KR20110078260A - Mobile communication systems - Google Patents

Abstract

The present invention provides a mobile communication system including a user terminal and a mobility management entity that provides an incoming call service to the user terminal. The incoming call service may include managing the location of the user terminal and determining the location of the user terminal by performing paging when there is an incoming call to the user terminal. The mobile communication system according to the present invention also detects whether a mobility management node has a failure, and provides a call service to a user terminal on behalf of the mobility management node when the mobility management node has failed. management entity).

Mobile communication system, mobility management node, terminal, failure, 3GPP, LTE

Description

Mobile communication system {MOBILE COMMUNICATION SYSTEM}

The present invention relates to a mobile communication system, and more particularly, to a mobile communication system capable of providing a continuous incoming call service to a terminal even when a failure occurs in a mobility management entity (MME) for the terminal. will be.

One of the main goals of next generation mobile communication is the seamless provision of IP multimedia services to users. To achieve this goal, mobility management of mobile terminals and users is essential. Therefore, standard organizations related to next generation mobile communication are actively standardizing new mobility management technology to provide seamless service in next generation mobile communication network.

In the 3GPP LTE system, one of the core control nodes has a mobility management entity (MME) to manage mobility of terminals. Initially, a terminal that wants to access a mobile communication system registers with the system through an MME through an 'Initial Attach' procedure. The location of the terminal registered in the system is continuously managed and updated through the MME. The terminal informs its new location to the system through the MME by a tracking area update procedure when its location is changed in the dormant state when the signal connection with the network is lost.

In general, when there is an incoming call to a terminal from an external network, the MME registered with the corresponding terminal, which is the target of the incoming call, performs paging to determine the current location of the terminal. However, when a failure occurs in the MME in which a specific terminal registers its location, paging to the corresponding terminal cannot be performed, and thus, an incoming call service to the corresponding terminal is impossible until the MME is restored.

Therefore, even when a failure occurs in any MME, there is a need for a mobile communication system that enables continuous incoming call service to terminals registered in the MME.

Accordingly, the present invention provides a mobile communication system that enables continuous incoming service to terminals registered in the MME even when a failure occurs in a mobility management node (MME).

According to an aspect of the present invention, there can be provided a mobile communication system including a user terminal and a mobility management entity for providing an incoming call service to the user terminal. The incoming call service may include managing the location of the user terminal and determining the location of the user terminal by performing paging when there is an incoming call to the user terminal. The mobile communication system according to the present invention also detects whether a mobility management node has a failure, and provides a call service to a user terminal on behalf of the mobility management node when the mobility management node has failed. management entity).

According to an embodiment of the present invention, the mobile communication system may further include a home subscriber server communicating with the mobility management node and storing location information of the user terminal.

According to an embodiment of the present invention, the mobile communication system may be a 3GPP LTE system.

According to an embodiment of the present invention, the global mobility management node may detect whether the mobility management node has failed by transmitting a ping message to the mobility management node periodically.

According to an embodiment of the present invention, the global mobility management node may request the home subscriber server to update the location registration for the user terminal when the mobility management node fails.

According to an embodiment of the present invention, the user terminal may transmit a request for registration or update of its location information to the mobility management node, and the mobility management node that receives the request for registration or update of location information to the home subscriber server The registration or update of location information about the user terminal may be requested. The home subscriber server may also deliver information about the registration or update of the location information to the global mobility management node after completion of the registration or update of the location information about the user terminal.

According to an embodiment of the present invention, the global mobility management node receives a notification about an incoming call from the outside to the user terminal, selects a mobility management node corresponding to the received notification, and receives the selected mobility management node. Forwarded notifications.

According to an embodiment of the present invention, the global mobility management node receives a notification about an incoming call from the outside to the user terminal, selects a mobility management node corresponding to the received notification, and fails the selected mobility management node. If it is determined whether the selected mobility management node has a failure as a result of the determination, the incoming call service may be processed for the user terminal to which the incoming call is to be delivered.

According to the present invention, when the MME fails, proper paging for the terminal cannot be performed, and the incoming call cannot be properly delivered. According to the present invention, even when a failure occurs in any MME in the mobile communication system, the location registration is registered in the MME. Continuous incoming call service for the terminals is possible. In particular, according to the present invention, in the 3GPP LTE system in which data incoming service is active, the service continuity can be preserved regardless of the state of the MME, and thus, operators can obtain stable subscribers.

Embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following, when it is determined that there is a risk of unnecessarily obscuring the gist of the present invention, a detailed description of already known functions and configurations will be omitted. In addition, it should be understood that the following description relates to one embodiment of the present invention, but the present invention is not limited thereto.

1 schematically illustrates a configuration of a mobile communication system according to an embodiment of the present invention.

As shown, the mobile communication system 100 may include two tracking areas 102a and 102b. The tracking area 102a includes two cells 104aa and 104ab, and the tracking area 102b includes two cells 104ba and 104bb. Each tracking area 102a or 102b may be a basic unit set by the mobile communication system 100 to manage mobility of terminals in the system. Typically, the base station of each cell can broadcast information about which tracking area it belongs to, and each terminal in idle mode receives the broadcasted information so that the current tracking area in which it is currently registered is registered. Can be compared to the same tracking area. If the terminal determines that the currently located tracking area and the previously registered tracking area are different from each other, the terminal may request a tracking area update procedure such that its own location registered in the system becomes the currently located tracking area. Those skilled in the art will know the details of the tracking area update procedure of the terminal well, so the detailed description thereof will be omitted. Although the tracking regions 102a and 102b are shown to include two cells each in FIG. 1, it is obvious that the tracking regions may be configured to include more or fewer cells.

As shown, each of the cells 104aa, 104ab, 104ba, 104bb is associated with a base station (eNode B: hereinafter, eNB) 106aa, 106ab, 106ba, 106bb that supports the cells 104aa, 104ab, 104ba, 104bb. And User Equipment (UE) 108aa, 108ab, 108ba, 108bb located in cells 104aa, 104ab, 104ba, 104bb and communicating with respective corresponding eNBs 106aa, 106ab, 106ba, 106bb. can do. Typically, eNBs 106aa, 106ab, 106ba, and 106bb provide and manage radio resources for UEs 108aa, 108ab, 108ba, and 108bb located in corresponding cells 104aa, 104ab, 104ba, and 104bb (Radio Resource). Management (RRM), serving-gateway (S-GW) to route downlink or uplink user data to / from UEs 108aa, 108ab, 108ba, 108bb. The eNBs 106aa, 106ab, 106ba, 106bb may also perform scheduling and transmission of paging messages for positioning of each UE 108aa, 108ab, 108ba, 108bb. The UEs 108aa, 108ab, 108ba, and 108bb may be fixed or mobile user terminals, and various terms such as a mobile station, a user terminal, a subscriber station, and a wireless device. Can be referred to as As shown, the eNBs 106aa, 106ab, 106ba, 106bb each support one cell 104aa, 104ab, 104ba, 104bb and one UE 108aa within each cell 104aa, 104ab, 104ba, 104bb. Although only 108ab, 108ba, 108bb are indicated as being present, it should be understood that one eNB may support a greater number of cells or there may be a larger number of UEs within each cell.

The mobile communication system 100 also includes MMEs 110a and 110b, a Home Subscriber Server (HSS) 112, and a Serving Gateway (S-GW) 116. can do. The MME 110a, 110b performs paging for accurate positioning of the UE 108aa, 108ab, 108ba, 108bb when there is a downlink incoming call from the external network 120 to the UE 108aa, 108ab, 108ba, 108bb. can do. The MMEs 110a and 110b may also be involved in the update procedure of the tracking area for the terminal in the idle mode. For example, the MME 110a may communicate with each eNB 106aa, 106ab belonging to the tracking area 102a and each UE located in the tracking area 102a between the eNBs 106aa, 106ab and the HSS 112. (108aa, 108ab) can be responsible for the overall call processing associated with performing authentication and positioning. The MME 110b may communicate with each eNB 106ba, 106bb belonging to the tracking area 102b and perform authentication and location of each UE 106ba, 106bb between the eNB 106ba, 106bb and the HSS 112. Responsible for handling overall calls related to verification. The HSS 112 is a centralized database that stores and manages various information about subscribers of the mobile communication system 100 and locations of terminals, and may communicate with the MMEs 110a and 110b. The MME 110a, 110b may also be in communication with the S-GW 116. The S-GW 116 is a gateway for transmitting user data in uplink and downlink, and may be responsible for routing and forwarding user data. That is, the S-GW 116 may allocate and manage a radio bearer for transmission of user data, and may connect with the eNBs 106aa, 106ab, 106ba, and 106bb.

As shown, the mobile communication system 100 may also include a Global Mobility Management Entity (GMME) 114. GMME 114 may communicate with each MME 110a, 110b and HSS 112. The GMME 114 may receive information about UEs registered in the HSS 112 through communication with each MME 110a and 110b and the HSS 112 and backup data for each MME 110a and 110b. Can be built and stored. The GMME 114 may periodically check the states of the respective MMEs 110a and 110b. When the GMME 114 determines that the predetermined MMEs 110a and 110b have a failure, the GMME 114 stores the failure state of the corresponding MME and stores the MMEs 110a and 110b. Instead, the incoming call can be handled. That is, the GMME 114 continuously checks the state of the MME 110a and 110b to check whether there is a failure, and when there is a failure in the MME 110a and 110b where the specific UEs 108aa, 108ab, 108ba and 108bb are registered. It is a node that opens a new call for the corresponding UE (108aa, 108ab, 108ba, 108bb) so that the incoming call service can continue without interruption. The GMME 114 may also communicate with the S-GW 116 to participate in the establishment and updating of radio bearers.

The mobile communication system 100 may also include a packet data network gateway (P-GW) 118 and an external network 120. The P-GW 118 may assign an IP address and provide IP connectivity for each UE that wants to connect to the external network 120. That is, the P-GW 118 may serve as a gateway to the subscriber's external network 120 and may play a role of IP allocation and quality of service (QoS) control. According to an embodiment of the present invention, the external network 120 may be an internet network.

2 is a signal flow diagram of a request of a UE 108, ie, an 'Initial Attach' process, to first connect to a mobile communication system according to an embodiment of the present invention.

First, the UE 108 may send 202 a connection request to the eNB 106 of the cell to which it belongs. Upon receiving the access request, the eNB 106 may forward 204 the request to the MME 110 managing the cell. The MME 110 may then request 206 an identity (ID) for the UE 108 via the eNB 106 and the UE 108 may send its ID to the MME 110 in response ( 208). The MME 110 may then communicate with them between the UE 108 and the HSS 112 and perform 210 processing necessary for authentication and security of the UE 108. The MME 110 may send 212 a location registration request of the UE 108 to the HSS 112, and the HSS 112 performs 214 a location registration of the UE 108. An appropriate completion message may be sent 216 to the MME 110. The HSS 112 that has completed the location registration may send 218 information about the newly registered UE 108 to the GMME 114 and the GMME 114 sends a receive ACK for it to the HSS 220. can do. As a result, the 'Initial Attach' processing request of the UE 108 may be completed.

3 is a signal flow diagram related to a process of updating a registration position according to a position movement of the UE 108 according to one embodiment of the present invention.

First, UE 108 may determine 302 whether its current location is different from an existing registration location based on a message broadcast from eNB 106 of the cell in which it is currently located. If the UE 108 determines that its current location is different from the existing registration location, it transmits an update request of its registered location, i.e., tracking area, to the eNB 106 supporting the cell of the current location (304). )can do. Upon receiving the update request of the tracking area, the eNB 106 may forward 306 the received request to a new MME 110A managing the cell. Upon receipt of the request, the new MME 110A may send 308 a request for contextual information about the UE 108 to the previous MME 110B that previously managed the location of the UE 108, The MME 110B may send 310 the requested context information to the new MME 110A. The new MME 110A may then communicate with them between the UE 108 and the HSS 112 and perform 312 the processing necessary for authentication and security of the UE 108. The new MME 110A may send 314 an acknowledgment message of context information to the old MME 110B. Although not shown in FIG. 3, the new MME 110A may establish and update a new radio bearer between the S-GW 116 and the P-GW 118 connected thereto, and the former MME 110B May release an existing radio bearer between the S-GW 116 and the P-GW 118 connected thereto. As shown again, the new MME 110A may send 316 the location update request of the UE 108 to the HSS 112, and the former MME 110B is located relative to the HSS 112. A request to delete the registration may be sent 318. The HSS 112 may perform 320 a location update and a previous location registration deletion of the UE 108 and then send 322 appropriate completion messages for the new MME 110A and the old MME 110B. have. After completing the location update, the HSS 112 may transmit 324 information about the location updated UE 108 to the GMME 114 and the GMME 114 sends an HACK 112 to it. May be sent (326). Thereby, the update process of the location registration according to the positional movement of the UE 108 can be completed.

4 illustrates an incoming call forwarding when there is no obstacle in the MME 110 managing the UE 108 when a downlink incoming call to a specific UE 108 is received from an external network according to an embodiment of the present invention. Signal flow chart for

First, P-GW 118 communicates 402 to S-GW 116 that a downlink incoming call has arrived from an external network. The S-GW 116 notifies the GMME 114 that the incoming call has arrived 404 and the GMME 114 can make an appropriate ACK 406 to the S-GW 116. The GMME 114 may then select 408 the MME 110 managing the UE 108 based on the information stored therein, and inform the selected MME 110 that an incoming call has been delivered (410). ). The MME 110 may make an appropriate ACK 412 for the GMME 114, and the MME 110 may perform paging on the incoming call to the eNB 106 for correct positioning of the UE (414). Can be. The eNB 106 may forward 416 a paging message for the incoming call to the UE 108, which may receive 418 the appropriate response to the paging message. The UE 108 may then receive 420 incoming calls of the downlink from the external network via the P-GW 118 and the S-GW 116.

5 is a signal flow diagram when there is a failure in the MME 110 managing the UE 108 when an incoming call to a specific UE 108 is received from an external network according to an embodiment of the present invention.

First, GMME 114 may perform a periodic status check process 502 to detect 504 a failure of MME 110. According to one embodiment of the present invention, the periodic status check process of the GMME 114 may be performed, for example, by pinging the MME 110. If a failure of the MME 110 is detected, the GMME 114 may store the failure state of the MME 110 and enter an incoming call processing agent mode for the MME 110 (506). In this case, the GMME 114 may request 508 an identity (ID) for the UE 108 and the UE 108 may transmit 510 its ID in response. GMME 114 may then communicate with them between UE 108 and HSS 112 and perform processing necessary for authentication and security of that UE 108 (512). Although not specifically illustrated in FIG. 5, the GMME 114 may transmit a delete request for an existing radio bearer associated with the failed MME 110 for the S-GW 116 and the P-GW 118. As shown again in FIG. 5, the GMME 114 may send 514 a location update request of the UE 108 to the HSS 112, and the HSS 112 may locate the UE 108. Registration may be performed (516) and then an appropriate completion message may be sent to GMME 114 (518). Although not specifically illustrated in FIG. 5, the GMME 114 may send a create request for a new radio bearer for the S-GW 116 and the P-GW 118. As again shown in FIG. 5, the GMME 114 may also send 520 a request to set up new contextual information about the UE 108 to the eNB 106, from the eNB 106 that performed it. A complete response may be received 522. The GMME 114 may also assign 524 a temporary ID to the UE 108 and receive 526 a reception complete response from it from the UE 108. This allows the UE 108 to receive an incoming call from the outside via the P-GW 118 and the S-GW 116 (528). GMME 114 may report 530 the location information update completion of UE 108 to HSS 112 and HSS 112 may delete the failed MME 110 from the MME pool (532).

Embodiments according to the present invention may be implemented by various means, such as hardware, firmware, software, or a combination thereof. When implemented by hardware, an embodiment of the present invention may include one or more ASICs, application specific integrated circuits (DSPs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), Field Programmable Gate Arrays (FPGAs), processors, controllers, microcontrollers, microprocessors and the like can be implemented in various forms. When implemented by firmware or software, one embodiment of the present invention may be implemented by various forms such as modules, procedures, and functions for performing the functions or operations described above. The software code may be stored in a memory unit which may be located inside or outside the processor and may exchange data with the processor by various known means, and may be driven by the processor.

As will be appreciated by those skilled in the art, the present invention is not limited to the examples described herein but may be variously modified, reconfigured and replaced without departing from the scope of the present invention. Therefore, it is intended that the present invention cover all modifications and variations that fall within the true spirit and scope of the present invention.

1 is a diagram schematically showing a configuration of a mobile communication system according to an embodiment of the present invention.

2 is a signal flow diagram of a request of a UE to first connect to a mobile communication system, that is, an 'Initial Attach' process, according to an embodiment of the present invention.

Fig. 3 is a signal flow diagram illustrating an update process of a registration position according to a position movement of a UE, according to an embodiment of the present invention.

4 is a signal flow diagram for an incoming call forwarding when there is no obstacle in the MME managing the UE when a downlink incoming call for a specific UE is received from an external network according to an embodiment of the present invention.

5 is a signal flow diagram when there is a failure in the MME 110 managing the UE when an incoming call to a specific UE is received from an external network according to an embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

102a, 102b: tracking area 104aa-104bb: cell

106aa-106bb: base station 108aa-108bb: terminal

110a, 110b: mobility management node 112: home subscriber server

114: global mobility management node 116: serving-gateway

118: packet data network gateway

Claims (8)

As a mobile communication system, User equipment; A mobility management entity that provides an incoming call service to the user terminal-The incoming call service manages the location of the user terminal and performs paging when there is an incoming call to the user terminal. Includes the location of-; And A global mobility management entity that detects whether a failure of the mobility management node occurs, and provides an incoming call service to the user terminal on behalf of the mobility management node when the mobility management node fails. Mobile communication system comprising a. The method of claim 1, And a home subscriber server in communication with the mobility management node, the home subscriber server storing location information of the user terminal. The method of claim 2, The mobile communication system is a 3GPP LTE system. The method of claim 2, And the global mobility management node detects whether the mobility management node has failed by periodically sending a ping message to the mobility management node. The method of claim 2, And wherein the global mobility management node requests the home subscriber server to update the location registration with respect to the user terminal when the mobility management node fails. The method of claim 2, The user terminal may transmit a request for registration or update of its location information to the mobility management node, The mobility management node receiving the request for registration or update of the location information may request the home subscriber server to register or update location information about the user terminal. And the home subscriber server delivers information about registration or update of the location information to the global mobility management node after completion of registration or update of location information on the user terminal. The method of claim 2, The global mobility management node receives a notification regarding an incoming call from the outside to the user terminal, selects a mobility management node corresponding to the received notification, and delivers the received notification to the selected mobility management node. Mobile communication system. The method of claim 2, The global mobility management node receives a notification regarding an incoming call from the outside to the user terminal, selects a mobility management node corresponding to the received notification, determines whether the selected mobility management node has failed, And processing the incoming call service for the user terminal to which the incoming call is to be delivered when it is determined that the selected mobility management node has failed.

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