KR20160084516A - VoLTE SYSTEM, CONTROL METHOD THEREOF, PGW AND CSCF COMPRISED IN THE SYSTEM, CONTROL METHOD THEREOF - Google Patents

Abstract

The present invention relates to a voice over long term evolution (VoLTE) system for recovering subscriber information in a packet data network (PDN) gateway (PGW) when an incoming call is generated in a corresponding communication terminal, a control method thereof, a PGW and a call session control function (CSCF) included in same, and a control method thereof. According to the present invention, a method for controlling a VoLTE system including a mobility management entity (MME), a home subscriber server (HSS), a PGW and a CSCF comprises the following steps: the PGW determining existence of receiver information corresponding to an incoming packet when receiving the incoming packet from the CSCF; the PGW transmitting a receiver information absence notification signal to the CSCF transmitting the incoming packet when the receiver information does not exist on the basis of a determination result of the previous step; the CSCF transmitting a subscriber session removal notification signal to the HSS when receiving the receiver information absence notification signal from the PGW; the HSS transmitting a subscriber location information removal request signal to the MME when receiving the subscriber session removal notification signal from the CSCF; and the MME transmitting a re-connection control signal to a corresponding receiver terminal when receiving the subscriber location information removal request message from the HSS.

Description

TECHNICAL FIELD [0001] The present invention relates to a Voice over Long Term Evolution (VoLTE) system and a control method thereof, and a PGN (PDN Gateway) and a CSCF (Call Session Control Function) THE SYSTEM, CONTROL METHOD THEREOF}

The present invention relates to a Voice over Long Term Evolution (VoLTE) system and its control method, a PGN (PDN Gateway) and a CSCF (Call Session Control Function) included in the system and a control method thereof, A VoLTE system and a control method thereof for rapidly recovering subscriber information in a PGW so that an incoming call can be normally connected when subscriber information does not exist, and a PGW and a CSCF included in the system.

The subscriber information for session connection or maintenance is stored and managed in the PGW (PDN Gateway), which is a component of the Voice over Long Term Evolution (VoLTE) system. When the subscriber information is deleted from the PGW May occur.

Conventionally, when there is no subscriber information in the PGW, when the communication terminal attempts to originate a reattach procedure, the subscriber information is restored to the PGW. However, if an incoming call occurs, the subscriber information is not recovered.

That is, when the incoming packet is received in the PGW in the state that there is no subscriber information in the PGW, the PGW discards the incoming packet as it is. Therefore, until the destination terminal user attempts to originate the call using the destination terminal, A problem that can not be received occurs.

Published Japanese Patent Application No. 10-2013-0006284

SUMMARY OF THE INVENTION The present invention is conceived to solve the above-described conventional problems, and it is an object of the present invention to provide a subscriber identity management system, A VoLTE system and its control method for recovering information, and a PGW and a CSCF included in the system and a control method thereof.

A voice over long term evolution (VoLTE) system including an MME (Mobility Management Entity), an HSS (Home Subscriber Server), a PGW (PDN Gateway) and a CSCF (Call Session Control Function) The control method of the system includes the steps of: when the PGW receives an incoming packet from the CSCF, determining whether or not the called party information corresponding to the incoming packet exists; If the called party information does not exist as a result of the determination, the PGW transmits a called party information absence notification signal to the CSCF that has transmitted the incoming packet; Transmitting a subscriber session deletion announcement signal to the HSS when the CSCF receives the subscriber station absence notification signal from the PGW; Transmitting a subscriber location information deletion request message to the MME when the HSS receives a subscriber session deletion notification signal from the CSCF; And transmitting a reconnection control signal to the called terminal when the MME receives the subscriber location information deletion request message from the HSS.

In order to achieve the above object, a control method of a PGW (PDN Gateway) included in a Voice over Long Term Evolution (VoLTE) system according to the present invention and communicating with a CSCF (Call Session Control Function) Determining whether the called party information corresponding to the incoming packet exists if the packet is received; And if the called party information does not exist as a result of the determining step, transmitting a called party information absence notification signal to the CSCF that has transmitted the incoming packet.

In order to achieve the above object, a control method of a CSCF (Call Session Control Function) included in a voice over long term evolution (VoLTE) system according to the present invention and communicating with an HSS (Home Subscriber Server) and a PGW (PDN Gateway) The method includes sending an incoming packet to the PGW; And transmitting a subscriber session deletion announcement signal to the HSS for inducing reconnection of the called terminal corresponding to the incoming packet when the called party information absence notification signal is received from the PGW that transmitted the incoming packet.

In order to achieve the above object, a VoLTE system according to the present invention includes a Mobility Management Entity (MME), a Home Subscriber Server (HSS), a PDW Gateway (PGW), and a Call Session Control Function (CSCF) When receiving the incoming packet from the CSCF, the PGW determines whether or not the called party information corresponding to the incoming packet exists. If the called party information does not exist as a result of the determination, the PGW transmits a called party information absence notification signal to the CSCF that has transmitted the incoming packet The CSCF transmits a subscriber session deletion notification signal to the HSS when the subscriber information notification signal is received from the PGW after transmitting the reception packet to the PGW. The HSS transmits a subscriber session deletion notification from the CSCF The MME transmits a subscriber location information deletion request message to the MME, and the MME receives a subscriber location information deletion request message from the HSS It characterized in that sending the reconnection control signal to the called terminal to.

In order to achieve the above object, a PGW (PDN Gateway) included in a Voice over Long Term Evolution (VoLTE) system according to the present invention and communicating with a CSCF (Call Session Control Function) receives an incoming packet from the CSCF ; A determination unit configured to determine whether or not the called party information corresponding to the incoming packet received by the receiving unit exists; And a transmission unit for transmitting a called party information absence notification signal to the CSCF that has transmitted the incoming packet when the determination unit determines that the called party information does not exist.

In order to achieve the above object, a CSCF (Call Session Control Function) included in a Voice over Long Term Evolution (VoLTE) system according to the present invention and communicating with an HSS (Home Subscriber Server) and a PGW (PDN Gateway) A receiving unit for receiving a called party information absence notification signal from the PGW; When a reception information absence notification signal is received from the PGW as a response to the incoming packet, the subscriber session deletion notification signal for inducing the reconnection of the called terminal corresponding to the incoming packet is received And a transmitting unit for transmitting to the HSS.

As described above, according to the present invention, when the called party information is deleted in the PGW, the called party information corresponding to the called party can be newly registered in the PGW by the action of the PGW and the CSCF at the time when the incoming signal to the called party is received have.

Accordingly, it is possible to solve the problem that an incoming call is not received to the called party whose called party information is deleted from the PGW.

1 is a schematic configuration diagram of a VoLTE system according to an embodiment of the present invention,
Figure 2 is a functional block diagram of the PGW of Figure 1,
Figure 3 is a functional block diagram of the CSCF of Figure 1,
4 is a control flowchart of a VoLTE system according to an embodiment of the present invention,
5 is a control flowchart of a PGW according to an embodiment of the present invention,
6 is a control flowchart of a CSCF according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

Hereinafter, embodiments of the present invention will be described in order to facilitate understanding of the present invention, and the present invention is not limited to these embodiments. In particular, the present invention can be configured by combining at least any one of individual components, individual functions, or individual steps included in each embodiment.

A schematic configuration of a Voice over Long Term Evolution (VoLTE) system according to an embodiment of the present invention is shown in FIG.

FIG. 1 shows a VoLTE system configuration connected to a called terminal for convenience, and a configuration connected to a calling terminal is omitted.

The VoLTE system may be divided into an LTE (Long Term Evolution) part and an IMS (IP Multimedia Subsystem) part. In this case, the CSCF 200 of FIG. 1 may belong to the IMS part, The present embodiment describes that each component belongs to the VoLTE system regardless of individual systems or networks.

The VoLTE system according to an exemplary embodiment of the present invention transmits VoIP (Voice over IP) packets via an LTE network to enable mutual communication. The VoLTE system includes an Evolved Node B (eNB) 600, A Mobility Management Entity (MME) 400, an HSS (Home Subscriber Server) 300, a SGW (Serving Gateway) 500, a PGW (PDN Gateway) 100, a CSCF (Call Session Control Function) As shown in FIG.

A brief description of the functions defined in the international standards for these components is as follows.

The eNB 600 may be called an 'LTE base station' and is a device for providing a radio connection between a UE (User Equipment) 700 and an LTE network. In FIG. 1, a UE 700 and an eNB 600 Wireless connection, and the remainder is a wired connection.

Here, the UE 700 means a user terminal, and may be a terminal having a calling function such as a smart phone, or a USB dongle (for connecting to a notebook using a USB type and using a wireless Internet) for data communication only have.

The MME 400 authenticates the UE 700 as an apparatus serving as a brain of the LTE network. At this time, the MME 400 receives key information for authenticating the UE 700 from the HSS 300 and performs authentication of the UE 700 do. The MME 400 manages the EPS bearer, where the EPS bearer is configured to allow the UE 700 to transmit the logical < RTI ID = 0.0 > (eNB600) -SGW-P-GW & (GTP tunnel). The MME 400 is a device that participates in an action such as creation / modification / release of the tunnel.

Further, the MME 400 manages the mobility state of the subscriber, in particular, manages whether the UE 700 is attached to the network, is not attached, attached to the network, uses the Internet, or is in an idle state .

The HSS 300 serves as a central database of an LTE network having key information and a subscriber profile for authentication for each UE 700 (subscriber). The subscriber profile includes a QoS class for each subscriber Information (priority, maximum usable bandwidth, etc.), and the key information for authentication and the subscriber profile are transmitted to the MME 400 as described above when the UE 700 accesses the LTE network.

The SGW 500 performs an anchoring function during the handover between the eNB 600 and the SGW 500. For example, in the handover state of the UE 700, ) Moves to disconnect the connection with the eNB 600 (1) and connects with the eNB (600) 2).

The PGW 100 allocates an IP address to the UE, anchoring the SGWs 500 in a handover state, and applying different QoS policies for each UE 700 (priority, bandwidth control, etc.) And performs accounting data management for each UE 700. [

In addition, the CSCF 200 is a device that performs SIP-based call control and session handling functions and can provide various multimedia services.

CSCF 200 can be divided into various parts according to its logical function. For example, it can be divided into P-CSCF (Proxy-CSCF), I-CSCF (Interrogating-CSCF), and S-CSCF have.

Here, the P-CSCF proxies the SIP message as a point of contact with the UE 700 in the IMS network, and provides functions such as security and compression with the UE 700. The I-CSCF operates as a contact point of the IMS network of the network operator And routes the SIP message to another node in the IMS network.

The S-CSCF manages the session state for the SIP message, performs call control for providing the service requested by the subscriber through routing to the AS, processes the registration request from the UE 700 as a SIP registrar, And performs the function of managing the state.

Hereinafter, each of the constituent elements will be described focusing on the functions of the present invention other than the functions defined in the 3GPP (Third Generation Partnership Project) standard.

First, the PGW 100 can receive an incoming packet from the CSCF 200. Here, the incoming packet means a packet to be transmitted to a predetermined called party (called party terminal).

The PGW 100 determines whether or not the called party information corresponding to the incoming packet exists and, if it is determined that the called party information does not exist, transmits the called party information absence notification signal to the CSCF 200 that has transmitted the incoming packet .

That is, when the called party information corresponding to the incoming packet does not exist, the conventional PGW 100 discards the corresponding packet. However, the PGW 100 according to the embodiment of the present invention transmits the called party information absence notification signal to the CSCF 200 ).

The PGW 100 may include a receiving unit 110, a determining unit 120, a transmitting unit 130, and a storage unit 140, as shown in FIG.

Herein, the storage unit 140 stores information on each subscriber for packet processing.

The receiving unit 110 performs a function of receiving the incoming packet from the CSCF 200 and the determining unit 120 stores the called party information corresponding to the incoming packet received in the receiving unit 110 in the storage unit 140 Or not. That is, the determination unit 120 determines whether or not the called party information exists. Determination of the presence or absence of the recipient information corresponding to the incoming packet corresponds to a known technique, and a detailed description thereof will be omitted.

When the determination unit 120 determines that the called party information does not exist, the transmitting unit 130 transmits the called party information absence notification signal to the CSCF 200 that has transmitted the incoming packet.

Here, if the called party information does not exist as a result of the determination by the determination unit 120, the transmitting unit 130 transmits the called party information only when the incoming packet received from the CSCF 200 is an INVITE packet according to SIP (Session Initiation Protocol) A notification signal can be transmitted to the CSCF 200. That is, when the incoming packet is a packet other than the INVITE packet, when the called party information does not exist, the packet is discarded as it is.

Herein, the subscriber session deletion notification signal transmitted to the CSCF 200 may be an Internet Control Message Protocol (ICMP) Destination Unreachable packet. That is, the transmitting unit 130 transmits to the CSCF 200 a packet indicating that the Internet Control Message Protocol (ICMP) type 3 "object can not be connected ".

On the other hand, when the CSCF 200 receives the incoming information absence notification signal from the PGW 100 after transmitting the incoming packet received from the calling party to the PGW 100, the CSCF 200 transmits a subscriber session deletion notification signal to the HSS 300 And performs the function of transmitting.

3, the CSCF 200 may include a receiving unit 210 and a transmitting unit 220. The receiving unit 210 may include a function of receiving an incoming packet for a called party from a calling party, And performs a function of receiving the called party information absence notification signal from the PGW 100,

The transmission unit 220 not only has a function of transmitting the incoming packet received from the calling side to the PGW 100 but also receives the incoming information absence notification signal from the PGW 100 in response to the incoming packet to the receiving unit 210 And transmits a subscriber session deletion notification signal to the HSS 300 to induce reconnection of the called terminal corresponding to the incoming packet.

Here, the subscriber session deletion notification signal transmitted from the PGW 100 may be an Internet Control Message Protocol (ICMP) Destination Unreachable packet as described above, and the subscriber session deletion notification signal transmitted to the HSS 300 may be an ASR -Request message.

The HSS 300 transmits a subscriber location information deletion request message to the MME 400 when the subscriber session deletion notification signal is received from the CSCF 200. The HSS 300 transmits a subscriber location information deletion request message to the MME 400 from the HSS 300, And transmits a reconnection control signal to the corresponding destination terminal when the location information deletion request message is received.

Accordingly, the called terminal performs the reconnection process. The reconnection process performed by the predetermined terminal in accordance with the reconnection control signal of the MME 400 is a known technology, and thus a detailed description thereof will be omitted.

According to the above description, when the called party information is deleted from the PGW 100 and the incoming call to the called terminal is received, the PGW 100 transmits a kind of request signal to the CSCF 200, And the incoming information is restored to the PGW 100 so that the called terminal can be in a state in which it can talk.

Hereinafter, a general control flow of the VoLTE system according to an embodiment of the present invention will be described with reference to FIG.

In FIG. 4, the eNB 600 and the SGW 500 are merely performing known techniques, and therefore, the illustration thereof is omitted.

It is assumed that the subscriber information exists in the current terminal, the MME 400, the HSS 300, and the CSCF 200, and the subscriber information is deleted in the PGW 100 due to an error in the device.

In this state, when the CSCF 200 transmits an incoming signal received from the calling side, that is, an INVITE message to the PGW 100 (step S1), the PGW 100 determines whether there is the called party information corresponding to the INVITE message The PGW 100 transmits a Destination Unreachable packet corresponding to the ICMP type 3 to the CSCF 200 because the recipient information does not exist in the PGW 100 in step S3.

Upon receiving the ICMP packet from the PGW 100, the CSCF 200 transmits an Abort Session Request (Cause: Timeout De-reg) signal corresponding to the subscriber session cancellation notification signal to the HSS 300 (step S5).

The HSS 300 having received the above Abort Session Request from the CSCF 200 transmits an Abort Session Answer signal as a response to the CSCF 200 (step S7) And transmits a Cancel Location Request (Subscription withdrawal) signal corresponding to the message (Step S9).

The MME 400 having received the Cancel Location Request from the HSS 300 transmits a Detach Request (Reattach required) signal corresponding to the reconnection control signal to the corresponding called terminal (step S23).

In FIG. 1, steps S11 to S21 correspond to known general processes, and therefore, a detailed description thereof will be omitted.

The called terminal that has received the above-described Detach Request from the MME 400 performs new attach (step S27), and then performs SIP REGISTER (step S29).

Through the reconnection process of the called terminal, the called party information corresponding to the called party is registered in the PGW 100, so that the incoming call can reach the corresponding called terminal.

Here, the PGW 100 in which the called party information corresponding to the called terminal is registered may correspond to the PGW 100 in which the corresponding called party information was previously registered, or may correspond to another PGW (not shown).

Hereinafter, a control process of the PGW 100 according to an embodiment of the present invention will be described with reference to FIG.

When the incoming packet is received from the CSCF 200 (step S31), the PGW 100 analyzes the received incoming packet (step S33), and judges whether there is any recipient information corresponding to the incoming packet (step S35 ).

If the called party information exists as a result of the determination, the PGW 100 transmits the packet to the called party (for example, the called party via the SGW 500) to allow the communication to be performed (step S37) If the incoming packet is not an INVITE message (step S39), the PGW 100 discards the incoming packet (step S41). If the incoming packet is an INVITE message (step S39), the PGW 100 deletes the ICMP packet (Step S43) and transmits it to the CSCF 200 (step S45).

6 is a flowchart illustrating a control process of the CSCF 200 according to an exemplary embodiment of the present invention.

The CSCF 200 transmits the received INVITE message received from the calling side to the PGW 100 (step S51), and waits until the 180 Ringing signal is received (step S53).

If the 180 Ringing signal is received from the PGW 100 in step S55, the CSCF 200 performs normal call processing according to the known method (step S57). If the ICMP Destination Unreachable packet is received from the PGW 100 (Step S59), the CSCF 200 transmits an ASR (Timeout De-reg) signal to the HSS 300 (step S61).

Meanwhile, it goes without saying that the process of performing each of the above-described embodiments can be performed by a program or an application stored in a predetermined recording medium (for example, a computer-readable). Here, the recording medium includes an electronic recording medium such as a RAM (Random Access Memory), a magnetic recording medium such as a hard disk, and an optical recording medium such as a CD (Compact Disk).

At this time, the program stored in the recording medium may be executed on hardware such as a computer or a smart phone to perform each of the above embodiments. In particular, at least one of the functional blocks of the PGW and CSCF according to the present invention described above can be implemented by such a program or application.

The present invention is not limited to the above-described specific embodiments, and various modifications and changes may be made without departing from the gist of the present invention. It is to be understood that such variations and modifications are intended to be included in the scope of the appended claims.

100: PGW 200: CSCF
300: HSS 400: MME
500: SGW 600: eNB
700: UE 110:
120: determination unit 130:
140: storage unit 210: receiving unit
220:

Claims (16)

A control method of a Voice over Long Term Evolution (VoLTE) system including an MME (Mobility Management Entity), an HSS (Home Subscriber Server), a PGW (PDN Gateway), and a CSCF (Call Session Control Function)
(a) when the PGW receives an incoming packet from the CSCF, determining whether the called party information corresponding to the incoming packet exists;
(b) if the called party information does not exist as a result of the determination in step (a), the PGW transmits a called party information absence notification signal to the CSCF that has transmitted the incoming packet;
(c) transmitting a subscriber session deletion notification signal to the HSS when the CSCF receives an incoming information absence notification signal from the PGW;
(d) transmitting a subscriber location information deletion request message to the MME when the HSS receives a subscriber session deletion notification signal from the CSCF;
(e) when the MME receives the subscriber location information deletion request message from the HSS, transmitting a reconnection control signal to the corresponding called terminal. The method according to claim 1,
In step (b), when the incoming packet received from the CSCF is an INVITE packet according to SIP (Session Initiation Protocol), the PGW generates an Internet Control Message Protocol (ICMP) Destination Unreachable packet as the subscriber session deletion notification signal To the CSCF. If the incoming packet received from the CSCF is not an INVITE packet according to SIP (Session Initiation Protocol), the control unit discards the incoming packet. The method according to claim 1,
Wherein the subscriber session cancellation notification signal transmitted from the CSCF to the HSS in step (c) is an Abort-Session-Request (ASR) message. A control method of a PGW (PDN Gateway) included in a Voice over Long Term Evolution (VoLTE) system and communicating with a CSCF (Call Session Control Function)
(a) receiving an incoming packet from the CSCF, determining whether the called party information corresponding to the incoming packet exists;
(b) if the called party information does not exist as a result of the determination in step (a), transmitting a called party information absence notification signal to the CSCF that has transmitted the incoming packet. 5. The method of claim 4,
In step (b), if the incoming packet received from the CSCF is an INVITE packet according to SIP (Session Initiation Protocol), an Internet Control Message Protocol (ICMP) Destination Unreachable packet is generated as the subscriber session deletion notification signal, If the incoming packet received from the CSCF is not an INVITE packet according to SIP (Session Initiation Protocol), discards the incoming packet. A control method of a CSCF (Call Session Control Function) included in a Voice over Long Term Evolution (VoLTE) system and communicating with an HSS (Home Subscriber Server) and a PGW (PDN Gateway)
(a) transmitting an incoming packet to the PGW;
(b) transmitting a subscriber session deletion announcement signal to the HSS for inducing reconnection of the called terminal corresponding to the incoming packet when the called party information absence notification signal is received from the PGW that transmitted the incoming packet Gt; CSCF < / RTI > The method according to claim 6,
Wherein the subscriber's session absence notification signal received from the PGW is an Internet Control Message Protocol (ICMP) Destination Unreachable packet and the subscriber session deletion notification signal transmitted to the HSS is an Abort-Session-Request (ASR) message. Control method. A computer-readable recording medium recording a program for executing the method according to any one of claims 1 to 7. 7. An application stored in a medium for executing the method of any one of claims 1 to 7 in combination with hardware. A Mobility Management Entity (MME), a Home Subscriber Server (HSS), a PDW Gateway (PGW), and a Call Session Control Function (CSCF)
When the PGW receives the incoming packet from the CSCF, the PGW determines whether or not the called party information corresponding to the incoming packet exists. If the called party information does not exist as a result of the determination, the PGW sends a CSCF, which has transmitted the incoming packet, Lt; / RTI >
The CSCF transmits a subscriber session deletion notification signal to the HSS when receiving an incoming information absence announcement signal from the PGW after transmitting an incoming packet to the PGW,
The HSS transmits a subscriber location information deletion request message to the MME when a subscriber session deletion notification signal is received from the CSCF,
Wherein the MME transmits a reconnection control signal to a corresponding called terminal upon receiving a subscriber location information deletion request message from the HSS. 11. The method of claim 10,
If the called party information does not exist, the PGW generates an Internet Control Message Protocol (ICMP) Destination Unreachable packet as the subscriber session cancellation notification signal if the incoming packet received from the CSCF is an INVITE packet according to SIP (Session Initiation Protocol) CSCF. If the incoming packet received from the CSCF is not an INVITE packet according to SIP (Session Initiation Protocol), the VoLTE system discards the incoming packet. 11. The method of claim 10,
Wherein the subscriber session deletion notification signal transmitted by the CSCF to the HSS is an Abort-Session-Request (ASR) message. In a PGW (PDN Gateway) included in a Voice over Long Term Evolution (VoLTE) system and communicating with a CSCF (Call Session Control Function)
A receiving unit for receiving an incoming packet from the CSCF;
A determination unit configured to determine whether or not the called party information corresponding to the incoming packet received by the receiving unit exists;
And a transmission unit for transmitting a called party information absence notification signal to the CSCF that has transmitted the incoming packet if there is no called party information as a result of the determination by the determination unit. 14. The method of claim 13,
If the called party information does not exist as a result of the determination by the determination unit and the incoming packet received from the CSCF is an INVITE packet according to SIP (Session Initiation Protocol), the transmitter transmits an Internet Control Message Protocol (ICMP) Destination Unreachable And transmits the packet to the CSCF. If the incoming packet received from the CSCF is not an INVITE packet according to SIP (Session Initiation Protocol), the PGW discards the corresponding incoming packet. In a CSCF (Call Session Control Function) included in a Voice over Long Term Evolution (VoLTE) system and communicating with an HSS (Home Subscriber Server) and a PGW (PDN Gateway)
A receiving unit for receiving a called party information absence notification signal from the PGW;
When a reception information absence notification signal is received from the PGW as a response to the incoming packet, the subscriber session deletion notification signal for inducing the reconnection of the called terminal corresponding to the incoming packet is received And a transmission unit for transmitting the CSCF to the HSS. 16. The method of claim 15,
Wherein the CSCF is an Internet Control Message Protocol (CSCF) Destination Unreachable packet received from the PGW, and the subscriber session deletion notification signal transmitted to the HSS is an Abort-Session-Request (ASR) message.

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