JP7376166B2 - A first CN node, a method performed at the first CN node, and a method performed at a UE - Google Patents

Description

The present disclosure relates to a gateway device, a mobility management device, a base station, a communication method, a control method, a paging method, and a program. This invention relates to a paging method and program.

In 3GPP (3rd Generation Partnership Project), which defines standards for mobile networks, UE (User Equipment), which is a communication terminal, notifies the MME (Mobility Management Entity), which is a control device, of changes in its tracking area (TA). A TAU (Tracking Area Update) process is defined as a process to perform the following. For example, the details of TAU processing are defined in Section 5.3.3.1 of Non-Patent Document 1. In TAU processing, the UE identifier is not IMSI (International Mobile Subscriber Identity), which is a UE-specific identifier, but GUTI (Globally Unique Temporary UE Identity), which is a Temporary ID (Identity) issued by the MME to the UE in advance. used. It is desirable that the GUTI be changed periodically from a security perspective. Therefore, the GUTI is changed in the GUTI Reallocation process (see Section 5.3.7 of Non-Patent Document 1). The GUTI Reallocation process may be performed within the TAU process or at an opportunity independent of the TAU process. Thereby, the changed GUTI is notified from the MME to the UE.

In the TAU process, the MME notifies the UE of the changed GUTI by transmitting a TAU Accept message including the changed GUTI to the UE. The UE also transmits a TAU Complete message to the MME as a response to the TAU Accept message. By receiving the TAU Complete message, the MME can recognize that the UE has been notified of the changed GUTI.

Next, the packet arrival operation defined in 3GPP will be explained. For example, in Section 5.3.4.3 of Non-Patent Document 1, NW (Network) Triggered Service Request processing is defined as a specific example of the packet arrival operation. In the NW Triggered Service Request process, the MME that receives a notification that a packet has been received transmits a Paging message to an eNB (evolved NodeB), which is a base station. Furthermore, upon receiving the Paging message, the eNB executes Paging for the UE. Thereby, the UE is notified of the packet arrival.

The UE executes a DRX (Discontinuous Reception) function that periodically monitors the Paging Channel. In addition, when an IoT (Internet of Things) device is used as a UE, the IoT device uses eDRX (Extended Idle Mode DRX), in which the monitoring cycle is longer than when the DRX function is executed, in order to reduce battery consumption. May perform functions. When the UE executes the eDRX function, the Paging Channel monitoring cycle is approximately 43 minutes at maximum.

When the UE executes the eDRX function and monitors the Paging Channel, the monitoring cycle is determined using S-TMSI (SAE (System Architecture Evolution)-Temporary Mobile Subscriber Identity), which consists of eDRX parameters and a part of GUTI. Calculated. The monitoring cycle is calculated in each of the UE, MME, and eNB. The eDRX parameter may be, for example, a paging time window that indicates a period during which the UE continues monitoring after the UE starts monitoring the Paging Channel. The relationship between GUTI and S-TMSI will be explained below.

GUTI includes MCC (Mobile Country Code), MNC (Mobile Network Code), MME Group ID, MME Code, and M (MME)-TMSI. On the other hand, S-TMSI includes MME Code and M-TMSI. That is, the S-TMSI includes the MME Code and M-TMSI that constitute part of the GUTI. M-TMSI is an identifier that is changed in GUTI Reallocation processing. That is, by executing the GUTI Reallocation process, the S-TMSI including the M-TMSI is also changed.

Next, a packet receiving operation when a failure occurs in the MME will be described. When the MME recovers after a failure occurs, it loses the information related to the UE that it had stored before the failure. The information regarding the lost UE is, for example, an IMSI that identifies the UE, a GUTI temporarily assigned to the UE, and the like. In such a state, even if the MME receives a message notifying the arrival of a packet from the SGW (Serving Gateway), which is a gateway device, it cannot perform paging processing because it cannot identify the target UE. Can not. Therefore, in order to avoid such an event, when a packet arrives regarding a UE managed by an MME in which a failure has occurred, the SGW sends a message containing the IMSI, which is a unique identifier of the UE, to the MME. do. Thereby, when the MME transmits a Paging message in which the IMSI notified from the SGW is set to the eNB, the eNB can perform paging for the UE. A series of operations in which the MME performs paging processing using the IMSI notified from the SGW in this manner is referred to as a Network Triggered Service Restoration function. Chapter 25 of Non-Patent Document 2 describes processing related to Network Triggered Service Restoration.

3GPP TS23.401 V14.1.0 (2016-09) Chapter 5.3.3.1, Chapter 5.3.4.3, Section 5.3.7 3GPP TS23.007 V14.1.0 (2016-09) Chapter 25

A UE running the eDRX function monitors the Paging Channel in a monitoring period calculated based on the S-TMSI and eDRX parameters. However, after the MME has recovered from the failure and in a state where the MME has lost information regarding the UE, the MME and the eNB execute the paging process based on the IMSI notified from the SGW. Therefore, the timing at which the eNB executes Paging to the UE and the timing at which the UE monitors the Paging Channel are different. As a result, a problem arises in that the UE is unable to notice Paging targeted at its own device.

The purpose of the present disclosure is to ensure that even if the control device has lost information regarding the communication terminal (for example, the UE) when a failure that has occurred in the control device (for example, the MME) is recovered, the control device can manage the information. An object of the present invention is to provide a gateway device, a mobility management device, a base station, a communication method, a control method, a paging method, and a program that can normally perform paging for communication terminals.

The gateway device according to the first aspect of the present disclosure includes a storage unit that stores temporary allocation identification information assigned to a communication terminal and eDRX (Extended Idle Mode Discontinuous Reception) parameters regarding the communication terminal, and a mobility management device that If the mobile management device receives downlink data for the communication terminal that it was managing after the occurrence of the A communication unit for transmitting data to a management device.

A mobility management device according to a second aspect of the present disclosure is configured to receive the temporary allocation identification information and the eDRX parameters from a gateway device that stores temporary allocation identification information assigned to a communication terminal and eDRX parameters regarding the communication terminal. The communication unit includes a communication unit that receives a set notification message from the gateway device, and a calculation unit that uses the temporary allocation identification information and the eDRX parameter to determine the timing of transmitting a paging message to the base station.

A base station according to a third aspect of the present disclosure includes an eDRX parameter regarding a communication terminal, a GUTI temporarily assigned to the communication terminal or an S-TMSI included in the GUTI, and the communication terminal as temporary assignment identification information. comprising a communication unit that receives IMSI, which is identification information of a terminal, from a mobility management device; and a calculation unit that calculates timing for paging the communication terminal using the temporary allocation identification information and the eDRX parameter, The communication unit performs paging using the IMSI at the timing calculated by the calculation unit.

A communication method according to a fourth aspect of the present disclosure stores temporary allocation identification information assigned to a communication terminal and eDRX parameters regarding the communication terminal, and after a failure occurs in the mobility management device, the mobility management device When downlink data for the communication terminal being managed is received, a notification message in which the temporary allocation identification information and the eDRX parameters are set is transmitted to the mobility management device or another mobility management device.

In a control method according to a fifth aspect of the present disclosure, the temporary allocation identification information and the eDRX parameters are set from a gateway device that stores temporary allocation identification information assigned to a communication terminal and eDRX parameters regarding the communication terminal. A notification message is received from the gateway device, and a timing for transmitting a paging message to a base station is determined using the temporary allocation identification information and the eDRX parameter.

A paging method according to a sixth aspect of the present disclosure includes an eDRX parameter regarding a communication terminal, a GUTI temporarily assigned to the communication terminal or an S-TMSI included in the GUTI, and the communication Receive IMSI, which is the identification information of the terminal, from the mobility management device, calculate the timing for paging the communication terminal using the temporary allocation identification information and the eDRX parameter, and transmit the IMSI at the calculated timing. Perform paging using

A program according to a seventh aspect of the present disclosure stores temporary allocation identification information assigned to a communication terminal and eDRX parameters regarding the communication terminal, and after a failure occurs in the mobility management device, the mobility management device manages the eDRX parameters. causes a computer to transmit a notification message in which the temporary allocation identification information and the eDRX parameter are set to the mobility management device or another mobility management device when downlink data for a communication terminal that has been previously used is received; .

According to the present disclosure, even if the control device has lost information regarding the communication terminal (for example, UE) when a failure that occurred in the control device (for example, MME) is recovered, the communication that was managed by the control device It is possible to provide a gateway device, a mobility management device, a base station, a communication method, a control method, a paging method, and a program that can successfully execute paging for a terminal.

1 is a configuration diagram of a gateway device according to a first embodiment; FIG. FIG. 2 is a configuration diagram of a communication system according to a second embodiment. FIG. 2 is a configuration diagram of an MME according to a second embodiment. FIG. 2 is a configuration diagram of an eNB according to a second embodiment. FIG. 2 is a configuration diagram of a UE according to a second embodiment. FIG. 7 is a diagram showing the flow of TAU processing according to the second embodiment. FIG. 7 is a diagram showing the flow of GUTI notification processing according to the second embodiment. 7 is a diagram showing the flow of packet arrival processing according to the second embodiment. FIG. FIG. 7 is a diagram showing the flow of packet arrival processing according to the third embodiment. FIG. 7 is a diagram showing information set in a paging message according to Embodiment 3; FIG. 7 is a diagram showing the flow of packet arrival processing according to the fourth embodiment. FIG. 2 is a configuration diagram of an eNB according to each embodiment. It is a block diagram of UE of each embodiment. It is a block diagram of MME and SGW of each embodiment.

(Embodiment 1)
Embodiments of the present disclosure will be described below with reference to the drawings. A configuration example of the gateway device 10 according to the first embodiment will be described using FIG. 1. The gateway device 10 may be a computer device that operates by a processor executing a program stored in a memory. The gateway device 10 may be an SGW or a GGSN (Gateway GPRS (General Packet Radio Service) Support Node) defined in 3GPP.

The gateway device 10 has a storage section 11 and a communication section (transceiver) 12. The storage unit 11 and the communication unit 12 may be software or modules whose processing is executed by a processor executing a program stored in a memory. Alternatively, the storage section 11 and the communication section 12 may be hardware such as a circuit or a chip. The communication unit may be a transmitter and a receiver.

The storage unit 11 stores temporary allocation identification information temporarily allocated to a communication terminal and eDRX parameters related to the communication terminal. The communication terminal may be a mobile phone terminal, a smartphone terminal, or a tablet terminal. Alternatively, the communication terminal may be an IoT device, an M2M (Machine to Machine) device, or an MTC (Machine Type Communication) device used for an IoT (Internet of Things) service.

The temporary allocation identification information may be, for example, a GUTI, or an S-TMSI consisting of an M-TMSI and MMEC included in the GUTI. The eDRX parameter is information used when a communication terminal executes an eDRX function. The eDRX parameters may be, for example, paging time window and eDRX value. The gateway device 10 may obtain temporary allocation identification information and eDRX parameters from the MME, for example. The gateway device 10 may store the acquired temporary allocation identification information and eDRX parameters in the storage unit 11.

The communication unit 12 communicates with a plurality of mobility management devices including the mobility management devices 20 and 21. The mobility management device 20 may be, for example, an MME or an SGSN (Serving GPRS Support Node). Here, it is assumed that the gateway device 10 receives, via the communication unit 12, downlink data destined for a communication terminal managed by the mobility management device 20 after a failure occurs in the mobility management device 20. do. Note that the gateway device 10 can detect a failure occurring in the mobility management device 20 and recovery from the failure, based on, for example, a health check process performed with the mobility management device 20. The health check process may be performed by sending and receiving ECHO requests and ECHO responses defined by the GTP protocol. Even when the mobility management device 20 recovers from a failure, it may have lost information regarding the communication terminals it was managing before the failure. Note that the information regarding the communication terminal may be temporary allocation identification information, eDRX parameters, etc. Furthermore, the information regarding the communication terminal may be an IMSI that identifies the communication terminal. In such a case, the communication unit 12 of the gateway device 10 sends a notification message containing the temporary allocation identification information and eDRX parameters regarding the communication terminal that is the destination of the downlink data stored in the storage unit 11 to the mobility management device. 20 or another mobility management device 21 different from the mobility management device 20.

The notification message is used to notify the mobility management device 20 or another mobility management device 21 different from the mobility management device 20 that downlink data destined for the communication terminal has been received. Here, the communication unit 12 may send the notification message to the mobility management device 20 that has recovered from the failure, or may send the notification message to another mobility management device 21 different from the mobility management device 20.

The mobility management device 20 or other mobility management device 21 that has received the notification message can execute paging processing for the communication terminal using the temporary allocation identification information and eDRX parameters included in the notification message. In other words, the mobility management device 20 or another mobility management device 21 can calculate the timing to perform paging using the S-TMSI and eDRX parameters included in the GUTI. Furthermore, the communication terminal calculates the timing for monitoring the Paging Channel using the S-TMSI and eDRX parameters included in the GUTI notified during TAU processing. Therefore, the timing at which the communication terminal executing the eDRX function monitors the Paging Channel can be matched with the timing at which the mobility management device 20 executes paging via the base station. As a result, the communication terminal can normally perform processing related to paging addressed to the communication terminal.

(Embodiment 2)
Next, a configuration example of the communication system according to the second embodiment will be described using FIG. 2. The communication system in FIG. 2 is a communication system that supports LTE as a wireless communication method, and includes a communication system defined as EPS (Evolved Packet System) in 3GPP. Note that Figure 2 is based on the diagram in TS 23.401 V 13.8.0 Figure 4.2.1-1.

The communication system in FIG. 2 includes a UE 40, an E-UTRAN (Evolved-Universal Terrestrial Radio Access Network) 41, an MME 42, an HSS (Home Subscriber Server) 43, an SGSN 44, an SGW (Serving Gateway) 45, and a PGW (Packet Data Network Gateway) 46. , PCRF (Policy and Charging Rules Function) entity 47 (hereinafter referred to as PCRF 47), UTRAN 48, GERAN (GSM (Global System for Mobile communications) (registered trademark) EDGE (Enhanced Data Rates for Global Evolution) Radio Access Network) 49, It has Operator's IP Services50.

The MME 42 corresponds to the mobility management device 20 in FIG. The SGW 45 corresponds to the gateway device 10 in FIG. The SGSN 44 corresponds to the mobility management device 20 in FIG. GGSN corresponds to the gateway device 10 in FIG.

UE is a term used as a general term for communication terminals in 3GPP. The UE may be replaced with an MS (Mobile Station). The E-UTRAN 41 is a RAN (Radio Access Network) that uses LTE as a radio access system and includes an eNB. The UTRAN 48 is a RAN that uses a 3G wireless system as a wireless access system and includes a NodeB. GERAN49 is a RAN that uses a 2G wireless system as a wireless access system.

MME42 and SGSN44 are nodes that perform mobility management, session management, etc. regarding UE40. HSS43 is a node that manages subscriber information regarding UE40. The subscriber information may include information regarding services used by the UE 40. SGW 45 and PGW 46 are gateways that relay data transmitted between UE 40 and Operator's IP Services 50. The Operator's IP Services 50 may be, for example, a server device or a group of server devices managed by a business operator that provides services to the UE 40. Further, Operator's IP Services 50 may be a server device that provides connection to INTERNET.
The PCRF 47 is a node that manages policies, billing rules, and the like.

An LTE-Uu reference point is defined between the UE 40 and the E-UTRAN 41. An S1-MME reference point is defined between the E-UTRAN 41 and the MME 42. An S6 reference point is defined between the MME 42 and the HSS 43. An S3 reference point is defined between the MME 42 and the SGSN 44. An S1-U reference point is defined between the E-UTRAN 41 and the SGW 45. An S11 reference point is defined between the MME 42 and the SGW 45. An S4 reference point is defined between SGSN44 and SGW45. An S12 reference point is defined between the SGW 45 and the UTRAN 48. S5/S8 reference points are defined between SGW 45 and PGW 46. A Gx reference point is defined between the PGW 46 and the PCRF 47. An SGi reference point is defined between the PGW 46 and Operator's IP Services 50. An Rx reference point is defined between the PCRF 47 and Operator's IP Services 50. An S1-10 reference point is defined between the MME 42 and other MMEs.

Next, a configuration example of the MME 42 according to the second embodiment will be described using FIG. 3. The MME 42 includes a calculator 71 and a transceiver 72. The calculation unit 71 and the communication unit 72 may be software or modules whose processing is executed by a processor executing a program stored in a memory. Alternatively, the calculation section 71 and the communication section 72 may be hardware such as a chip or a circuit. The communication unit may be a transmitter and a receiver.

The communication unit 72 transmits the GUTI assigned to the UE 40 or the S-TMSI included in the GUTI and the eDRX parameters regarding the UE 40 to the SGW 45. The timing at which the communication unit 72 transmits the GUTI etc. assigned to the UE 40 to the SGW 45 will be detailed later. The SGW 45 has the same configuration as the gateway device 10 in FIG. 1. MME42 may acquire eDRX parameters regarding UE40 from UE40. Further, when the MME 42 recovers from the failure after the failure occurs, the communication unit 72 receives a DDN (Downlink Data Notification) message from the SGW 45 that includes the GUTI assigned to the UE 40 or the S-TMSI included in the GUTI and the eDRX parameters regarding the UE 40. receive. The DDN message is a message used to notify the MME 42 that Downlink Data addressed to the UE 40 has been transmitted to the SGW 45.

The MME 42 manages information regarding a plurality of UEs including the UE 40, specifically, the subscriber data of the UEs. However, when the MME 42 recovers from the failure after the failure occurs, the MME 42 loses information regarding the plurality of UEs.

When the MME 42 recovers from a failure and receives a DDN message, the calculation unit 71 uses the S-TMSI and eDRX parameters included in the DDN message to calculate the Paging Channel monitoring cycle in the UE 40 to which the eDRX function is applied. do.

The communication unit 72 transmits the Paging message to the eNB 51 included in the E-UTRAN 41 in time for the monitoring cycle calculated by the calculation unit 71. The Paging message includes the GUTI assigned to the UE 40 or the S-TMSI included in the GUTI, and eDRX parameters regarding the UE 40.

Next, a configuration example of the eNB 51 according to the second embodiment will be described using FIG. 4. The eNB 51 includes a calculation section 81 and a communication section 82. The calculation unit 81 and the communication unit 82 may be software or modules whose processing is executed by a processor executing a program stored in a memory. Alternatively, the calculation section 81 and the communication section 82 may be hardware such as a chip or a circuit.

The communication unit 82 receives the Paging message from the MME 42. The Paging message includes the GUTI assigned to the UE 40 or the S-TMSI included in the GUTI, and eDRX parameters regarding the UE 40.

When the calculation unit 81 receives the Paging message, the calculation unit 81 uses the S-TMSI and the eDRX parameters to calculate the monitoring cycle of the Paging Channel in the UE 40 to which the eDRX function is applied.

The communication unit 72 executes paging for a plurality of UEs including the UE 40 in accordance with the monitoring cycle calculated by the calculation unit 71.

Next, a configuration example of the UE 40 according to the second embodiment will be described using FIG. 5. The UE 40 includes a communication unit (transceiver) 61 and a control unit (controller) 62. The communication unit 61 and the control unit 62 may be software or modules whose processing is executed by a processor executing a program stored in a memory. Alternatively, the communication unit 61 and the control unit 62 may be hardware such as a chip or a circuit.

The control unit 62 executes an eDRX function. For example, the control unit 62 monitors whether paging directed to the UE 40 is being performed via the communication unit 61 according to the eDRX cycle. In other words, the control unit 62 monitors the Paging Channel via the communication unit 61 according to the eDRX cycle. When the control unit 62 determines that paging directed to the UE 40 is being executed, the control unit 62 transmits a response message to the eNB 51 via the communication unit 61. Further, the communication unit 61 receives the GUTI from the MME 42 via the eNB 51 during TAU processing, Attach processing, or any timing. The control unit 62 calculates the Paging Channel monitoring timing using the eDRX parameters and the S-TMSI included in the GUTI.

When the GUTI is updated in the MME 42, the control unit 62 receives the new updated GUTI from the MME 42 via the communication unit 61. The control unit 62 calculates new monitoring timing using the new S-TMSI and eDRX parameters included in the received GUTI. Since the Paging Channel monitoring timing is determined based on the S-TMSI and eDRX parameters, when the S-TMSI is updated, the Paging Channel monitoring timing is also changed.

Next, the flow of TAU processing will be explained using FIG. 6. First, the UE 40 transmits an RRC message including a TAU Request message to the eNB 51 at a predetermined timing or at a timing when the TA indicating the serving area is changed (S11). It is assumed that the UE 40 is an eDRX applicable terminal. In this case, the TAU Request message sent by the UE 40 includes the eDRX parameter. Next, the eNB 51 transmits an S1-AP message including the TAU Request message transmitted from the UE 40 to the MME 42 (S12).

The MME 42 executes the GUTI Reallocation Procedure (S13). Specifically, the MME 42 updates the GUTI (old GUTI) currently assigned to the UE 40 and generates a new GUTI (new GUTI). For example, the MME 42 updates the M-TMSI included in the old GUTI.

The MME 42 transmits an S1-AP message including a TAU Accept message including a new GUTI to the eNB (S14). Since the TAU process executed between steps S12 and S14 is a known process, detailed explanation will be omitted. Next, the eNB 51 transmits an RRC message including the TAU Accept message transmitted from the MME 42 to the UE 40 (S15).

After transmitting the S1-AP message including the TAU Accept message to the eNB 51 in S14, the MME 42 transmits a Modify Bearer Request message to the SGW 45 (S16). The Modify Bearer Request message sent by the MME 42 includes a new GUTI and eDRX parameters regarding the UE 40. Furthermore, the MME 42 may transmit the Modify Bearer Request message to the SGW 45 after executing the GUTI Reallocation Procedure in step S13 and before transmitting the TAU Accept message to the eNB 51 in step S14.

By executing the processes of steps S11 to S16, the SGW 45 can acquire the GUTI temporarily assigned to the UE 40 and the eDRX parameters regarding the UE 40. Further, in step S16, the Modify Bearer Request sent by the MME 42 may include the S-TMSI included in the new GUTI instead of the new GUTI.

In addition, in FIG. 6, it is explained that GUTI and eDRX parameters are sent to the SGW 45 in TAU processing, but in Attach processing, GUTI or S-TMSI included in GUTI and eDRX parameters are sent as in TAU processing. may be transmitted to the SGW 45. In the Attach process, an Attach Request message is used in steps S11 and S12 instead of the TAU Request message. Furthermore, in steps S14 and S15, an Attach Accept message is used instead of the TAU Accept message. In steps S13 and S16, the Attach process is performed in the same way as the TAU process. Further, in the Attach process, after step S13, the GUTI or the S-TMSI included in the GUTI and the eDRX parameters may be set in the Create Session Request message sent by the MME 42 and sent to the SGW 45. Alternatively, even in periodic TAU, S1 connection recovery is not performed (Active Flag=OFF), or movement is mainly performed with S1 connection, that is, as specified in Section 5.5 of Non-Patent Document 1. After Handover processing occurs, there is no opportunity to send Create Session Request/Modify Bearer Request in the TAU that is sent by Uplink NAS Transport only to notify the changed TA, so in these cases, the MME42 , new GUTI, etc. may be sent to the SGW 45 using other messages.

Next, the GUTI notification sequence according to the second embodiment will be described using FIG. 7. FIG. 7 shows that the MME 42 transmits the updated GUTI (new GUTI) to the UE 40 at an arbitrary timing. The MME 42 transmits a GUTI Reallocation Command message to the UE 40 via the eNB 51 at an arbitrary timing (S21). The GUTI Reallocation Command message includes new GUTI. Next, the UE 40 transmits a GUTI Reallocation Complete message to the MME 42 via the eNB 51 as a response to the GUTI Reallocation Command message (S22). Next, the MME 42 transmits a Change Notification Request message to the SGW 45 (S23). The Change Notification Request message sent by the MME 42 includes a new GUTI and eDRX parameters regarding the UE 40.

Next, the SGW 45 transmits a Change Notification Response message to the MME 42 as a response to the Change Notification Request message (S24).

By executing the processes of steps S21 to S24, the SGW 45 can acquire the GUTI temporarily assigned to the UE 40 and the eDRX parameters regarding the UE 40. Furthermore, in step S23, the Change Notification Request message sent by the MME 42 may include the S-TMSI included in the new GUTI instead of the new GUTI.

In FIG. 7, an example was shown in which the MME 42 uses a Change Notification Request message to send the new GUTI and eDRX parameters regarding the UE 40 to the SGW 45, but the MME 42 uses other messages to send the new GUTI, etc. to the SGW 45. You can also send it to

In addition, in FIGS. 6 and 7, an example is shown in which new GUTI etc. are sent to the SGW 45 in the TAU process, the Attach process, and the process of notifying the GUTI at an arbitrary timing, but the MME 42, in processes other than these, New GUTI etc. may be transmitted to the SGW 45. Specifically, during periodic TAU, TAU is not performed until S1 connection recovery (Active Flag=OFF), or UE movement while S1 connection is present, that is, stipulated in Section 5.5 of Non-Patent Document 1. After Handover processing occurs, there are cases where Create Session Request or Modify Bearer Request is not sent in the TAU that is sent by Uplink NAS Transport only to notify the changed TA.

Next, the flow of packet arrival processing according to the second embodiment will be explained using FIG. 8. Here, a failure occurs in the MME 42 (S30), and then the generated failure is recovered (S33). When the MME 42 recovers from a failure, it loses information regarding multiple UEs including the UE 40 that it was managing before the failure.

In addition, the SGW 45 notifies the UE's GUTI managed in the MME 42 or the S-TMSI included in the GUTI and the eDRX parameters related to the UE in the TAU process, the Attach process, or the GUTI Reallocation process performed at an arbitrary timing. and manages the information notified. Therefore, the SGW 45 maintains a session connection state regarding a plurality of UEs including the UE 40 with the PGW 46 (S31). Further, even after the SGW 45 detects the failure that has occurred in the MME 42 in step S31 (S32), the SGW 45 maintains the session connection state regarding the UE that was managed in the MME 42 before the failure occurred. The SGW 45 may detect a failure occurring in the MME 42 by performing a health check on the MME 42 or using the Restart Counter received from the MME 42 . Furthermore, failure detection is not limited to these methods.

Maintaining the session connection state regarding the UE 40 means, for example, that the SGW 45 maintains the GUTI assigned to the UE 40 or the S-TMSI included in the GUTI notified from the MME 42 in FIG. 6 or 7, the eDRX parameters regarding the UE 40, and the It is also possible to continue to store the identifying IMSI. Furthermore, maintaining the session connection state regarding the UE 40 may mean continuing to set up a bearer regarding the UE 40 between the SGW 45 and the PGW 46. The SGW 45 may detect that the failure that occurred in the MME 42 has been recovered using a health check on the MME 42 or a Restart Counter received from the MME 42. (S34) Furthermore, failure detection is not limited to these methods.

Next, upon receiving Downlink Data destined for the UE 40 from the Operator's IP Services 50 or the like, the PGW 46 transmits the Downlink Data to the SGW 45 (S35). Next, the SGW 45 transmits a DDN message to the MME 42 in order to notify the MME 42 that Downlink Data addressed to the UE 40 has been received (S36). The DDN message sent by the SGW 45 includes the GUTI assigned to the UE 40 or the S-TMSI included in the GUTI, eDRX parameters regarding the UE 40, and IMSI that identifies the UE 40.

Next, the MME 42 uses the S-TMSI and the eDRX parameters to calculate the timing at which the UE 40 monitors the Paging Channel (S37). In other words, the MME 42 calculates the timing for paging the UE 40 using the S-TMSI and the eDRX parameters.

Next, the MME 42 transmits a DDN Ack (Acknowledge) message to the SGW 45 as a response to the DDN message (S38). Next, in the process of S37, the MME 42 checks whether the GUTI included in the DDN message (S36) has already been distributed to another UE. After confirming that the GUTI included in the DDN message (S36) has not yet been distributed to any UE, the MME 42 sends the message to the eNB 51 in time for paging the UE 40 calculated in step S37. A paging message is sent (S39). The Paging message sent by the MME 42 includes the GUTI assigned to the UE 40 or the S-TMSI included in the GUTI, and eDRX parameters regarding the UE 40. Furthermore, the IMSI may be included in the Paging message (S39). On the other hand, in the process of S37, if the GUTI included in the DDN message (S36) has already been distributed to another UE, the GUTI assigned to the UE 40 is In addition to the GUTI or the S-TMSI included in the GUTI and the eDRX parameters regarding the UE 40, an IMSI that identifies the UE 40 is further included.

Next, the eNB 51 executes paging for the UE 40 at the paging timing calculated using the S-TMSI and eDRX parameters regarding the UE 40 (S40). When the UE 40 detects a Paging Channel addressed to itself that includes the GUTI assigned to the UE 40, the UE 40 executes a Service Request Procedure (S41).

As described above, by using the communication system according to the second embodiment, the SGW 45 can acquire the GUTI assigned to the UE 40 or the S-TMSI included in the GUTI and the eDRX parameters. Furthermore, when the MME 42 recovers after a failure occurs, the MME 42 loses information regarding the UE 40. Even in such a case, when the SGW 45 receives Downlink Data regarding the UE 40, it can transmit the GUTI assigned to the UE 40 or the S-TMSI included in the GUTI and the eDRX parameters to the MME 42.

The MME 42 and the eNB 51 can calculate the monitoring timing of the Paging Channel that the UE 40 is monitoring by using the S-TMSI and eDRX parameters transmitted from the SGW 45. As a result, even if the MME 42 loses information regarding the UE 40, it can normally perform paging for the UE 40.

Further, in FIG. 8, the SGW 45 transmits the DDN message to the MME 42 after recovering from the failure, but the SGW 45 may transmit the DDN message to another MME different from the MME 42. This may occur when the SGW 45 receives Down Link Data (S35) before the failure of the MME 42 is recovered (before S34). The other MMEs may specifically be other MMEs in the MME pool that includes the MME 42. The MME pool is a technology that increases the fault tolerance of MMEs by connecting multiple MMEs to an eNB. Other MMEs in the MME pool do not manage the information regarding the UE that was managed by MME 42. Similar to the MME 42 in FIG. 8, when the other MME receives the DDN message transmitted from the SGW 45, the other MME uses the S-TMSI and eDRX parameters of the UE 40 to calculate the cycle at which the UE 40 monitors the Paging Channel. In other words, the other MMEs perform the same processing as in and after step S37 in FIG. However, in this case, the Paging message sent by the other MME includes the GUTI assigned to the UE 40 or the S-TMSI included in the GUTI, the eDRX parameters regarding the UE 40, and the IMSI that identifies the UE 40.

(Embodiment 3)
Next, the flow of packet arrival processing according to the third embodiment will be described using FIG. 9. The process flow shown in steps S30 to S40 in FIG. 9 is the same as steps S30 to S40 in FIG. 8, and therefore will be described using the same reference numerals as in FIG.

In the paging process of FIG. 9, the parameters set in the messages transmitted after step S39 are different from the paging process of FIG. 8.

In addition to the GUTI assigned to the UE 40 or the S-TMSI included in the GUTI, and the eDRX parameters regarding the UE 40, the Paging message transmitted in step S39 of FIG. The IMSI that newly identifies the UE 40 is included.

Here, the information elements set in the Paging message will be explained using FIG. 10. FIG. 10 shows that two UE Paging identities, UE Paging Identity and UE Paging Identity2, are set as information elements set in the Paging message. For example, the S-TMSI regarding the UE 40 may be set in the UE Paging Identity, and the IMSI regarding the UE 40 may be set in the UE Paging Identity2. Further, the name UE Paging Identity2 is not limited to this, and other names may be used.

Returning to FIG. 9, in step S40 of FIG. 9, the eNB 51 executes paging for the UE 40 at the paging timing calculated using the S-TMSI and eDRX parameters regarding the UE 40. However, in step S40 of FIG. 9, the eNB 51 executes paging using IMSI as the identification information of the UE 40. When the UE 40 detects a Paging Channel addressed to itself that includes an IMSI indicating the UE 40, the UE 40 executes an Attach Procedure (S51). Furthermore, in FIG. 8, even when the GUTI included in the DDN message (S36) has already been distributed to another UE, or when another MME executes the Paging message (S39), the eNB 51 , paging is performed using the IMSI as the identification information of the UE 40 at the paging timing calculated using the S-TMSI and eDRX parameters regarding the UE 40.

Paging in which IMSI is used as the identification information of UE 40 is normally performed after the MME recovers from a failure and in a state where MME 42 does not have information regarding UE 40. Therefore, when the UE 40 detects a Paging Channel including the IMSI indicating the UE 40, the UE 40 executes an Attach process in order to register information regarding the UE 40 in the MME 42.

The effects of the paging process in FIG. 9 compared to the paging process in FIG. 8 will be described below. In FIG. 8, after the MME 42 recovers from the failure, paging is performed using GUTI as the identification information of the UE 40 in a state where the information regarding the UE 40 managed by the MME 42 has disappeared. Therefore, the UE 40 executes the Service Request Procedure on the premise that information regarding the UE 40 is managed in the MME 42.

However, since the MME 42 has lost the information regarding the UE 40, it is unable to continue the Service Request process. As a result, the MME 42 transmits a Reject message to the UE 40 that has transmitted the Service Request message. Upon receiving the Reject message, the UE 40 causes the MME 42 to register information regarding the UE 40 by performing an Attach Procedure.

On the other hand, in the paging process of FIG. 9, IMSI is used as the identification information of the UE 40. Although GUTI or S-TMSI is also set in the Paging message in step S39 of FIG. 9, GUTI or S-TMSI is used only to calculate the timing to execute paging. That is, in step S40 of FIG. 9, the information set in the Paging Channel to identify the UE 40 is the IMSI of the UE 40. If the Paging message transmitted from the MME 42 includes GUTI and IMSI, the eNB 51 may prioritize paging using IMSI.

When the UE 40 detects the Paging Channel including the IMSI indicating the UE 40, the UE 40 can execute the Attach Procedure without executing the Service Request Procedure. Therefore, in the paging process of FIG. 9, the Service Request Procedure is not executed, so compared to the paging process of FIG. 8, the processing load associated with the Service Request Procedure is reduced.

(Embodiment 4)
Next, the flow of packet arrival processing according to the fourth embodiment will be described using FIG. 11. In FIG. 11, it is assumed that the events of steps S31 to S34 in FIG. 8 have occurred. Furthermore, in FIG. 11, it is assumed that after the MME 42 recovers from a failure, the SGW 45 simultaneously receives a large amount of Downlink Data for the UEs managed by the MME 42 (S61).

When the SGW 45 receives a large amount of Downlink Data all at once and sends a large amount of DDN messages to the MME 42 all at once, the processing load on the MME 42 increases rapidly, and the failure state may occur again. In order to avoid such a situation, even when the SGW 45 receives a large amount of Downlink Data all at once, it gradually transmits the DDN message to the MME 42 (S62 to S64).

For example, when the SGW 45 newly receives a predetermined number or more of Downlink Data within a predetermined period, the SGW 45 may gradually transmit the DDN message to the MME 42. The SGW 45 transmitting the DDN message to the MME 42 gradually and slowly may mean that the interval at which the DDN message is transmitted is set for a predetermined period or more to the extent that the processing load on the MME 42 does not increase rapidly. For example, when the SGW 45 newly receives a predetermined number or more of Downlink Data within a predetermined period, the SGW 45 may determine the interval for transmitting the DDN message using a predetermined timer. Here, we have explained the operation when the SGW 45 receives a large amount of Downlink Data all at once, but this operation is only possible when the SGW 45 has already buffered the Downlink Data for the UE at the time the MME 42 recovers from the failure. It can be similarly applied to In this case, the Downlink Data Notification message (S62, S63, and S64) in FIG. 11 is not triggered by the reception of Downlink Data (S61), but is a spontaneous operation of the SGW 45.

In the future, when the number of IoT devices with eDRX functionality increases dramatically and the number of IoT devices managed by MME42 increases, Downlink Data will be sent all at once to the UEs managed by MME42 that has recovered from the failure. It is also possible. Even in such a case, the SGW 45 can prevent the processing load of the MME 42 from increasing rapidly by controlling the interval at which the DDN message is transmitted.

(Embodiment 5)
Next, a period for maintaining the session connection state of the UE between the SGW 45 and the PGW 46 according to the fifth embodiment will be described. The UE 40 periodically performs TAU processing even if the TA in its area does not change. TAU processing that is performed periodically may be referred to as periodic location registration or periodic TAU. The interval at which the UE 40 performs periodic location registration is determined based on the T3412 timer defined in 3GPP. For example, the maximum interval at which the UE 40 performs periodic location registration is determined to be approximately 186 minutes based on the T3412 timer.

Further, T3412 extended value is defined in 3GPP for the purpose of lengthening the interval at which periodic location registration is performed in order to suppress battery consumption of the UE 40 and reduce the load on the network. The maximum interval at which the UE 40 performs periodic location registration is extended to a maximum of approximately 413 days based on the T3412 extended value. It is being considered that periodic location registration based on T3412 extended value is mainly applied to IoT devices.

In the fifth embodiment, the SGW 45 determines the period for maintaining the session connection state of the UE in step S32 of FIGS. 8 and 9 based on the T3412 timer or the T3412 extended value.

Specifically, in the TAU process or Attach process in FIG. 6, the MME 42 sets a T3412 timer or a T3412 extended value in the TAU Accept message or Attach Accept message in order to notify the UE 40 of the cycle of periodic location registration. Furthermore, the MME 42 sets the T3412 timer or T3412 extended value set in the TAU Accept message or Attach Accept message in the Modify Bearer Request message or Create Session Request message.

When the SGW 45 receives the Modify Bearer Request message or the Create Session Request message in which the T3412 timer is set, for example, after detecting the failure of the MME 42 in step S33 of FIGS. 8 and 9, the SGW 45 uses the period determined based on the T3412 timer. The session connection state of the UE is maintained for the same period as the location registration interval. In addition, when the SGW 45 receives a Modify Bearer Request message or a Create Session Request message in which the T3412 extended value is set, for example, after detecting a failure of the MME 42 in step S33 of FIGS. 8 and 9, the SGW 45 The session connection state of the UE is maintained for the same period as the periodic location registration interval determined by the UE. By determining the period for maintaining the session connection state of the UE in this way, the following effects can be obtained.

If the SGW 45 does not receive the Modify Bearer Request message in which the T3412 timer or the T3412 extended value is set, the SGW 45 cannot recognize the periodic location registration interval of the UE 40. Therefore, for example, the SGW 45 may decide to maintain the session connection state of the UE for the same period as the periodic location registration interval uniformly determined based on the T3412 timer. However, in this case, if the periodic location registration interval of the UE 40 is determined based on the T3412 extended value, the SGW 45 transmits a DDN message regarding Downlink Data received after the session connection state of the UE 40 is released to the MME 42. become unable to do so. This is because when the session connection state of the UE 40 is released, the SGW 45 also loses the GUTI, IMSI, etc. related to the UE 40, and therefore cannot set the identification information of the UE 40 in the DDN message.

It is also conceivable that the SGW 45 decides to maintain the session connection state of the UE for the same period as the periodic location registration interval uniformly determined based on the T3412 extended value. Here, due to a failure of the UE 40 or a power transition from an ON state to an OFF state in a place where radio waves cannot reach, the UE 40 cannot even notify the eNB of the state transition to power OFF and is unable to communicate. shall be. In such a case, if the SGW 45 maintains the session connection state of the UE for the same period as the periodic location registration interval determined based on the T3412 timer, the session connection state of the UE 40 may be canceled after a maximum of approximately 186 minutes. I can do it. However, if the SGW 45 maintains the session connection state of the UE for the same period as the periodic location registration interval determined based on the T3412 extended value, the session connection state of the UE 40, which cannot communicate, will be maintained for a maximum of 413 days. There is a need to.

In this way, if the SGW 45 decides to maintain the session connection state of the UE without recognizing that the periodic location registration interval of the UE 40 is determined based on either the T3412 timer or the T3412 extended value, The above problem occurs.

On the other hand, in the fifth embodiment, the SGW 45 can receive a Modify Bearer Request message or a Create Session Request message in which either the T3412 timer or the T3412 extended value is set. Therefore, the SGW 45 can recognize whether the periodic location registration interval of the UE 40 is determined based on either the T3412 timer or the T3412 extended value. From this, the SGW 45 can determine the period for maintaining the session connection state for each UE, so it may become impossible to send a DDN message to the MME 42 by canceling the session connection state, or it may become impossible to communicate. It is also possible to avoid maintaining a session connection state for a long period of time for UEs that are unable to do so.

Next, configuration examples of the eNB 51, the UE 40, the MME 42, and the SGW 45 described in the plurality of embodiments described above will be described below. FIG. 12 is a block diagram showing a configuration example of the eNB 51. Referring to FIG. 12, the eNB 51 includes an RF transceiver 1001, a network interface 1003, a processor 1004, and a memory 1005. RF transceiver 1001 performs analog RF signal processing to communicate with UEs. RF transceiver 1001 may include multiple transceivers. RF transceiver 1001 is coupled to antenna 1002 and processor 1004. RF transceiver 1001 receives modulation symbol data (or OFDM symbol data) from processor 1004, generates a transmit RF signal, and provides the transmit RF signal to antenna 1002. Further, RF transceiver 1001 generates a baseband reception signal based on the reception RF signal received by antenna 1002 and supplies this to processor 1004.

Network interface 1003 is used to communicate with network nodes (e.g. other core network nodes). Network interface 1003 may include, for example, a network interface card (NIC) compliant with the IEEE 802.3 series.

Processor 1004 performs data plane processing and control plane processing including digital baseband signal processing for wireless communications. For example, in the case of LTE and LTE-Advanced, digital baseband signal processing by processor 1004 may include MAC layer and PHY layer signal processing.

Processor 1004 may include multiple processors. For example, processor 1004 may include a modem processor (e.g., DSP) that performs digital baseband signal processing and a protocol stack processor (e.g., CPU or MPU) that performs control plane processing.

Memory 1005 is configured by a combination of volatile memory and nonvolatile memory. Memory 1005 may include multiple physically independent memory devices. Volatile memory is, for example, Static Random Access Memory (SRAM) or Dynamic RAM (DRAM) or a combination thereof. Non-volatile memory is masked Read Only Memory (MROM), Electrically Erasable Programmable ROM (EEPROM), flash memory, or a hard disk drive, or any combination thereof. Memory 1005 may include storage located remotely from processor 1004. In this case, processor 1004 may access memory 1005 via network interface 1003 or an I/O interface (not shown).

The memory 1005 may store a software module (computer program) including a group of instructions and data for performing the processing by the eNB 51 described in the above-described embodiments. In some implementations, the processor 1004 may be configured to retrieve and execute the software modules from the memory 1005 to perform the processing of the eNB 51 described in the embodiments above.

FIG. 13 is a block diagram showing a configuration example of the UE 40. A Radio Frequency (RF) transceiver 1101 performs analog RF signal processing to communicate with the eNB 51. Analog RF signal processing performed by RF transceiver 1101 includes frequency upconversion, frequency downconversion, and amplification. RF transceiver 1101 is coupled with antenna 1102 and baseband processor 1103. That is, RF transceiver 1101 receives modulation symbol data (or OFDM symbol data) from baseband processor 1103, generates a transmit RF signal, and supplies the transmit RF signal to antenna 1102. Further, RF transceiver 1101 generates a baseband reception signal based on the reception RF signal received by antenna 1102, and supplies this to baseband processor 1103.

The baseband processor 1103 performs digital baseband signal processing (data plane processing) and control plane processing for wireless communication. Digital baseband signal processing includes (a) data compression/decompression, (b) data segmentation/concatenation, (c) transmission format (transmission frame) generation/decomposition, and (d) transmission path encoding/decoding. , (e) modulation (symbol mapping)/demodulation, and (f) generation of OFDM symbol data (baseband OFDM signal) by Inverse Fast Fourier Transform (IFFT). Control plane processing, on the other hand, includes layer 1 (e.g., transmit power control), layer 2 (e.g., radio resource management, and hybrid automatic repeat request (HARQ) processing), and layer 3 (e.g., attach, mobility, and call management). including communication management (signaling related to communication).

For example, in the case of LTE and LTE-Advanced, the digital baseband signal processing by the baseband processor 1103 includes signal processing of the Packet Data Convergence Protocol (PDCP) layer, Radio Link Control (RLC) layer, MAC layer, and PHY layer. But that's fine. Further, the control plane processing by the baseband processor 1103 may include processing of a Non-Access Stratum (NAS) protocol, an RRC protocol, and a MAC CE.

The baseband processor 1103 includes a modem processor (e.g., Digital Signal Processor (DSP)) that performs digital baseband signal processing, and a protocol stack processor (e.g., Central Processing Unit (CPU)) or Micro Processing Unit that performs control plane processing. (MPU)). In this case, the protocol stack processor that performs control plane processing may be shared with the application processor 1104, which will be described later.

Application processor 1104 is also referred to as a CPU, MPU, microprocessor, or processor core. Application processor 1104 may include multiple processors (multiple processor cores). The application processor 1104 executes a system software program (Operating System (OS)) read from the memory 1106 or a memory not shown, and various application programs (for example, a telephone call application, a web browser, a mailer, a camera operation application, a music playback application, etc.). By executing the application), various functions of the UE 40 are realized.

In some implementations, baseband processor 1103 and application processor 1104 may be integrated on one chip, as shown by the dashed line (1105) in FIG. 13. In other words, the baseband processor 1103 and the application processor 1104 may be implemented as one System on Chip (SoC) device 1105. An SoC device is sometimes called a system Large Scale Integration (LSI) or chipset.

Memory 1106 is volatile memory or non-volatile memory or a combination thereof. Memory 1106 may include multiple physically independent memory devices. Volatile memory is, for example, Static Random Access Memory (SRAM) or Dynamic RAM (DRAM) or a combination thereof. Non-volatile memory is masked Read Only Memory (MROM), Electrically Erasable Programmable ROM (EEPROM), flash memory, or a hard disk drive, or any combination thereof. For example, memory 1106 may include external memory devices accessible from baseband processor 1103, application processor 1104, and SoC 1105. Memory 1106 may include embedded memory devices integrated within baseband processor 1103, within application processor 1104, or within SoC 1105. Additionally, memory 1106 may include memory within a Universal Integrated Circuit Card (UICC).

Memory 1106 may store software modules (computer programs) that include instructions and data for processing by UE 80 as described in the embodiments above. In some implementations, baseband processor 1103 or application processor 1104 may be configured to retrieve and execute the software modules from memory 1106 to perform the processing of UE 40 described in the embodiments above.

FIG. 14 is a block diagram showing a configuration example of the MME 42 and the SGW 45. Referring to FIG. 14, the MME 42 and SGW 45 include a network interface 1201, a processor 1202, and a memory 1203. Network interface 1201 is used to communicate with network nodes (e.g., SGSN 44, HSS 43, PGW 46, etc.). Network interface 1201 may include, for example, a network interface card (NIC) compliant with the IEEE 802.3 series.

The processor 1202 reads software (computer program) from the memory 1203 and executes it, thereby performing the processing of the center node 20 explained using the sequence diagram and flowchart in the above embodiment. Processor 1202 may be, for example, a microprocessor, MPU, or CPU. Processor 1202 may include multiple processors.

Processor 1202 performs data plane processing and control plane processing including digital baseband signal processing for wireless communications. For example, for LTE and LTE-Advanced, digital baseband signal processing by processor 1004 may include signal processing of the PDCP layer, RLC layer, and MAC layer. Further, the signal processing by the processor 1202 may include signal processing of the GTP-U/UDP/IP layer at the X2-U interface and the S1-U interface. Furthermore, the control plane processing by the processor 1004 may include processing of the X2AP protocol, S1-MME protocol, and RRC protocol.

Processor 1202 may include multiple processors. For example, the processor 1004 includes a modem processor (e.g., DSP) that performs digital baseband signal processing, a processor (e.g., DSP) that performs GTP-U/UDP/IP layer signal processing on the X2-U interface and the S1-U interface, DSP) and a protocol stack processor (e.g., CPU or MPU) that performs control plane processing.

Memory 1203 is configured by a combination of volatile memory and nonvolatile memory. Memory 1203 may include storage located remotely from processor 1202. In this case, processor 1202 may access memory 1203 via an I/O interface (not shown).

In the example of FIG. 14, memory 1203 is used to store software modules. The processor 1202 can perform the processing of the MEC server 40 described in the above embodiment by reading out and executing these software module groups from the memory 1203.

As explained using FIGS. 12 to 14, each of the processors included in the eNB 51, UE 40, MME 42, and SGW 45 in the above embodiment executes a group of instructions for causing a computer to execute the algorithm explained using the drawings. Execute one or more programs containing.

In the examples above, the program may be stored and provided to the computer using various types of non-transitory computer readable media. Non-transitory computer-readable media includes various types of tangible storage media. Examples of non-transitory computer-readable media include magnetic recording media (e.g., flexible disks, magnetic tapes, hard disk drives), magneto-optical recording media (e.g., magneto-optical disks), CD-ROMs (Read Only Memory), CD-Rs, CD-R/W, semiconductor memory (for example, mask ROM, PROM (Programmable ROM), EPROM (Erasable PROM), flash ROM, RAM (Random Access Memory)). The program may also be provided to the computer on various types of transitory computer readable media. Examples of transitory computer-readable media include electrical signals, optical signals, and electromagnetic waves. The temporary computer-readable medium can provide the program to the computer via wired communication channels, such as electrical wires and fiber optics, or wireless communication channels.

Note that the present disclosure is not limited to the above embodiments, and can be modified as appropriate without departing from the spirit. Further, the present disclosure may be implemented by appropriately combining the respective embodiments. Further, an SGSN may be used instead of the MME described in the above embodiment, and an RNC may be used instead of the eNB. In this case, TAU is replaced with RAU (Routing Area Update), and GUTI, S-TMSI, and M-TMSI are replaced with P (Packet)-TMSI. Furthermore, MMF (Mobility Management Function) may be used instead of MME described in the above embodiments, UPF (U-Plane Function) may be used instead of SGW, and NR may be used instead of eNB.

10 gateway device 11 storage unit 12 communication unit 20 mobility management device 40 UE
41 E-UTRAN
42 MME
43 HSS
44 SGSN
45 SGW
46 PGW
47 PCRF
48 UTRAN
49 GERAN
50 Operator's IP Services
51 eNB
61 communication section 62 control section 71 calculation section 72 communication section 81 calculation section 82 communication section

Claims (14)

A first CN (Core Network) node having at least a mobility management function,
comprising means for communicating with a second CN node;
The third CN node having at least the mobility management function is configured to store information related to UE (User Equipment) to the second CN node,
further comprising means for acquiring the information from the second CN node when a failure of the third CN node is detected;
The information includes a first identifier;
the first identifier is used by the UE in a Registration Procedure;
the first identifier is used by the third CN node for mobility management processing of the UE;
further comprising means for transmitting a message to a RAN (Radio Access Network) node;
the message includes a second identifier associated with the UE and a third identifier associated with the UE;
The second identifier corresponds to the first identifier,
the third identifier is used by the RAN node;
First CN node. the first identifier is associated with the third CN node;
The first CN node according to claim 1. The Registration Procedure is Initial Registration.
The first CN node according to claim 1 or 2 . The first CN node and the third CN node are included in the same set that includes a plurality of CN nodes having at least the mobility management function,
The first CN node according to claim 1 or 2. A method executed in a first CN (Core Network) node having at least a mobility management function, the method comprising:
communicating with a second CN node;
The third CN node having at least the mobility management function is configured to store information related to UE (User Equipment) to the second CN node,
acquiring the information from the second CN node when a failure of the third CN node is detected;
The information includes a first identifier;
the first identifier is used by the UE in a Registration Procedure;
the first identifier is used by the third CN node for mobility management processing of the UE;
Method. the first identifier is associated with the third CN node;
The method according to claim 5. The Registration Procedure is Initial Registration.
The method according to claim 5 or 6 . Sends a message to a RAN (Radio Access Network) node,
the message includes a second identifier associated with the UE and a third identifier associated with the UE;
The second identifier corresponds to the first identifier,
the third identifier is used by the RAN node;
The method according to claim 5 or 6 . The first CN node and the third CN node are included in the same set that includes a plurality of CN nodes having at least the mobility management function,
The method according to claim 5 or 6 . A method executed in a UE (User Equipment), the method comprising:
communicates with a RAN (Radio Access Network) node,
Execute the Registration Procedure using the first identifier ,
A first CN (Core Network) node having at least a mobility management function is configured to use the first identifier for mobility management processing of the UE,
the first CN node is configured to save information related to the UE to a second CN node;
the information includes the first identifier ;
The third CN node having at least the mobility management function acquires the information including the first identifier from the second CN node when a failure of the first CN node is detected. configured to
Method. the first identifier is associated with the first CN node;
The method according to claim 10. The Registration Procedure is Initial Registration.
The method according to claim 10 or 11 . the third CN node is configured to send a message to the RAN node ;
the message includes a second identifier associated with the UE and a third identifier associated with the UE;
The second identifier corresponds to the first identifier,
the RAN node is configured to use the third identifier;
The method according to claim 10 or 11 . The first CN node and the third CN node are included in the same set that includes a plurality of CN nodes having at least the mobility management function,
The method according to claim 10 or 11 .

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