JP2013055497A - Mobile communication method, core network apparatus, and serving gateway apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform an appropriate Inter-RAT handover (Inter-RAT HO) when a mobile station is in an active ISR state.SOLUTION: A mobile communication method includes: a step in which an S-GW for a UE establishes an EPS bearer between the S-GW and an SGSN#2 as an EPS bearer for the UE with active ISR; a step in which an HSS changes location information of the UE in a UTRAN/GERAN such that the location of the UE has changed from a cell served by an SGSN#1 to a cell served by the SGSN#2; a step in which the HSS transmits "MAP_CL" to the SGSN#1; and a step in which the SGSN#1 releases an EPS bearer between the SGSN#1 and the S-GW without transmitting a "GTPv2_Delete Session Request" to the S-GW if the "MAP_CL" contains "Cancellation type=Update Procedure".

Description

  The present invention relates to a mobile communication method, a core network device, and a serving gateway device.

  As shown in FIG. 11, in a mobile communication system defined by the conventional 3GPP, when an ISR (Idle-mode Signaling Reduction) of a UE (User Equipment, mobile station) is active, the UE is connected to an SGSN (GPRS Support). Node, packet switch) # 1 subordinate cell (lu-Pool # 1) and MME (Mobility Management Entity, mobility management node) # 1 subordinate cell (S1-Pool # 1) Also, the transmission of the location registration signal (TAU (Tracking Area Update) / RAU (Routing Area Update)) can be omitted.

  Here, the HSS (Home Subscriber Server, subscriber management server) manages the cell (S1-Pool #) under the MME # 1 as the location information of the UE in the E-UTRAN (Evolved Universal Terrestrial Radio Access Network). It is assumed that a cell (lu-Pool # 1) under SGSN # 1 is managed as UE location information in UTRAN (Universal Terrestrial Radio Accecc Network) / GERAN (GSM EDGE Radio Accecc Network).

  Further, the UE's S-GW (Serving Gateway, Serving Gateway Device) has an ESR (Evolved Packet System) with the MME # 1 as a bearer (EBI (EPS Bearer ID) = 0) for the UE whose ISR is active. ) Assume that an EPS bearer has been established between the bearer and SGSN # 1.

  As shown in FIG. 12, after the UE performs handover (Inter-RAT HO) from the cell (lu-Pool # 1) under SGSN # 1 to the cell (S1-Pool # 1) under MME # 1, MME # When a handover is performed from a subordinate cell (S1-Pool # 1) to a cell (lu-Pool # 2) under SGSN # 2, the S-GW is an EPS bearer (EBI = 0) for the UE whose ISR is active. In addition to the EPS bearer with MME # 1 and the EPS bearer with SGSN # 1, it is configured to establish an EPS bearer with SGSN # 2.

3GPP TS 23.401, 5.3.3.3 3GPP TS 29.002, 8.1.3.3 3GPP TS 23.060, 6.9.1.1.2.2 3GPP TS 29.274, 7.2.9.1

  As shown in FIG. 13 and FIG. 14, in the mobile communication system defined by the conventional 3GPP, when the handover shown in FIG. 12 is performed (step S3001), the HSS makes the UE “MAP_CL” requesting to delete the location information is transmitted (step S3006), and SGSN # 1 requests the S-GW to delete the EPS bearer (EBI = 0) for UE. GTPv2_Delete Session Request ”is transmitted (step S3008).

  Here, when the S-GW receives such “GTPv2_Delete Session Request”, the SGSN used in communication by the UE as well as the EPS bearer with the MME # 1 and the EPS bearer with the SGSN # 1. There was a problem that the EPS bearer between # 2 was released.

  Therefore, the present invention has been made in view of the above-described problems, and a mobile communication method and a core network that can appropriately perform inter-RAT handover (Inter-RAT HO) when an ISR of a mobile station is active An object is to provide a device and a serving gateway device.

  The first feature of the present invention is that when the ISR of the mobile station is active, the subscriber management server uses the cell under the first core network device of the first communication system and the second communication as the location information of the mobile station. When the mobile station manages a cell under the second core network apparatus of the system, the mobile station performs handover from the cell under the first core network apparatus to the cell under the third core network apparatus of the second communication system In the communication method, the serving gateway device of the mobile station is a bearer between the first core network device and the second core network device as a bearer for the mobile station in an ISR active state. In addition to the bearer, the step of establishing a bearer with the third core network device, and the subscriber management server in the second communication method Changing the location information of the mobile station from a cell under the second core network device to a cell under the third core network device, and the subscriber management server to the second core network device Transmitting a location information deletion request signal for requesting deletion of the location information of the mobile station, and the second core network device indicating an update of the location information of the mobile station in the location information deletion request signal When the type information is included, the bearer with the serving gateway apparatus is not transmitted to the serving gateway apparatus without transmitting a bearer deletion request signal for requesting to delete the bearer for the mobile station. And a step of releasing the above.

  The second feature of the present invention is that, in a state where the ISR of the mobile station is active, the subscriber management server uses the cell under the first core network device of the first communication system and the second communication as the location information of the mobile station. When the mobile station manages a cell under the second core network apparatus of the system, the mobile station performs handover from the cell under the first core network apparatus to the cell under the third core network apparatus of the second communication system In the communication method, the serving gateway device of the mobile station is a bearer between the first core network device and the second core network device as a bearer for the mobile station in an ISR active state. In addition to the bearer, the step of establishing a bearer with the third core network device, and the subscriber management server in the second communication method Changing the location information of the mobile station from a cell under the second core network device to a cell under the third core network device, and the subscriber management server to the second core network device Transmitting a location information deletion request signal requesting to delete the location information of the mobile station, and the second core network device responding to the location information deletion request signal to the serving gateway device Transmitting a bearer deletion request signal for requesting deletion of the bearer for the mobile station and releasing the bearer with the serving gateway device; and the serving gateway device from the second core network device Receiving the bearer deletion request signal and changing the bearer for the mobile station within a predetermined period. If not received the bearer modification request signal is directed to subject matter that a step is not performed deletion processing bearer for the mobile station.

  The third feature of the present invention is that, when the ISR of the mobile station is active, the subscriber management server uses the cell and the second communication under the control of the first core network device of the first communication method as the location information of the mobile station. When a cell under the control of the second core network device of the system is managed, the mobile station performs handover from the cell under the control of the first core network device to the cell under the third core network device of the second communication system In the mobile communication system capable of performing the above, a core network device that can operate as the second core network device, and requests to delete the location information of the mobile station from the subscriber management server When a signal is received, and the location information deletion request signal includes type information indicating an update of the location information of the mobile station It is configured to release a bearer with the serving gateway device without transmitting a bearer deletion request signal requesting the serving gateway device to delete the bearer for the mobile station. Is the gist.

  According to a fourth aspect of the present invention, in a state where the ISR of the mobile station is active, the subscriber management server uses the cell and the second communication under the first core network device of the first communication method as the location information of the mobile station. When a cell under the control of the second core network device of the system is managed, the mobile station performs handover from the cell under the control of the first core network device to the cell under the third core network device of the second communication system In a mobile communication system capable of performing the above, a serving gateway apparatus that can operate as a serving gateway apparatus for the mobile station, and that requests to delete the bearer for the mobile station from the second core network apparatus A request signal is received, and a bearer for the mobile station is established in another serving gateway device; If it is determined that that is the subject matter that is configured so as not to perform the removal process of the bearer for the mobile station.

  As described above, according to the present invention, a mobile communication method, a core network apparatus, and a serving gateway apparatus that can appropriately perform inter-RAT handover (Inter-RAT HO) in a state where the ISR of a mobile station is active are provided. Can be provided.

1 is an overall configuration diagram of a mobile communication system according to a first embodiment of the present invention. It is a functional block diagram of SGSN which concerns on the 1st Embodiment of this invention. FIG. 3 is a sequence diagram showing an operation of the mobile communication system according to the first embodiment of the present invention. It is a figure for demonstrating operation | movement of the mobile communication system which concerns on the 1st Embodiment of this invention. It is a flowchart which shows operation | movement of HSS which concerns on the 1st Embodiment of this invention. It is a flowchart which shows operation | movement of SGSN which concerns on the 1st Embodiment of this invention. It is a functional block diagram of S-GW concerning the modification 1 of this invention. It is a sequence diagram which shows operation | movement of the mobile communication system which concerns on the modification 1 of this invention. It is a figure for demonstrating operation | movement of the mobile communication system which concerns on the modification 1 of this invention. It is a flowchart which shows operation | movement of S-GW which concerns on the example 1 of a change of this invention. It is a figure for demonstrating the conventional mobile communication system. It is a figure for demonstrating the conventional mobile communication system. It is a figure for demonstrating the conventional mobile communication system. It is a figure for demonstrating the conventional mobile communication system.

(Mobile communication system according to the first embodiment of the present invention)
With reference to FIG. 1 thru | or FIG. 6, the mobile communication system which concerns on the 1st Embodiment of this invention is demonstrated.

  As shown in FIG. 1, the mobile communication system according to the present embodiment includes an HSS, an S-GW, SGSN # 1, SGSN # 2, and MME # 1.

  As shown in FIG. 2, SGSN # 1 includes a reception unit 11, a determination unit 12, and a transmission unit 13.

  The receiving unit 11 is configured to receive various signals from HSS, UE, and the like. For example, the receiving unit 11 is configured to receive “MAP_CL” from the HSS.

  The determination unit 12 is configured to determine whether or not “MAP_CL” received by the reception unit 11 includes “Cancelation type = Update Procedure”.

  In addition, when the determination unit 12 determines that “Cancellation type = Update Procedure” is included in the “MAP_CL”, the communication in which the ISR is in the active state as the EPS bearer for the UE related to the “MAP_CL” It is configured to determine whether or not an EPS bearer is present.

  Furthermore, when the determination unit 12 determines that the “MAP_CL” includes “Cancellation type = Update Procedure”, and the EPS bearer for the UE related to the “MAP_CL”, the ISR is in an active state. When it is determined that an EPS bearer in communication exists, the S-GW does not transmit a “GTPv2_Delete Session Request” requesting to delete the EPS bearer for the UE. Decide to release the EPS bearer in between.

  On the other hand, the determination unit 12 determines that the “MAP_CL” includes “Cancellation type = Update Procedure”, and the EPS bearer for the UE related to the “MAP_CL” is in an active state. When it is determined that there is no EPS bearer in communication, the transmission unit 13 is instructed to transmit “GTPv2_Delete Session Request” requesting to delete the EPS bearer for the UE.

  In addition, when the determination unit 12 determines that “Cancellation type = Update Procedure” is not included in the “MAP_CL”, the determination unit 12 determines to perform processing corresponding to “Cancellation type” on the “MAP_CL”. .

  The transmission unit 13 is configured to transmit various signals to the HSS, the UE, and the like.

  For example, the transmission unit 13 is configured to transmit “GTPv2_Delete Session Request” requesting the S-GW to delete the EPS bearer for the UE in response to the instruction from the determination unit 12 described above. Has been.

  Hereinafter, an example of the operation of the mobile communication system according to the present embodiment will be described with reference to FIGS. 3 to 6.

  Firstly, with reference to FIG. 3 and FIG. 4, the operation when the inter-RAT handover is performed in the mobile communication system according to the present embodiment while the UE ISR is active will be described.

  In step S1000, it is assumed that the UE is communicating via a cell under MME # 1 while the ISR is active.

  In step S1001, the UE performs handover (Inter-RAT HO) from the cell (S1-Pool # 1) under MME # 1 to the cell (lu-Pool # 2) under SGSN # 2.

  In step S1002, the UE transmits “SMM_RAU Request” including “P-TMSI” of the UE to SGSN # 2, and in step S1003, SGSN # 2 transmits “MAP_UGL” to the HSS. To do.

  In step S1004, the HSS transmits “MAP_UGL Ack” to SGSN # 2, and in step S1005, SGSN # 2 transmits “GMM_RAU Accept” to the UE.

  In step S1006, the HSS transmits “MAP_CL” including “Cancellation type = Update Procedure” to SGSN # 1.

  SGSN # 1 determines that “Cancellation type = Update Procedure” is included in the “MAP_CL”, and the EPS bearer for the UE related to the “MAP_CL” is in communication in which ISR is active It is determined that there is no EPS bearer, and in step S1007, “MAP_CL Ack” is transmitted to the HSS. In step S1008, the EPS bearer with the S-GW is released.

  Secondly, the operation of the HSS in the operations shown in FIGS. 3 and 4 will be described with reference to FIG.

  As shown in FIG. 5, when the HSS receives “MAP_UGL” from the SGSN # 2 in step S101 (step S1003 in FIG. 3), the location information of the UE in UTRAN / GERAN is subordinate to the SGSN # 1 in step S102. It is determined whether or not the cell has been changed.

  If “Yes”, the operation proceeds to step S 103, and if “No”, the operation ends.

  In step S103, the HSS transmits “MAP_CL” including “Cancellation type = Update Procedure” to SGSN # 1 (step S1006 in FIG. 3).

  Thirdly, the SGSN # 1 operation in the operations shown in FIGS. 3 and 4 will be described with reference to FIG.

  As illustrated in FIG. 6, when the SGSN # 1 receives “MAP_CL” from the HSS in step S201, the SGSN # 1 determines whether or not “Cancelation type = Update Procedure” is included in the “MAP_CL” in step S202. To do.

  In the case of “Yes”, the operation proceeds to step S203, and in the case of “No”, the operation proceeds to step S206.

  In step S203, SGSN # 1 determines whether or not there is an EPS bearer in communication in which the ISR is active as the EPS bearer of the UE related to “MAP_CL”.

  In the case of “Yes”, the operation proceeds to step S204, and in the case of “No”, the operation proceeds to step S205.

  In step S204, SGSN # 1 transmits "GTPv2_Delete Session Request" requesting the S-GW to delete the EPS bearer for the UE.

  In step S205, SGSN # 1 performs a process corresponding to “Cancellation type = Update Procedure”, that is, releases an EPS bearer with the S-GW.

  In step S <b> 206, SGSN # 1 performs processing corresponding to “Cancellation type” included in “MAP_CL”.

  According to the mobile communication system according to the present embodiment, when the inter-RAT handover (Inter-RAT HO) is performed while the ISR of the mobile station is active, the “MAP_CL” received from the HSS by the SGSN # 1 It is determined that there is an in-communication EPS bearer in which the ISR is active as an EPS bearer for the UE related to the “MAP_CL” when it is determined that “Cancellation type = Update Procedure” is included in In this case, it is configured to release the EPS bearer with the S-GW without transmitting “GTPv2_Delete Session Request” requesting the S-GW to delete the EPS bearer for the UE. Used in communication by the UE. It is possible to solve the problem that the EPS bearer between the S-GW and the SGSN # 2 is released.

(Modification 1)
Hereinafter, the mobile communication system according to the first modification of the present invention will be described with reference to FIG. 7 to FIG. 10 while focusing on the differences from the mobile communication system according to the first embodiment.

  In the mobile communication system according to the first modification, as shown in FIG. 7, the S-GW includes a reception unit 21, a determination unit 22, and a transmission unit 23.

  The receiving unit 21 is configured to receive various signals from SGSN # 1, SGSN # 2, MME # 1, and the like. For example, the receiving unit 21 is configured to receive “GTPv2_Delete Session Request” from the SGSN # 1.

  When the reception unit 21 receives “GTPv2_Delete Session Request” for the UE EPS bearer, the determination unit 22 requests to change the UE EPS bearer within a predetermined period of time, “Modify Bearer Request”. Is configured to determine whether or not is received.

  For example, the predetermined period may be a predetermined period before the reception time of “GTPv2_Delete Session Request” by the reception unit 21.

  Here, the determination unit 22 receives “GTPv2_Delete Session Request” for the UE EPS bearer by the reception unit 21, and requests to change the UE EPS bearer within a predetermined period of time “Modify Bearer Request”. Is determined not to be received, it is determined not to delete the EPS bearer for the UE.

  In addition, when the determination unit 22 receives “GTPv2_Delete Session Request” for an EPS bearer for UE from SGSN # 1, and determines that the EPS bearer for UE is established in another S-GW , It may be configured to determine not to delete the EPS bearer for UE.

  The transmission unit 23 is configured to transmit various signals to SGSN # 1, SGSN # 2, MME # 1, and the like.

  For example, the transmission unit 23 is configured to transmit “GTPv2_Delete Session Response” to SGSN # 1.

  Hereinafter, an example of the operation of the mobile communication system according to the first modification will be described with reference to FIGS. 8 to 10.

  Firstly, with reference to FIG. 8 and FIG. 9, the operation when the inter-RAT handover is performed in the mobile communication system according to the first modification while the UE ISR is active will be described.

  The operations in steps S2000 to S2006 shown in FIG. 8 are the same as the operations in steps S1000 to S1006 shown in FIG.

  When SGSN # 1 receives “MAP_CL” including “Cancellation type = Update Procedure”, it transmits “MAP_CL Ack” to the HSS in step S2007, and in step S2008 to the S-GW for the UE. “GTPv2_Delete Session Request” for the EPS bearer (EBI = 0) is transmitted.

  In step S2009, since the “Modify Bearer Request” requesting to change the EPS bearer for the UE is not received from the SGSN # 2 within the predetermined period, the S-GW receives “for the EPS bearer for the UE. “GTPv2_Delete Session Request” is not accepted, that is, the deletion process of the EPS bearer for the UE is not performed.

  Secondly, the operation of the S-GW in the operations shown in FIGS. 8 and 9 will be described with reference to FIG.

  As shown in FIG. 10, upon receiving “GTPv2_Delete Session Request” from SGSN # 2 in step S301, the S-GW requests to change the EPS bearer for the UE within a predetermined period in step S302. It is determined whether or not “Modify Bearer Request” is received.

  If “Yes”, the operation ends. If “No”, the operation proceeds to step S303.

  In step S303, the S-GW accepts “GTPv2_Delete Session Request” for the UE EPS bearer, that is, performs a deletion process (release process) of the UE EPS bearer.

  According to the mobile communication system according to the first modification, when an inter-RAT handover (Inter-RAT HO) is performed in a state where the ISR of the mobile station is active, the S-GW is changed from the SGSN # 2 to the UE. When a “GTPv2_Delete Session Request” for an EPS bearer for the UE is received and a “Modify Bearer Request” requesting to change the EPS bearer for the UE is not received within a predetermined period, the EPS for the UE is not received. Since it is configured not to perform bearer deletion processing, it is possible to solve the problem of releasing the EPS bearer between the S-GW and SGSN # 2 used in communication by the UE. .

  The characteristics of the present embodiment described above may be expressed as follows.

  The first feature of the present embodiment is that, in a state where the ISR of the UE (mobile station) is active, the HSS (subscriber management server) uses MME # 1 (first core of the first communication scheme) as the UE location information. When a cell under the network device) and a cell under SGSN # 1 (second core network device of the second communication method) are managed, the UE receives SGSN # 2 (second communication) from the cell under MME # 1. 3rd core network apparatus) is a mobile communication method for handing over to a subordinate cell, where an S-GW (serving gateway apparatus) of a UE is an EPS bearer (EBI = 0) for an UE whose ISR is active, Establishing an EPS bearer with SGSN # 2 in addition to an EPS bearer with MME # 1 and an EPS bearer with SGSN # 1, and The step of changing the location information of the UE in TRAN / GERAN (second communication scheme) from the cell under SGSN # 1 to the cell under SGSN # 2, and the HSS sends the location information of the UE to SGSN # 1 The process of transmitting “MAP_CL (location information deletion request signal)” requesting deletion, and SGSN # 1 sends “Cancellation type = Update Procedure (type information indicating update of location information of UE) to“ MAP_CL ”. ”Is included in the S-GW apparatus without transmitting“ GTPv2_Delete Session Request (bearer deletion request signal) ”requesting the S-GW to delete the EPS bearer for the UE. And the step of releasing the EPS bearer between the two.

  The second feature of the present embodiment is that when the UE's ISR is active, the HSS manages the cell under MME # 1 and the cell under SGSN # 1 as UE location information. Is a mobile communication method for performing handover from a cell under MME # 1 to a cell under SGSN # 2, in which the S-GW of the UE is used as a bearer (EBI = 0) for the UE whose ISR is active. In addition to the EPS bearer between SGSN # 1 and the EPS bearer between SGSN # 1, establishing the EPS bearer with SGSN # 2, and the HSS, the UE's location information in UTRAN / GERAN, The process of changing from the cell under # 1 to the cell under SGSN # 2, and the HSS requests SGSN # 1 to delete the location information of the UE “MAP_C SGSN # 1 transmits “GTPv2_Delete Session Request” requesting the S-GW to delete the EPS bearer for UE in response to the “MAP_CL”. The process of releasing the EPS bearer with the GW, and the S-GW receives the “GTPv2_Delete Session Request” for the EPS bearer for the UE from the SGSN # 1, and changes the EPS bearer for the UE within a predetermined period. In the case where the “Modify Bearer Request” requesting to be received is not received, the gist of the present invention is to include a step of not performing the process of deleting the EPS bearer for the UE.

  The third feature of this embodiment is that when the UE's ISR is active, the HSS manages the cells under MME # 1 and the cells under SGSN # 1 as UE location information. Is a SGSN (core network device) that can operate as SGSN # 1 in a mobile communication system that can be handed over from a cell under MME # 1 to a cell under SGSN # 2, and from the HSS, “MAP_CL ", And when" Cancellation type = Update Procedure "is included in" MAP_CL ", it requests the S-GW to delete the EPS bearer for UE" GTPv2_Delete " Without sending "Session Request", S-GW The gist is that it is configured to release the EPS bearer between.

  The fourth feature of the present embodiment is that when the ISR of the UE is active, the HSS manages the cells under MME # 1 and the cells under SGSN # 1 as UE location information. Is an S-GW used in a mobile communication system that can be handed over from a cell under MME # 1 to a cell under SGSN # 2, from SGSN # 1 to the "GTPv2_Delete Session Request" for an EPS bearer for UE. If the UE-based EPS bearer is determined to be established in another S-GW, the UE-based EPS bearer is not deleted. .

  Note that the operations of the above-described UE, eNB, MME # 1, SGSN # 1 / SGSN # 2, S-GW, HSS, etc. may be implemented by hardware or implemented by a software module executed by a processor. It may be implemented by a combination of both.

  The software module includes a RAM (Random Access Memory), a flash memory, a ROM (Read Only Memory), an EPROM (Erasable Programmable ROM), an EEPROM (Electronically Erasable and Programmable ROM, a hard disk, a registerable ROM, a hard disk). Alternatively, it may be provided in a storage medium of an arbitrary format such as a CD-ROM.

  Such a storage medium is connected to the processor so that the processor can read and write information from and to the storage medium. Further, such a storage medium may be integrated in the processor. Such a storage medium and processor may be provided in the ASIC. Such an ASIC may be provided in the UE, eNB, MME # 1, SGSN # 1 / SGSN # 2, S-GW, HSS, or the like. Further, the storage medium and the processor may be provided in the UE, eNB, MME # 1, SGSN # 1 / SGSN # 2, S-GW, HSS, or the like as a discrete component.

  Although the present invention has been described in detail using the above-described embodiments, it is obvious to those skilled in the art that the present invention is not limited to the embodiments described in this specification. The present invention can be implemented as modified and changed modes without departing from the spirit and scope of the present invention defined by the description of the scope of claims. Therefore, the description of the present specification is for illustrative purposes and does not have any limiting meaning to the present invention.

UE ... mobile station eNB ... radio base station MME # 1 ... mobile management node SGSN # 1, SGSN # 2 ... packet exchange S-GW ... serving gateway device HSS ... subscriber management server 11, 21 ... receiver 12, 22 ... determination Units 13, 23 ... Transmitter

Claims (4)

In a state where the ISR of the mobile station is active, the subscriber management server uses the cell under the first core network device of the first communication system and the second core network device of the second communication system as the location information of the mobile station. A mobile communication method in which, when managing a cell, the mobile station performs a handover from a cell under the first core network device to a cell under the third core network device of the second communication method,
In addition to the bearer between the first core network device and the bearer between the second core network device, the serving gateway device of the mobile station, as the bearer for the mobile station in which the ISR is active, Establishing a bearer with the third core network device;
The subscriber management server changing the location information of the mobile station in the second communication method from a cell under the second core network device to a cell under the third core network device;
The subscriber management server sending a location information deletion request signal requesting the second core network device to delete the location information of the mobile station;
When the second core network device includes type information indicating update of the location information of the mobile station in the location information deletion request signal, the second core network device transmits a bearer for the mobile station to the serving gateway device. And a step of releasing a bearer with the serving gateway device without transmitting a bearer deletion request signal for requesting deletion. In a state where the ISR of the mobile station is active, the subscriber management server uses the cell under the first core network device of the first communication system and the second core network device of the second communication system as the location information of the mobile station. A mobile communication method in which, when managing a cell, the mobile station performs a handover from a cell under the first core network device to a cell under the third core network device of the second communication method,
In addition to the bearer between the first core network device and the bearer between the second core network device, the serving gateway device of the mobile station, as the bearer for the mobile station in which the ISR is active, Establishing a bearer with the third core network device;
The subscriber management server changing the location information of the mobile station in the second communication method from a cell under the second core network device to a cell under the third core network device;
The subscriber management server sending a location information deletion request signal requesting the second core network device to delete the location information of the mobile station;
In response to the location information deletion request signal, the second core network device transmits a bearer deletion request signal requesting the serving gateway device to delete the bearer for the mobile station, and the serving gateway Releasing the bearer to and from the device;
The serving gateway apparatus receives the bearer deletion request signal from the second core network apparatus, and receives a bearer change request signal requesting to change the bearer for the mobile station within a predetermined period. If not, a mobile communication method comprising: a step of not performing bearer deletion processing for the mobile station. In a state where the ISR of the mobile station is active, the subscriber management server uses the cell under the first core network device of the first communication system and the second core network device of the second communication system as the location information of the mobile station. In the mobile communication system in which the mobile station can perform handover from the cell under the first core network device to the cell under the third core network device of the second communication method when managing the cell, A core network device capable of operating as a two-core network device,
When a location information deletion request signal for requesting deletion of the location information of the mobile station is received from the subscriber management server, and the location information deletion request signal indicates an update of the location information of the mobile station When the type information is included, the bearer with the serving gateway apparatus is not transmitted to the serving gateway apparatus without transmitting a bearer deletion request signal for requesting to delete the bearer for the mobile station. A core network device configured to release the network. In a state where the ISR of the mobile station is active, the subscriber management server uses the cell under the first core network device of the first communication system and the second core network device of the second communication system as the location information of the mobile station. In the mobile communication system in which the mobile station can perform handover from a cell under the first core network device to a cell under the third core network device of the second communication method when managing a cell, A serving gateway device that can operate as a serving gateway device for a station,
When a bearer deletion request signal for requesting to delete the bearer for the mobile station is received from the second core network apparatus, and the bearer for the mobile station is established in another serving gateway apparatus The serving gateway apparatus is configured not to perform the process of deleting the bearer for the mobile station when it is determined.

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