Terminal device, base station device, mme, and communication control method

Abstract

An MME detects that a PDN connection is not effective and changes from a non-optimal gateway to a bearer established in a PDN connection using a more optimal gateway as an endpoint node. This configuration allows an already-established PDN connection to switch to a new PDN connection using the more optimal gateway, which achieves optimal communication control for continuing communication of UE.

1 . A terminal device configured to:
 establish a Packet Data Network (PDN) connection by transmitting an Access Point Name (APN) to a core network;   establish a PDN connection, the PDN connection having a communication path thereof constituted of a communication path to a first gateway device and a communication path to a second gateway device;   transmit and receive user data to and from the first gateway device using the PDN connection;   initiate a service request procedure or a tracking area update procedure by transmitting, to a base station device, a SERVICE REQUEST message to make a transition from an idle state to an active state or a TRACKING AREA UPDATE REQUEST message to update a tracking area; and   transmit and receive user data to and from the second gateway device using the PDN connection in accordance with the service request procedure or the tracking area update procedure.   
     
     
         2 . The terminal device according to  claim 1 , wherein
 the APN is associated with permission information allowing a change of a gateway device from the first gateway device to the second gateway device, the terminal device transmitting and receiving user data to and from the gateway device using the PDN connection.   
     
     
         3 . The terminal device according to  claim 1 , configured to:
 obtain, from the core network, a first and second IP addresses associated with the PDN connection;   transmit and receive, using the first IP address, user data to and from the first gateway device using the PDN connection; and   transmit and receive, using the second IP address, user data to and from the second gateway device using the PDN connection.   
     
     
         4 . The terminal device according to  claim 3 , configured to:
 receive, from the base station device, identification information indicating use of the second IP address in accordance with the service request procedure or the tracking area procedure; and   transmit and receive, using the second IP address in accordance with the identification information, user data to and from the second gateway device using the PDN connection.   
     
     
         5 . The terminal device according to  claim 1 , wherein
 the first gateway device is a Local Gateway (LGW) located for offloading, and   the second gateway device is a Packet Data Gateway (PGW) located in the core network.   
     
     
         6 . A Mobility Management Entity (MME) configured to:
 receive, from a base station device, a SERVICE REQUEST message transmitted by a terminal device to make a transition from an idle state to an active state, or a TRACKING AREA UPDATE REQUEST message transmitted by the terminal device to update a tracking area;   initiate a gateway change procedure for a Packet Data Network (PDN) connection in response to reception of the SERVICE REQUEST message or the TRACKING AREA UPDATE REQUEST message, the PDN connection having a communication path thereof constituted of a communication path to a first gateway device and a communication path to a second gateway device, the PDN connection being established by the terminal device, the gateway change procedure being a procedure for changing a communication path to be used for communication using the PDN connection from the communication path to the first gateway device to the communication path to the second gateway device; and   transmit, to a base station device in the gateway change procedure, at least notification information for switching communication paths.   
     
     
         7 . The MME according to  claim 6 , wherein
 the PDN connection is established using an Access Point Name (APN), the APN being associated with at least permission information allowing establishment of the PDN connection constituting the communication path to the first gateway device and the communication path to the second gateway device.   
     
     
         8 . The MME according to  claim 7 , configured to:
 receive the APN from the terminal device in accordance with an attach procedure;   select the first gateway device and the second gateway device in accordance with the APN;   transmit a first Create Session request message for establishing the communication path to the first gateway device, to a Serving Gateway (SGW) or the first gateway device connecting the base station device and a core network; and   transmit a second Create Session request message for establishing the communication path to the second gateway device, to the SGW or the second gateway device.   
     
     
         9 . The MME according to  claim 6 , wherein
 the first gateway device is a Local Gateway (LGW) located for offloading, and   the second gateway device is a Packet Data Gateway (PGW) located in a core network.   
     
     
         10 . A base station device configured to:
 in accordance with an attach procedure initiated by a terminal device,   receive, from a core network, an ATTACH ACCEPT message including a first and second IP addresses associated with a Packet Data Network (PDN) connection and allocated to the terminal device, the PDN connection having a communication path thereof constituted of a communication path to a first gateway device and a communication path to a second gateway device; and   transmit the ATTACH ACCEPT message to the terminal device.   
     
     
         11 . The base station device according to  claim 10 , configured to notify the terminal device of identification information indicating use of the first IP address or the second IP address in a service procedure or a tracking area procedure initiated by the terminal device. 
     
     
         12 . A communication control method for a terminal device, the method comprising the steps of:
 establishing a Packet Data Network (PDN) connection by transmitting an Access Point Name (APN) to a core network, the PDN connection having a communication path thereof constituted of a communication path to a first gateway device and a communication path to a second gateway device;   transmitting and receiving user data to and from the first gateway device using the PDN connection;   initiating a service request procedure or a tracking area update procedure by transmitting, to a base station device, a SERVICE REQUEST message to make a transition from an idle state to an active state or a TRACKING AREA UPDATE REQUEST message to update a tracking area; and   transmitting and receiving user data to and from the second gateway device using the PDN connection in accordance with the service request procedure or the tracking area update procedure.   
     
     
         13 . The communication control method for a terminal device according to  claim 12 , wherein the APN is associated with permission information allowing a change of a gateway device from the first gateway device to the second gateway device, the terminal device transmitting and receiving user data to and from the gateway device using the PDN connection. 
     
     
         14 . The communication control method for a terminal device according to  claim 12 , the method further comprising the steps of:
 obtaining, from the core network, a first and second IP addresses associated with the PDN connection;   transmit and receive, using the first IP address, user data to and from the first gateway device using the PDN connection; and   transmit and receive, using the second IP address, user data to and from the second gateway device using the PDN connection.   
     
     
         15 . The communication control method for a terminal device according to  claim 14 , the method further comprising the steps of:
 receiving, from the base station device, identification information indicating use of the second IP address in accordance with the service request procedure or the tracking area procedure; and   selecting, in accordance with the identification information, the second IP address as an IP address to be used for transmission and reception of user data to and from the second gateway device using the PDN connection.   
     
     
         16 . The communication control method for a terminal device according to  claim 12 , wherein
 the first gateway device is a Local Gateway (LGW) located for offloading, and   the first gateway device is a Packet Data Gateway (PGW) located in the core network.   
     
     
         17 . A communication control method for a Mobility Management Entity (MME), the method comprising the steps of:
 receiving, from a base station device, a SERVICE REQUEST message transmitted by a terminal device to make a transition from an idle state to an active state, or a TRACKING AREA UPDATE REQUEST message transmitted by the terminal device to update a tracking area;   initiating a gateway change procedure for a Packet Data Network (PDN) connection in response to reception of the SERVICE REQUEST message or the TRACKING AREA UPDATE REQUEST message, the PDN connection having a communication path thereof constituted of a communication path to a first gateway device and a communication path to a second gateway device, the PDN connection being established by the terminal device, the gateway change procedure being a procedure for changing a communication path to be used for communication using the PDN connection from the communication path to the first gateway device to the communication path to the second gateway device; and   transmitting, to a base station device in the gateway change procedure, at least notification information for switching communication paths.   
     
     
         18 . The communication control method for an MME according to  claim 17 , wherein
 the PDN connection is established using an Access Point Name (APN), the APN being associated with at least permission information allowing establishment of a PDN connection constituting the communication path to the first gateway device and the communication path to the second gateway device.   
     
     
         19 . The communication control method for an MME according to  claim 18 , the method further comprising the steps of:
 receiving the APN from the terminal device in accordance with an attach procedure;   selecting the first gateway device and the second gateway device in accordance with the APN;   transmitting a first Create Session request message for establishing the communication path to the first gateway device, to a Serving Gateway (SGW) or the first gateway device connecting the base station device and a core network; and   transmitting a second Create Session request message for establishing the communication path to the second gateway device, to the SGW or the second gateway device.   
     
     
         20 . The communication control method for an MME according to  claim 17 , wherein
 the first gateway device is a Local Gateway (LGW) located for offloading, and   the second gateway device is a Packet Data Gateway (PGW) located in a core network.   
     
     
         21 . A communication control method for a base station device, the method comprising the steps of:
 in accordance with an attach procedure initiated by a terminal device,   receiving, from a core network, an ATTACH ACCEPT message including a first and second IP addresses associated with a Packet Data Network (PDN) connection and allocated to the terminal device, the PDN connection having a communication path thereof constituted of a communication path to a first gateway device and a communication path to a second gateway device; and   transmitting the ATTACH ACCEPT message to the terminal device.   
     
     
         22 . The communication control method for a base station device according to  claim 21 , the method further comprising the step of notifying the terminal device of identification information indicating use of the first IP address or the second IP address in a service procedure or a tracking area procedure initiated by the terminal device.