS Support Nodes (SGSN) 20 and 25 are service nodes that manage subscriber information and location information of the user terminals 10 and 15 and are responsible for session management and billing information generation. The SGSNs 20 and 25 are connected to the wireless network through the Iu interface, and the GGSNs 30 and 35 are connected through the Gn interface to transmit and receive packet data and control messages. That is, the SGSN 20 and 25 may manage mobility of the terminal device 100, a call processing procedure, a session management for transmitting / receiving packet data and a packet data transmission / reception function, an authentication and charging function, and a packet data routing process for a GPRS service. Has the function. On the other hand, SGSN manages the QoS of the radio section.

Gateway GPRS Support Nodes (GGSNs) 30 and 35 are serving nodes of an IP-based packet network providing high-speed packet data services for packet data services of GPRS. ) Provides IP address assignment, session management, packet data routing, and interface between WCDMA and the Internet.

In this embodiment, the GGSNs 30 and 35 select the PCRF according to a predetermined policy or the state of the PCRF. PCRFs managing PCC rules may be classified according to identification information of a user terminal. The identification information of the user terminal may be, for example, IMSI or MSISDN, MDN, IP address, or the like. It is a matter of implementation whether the PCRF is to be distinguished based on identification information of which of the calling user terminal or the called user terminal. For a user terminal newly IP-CAN Attached, if the state of the PCRF specified by the identification information of the user terminal is abnormal, it is linked with another PCRF which is a normal state. However, the user terminal that has been serviced by the PCRF in an abnormal state cannot operate normally with respect to Rx signaling, that is, a SIP INVITE message transmitted from another user terminal, and thus a new session should be established.

On the other hand, GGSN (30, 35) manages the QoS of the IP interval. In order to manage the QoS of the IP Multimedia Subsystem (IMS), the GGSNs 30 and 35 include a Policy and Charging Enforcement Function (PCEF). PCEF includes a flow based on policy enforcement and charging functions. This enables control of user plane traffic handling and QoS management. That is, for service data flows under policy control, the PCEF allows service data flows to pass only if the corresponding gate is open. In addition, for data flows under billing control, there must be a corresponding PCC (Policy and Charging Control) rule to allow service data flows to communicate through the gateway.

The PCC rule is for detecting a packet belonging to a service data flow and applying an authorized QoS. PCC rules include a dynamic PCC rule and a basic PCC rule. The dynamic PCC rule is a PCC rule applied by the PCRFs 40 and 45, and the basic PCC rule is a PCC rule preset in the PCEF. Basic PCC rules can be activated or inactivated by PCRF. PCC rules include rule name, service identifier, service data flow filter, priority, gate state, QoS parameter, charging key, charging parameter. Among them, the QoS parameter is information about authorized QoS (QoS Class Indicator), and includes bitrates applied for uplink and downlink. The QoS class consists of a Conversational class, a Streaming class, an Interactive class, and a background class. In the present embodiment, the basic PCC rule is designated as a background class. Background class is the lowest level of the four classes, the user terminal 10, 15 can use the service that can not expect the packet to arrive within a certain time.

PCRFs 40 and 45 include flows based on policy control decisions and charging control functions. The PCRFs 40 and 45 perform network control on flows based on service data flow detection, gate control, QoS, and charging for PCEF. The PCRFs 40 and 45 receive the session information and the media information from the AF 50, and notify the AF 50 of the event of the traffic plane. For this purpose, the PCRFs 40 and 45 determine the PCC rules and set them in the PCEF located in the GGSN 30. Information necessary for PCC rule determination is provided from the AF 50 or the GGSNs 30 and 35. The information provided from the AF 50 is session, media, and subscriber information, and the information provided from the GGSN 30, 35 is IP-CAN bearer attribute, request format, and subscriber information.

The P-CSCF 50 is a system for providing an IP-based service and corresponds to an application function (AF). In this embodiment, an IMS will be described. In IMS, AF consists of P-CSCFs. P-CSCF is a point where a user terminal meets when accessing an IMS domain through an access network. The P-CSCF forwards a SIP Registration Request from the user terminal to the I-CSCF. The S-CSCF establishes a call session and plays a role of receiving and processing a Session Initiation Protocol (SIP) message transmitted from a user terminal.

2 is a flowchart illustrating a session establishment process between a user terminal and a GGSN in a multiple PCRF environment according to an embodiment of the present invention.

The user terminal 10 requests a PDP context to establish a session (S100). When the user terminal 10 transmits an Activate PDP Context request, the SGSN 20 allocates a radio network resource to establish a communication path with the user terminal 10, and then, requests the Create PDP Context to the GGSN 30, that is, The IP-CAN session establishment request is transmitted, and includes the attributes of the IP-CAN bearer, the request format, and the subscriber information of the user terminal. The active PDP context request includes QoS information requested by the user terminal 10. Through this, the SGSN 20 performs QoS negotiation with the GGSN 30.

Receiving the IP-CAN session establishment request, the GGSN 30 selects the PCRF and notifies the session establishment with the user terminal 10 (S110). The GGSN 30 displays the diameter information CCR (Diameter CC-Request) command through the identification information of the user terminal, the IP address information assigned to the user terminal, the default charging policy set in advance when the PCRF is interlocked, and the QoS information requested through the PDP context. Including in the transfer to PCRF.

At this time, the GGSN 30 selects the PCRF according to a predetermined policy or the state of the PCRF. PCRFs managing PCC rules may be classified according to identification information of a user terminal. Since the PDP context includes identification information of the user terminal, for example, IMSI or MSISDN, it can be used. On the other hand, in order to select the PCRF according to the state of the PCRF, the GGSN 30 stores both the connection information for the first PCRF 40 and the second PCRF 45. In the case of operating three or more PCRFs, the GGSN 30 may further store PCRF selection criteria to replace the PCRF having an abnormal condition. When the first PCRF 40 is set as the main PCRF of the GGSN 30, the GGSN 30 sends a diameter CCR command to the first PCRF 40 to receive the PCC rule. If the PCC rule is not answered within a predetermined time after the diameter CCR command is transmitted, the state of the first PCRF 40 is determined to be an out of service, and the diameter CCR command is transmitted to the second PCRF 45. . On the other hand, the PCRF to which the GGSN 30 will work may be determined and notified by the P-CSCF 50. In addition, the state of the PCRF may also notify the GGSN 30 from the P-CSCF 50. In addition to the GGSN 30 can be used in a variety of ways to check the state of the PCRF is, of course. In this example, it is assumed that the first PCRF 40 is in an abnormal state or the GGSN 30 is set to interwork with the second PCRF 45.

After receiving the diameter CCR command, the second PCRF 45 stores the information included in the diameter CCR command (S120) and requests and receives subscription information from the subscription profile storage unit 70. There is (S130, S140). Subscription information includes available services, QoS, and PCC rules. Since steps S130 and S140 are not essential procedures, they may not be performed depending on the embodiment.

The second PCRF 45 determines the PCC rules and policies (S150). The second PCRF 45 may select or generate a PCC rule. In addition, the second PCRF 45 may determine a policy as to whether to activate or deactivate the allowed QoS and the service flow specified in the PCC rule. Thereafter, the second PCRF 45 stores the determined PCC rules and policies (S160).

The second PCRF 45 transmits the PCC rule determined through the diameter CCA (Command Diameter) command to the GGSN 30 (S170). This allows the allowed QoS to be delivered to the GGSN 30.

When receiving the diameter CCA command, the GGSN 30 stores the received PCC rule (S180) and applies the PCC rule. The GGSN 30 applies the authorized QoS and activates or deactivates the service flow according to the flow status of the PCC rule. Thereafter, the GGSN 30 transmits a response to the IP-CAN session establishment request to the user terminal (S190).

On the other hand, when the first PCRF 40 is in an abnormal state, the CCA command is not delivered in step S170. Therefore, in this case, the GGSN 30 performs call processing that does not support QoS. That is, the QoS requested from the user terminal 10 is ignored and Background Class QoS, which is the lowest level according to the PCC rule, is provided. In this case, the GGSN 30 does not guarantee quality.

3 is a flowchart illustrating a session establishment process between a user terminal and a GGSN in a multiple PCRF environment according to an embodiment of the present invention, and FIGS. 4A to 4C illustrate SIP messages including user identification information.

The user terminal 10 transmits a SIP INVITE message to the P-CSCF 50 to establish a call, that is, a session (S200).

Upon receiving the SIP INVITE message transmitted by the user terminal 10, the P-CSCF 50 transmits the SIP INVITE message to the S-CSCF 60 (S205). The SIP INVITE message sent by the P-CSCF 50 is based on the SIP INVITE message transmitted by the user terminal 10. Here, the PCRF to be linked with the P-CSCF 50 may be selected. The SIP INVITE message includes identification information of the user terminal. 4A and 4B illustrate a SIP INVITE message transmitted from the user terminal 10. The SIP INVITE message includes identification information of the user terminal in the message name header 300, the FROM / TO header 310, the Via header 320, and the contact header 330. In detail, when the PCRF is selected based on the subscriber number, the P-CSCF 50 extracts identification information of the user terminal from the message name header 300 or the FROM / TO header 310 of the SIP INVITE message. Determine the PCRF. On the other hand, when the PCRF is selected based on the subscriber IP, the P-CSCF 50 extracts the IP address assigned to the user terminal included in the Via header 320 or the contact header 330 of the SIP INVITE message, and Determine the PCRF. The process of the S-CSCF 60 interworking with the called user terminal 15 is omitted to avoid duplication of explanation. When the PCRF to be processed is selected using the identification information of the user terminal, the user terminal may be either the calling user terminal or the called user terminal.

Upon receiving the SIP INVITE message sent by the P-CSCF 50, the S-CSCF 60 transmits a 100 Trying message to the P-CSCF 50 in response. The S-CSCF 60 transmits a SIP INVITE message to the called terminal 15, receives a 100 trying message in response thereto, and then receives a 183 message, which is a session progress message. Thereafter, the session progress message is transmitted to the P-CSCF 50 (S215).

Upon receiving the session progress message sent by the S-CSCF 60, the P-CSCF 50 determines a PCRF to determine the PCC rule for the downlink (S220). The P-CSCF 50 determines service information, for example, QoS, IP address of an IP flow, port number, media type, and the like, and then determines a PCRF to which it is applied. The P-CSCF 50 selects a PCRF according to a predetermined policy or the state of the PCRF. PCRFs managing PCC rules may be classified according to identification information of a user terminal. 4C is a session progress message sent by the S-CSCF 60 and includes identification information of a user terminal. The session progress message includes identification information of the user terminal in the FROM / TO header 340. Specifically, when the PCRF is selected based on the subscriber number, the P-CSCF 50 extracts identification information of the user terminal from the FROM / TO header 340 of the session progress message and uses the same to determine the PCRF. On the other hand, when the PCRF is selected based on the subscriber IP, the P-CSCF 50 extracts the IP address assigned to the user terminal included in the contact header (not shown) of the session progress message, and determines the PCRF using the same. do.

The P-CSCF 50 stores both connection information for the first PCRF 40 and the second PCRF 45. If the first PCRF 40 is set as the main PCRF for processing the user terminal 10, but the first PCRF 40 is in an abnormal state, the P-CSCF 50 returns the diameter AAR to the second PCRF 45. Send a command to receive QoS. The P-CSCF 50 determines that the PCRF is in an abnormal state when there is no response message of 200k by exchanging OPTIONS method with the PCRF. In this example, it is assumed that the first PCRF 40 is in an abnormal state or the GGSN 30 is set to work with the second PCRF 45. On the other hand, when the P-CSCF 50 selects the PCRF due to the abnormal state, the GGSN 30 and 35 provide information about the PCRF selected to process the request of the user terminal or information about the PCRF in which the abnormal state has occurred. You can notify.

The P-CSCF 50 transmits a diameter AA-Request (AAR) command including service information to the second PCRF 45 (S225). Upon receiving the diameter AAR command, the second PCRF 45 authenticates the included service information (S230). After storing the service information, the second PCRF 45 may request and receive subscription information from the subscription profile storage unit 70. Subscription information includes available services, QoS, and PCC rule information. The second PCRF 45 then determines a PCC rule that includes QoS for the downlink.

On the other hand, if the user terminal transmitting the SIP INVITE message in step S200 was serviced through the first PCRF 40, the SIP INVITE message is failed. The P-CSCF 50 may know that the user terminal 10 was being serviced through the first PCRF 40, but the first PCRF 40 may not process a call due to an abnormal state. In this case, since the second PCRF 45 has no information on the user terminal 10, call processing cannot be performed again. Accordingly, the SIP INVITE message from the user terminal 10 is failed and the user terminal 10 must register with the second PCRF 45 through a new IP-CAN session establishment procedure with the GGSN 30 to use the service. It becomes possible.

The second PCRF 45 transmits the PCC rule determined through the diameter AA-Answer (AAA) command to the P-CSCF 50 (S235). This allows the allowed QoS to be delivered to the P-CSCF 50.

Upon receiving the diameter AAA command, the P-CSCF 50 sends a 183 message to the user terminal 183.

Thereafter, the user terminal may request an additional session by transmitting a secondary PDP context (A). Since this process is the same as the process described with reference to FIG. 2, a detailed description thereof will be omitted.

From the S-CSCF 60, a session establishment response message (i.e. 200 ok message) (S245), the P-CSCF 50 determines the service information for the uplink (S250), and through the diameter AAR command Transfer to the second PCRF 45.

Receiving the diameter AAR command, the second PCRF 45 determines the QoS and exchanges a Re-Auth-Request (RAR) command and a Re-Auth-Answer (RAA) command through the GGSN 30 and the Gx interface. In step S260, the PCC rule is set, or the PCC rule is set and the authorized QoS is applied. Thereafter, the second PCRF 45 transmits the diameter AAA command to the P-CSCF 50 (S265).

Upon receiving the diameter AAA command from the second PCRF 45, the P-CSCF 50 transmits the session establishment response message to the user terminal 10 (S270), and receives the received ACK message in response thereto. (S275), and delivers it to the S-CSCF (60) (S275).

On the other hand, the call processing method according to an embodiment of the present invention can be implemented in the form of program instructions that can be executed through various electronic means for processing information can be recorded in the storage medium. The storage medium may include program instructions, data files, data structures, etc. alone or in combination.

The program instructions recorded in the storage medium may be those specially designed and constructed for the present invention, or may be known and available to those skilled in the software art. Examples of storage media include magnetic media such as hard disks, floppy disks and magnetic tape, optical media such as CD-ROMs, DVDs, and magnetic-optical media such as floptical disks. hardware devices specifically configured to store and execute program instructions such as magneto-optical media and ROM, RAM, flash memory, and the like. In addition, the above-described medium may be a transmission medium such as an optical or metal wire, a waveguide, or the like including a carrier wave for transmitting a signal specifying a program command, a data structure, and the like. Examples of program instructions include not only machine code generated by a compiler, but also devices that process information electronically using an interpreter, for example, high-level language code that can be executed by a computer.

The hardware device described above may be configured to operate as one or more software modules to perform the operations of the present invention, and vice versa.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention as defined in the appended claims. It will be understood that the invention may be varied and varied without departing from the scope of the invention.

1 is a block diagram of a mobile communication system for call processing using multiple PCRFs according to an embodiment of the present invention.

2 is a flowchart illustrating a session establishment process between a user terminal and a GGSN in a multiple PCRF environment according to an embodiment of the present invention.

3 is a flowchart illustrating a session establishment process between a user terminal and a GGSN in a multiple PCRF environment according to an embodiment of the present invention.

4A-4C illustrate SIP messages containing user identification information.

Claims (9)

A plurality of policy and charging rule functions (PCRFs) for determining a policy and charging control (PCC) rule to be applied to a call requested from a user terminal; A proxy-call session control function (P-CSCF) for selecting a PCRF to determine a PCC rule for the call among the plurality of PCRFs; And And a Gateway GPRS Support Node (GGSN) for providing a QoS service to the call according to the PCC rule determined by the PCRF. The method of claim 1, The GGSN selects a PCRF to determine a PCC rule to be applied to the user terminal among the plurality of PCRF. The method according to claim 1 or 2, And the P-CSCF selects a PCRF to determine a PCC rule for the call according to the states of the plurality of PCRFs. The method according to claim 1 or 2, And the GGSN selects a PCRF to determine a PCC rule for the session according to the states of the plurality of PCRFs. The method according to claim 1 or 2, The P-CSCF selects a PCRF to determine a PCC rule for the call according to the identification information of the user terminal. The method according to claim 1 or 2, The GGSN selects a PCRF to determine a PCC rule for the session according to the identification information of the user terminal. When receiving a call request from a user terminal, selecting a PCRF to determine a policy and charging control (PCC) rule to be applied to the downlink of the call from a plurality of policy and charging rule functions (PCRFs); Transmitting service information for the call to the selected PCRF; Receiving a PCC rule for the downlink of the call from the PCRF; And Receiving a call setup response message for the call request, sending service information of the call to the selected PCRF to determine a PCC rule for the uplink of the call. The method of claim 7, wherein The method of call processing in a multiple PCRF environment is performed using the identification information of the subscriber station. The method of claim 7, wherein The method of call processing in a multiple PCRF environment is performed by referring to the state of the plurality of PCRFs.

Images