KR102111763B1 - Method and apparatus for providing single radio voice call continuity - Google Patents

Abstract

A method for providing call continuity is provided, and receiving a message corresponding to a handover failure of a wireless terminal connected to a second network to a first network from a first network or a switched network, guarding based on the received message The step of driving a timer (Guard Timer), and when receiving a handover request message from the wireless terminal, for a predetermined time in the guard timer, transmits a failure response to the handover request message to the wireless terminal or is set in the guard timer For a period of time, not responding to the handover request message.

Description

METHOD AND APPARATUS FOR PROVIDING SINGLE RADIO VOICE CALL CONTINUITY}

The present invention relates to a method and apparatus for providing call continuity, and more specifically, a method and apparatus for preventing network resource consumption by failing to process SRVCC operation request under a preset condition in which Single Radio Voice Call Continuity (SRVCC) is impossible It is about.

Recently, as the spread of wireless terminals (UEs) such as smart pads, tablet PCs, and smartphones increases, wireless terminals using LTE networks are increasing to provide better services than 3G.

At this time, a method of supporting call continuity in a wireless terminal is made by using an identifier. In this regard, in Korean Patent Publication No. 2012-0095897 (published on August 29, 2012), which is a prior art, there is a method of managing a video bearer and a voice bearer using an identifier during handover from a first communication network to a second communication network in a wireless terminal. Is disclosed.

However, the wireless terminal may be handed over to a 2G or 3G network if it is outside the scope of the LTE network. Here, when the wireless terminal is in a multi-party call state, it is set not to perform a handover operation for the SRVCC of the wireless terminal, but when the wireless terminal is located in the weak electric field, the base station requests handover indefinitely. At the request of the base station, resources of the 2G or 3G network are continuously allocated.

Korean Patent Publication No. 2012-0095897 (published on August 29, 2012) discloses a "method and system for supporting single wireless video call continuity during handover".

According to an embodiment of the present invention, when the wireless terminal requests a handover based on a specific electric field condition even though the wireless terminal is in a state not to perform a handover operation for SRVCC, it is previously set in a guard timer. It is possible to provide a method and apparatus for providing call continuity that can prevent unnecessary network resource allocation due to continuous handover requests by transmitting a failure response for a period of time. However, the technical problem to be achieved by the present embodiment is not limited to the technical problem as described above, and other technical problems may exist.

The method for providing call continuity according to the first aspect is a method for providing call continuity executed in a device for providing continuity of calls in the first network network in a mixed communication environment of a first network network, a second network network, and an IP Multimedia Subsystem (IMS) network. The method of claim 1, further comprising: receiving a request for handover from the second network network to the first network network for the voice call of the wireless terminal from the second network network, and in response to the handover request, the first network network and Attempting to perform handover processing with the IMS network, and if the attempt of the handover processing fails according to the handover setting for Single Radio Voice Call Continuity (SRVCC) for the voice call, the request for the handover is performed. Not responding for a set time or sending a failure response to the handover request to the second network Steps.
A method for providing continuity of calls according to a second aspect of the present invention provides a method for providing continuity of calls performed in a device for providing continuity of calls in a second network in a mixed communication environment of a first network, a second network, and an IMS network. Receiving a handover from the second network network to the first network network for a voice call from the base station in the second network network, and requesting the IMS network to the first network network at the request of the handover Requesting a handover processing attempt, and requesting the handover when receiving a failure response of the handover processing according to the handover setting for SRVCC for the voice call from the IMS network through the first network network Respond to a failure response to the request of the handover or not responding for a preset time for 2 transmitting to the base station in the network access.

According to any one of the above-described problem solving means of the present invention, it is possible to eliminate the network resource consumption due to the SRVCC re-request that persists in a state where SRVCC operation is impossible.

1 is a block diagram illustrating a data network system according to an embodiment of the present invention.
FIG. 2 is a configuration diagram illustrating the terminal exchange device illustrated in FIG. 1.
FIG. 3 is a configuration diagram illustrating the mobility management device illustrated in FIG. 1.
4 is a diagram illustrating a process in which data is transmitted and received between each of the components included in the data network system of FIG. 1 according to an embodiment of the present invention.
5 is a diagram illustrating a process in which data is transmitted and received between each of the components included in the data network system of FIG. 1 according to another embodiment of the present invention.
6 is an operation flowchart for explaining a method for providing call continuity according to an embodiment of the present invention.
7 is an operation flowchart for explaining a method for providing call continuity according to another embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art to which the present invention pertains may easily practice. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. In addition, in order to clearly describe the present invention in the drawings, parts irrelevant to the description are omitted, and like reference numerals are assigned to similar parts throughout the specification.

Throughout the specification, when a part is "connected" to another part, this includes not only "directly connected" but also "electrically connected" with another element in between. . Also, when a part is said to "include" a certain component, it means that the component may further include other components, not exclude other components, unless specifically stated otherwise. However, it should be understood that the existence or addition possibilities of numbers, steps, actions, components, parts or combinations thereof are not excluded in advance.

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

1 is a block diagram illustrating a data network system according to an embodiment of the present invention. Referring to FIG. 1, a data network system may include a User Equipment (UE) 100, a first network network 300, a second network network 500, and an IP Multimedia Subsystem (IMS) network 700. At this time, the first network network 300 is Node B 310, RNC (Radio Network Control, 320), MSC (Mobile switching center, 330), GMSC (Gateway MSC, 340), PSTN (Public Switched Telephone Network, 350) ), SGSN (Serving GPRS Support Node, 360), GGSN (Gateway GPRS Support Node, 370), and PDN (Public Data Network, 380). The second network network 500 includes Evolved Node B (510), eNB (Serving Gateway, 520), MME (Mobility Management Entity, 530), PGW (PDN Gateway, 540), OCS (Online Charging System, 550) , OFCS (Offline Charging System, 560), SPR (Subscriber Profile Repository, 570), PCRF (Policy and Charging Rules Function, 580), PDN (Public Data Network, 590). The IMS network 700 includes a Call Session Control Function (CSCF) 710, a Telephony Application Server (TAS) 720, a Media Gateway Control Function (MGCF) 730, an SCC AS (Single Radio Voice Call Continuity Application Server, 740), It may include MGW (Media Gate Way, 750), HLR (Home Location Register, 760), MRF (Multimedia Resource Function, 770). However, since the data network system of FIG. 1 is only an embodiment of the present invention, the present invention is not limitedly interpreted through FIG. 1.

Hereinafter, each component of the data network system of FIG. 1 will be described in detail.

UE 100 may be a user terminal. At this time, the UE 100 may be implemented as a terminal that can access a remote server or terminal. The UE 100 is, for example, a wireless communication device in which portability and mobility are guaranteed, and all types of smartphones, smartpads, tablet PCs, and the like that can be connected to the PDN 590. It may include a handheld-based wireless communication device.

The Node B 310 may serve as a base station that guarantees the mobility of the UE 100. At this time, the Node B 310 may secure a frequency used for connection with the UE 100 and perform a function to ensure a stable connection with the UE 100.

The RNC 320 may manage radio resources, control a plurality of Node Bs 310, and perform management functions for interfaces between different network elements.

The MSC 330 may perform a central control function that processes incoming or outgoing signals and adjusts the first network network 300 to operate. In addition, the MSC 330 may control the radio link and the wired link, manage the location of the UE 100, and obtain location registration information of the UE 100 from the HLR 760. At this time, the HLR 760 may transmit various information such as the origination status, the reception status, and additional services of the UE 100 to the MSC 330 and data on the location of the UE 100.

The GMSC 340 may have an automatic tracking connection function to determine a mobile switching center (VMSC) and select and designate a call by referring to the location information of the UE 100 stored in the HLR 760.

The PSTN 350 may be a public switched telephone network. Here, a signal corresponding to a voice call (Circuit Service) may be transmitted through the paths of the MSC 330-GMSC 340-PSTN 350.

The SGSN 360 may be a node responsible for data packet delivery within a service area. At this time, the SGSN 360 may have functions such as packet routing and transmission, mobility management, logical link management, authentication and charging, and the location register of the SGSN 360 is a GPRS user location registered in the SGSN 360 Information, user profiles, etc. can be stored.

The GGSN 370 may be a node in charge of a connection function between the backbone network and the external packet data network. The GGSN 370 converts the GPRS packet transmitted from the SGSN 360 into an appropriate packet data protocol format and transmits it, and converts the PDP address of the incoming packet data into the recipient's GSM address. In addition, the GGSN 370 may store the address and user profile of the SGSN 360 of the current user existing in the location register of the SGSN 360, and may perform a rate addition function.

The PDN 380 is a public data network, and may be, for example, the Internet or an IP network. Here, a signal corresponding to a data call (Packet Service) may be transmitted through the path of the SGSN 360-GGSN 370-PDN 380.

The eNB 510 may be an LTE base station, or a device that provides a wireless connection between the UE 100 and an LTE network. That is, the eNB 510 can connect between the SGW 520 and the UE 100 and manage handover of the UE 100. At this time, the eNB 510 and the UE 100 may be connected wirelessly.

The SGW 520 controls movement of the UE 100 between 3GPP / E-UTRAN and may perform anchoring during handover of the eNB 510 to the UE 100. For example, when the UE 100 is handed over from one eNB 510 to the other eNB 510, handover of the UE 100 may occur with the SGW 520 as an axis. Accordingly, the SGW 520 may operate as an anchor point in intra-LTE mobility.

The MME 530 may control a signal between the eNB 510 and the SGW 520, determine routing, and authenticate the UE 100. At this time, the authentication protocol of the MME 530 may be EPS-AKA, and key information for authenticating the UE 100 may be stored in the HLR 760. Accordingly, the MME 530 may receive key information from the HLR 760 to perform authentication for the UE 100. Also, the MME 530 may manage the EPS bearer. At this time, the EPS bearer (Bearer), for example, UE (100) and PGW (540) between (UE (100) -eNB (510) -SGW (520) -PGW (540)) is a logical tunnel generated between The MME 530 may control the creation, change, and release of the tunnel.

The PGW 540 may allocate an IP address to the UE 100. At this time, the IP address may be assigned through the UE 100 access procedure defined in 3GPP, not the DHCP protocol. In addition, the PGW 540 can perform anchoring for the SGW 520.

The OCS 550 may centrally manage the residual usage (Balance or Credit) for real-time usage for each UE 100 when the UE 100 uses a prepaid. Here, real-time usage may be managed by the PGW 540 and the residual usage may be delivered to the OCS 550. At this time, the OCS 550 may inform the PGW 540 of the corresponding information so that the service can no longer be used for the UE 100 using all the remaining usage.

The OFCS 560 may receive and manage the CDRs transmitted by the PGW 540 centrally.

The SPR 570 may store policy and charging rules for each UE 100. Accordingly, the PCRF 580 may obtain information about the UE 100 from the SPR 570.

The PCRF 580 may be a device that determines rules for policies and charging for each UE 100. At this time, the policy may be QoS information to be used by the UE 100, and the charging may be information on whether to perform offline charging or online charging.

The PDN 590 is a public data network, and may be, for example, the Internet or an IP network.

The CSCF 710 is a function in charge of a part related to call processing, and may be composed of an Incoming CAll GateWay (ICGW), a CAll Control Function (CCF), a Serving Profile Database (SPD), and Address Handling (AH).

The TAS 720 may be a server that processes calls. In addition, the TAS 720 includes a subscriber database, an interworking interface, and can perform the functions of billing, operation, administration, and maintenance (OAM).

The MGCF 730 may perform signal conversion for interworking with the PSTN 350, ISUP (ISDN User Part), and CDMA used in the SIP and circuit-switched networks. For example, a voice call coming up from 3G through the PSTN 350 may be converted.

The SCC AS 740 may provide continuity of radio resources of the UE 100. For example, in a voice call using LTE or VoLTE, the voice call may be handed over to 3G or 2G so that the voice call is not disconnected where there is no LTE network. The SCC AS 740 may roam, for example, a voice call based on VoLTE into a voice call based on 2G or 3G. At this time, the roaming method may be a method of handing over a VoIP call to a CS (Circuit Switched) call.

The MGW 750 may be a gateway that serves to connect with the MGCF 730, and for interworking with the first network 300 and the second network 500 connected to the CSCF 710, signaling is performed. And media can be converted.

The HLR 760 may be a central database of an LTE network that holds key information for authentication for each UE 100, subscriber profiles, subscriber location information, and the like. At this time, the subscriber profile may include quality of service (QoS) rating information suitable for a service product subscribed to by each subscriber, for example, priority, maximum available bandwidth, and the like.

The MRF 770 may provide a media source in the IMS network 700. In addition, the MRF 700 can manage the call announcement broadcast provided to the UE 100 and can operate as a server for group calls.

The method for providing call continuity occurring in a data network system according to an embodiment of the present invention will be described as an example.

Recently, as the spread of wireless terminals (UEs) such as smart pads, tablet PCs, and smartphones increases, wireless terminals using LTE networks are increasing to provide better services than 3G.

At this time, the wireless terminal may be handed over to the 2G or 3G network if it is outside the scope of the LTE network. Here, according to the standard, when a wireless terminal is in a multi-party call state, a handover for a single radio voice call consistency (SRVCC) operation is not performed on the wireless terminal. SRVCC is a technology that provides (assurance) call continuity by handing over to a circuit network when a wireless terminal enters an LTE weak field during a Voice Over LTE (VoLTE) call. However, when the wireless terminal in the VoLTE call is located in the LTE weak field, the base station requests infinite handover, so the upper network end continuously allocates resources of the first network 300 according to the request of the base station. do.

Therefore, the method for providing continuity of a call according to an embodiment of the present invention is to request a handover based on a specific electric field condition, even though it is in a state in which the handover operation for SRVCC is not performed for the wireless terminal, By sending a failure response for a preset time to the guard timer, it is possible to prevent unnecessary network resource allocation due to continuous handover request.

FIG. 2 is a configuration diagram for describing the terminal exchange device illustrated in FIG. 1, and FIG. 3 is a configuration diagram for describing the mobility management apparatus illustrated in FIG. 1.

Referring to FIG. 2, the terminal exchange device 330 may include a receiving unit 331, a driving unit 333, a transmitting unit 335, and a generating unit 337. In this case, the UE 100 of FIG. 1 is defined as the wireless terminal 100, the MME 530 is defined as the mobility management device 530, and the IMS network 700 is defined as the switching network 700. In addition, the operation of the terminal switching device 330 may be performed by the MSC 330, but may also be performed by other devices, and the terminal switching device 330 in FIG. 2 may be referred to as a device for providing call continuity.

The configuration of the terminal exchange device 330 according to an embodiment of the present invention is as follows.

The reception unit 331 corresponds to a handover failure from the first network network 300 or the switched network 700 to the first network network 300 of the wireless terminal 100 connected to the second network network 500. Receive a message. In this case, the terminal switching device 330 may determine whether a call state (Call State: Active, Idle, etc.) and resource allocation success or failure in the first network network 300 in the switching network 700 are successful. At this time, the terminal switching device 330 may transmit a message corresponding to a handover success (PS to CS Response Success) only when a success signal comes from both the first network network 300 and the switching network 700. .

The driver 333 drives a guard timer based on the received message. At this time, the guard timer can be set in the terminal exchange device 330, for example, can be set to 10 seconds.

When receiving the handover request message from the wireless terminal 100, the transmitter 335 transmits a failure response to the handover request message to the wireless terminal 100 for a preset time in the guard timer. At this time, when receiving the handover request message from the wireless terminal 100, the transmitter 335 may not respond to the handover request message for a preset time in the guard timer.

Meanwhile, the configuration of the terminal exchange device 330 according to another embodiment of the present invention is as follows.

The receiving unit 331 is a message corresponding to a handover failure from the first network network 300 or the switching network 700 to the first network network 300 of the wireless terminal 100 connected to the second network network 500 To receive.

The generating unit 337 generates a call continuity failure message based on the received message. In this case, the terminal switching device 330 may determine whether a call state (Call State: Active, Idle, etc.) and resource allocation success or failure in the first network network 300 in the switching network 700 are successful. At this time, the terminal switching device 330 may transmit a message corresponding to a handover success (PS to CS Response Success) only when a success signal comes from both the first network network 300 and the switching network 700. . Therefore, the terminal switching device 330 receives a failure according to a Prepare Hand Over Request Failure of the first network network 300 or a call state of the switching network 700, or the like. An exchange failure response (PS to CS Response (Failure)) may be provided, including a reason (SRVCC Temporary Not Possible).

Therefore, the transmitter 335 transmits the exchange failure response including the generated call continuity failure message to the mobility management device 530. Accordingly, in the apparatus for providing continuity of calls according to an embodiment of the present invention and another embodiment, the wireless terminal 100 has a specific electric field condition, for example, RSRP (Reference Signal Received Power) of -115 dB or less Even in the case of requesting SRVCC by receiving a value, when the SRVCC operation is not actually possible, the SRVCC operation can be prevented for a specific time.

Referring to FIG. 3, the mobility management device 530 may include a receiver 531, a driver 533, and a transmitter 535. At this time, the UE 100 of FIG. 1 is defined as a wireless terminal 100, the MSC 330 is defined as a terminal switching device 330, and the IMS network 700 is defined as a switching network 700. Further, the operation of the mobility management device 530 may be performed by the MME 530, but may also be performed by another device, and the mobility management device 530 in FIG. 3 may be referred to as a call continuity providing device.

The reception unit 531 receives a call continuity failure message based on the handover failure of the wireless terminal 100 from the terminal switching device 330.

The driver 533 drives a guard timer based on the received call continuity failure message. At this time, the call continuity failure message, the terminal switching device 330, the first network network 300 of the wireless terminal 100 connected to the second network network 500 from the first network network 300 or the switching network 700 ) When a message corresponding to a handover failure is received.

When receiving the handover request message from the wireless terminal 100, the transmitter 535 transmits a failure response to the handover request message to the wireless terminal 100 for a preset time in the guard timer. In addition, when receiving the handover request message from the wireless terminal 100, the transmission unit 535 may not transmit the handover request message to the terminal exchange device 330 for a preset time in the guard timer.

The description of the method for providing continuity of calls in FIGS. 2 and 3 can be easily inferred from the contents described or described for the method for providing continuity of calls through FIG. 1, so that the following description will be omitted. do.

4 is a diagram illustrating a process in which data is transmitted and received between each of the components included in the data network system of FIG. 1 according to an embodiment of the present invention, and FIG. 5 is a data of FIG. 1 according to another embodiment of the present invention A diagram showing a process in which data is transmitted and received between each of the components included in the network system. Hereinafter, an example of a process in which data is transmitted and received between each of the components will be described with reference to FIGS. 4 and 5, but the present application is not limited to such an embodiment, and according to various embodiments described above, FIG. 4 And it is apparent to those skilled in the art that the process of transmitting and receiving data shown in FIG. 5 may be changed.

In this case, in FIGS. 4 and 5, the capital letter O is defined as originating, and the capital letter T is defined as terminating. For example, UE (0) may mean an originating terminal, and UE (T) may mean an incoming terminal.

4, the UE (0) (100 (0) transmits measurement reports (Measurement Reports) to the source eNB 510 for initiating a handover (S4100). Then, the eNB 510 is QoS , SRVCC operation based on the assigned bearer and priority, that is, determines whether a handover should occur (S4200), and notifies the MME 530 when the handover is determined (S4300).

When the MME 530 initiates the bearer separation (S4400), and sends a request to change from PS to CS to the MSC 330 to request handover processing (S4500), the MSC 330 receives the MSC (T ) (330 (T)) transmits a request to prepare for handover (S4510).

When the MST (T) 330 (T) sends a location reset request to the RNC (T) 320 (T) (S4520), and receives a response to the request from the RNC (T) 320 (T) (S4530), the MSC 330 transmits a response that the handover is ready (S4540).

Thereafter, a circuit is connected between the MSC 330 and the MSC (T) 330 (T) (S4600), and the MSC 330 transmits an in-byte message based on the start of the session movement to the IMS network 700. Upon receiving the response, data session delivery (STN-SR or E-STN-SR) is initiated (S4700).

At this time, if the MSC 330 receives a message corresponding to a handover failure for SRVCC operation for a voice call of VoLTE (for example, a failure according to a call state of the switching network 700) (S4800) ), The MSC 330 drives the guard timer (S4810), ignores the handover request of the MME 530 for a time set in the guard timer, or transmits a failure response (S4830).

On the other hand, if the MSC 330 receives a message corresponding to the handover success (S4800), the SRVCC response is transmitted to the MME 530 (S4900), and the MME 530 receiving the message is sent to the eNB 510. The handover command is transmitted (S4910), and the eNB 510 transmits it back to the UE (O) 100 (O) (S4920). At this time, the UE (O) 100 (O) is handed over from the second network 500, for example, the LTE network, to the first network 300, for example, the 3G network (S4930). Here, the IMS network 700 performs session movement and remote leg update (S4840), and then releases the IMS access leg (S4850).

In addition, when handover detection occurs in the RNC (T) 320 (T) (S4940), the UE (O) (100 (O)) sends a handover completion message to the MSC (T) 330 (T). Transmit to the MSC 330 via (S4950, S4960). Here, the MSC 330 reports that the SRVCC operation is completed to the MME 530 (S4970), and receives a response to the report (S4980).

Referring to Figure 5, UE (0) (100 (0) transmits measurement reports (Measurement Reports) to the source eNB (510) for initiating a handover (S5100). Then, the eNB (510) QoS , SRVCC operation based on the allocated bearer and priority, that is, determines whether a handover should occur (S5200), and notifies the MME 530 when the handover is determined (S5300).

The MME 530 starts the bearer separation (S5400), and when a request to change from PS to CS is transmitted to the MSC 330 (S5500), the MSC 330 is handed to the MSC (T) (330 (T)). A request to prepare for the over is transmitted (S5510).

When the MST (T) 330 (T) sends a location reset request to the RNC (T) 320 (T) (S5520), and receives a response to the request from the RNC (T) 320 (T) (S5530), the MSC 330 transmits a response that the handover is ready (S5540).

Then, the MSC 330 and the MSC (T) 330 (T) are connected to the circuit (S5600), and the MSC 330 transmits an in-byte message based on the start of session movement to the IMS network 700. Upon receiving the response, data session delivery (STN-SR or E-STN-SR) is initiated (S5700).

At this time, the MSC 330 receives a message corresponding to a handover failure for SRVCC operation for a voice call of VoLTE (for example, a failure according to a call state of the switching network 700) (S5800) ), Generates a call continuity failure message that handover is not possible (S5810), and transmits it to the MME 530. At this time, the call continuity failure message includes a specific reason for the failure (Cause: SRVCC Temporary Not Possible) and is transmitted (S5820).

After receiving the call continuity failure message, the MME 530 checks the information that the SRVCC included in the message of S5820 is temporarily impossible, and then drives the guard timer (S5830), and hands the eNB 510 for the time set in the guard timer. Ignore the over request or transmit a failure response (S5850).

On the other hand, if the MSC 330 receives a message corresponding to the handover success (S5800), the SRVCC response is transmitted to the MME 530 (S5900), and the MME 530 receiving the message is sent to the eNB 510. The handover command is transmitted (S5910), and the eNB 510 transmits it back to the UE (O) 100 (O) (S5920). At this time, the UE (O) 100 (O) is handed over from the second network 500, for example, the LTE network, to the first network 300, for example, the 3G network (S5930). Here, the IMS network 700 performs session movement and remote leg update (S5860), and then releases the IMS access leg (S5870).

In addition, when handover detection occurs in the RNC (T) 320 (T) (S5940), the UE (O) 100 (O) sends a handover completion message to the MSC (T) 330 (T). Transmit to the MSC 330 via (S5950, S5960). Here, the MSC 330 reports that the SRVCC operation has been completed to the MME 530 (S5970), and receives a response to the report (S5980).

The details not described with respect to the method of providing continuity of calls in FIGS. 5 and 6 can be easily inferred from the same or described contents of the methods of providing continuity of calls in FIGS. It should be omitted.

The order between the above-described steps (S4100 to S4980, S5100 to S5980) is only an example, and is not limited thereto. That is, the order between the above-described steps (S4100 to S4980, S5100 to S5980) may be mutually varied, some of which may be executed or deleted simultaneously.

6 is an operation flowchart for explaining a method for providing call continuity according to an embodiment of the present invention, and FIG. 7 is an operation flowchart for explaining a method for providing call continuity according to another embodiment of the present invention.

Referring to FIG. 6, the terminal switching apparatus receives a message corresponding to a handover failure of the wireless terminal connected to the second network network from the first network network or the switching network to the first network network (S6100).

Then, the terminal switching device drives a guard timer based on the received message (S6200).

In addition, when receiving a handover request message from the mobility management device (MME), the terminal switching device transmits a failure response to the handover request message to the mobility management device (MME) for a preset time in the guard timer ( S6300).

Referring to FIG. 7, the mobility management apparatus receives a call continuity failure message based on the handover failure of the wireless terminal from the terminal switching apparatus (S7100).

Here, the mobility management device drives the guard timer (Guard Timer) based on the received call continuity failure message (S7200).

Then, when receiving the handover request message from the base station (eNB), the mobility management apparatus transmits a failure response to the handover request message to the base station (eNB) for a preset time in the guard timer (S7300).

The details not described with respect to the method for providing continuity of calls in FIGS. 6 and 7 can be easily inferred from the same or described contents for the method for providing continuity of calls with reference to FIGS. It should be omitted.

The method for providing call continuity according to one embodiment and another embodiment described with reference to FIGS. 6 and 7 is also provided in the form of a recording medium including instructions executable by a computer, such as an application or program module executed by a computer. Can be implemented. Computer readable media can be any available media that can be accessed by a computer and includes both volatile and nonvolatile media, removable and non-removable media. In addition, computer readable media may include both computer storage media and communication media. Computer storage media includes both volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Communication media typically include computer readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave, or other transport mechanism, and includes any information delivery media.

The above description of the present invention is for illustration only, and those skilled in the art to which the present invention pertains can understand that the present invention can be easily modified into other specific forms without changing the technical spirit or essential features of the present invention. will be. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined form.

The scope of the present invention is indicated by the following claims rather than the above detailed description, and it should be interpreted that all changes or modified forms derived from the meaning and scope of the claims and equivalent concepts thereof are included in the scope of the present invention. do.

When providing a VoLTE SRVCC service in a mixed environment of a 3GPP LTE network and a legacy network, a method and apparatus for providing call continuity according to an embodiment of the present invention may be used. Here, the legacy network may include an environment in which various mobile communication systems are mixed, such as a wideband code division multiple access (WCDMA) mobile communication system, a global system for mobile (GSM), and a CDMA 2000 mobile communication system.

According to an embodiment of the present invention, unnecessary network resource allocation can be prevented when providing SRVCC service of VoLTE in a mixed environment of 3GPP LTE network and legacy network.

Claims (8)

delete delete delete delete A method for providing call continuity executed in an apparatus for providing call continuity in the first network network in a mixed communication environment of a first network network, a second network network, and an IP Multimedia Subsystem (IMS) network,
Receiving a request from the second network for handover from the second network to the first network for the voice call of the wireless terminal,
Attempting handover processing with the first network network and the IMS network at the request of the handover;
If the attempt of the handover processing fails according to the handover setting for Single Radio Voice Call Continuity (SRVCC) for the voice call, the request for the handover is prevented so that network resource allocation based on the request of the handover is prevented. Steps not responding for a set amount of time
A method of providing currency continuity, comprising: ◈ Claim 6 was abandoned when payment of the set registration fee was made.◈ The method of claim 5,
After receiving the handover failure response according to a call state of the wireless terminal from the IMS network after attempting the handover processing, it is determined as a failure of the handover processing according to the handover setting.
How to provide call continuity. A method for providing call continuity executed in an apparatus for providing call continuity in a second network network in a mixed communication environment of a first network network, a second network network, and an IP Multimedia Subsystem (IMS) network,
Receiving a handover from the second network network to the first network network for a voice call of a wireless terminal from a base station in the second network network;
Requesting a handover processing attempt with the IMS network to the first network network according to the request of the handover;
When the IMS network receives a failure response of the handover processing according to the handover setting for SRVCC (Single Radio Voice Call Continuity) for the voice call through the first network network, network resource allocation based on the request of the handover The step of not responding to the request of the handover for a predetermined time so that this is prevented
A method of providing currency continuity, comprising: ◈ Claim 8 was abandoned when payment of the set registration fee was made.◈ The method of claim 7,
When the handover processing failure response includes information that the SRVCC is temporarily impossible, it is determined as a failure of the handover processing according to the handover setting.
How to provide call continuity.

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