KR100890827B1 - Method and system of call processing in IMS network - Google Patents

Abstract

Provided are a method and a system for call processing in an IMS network.

A call processing method in an IMS network according to an embodiment of the present invention includes a call in an IMS network including a request call controller (I-CSCF), a serving call controller (S-CSCF), and a subscriber location search unit (SLF). A processing method comprising: (a) receiving a request message for obtaining information of a home subscriber server (HSS) to which a subscriber belongs; (b) determining whether information on the home subscriber server is normal according to the request message; And (c) generating a list including information of the home subscriber server determined to be normal as a result of the determination, and transmitting the list including the list in a response message to the request message.

P-CSCF, I-CSCF, SLF, HSS

Description

Method and system for call processing in IMS network {Method and system for call processing in IP Multimedia Subsystem}

The present invention relates to a call processing technology in an IMS network, and more particularly, to determine whether or not address information of a home subscriber server is normal in a call processing process between functional elements existing in an IMS network. The present invention relates to a call processing method and system in an IMS network.

The European-led 3GPP and the North American-led 3GPP, which proceeds with the IMT-2000 standard, proposed an ALL-IP network that replaces the infrastructure of the mobile communication network with IP. The ALL-IP network is proposed to satisfy the diverse service needs of increasing Internet users with wireless access services. The all-IP network uses IP structure and protocols to transmit data and signaling on an IP basis, and bears It separates control and service functions and provides multimedia communication in real time.

The all-IP network can provide services by interworking with the internet network regardless of access methods such as landlines, mobile phones, cables, and LANs by using IP. In addition, it provides a solution suitable for integrated multimedia services including voice, data, and real-time video services simultaneously, and can reduce costs through packet transmission. That is, the ALL-IP network may be referred to as an IP-based integrated network for supporting wired / wireless voice services, wired / wireless internet services, and wired / wireless multimedia services.

As a key technology for providing new services in such an All-IP based communication environment, an IP Multimedia Subsystem (hereinafter referred to as IMS) is defined to provide various services to subscribers based on an ALL-IP network. Is attracting attention. The IMS network standardized the ALL-IP reference model and accommodated various gateway functions with various interface schemes, and standardized interface schemes and protocols with other functional elements related to them by linking with IETF. The IMS network is divided into a control layer that provides a session control function based on a packet service domain, a user layer that provides traffic, and an application layer that provides a service function.

IMS network manages and authenticates mobility of IP multimedia users to CSCF, which is responsible for registration and multimedia call processing function using Session Initiation Protocol (SIP), IETF standard, and HLR function of legacy mobile network. It consists of an integrated HSS. In addition, the IMS network uses a PS-based domain to transmit multimedia signaling and bearer traffic, uses a Cx interface between the CSCF and the HSS, and uses a Dx interface between the CSCF and the SLF.

1 is a diagram illustrating a network connection configuration of a general IMS network. Referring to FIG. 1, a user equipment (UE) 10 in which a subscriber can receive an integrated service, a base station system 20 wirelessly connected to the UE 10, a base station system 20, and a cable The packet data node 30 is connected to the packet data node 30 and the IMS 40 is connected to the IP network. A network including the UE 10, the base station system 20, and the packet data node 30 is called an access network. The base station system 20 includes a Node-B and a base station controller (RNC), and the packet data node 30 is equipment located at the end of the access network, and in the case of WCDMA, includes a GGSN or SGSN.

The UE 10 receives a signal transmitted from the base station system 20 in a serving cell of the base station system 20 and wirelessly transmits a signal according to voice or data input from the subscriber to the base station system 20. send. The base station system 20 transmits a signal received from the UE 10 included in the corresponding service cell to the packet data node 30 connected to the wired network, and receives the signal from each packet data node 30. Is transmitted wirelessly to the UE 10 included in the corresponding serving cell. That is, the base station system 20 allocates or releases a radio channel for the UE 10 included in the serving cell, and handles a handoff to guarantee the mobility of the UE 10. In addition, the base station system 20 converts an analog signal received from the UE 10 included in the service cell into a digital signal that can be transmitted on an E1 / T1 level line, and transmits it to the packet data node 30 connected to the wired network. In addition, the digital signal received from the packet data node 30 is converted into an analog signal that can be transmitted wirelessly and transmitted to the UE 10.

In addition, the packet data node 30 converts a signal received from the base station system 20 into an IP packet and transmits the signal to the IMS 40, and converts an IP packet transmitted from the IMS 40 into a signal and converts the signal into a base station system 20. ). The IMS 40 provides the integrated service to the UE 10 according to the received IP packet.

2 is a diagram illustrating a call processing flow in an IMS network according to the prior art.

All IM service users must go through the registration process for the user's service control in the home network before receiving IM service through incoming / outgoing session. Therefore, after finding P-CSCF address along with PDP Context Activation, IM service The registration process should be performed.

First, the UE 10 transmits a SIP registration request message including parameters such as a user identifier and a home domain name to the P-CSCF 41 according to a user's input command (S12). The P-CSCF 41 obtains the address of the I-CSCF 42 through DNS from the home domain name included in the SIP registration request message received from the UE 10. At this time, the P-CSCF 41 inserts its own address and identifier information into the SIP registration request message and transmits it to the I-CSCF 42 corresponding to the found address (S14). The I-CSCF 42 refers to the registration request message received from the P-CSCF 41 and transmits a request message for obtaining address information of the HSS to which the subscriber belongs to the SLF 43 (S16). The SLF 43 transmits a response message including address information of the HSS 44 to the I-CSCF 42 in response to the request message received from the I-CSCF 41 (S18).

The I-CSCF 42 uses the address information of the HSS 44 included in the response message received from the SLF 43 to determine whether the user is registered and whether the user can roam the IMS network that he is currently visiting. Inquiry, and transmits an authentication request message (UAR) to the HSS 44 to obtain the information of the S-CSCF (45) (S20). The HSS 44 refers to the authentication request message (UAR) received from the I-CSCF 42 and the result information on whether the user is already registered and whether or not roaming is possible in the visiting network, and the S-CSCF 45 The authentication response message (UAA) including the information is transmitted to the I-CSCF 42 (S22). The I-CSCF 42 selects the corresponding S-CSCF 45 by referring to the information of the S-CSCF 45 included in the authentication response message (UAA) received from the HSS 44, and selects the selected S-CSCF. The SIP registration request message transmitted from the UE 10 is transmitted to the 45 (S24). The SIP registration request message includes the address information of the HSS 44.

After receiving the SIP registration request message sent from the I-CSCF 42, the S-CSCF 45 sends a Server Assignment Request (SAR) to request the authentication vector of the subscriber. 44) (S26). The HSS 44 transmits a server assignment response message (SAA) including information on the authentication vector of the subscriber to the S-CSCF 45 in response to the server assignment request message (SAR) received from the S-CSCF 45. (S28). Accordingly, the S-CSCF 45 may acquire information about the authentication vector of the subscriber through the server assignment response message (SAA).

The above-described detailed process of the call processing flow of FIG. 2 is described in detail in the 3GPP standard, and the detailed call processing flow is referred to the above specification document, which is briefly described here.

Meanwhile, in the process of the aforementioned call processing, the I-CSCF transmits a request message for acquiring the address of the HSS to which the subscriber belongs to the SLF, and the SLF transmits the HSS address list through the Server-Capabilities AVP to the I-CSCF 24. It is sent to (S16, S18). However, the HSS address list transmitted by the SLF is not only an idle HSS address but also a link with an HSS device (Out-Of-Service; OOS) or the link is alive but in the session configuration message of the Diameter protocol. It may also include a time-out, and the I-CSCF receiving it also processes without checking whether all the HSS addresses can be processed, thereby making the call processing between CSCF and SLF inefficient. There was a problem.

The present invention has been devised to solve the above problems, and a technical problem to be achieved by the present invention is that a plurality of SLFs in a call processing process between the functional elements existing in the IMS network, in particular, a call processing process between the CSCF and the SLF. The present invention provides a method and system for call processing in an IMS network that classifies an HSS address so that only a normal HSS address capable of subscriber processing is included in an HSS address list and transmitted.

In addition, another technical problem to be achieved by the present invention, in the call processing process between the CSCF and SLF, the CSCF analyzes the HSS address list received from the SLF to process only the HSS address capable of normal processing, the call in the IMS network It is to provide a processing method and system.

The object of the present invention is not limited to the above-mentioned object, and other objects that are not mentioned will be clearly understood by those skilled in the art from the following description.

Call processing method in an IMS network according to an embodiment of the present invention for achieving the above object, the request call control unit (I-CSCF), serving call control unit (S-CSCF) and subscriber location search unit (SLF) A call processing method in an IMS network, comprising: (a) receiving a request message for obtaining information of a home subscriber server (HSS) to which a subscriber belongs; (b) determining whether or not information on the home subscriber server is normal according to the request message; And (c) generating a list including information of the home subscriber server determined to be normal as a result of the determination, and transmitting the list including the list in a response message to the request message.

In addition, the call processing method in the IMS network according to an embodiment of the present invention for achieving the above object, the request call control unit (I-CSCF), serving call control unit (S-CSCF) and subscriber location search unit (SLF) A call processing method in an IMS network comprising: (a) transmitting a request message for obtaining information of a home subscriber server (HSS) to which a subscriber belongs; (b) receiving from the subscriber location search unit a response message comprising a list of information of the home subscriber server in accordance with the request message; (c) determining whether information on the home subscriber server constituting the list included in the received response message is normal.

In addition, a call processing system in an IMS network according to an embodiment of the present invention for achieving the above object, the call control unit for transmitting a request message for obtaining information of the home subscriber server (HSS) to which the subscriber belongs; The call controller determines whether the home subscriber server information is normal or not according to the request message, generates a list including information of the home subscriber server determined to be normal, and includes the information in the response message for the request message. The subscriber location search unit (SLF) for transmitting to.

Specific details of other embodiments are included in the detailed description and the drawings.

According to the embodiment of the present invention as described above one or more of the following effects exist.

In the call processing process between functional elements in the IMS network, the SLF classifies a plurality of HSS addresses and processes only the HSS addresses that are normally operated, which enables subscriber processing, thereby enabling more stable and efficient call processing control.

The CSCF analyzes the HSS address list received from the SLF and processes only the HSS addresses that can be processed normally, so that the CSCF and SLF call processing functions can be processed stably and efficiently.

The effects of the present invention are not limited to the above-mentioned effects, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be embodied in various different forms, and the present embodiments merely make the disclosure of the present invention complete, and are common in the art to which the present invention pertains. It is provided to fully inform those skilled in the art of the scope of the invention, which is to be defined only by the scope of the claims. Like reference numerals refer to like elements throughout.

The IMS used in the embodiment of the present invention is a concept defined in 3GPP that defines GSM and WCDMA, and the like. In 3GPP2 that defines CDMA and the like, a function similar to IMS is defined as a multimedia domain (MMD). In the embodiment described below, IMS is described as an example, but it can be seen that MMD can be equally applied.

3 is a call flow diagram illustrating a call processing method in an IMS network according to an embodiment of the present invention.

Referring to FIG. 3, the IMS service subscriber transmits a SIP registration request message to a Proxy-Call Cession Control Function (P-CSCF) 410 through a user terminal (UE) 100 ( In step S102, the P-CSCF 410 detects an address of an interrogating-call control control function (I-CSCF) 420 using the received SIP registration request message (S104).

The P-CSCF 410 transmits a registration request message to the I-CSCF 420 using the detected address of the I-CSCF 420 (S106). The I-CSCF 420 transmits a request message for obtaining information of the Home Subscriber Server (HSS) 440 to which the IMS service subscriber belongs, to the Subscription Locator Function (SLF) 430. (S108). In the embodiment of the present invention, the information of the HSS 440 may be information for identifying the HSS 440, and is preferably address information for accessing the HSS 440.

The SLF 430 determines the presence or absence of the address information list of the HSS 440 according to the HSS information request message transmitted from the I-CSCF 420 (S110). Here, the determination of whether the address information list is normal means whether the address information of each HSS 440 is in an idle state that can be processed normally, or an out-of-service service in which the HSS device is not currently driven. -Of-Service (OOS) status or whether the link of the HSS device corresponding to the current HSS address is alive but time-out occurs in the session setup message of the Diameter protocol. It means to judge. Here, the period in which the SLF 430 determines whether the HSS address information is normal may be a period of a predetermined interval determined by the operator, and the request message for the SLF 430 requesting the HSS address information from the I-CSCF 420. It may also be determined immediately at the moment of receiving.

After this determination, a list including only HSS address information determined as an idle state is generated and included in the response message and transmitted to the I-CSCF 420 (S112).

The I-CSCF 420 may proceed with the following process using the normal HSS address information received from the SLF 430, but may again determine whether the HSS address information is normal at the I-CSCF 420 (S114). ). That is, the I-CSCF 420 receiving the HSS information list included in the response message checks whether the HSS address information included in the list is in an idle state or an out-of-service (OOS) state. In this case, it may be determined again whether or not the time-out state has passed. This is because the HSS address information may change from an idle state to an out of service state or an expired state as time passes.

The I-CSCF 420 tries to use the address information that appears first among the address information of the HSS included in the HSS address list, and if it fails, the I-CSCF 420 tries to the HSS address corresponding to the address information arranged next. see. If all of the HSS address information is not in the idle state and fails, it can be attempted using the default information of the HSS address information.

On the other hand, the period in which the I-CSCF 420 determines whether the HSS address information is normal may be a period of a predetermined interval determined by the operator, it is determined immediately every time the I-CSCF 420 receives from the SLF (430) You may.

As a result of this determination, an authentication request message (User-Authorization-Request; UAR) for acquiring information of the S-CSCF 450 is transmitted to the HSS 440 by using the HSS address information determined as a normal idle state (S116). ). The HSS 440 transmits an authentication response message (User-Authorization-Answer; UAA) including information of the S-CSCF 450 to the I-CSCF 420 according to the received authentication request message (UAR) ( S118). The I-CSCF 420 selects a corresponding S-CSCF 450 by referring to the information of the S-CSCF 450 included in the authentication response message (UAA) received from the HSS 440, and selects the selected S-CSCF. In step S120, the SIP registration request message transmitted from the UE 100 is transmitted to the 450. Since the subsequent process is the same as the process S24 to S32 in FIG. 2 described in the prior art, further detailed description will be omitted here.

4 is a block diagram of a call processing system in an IMS network according to an embodiment of the present invention. Referring to FIG. 4, a call processing system in an IMS network includes a UE 100, a proxy-call session control function (P-CSCF) 410, and an interrogating-call session control function (I-CSCF) 420. ), A Serving-Call Session Control Function (S-CSCF) 450, a Subscription Locator Function (SLF) 430, and a Home Subscriber Server (HSS) 440.

The UE 100 is a plurality of terminals located in a communication area partitioned and allocated on a sector basis, and according to an embodiment of the present invention, a cellular phone, a personal communication service (PCS) phone, a PDA phone, on which a 3GPP SIP-based module is mounted, This includes GSM phones, CDMA-2000 phones, WCDMA phones, DMB phones, and so on.

The P-CSCF 410 is responsible for transmitting a SIP format message received from the UE 100 to the I-CSCF 420. In addition, the SIP registration request message is received from the UE 100 connected through the IMS network, and the address of the I-CSCF 420 is detected using the received SIP registration request message. The SIP registration request message is transmitted to the I-CSCF 420 using the detected address of the I-CSCF 420.

The I-CSCF 420 obtains subscriber profile of the corresponding UE 100 using the public user ID information of the UE 100 that has transmitted the message. In addition, the SLF 430 transmits a request message for acquiring information of the home subscriber server (HSS) to which the subscriber belongs.

The S-CSCF 450 establishes a call between the called terminal and the calling terminal according to the received message, or provides an integrated service such as a voice message service to the UE 100.

The HSS 440 manages subscriber information according to each UE 100 accessing the IMS network, and if there is a request for subscriber information according to each UE 100 from the I-CSCF 420, Provide subscriber information according to the public user ID information. However, if the number of UEs 100 connected to the IMS network increases, the number of HSSs 440 managing subscriber information also increases, so that the subscriber information according to the public user ID information of each UE 100. (profile) is distributed and managed by a plurality of HSS (440). Accordingly, a subscription locator function (SLF) 430 that can confirm address information for each HSS 440 should be added.

The SLF 430 manages the address information of the HSS 440, and when the address information of the HSS 440 is requested from the I-CSCF 420 according to the public user ID information of the UE 100, the SLF 430 of the HSS 440. After determining whether the address information is in a normal state (Idle), an out-of-service (OOS) state, and a time-out state, the address of the HSS 440 corresponding to the normal state Provide information.

The I-CSCF 420 acquires subscriber information of the UE 100 from the HSS 440 according to the address information of the HSS 440 transmitted from the SLF 430. In this case, the I-CSCF 420 determines whether the address information of the HSS 440 is normal and generates a list including the address information of the HSS 440 determined to be normal as a result of the I-CSCF 420. To send). Here, the process of determining whether the address information of the HSS 440 is normal includes whether the address information of the HSS 440 included in the list included in the response message received from the SLF 430 is in a normal state (Idle) or not. The process of determining whether the service is out-of-service (OOS) and the time-out has been described above.

Although embodiments of the present invention have been described above with reference to the accompanying drawings, those skilled in the art to which the present invention pertains may implement the present invention in other specific forms without changing the technical spirit or essential features thereof. I can understand that. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

1 is a diagram illustrating a network connection configuration of a general IMS network.

2 is a diagram illustrating a call processing flow in an IMS network according to the prior art.

3 is a call flow diagram illustrating a call processing method in an IMS network according to an embodiment of the present invention.

4 is a block diagram of a call processing system in an IMS network according to an embodiment of the present invention.

(Description of the main parts of the drawing)

100: UE 410: P-CSCF

420: I-CSCF 430: SLF

440: HSS 450: S-CSCF

Claims (18)

(a) receiving a request message for obtaining information of a home subscriber server (HSS) to which the subscriber belongs; (b) determining whether information on the home subscriber server is normal according to the request message; And (c) generating a list including information of the home subscriber server determined to be normal as a result of the determination, and transmitting the list including the list in a response message to the request message; In step (b), Determining whether the address information of the home subscriber server is in a normal state, an out-of-service state, and a time-out state. Call handling in. The method of claim 1, Information of the home subscriber server, And information about an address for accessing the home subscriber server. delete The method according to claim 1 or 2, Before step (a) above, Receiving, by the relay call controller, a registration request message from a terminal connected through the IMS network, and detecting an address of the request call controller by using the received registration request message; And And transmitting the registration request message to the request call controller using the detected address of the request call controller. The method according to claim 1 or 2, (d) The request call controller for receiving the response message indicates whether the address information of the home subscriber server included in the list is Idle, Out-of-Service (OOS), and the elapsed time. Determining whether or not (Time-Out); (e) transmitting to the home subscriber server an authentication request message (UAR) for acquiring information of a serving call controller using information of the home subscriber server determined to be normal as a result of the determination; And (f) in response to the authentication request message (UAR), the home subscriber server further comprises sending an authentication response message (UAA) including information of the serving call controller to the request call controller. Call processing method. The method of claim 5, In step (d), Determining the address information of the home subscriber server included in the list in the arrangement order; And And using the default address information of the home subscriber server when all address information does not correspond to the normal state as a result of the determination. (a) transmitting a request message for obtaining information of the home subscriber server (HSS) to which the subscriber belongs to the subscriber location search unit; (b) receiving from the subscriber location search unit a response message comprising a list of information of the home subscriber server in accordance with the request message; And (c) determining whether information on the home subscriber server constituting the list included in the received response message is normal or not; In step (c), Determining whether the address information of the home subscriber server is in a normal state, an out-of-service state, and a time-out state. Call handling in. The method of claim 7, wherein Information of the home subscriber server, And information about an address for accessing the home subscriber server. delete The method according to claim 7 or 8, In step (c), Determining the address information of the home subscriber server included in the list in the arrangement order; And And using the default address information of the home subscriber server when all address information does not correspond to the normal state as a result of the determination. The method according to claim 7 or 8, Before step (a) above, Receiving, by the relay call controller, a registration request message from a terminal connected through the IMS network, and detecting an address of the request call controller by using the received registration request message; And And transmitting the registration request message to the request call controller using the detected address of the request call controller. The method according to claim 7 or 8, (d) transmitting an authentication request message (UAR) to the home subscriber server for acquiring information of a serving call controller using information of the home subscriber server determined to be normal as a result of the determination; And (e) in response to the authentication request message (UAR), the home subscriber server further comprises sending an authentication response message (UAA) including information of the serving call controller to the request call controller, the call in the IMS network Treatment method. A call controller for transmitting a request message for acquiring information of a home subscriber server (HSS) to which the subscriber belongs; And The call controller determines whether the home subscriber server information is normal or not according to the request message, generates a list including information of the home subscriber server determined to be normal, and includes the information in the response message for the request message. Subscriber location search unit (SLF) for transmitting to, The subscriber location search unit, Call processing in the IMS network for determining whether the address information of the home subscriber server is in a normal state (Idle), an out-of-service (OOS) state, and a time-out state. system. The method of claim 13, Information of the home subscriber server, And information about an address for accessing the home subscriber server. delete The method according to claim 13 or 14, The call control unit, A request call controller for transmitting a request message for obtaining information of the home subscriber server (HSS) to the subscriber location search unit; And A relay call controller which receives a registration request message from a terminal connected through the IMS network, and detects an address of the request call controller by using the received registration request message; The relay call control unit, And transmitting the registration request message to the request call controller using the detected address of the request call controller. The method of claim 16, The request call controller, Whether the address information of the home subscriber server included in the list included in the response message received from the subscriber location search unit is in an idle state, an out-of-service state, and an expired state Call processing system in the IMS network to determine whether (Time-Out). The method of claim 17, The request call controller, The address information of the home subscriber server included in the list is determined in the order of arranging, and when all the address information does not correspond to the normal state as a result of the determination, the serving call controller uses the default address information of the home subscriber server. A call processing system in an IMS network for transmitting an authentication request message (UAR) for obtaining information to the home subscriber server.

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