JP6574734B2 - Communication system and control method - Google Patents

Description

  The present invention relates to a communication system such as EPC (Evolved Packet Core) which is a mobile core and a control method in the communication system.

  As devices constituting the EPC, an evolved Node B (eNB), a Mobility Management Entity (MME), a Serving Gateway (SGW), and a Packet Data Network Gateway (PGW) are known. eNB is a wireless base station. The MME is a device that performs user authentication and terminal movement management. The SGW is a device that relays signals between the eNB or the MME and the PGW. The PGW is a device serving as a connection point with an external network such as the Internet (see, for example, Non-Patent Document 1 and Non-Patent Document 2). In EPC, CPlane (Control Plane) to which control signals are transmitted and UPlane (User Plane: User Plane) to which user data such as voice and data transmitted and received between mobile terminals (UE) is transmitted. ) And exist.

3GPP specification “3GPP TS23.401 (V12.5.0)” “General Packet Radio Service (GPRS) enhancements for Evolved Universal Terrestrial Radio Access Network (E-UTRAN) access” 3GPP specification "3GPP TS23.714"

  Conventionally, SGW and PGW that perform both CPlane and UPlane processing are used. Since the terminals connected to the conventional EPC are mainly portable terminals, in the SGW and PGW, when the portable terminals transmit and receive voice and data, the load on the CPlane and the load on the UPlane are commensurate. Resources were permanently allocated. Therefore, even if the load on one of the CPlane and UPlane increases, the available resources cannot be changed.

  In recent years, the number of IoT (Internet Of Things) devices in which the load of CPlane is larger than the load of UPlane is increasing. When such an IoT device accesses the EPC, the processing load of UPlane is smaller than that of CPlane, and therefore the UPlane resource becomes redundant in the SGW or PGW. Therefore, in order to effectively use resources, an approach of CU separation that divides SGW and PGW for each plane is being studied. By dividing CPlane and UPlane in this way and using SGW for CPlane (hereinafter C-SGW) and SGW for UPlane (hereinafter U-SGW), it becomes possible to change resources for each plane. Can be used effectively.

  By the way, when the number of IoT devices increases as mobile terminals, the load on the C-SGW is likely to fluctuate depending on the state of the mobile terminals accommodated in the C-SGW. As a result, it is necessary to change the C-SGW that accommodates the mobile terminal to another C-SGW. However, conventionally, when the C-SGW is changed, the U-SGW is also changed at the same time.

  Therefore, the present invention has been made in view of these points, and an object of the present invention is to make it possible to change a CPlane gateway independently.

  A communication system according to a first aspect of the present invention includes a plurality of control plane gateways that transmit / receive control data to / from a mobile terminal, a user plane gateway that transmits / receives user data to / from the mobile terminal, In response to receiving a change request for changing a pre-change gateway, which is a control plane gateway used for communication with a mobile terminal, to another control plane gateway, the other control plane gateway And a selection device that selects a gateway after change, and after the selection device selects the gateway after change, a communication path is established between the gateway after change and the gateway for user plane.

The selection device transmits, for example, terminal identification information for identifying the mobile terminal with which the pre-change gateway communicated, to the post-change gateway.
Further, the selection device may transmit a session establishment request including the terminal identification information to the changed gateway.

  The post-change gateway transmits a change notification notifying that the control plane gateway has been changed, including the terminal identification information, to the user plane gateway in response to receiving the session establishment request. Thus, the communication path may be established.

  In response to receiving the change notification, the user plane gateway may store the terminal identification information and the changed gateway address in association with each other.

  The selection device may select the post-change gateway based on the address of the post-change gateway included in the change request.

  The pre-change gateway may transmit the change request based on an instruction received via a management terminal that manages the plurality of control plane gateways. The pre-change gateway may transmit the change request when its communication state satisfies a predetermined condition.

  A control method according to a second aspect of the present invention includes a plurality of control plane gateways that transmit and receive control data to and from a mobile terminal, and a user plane gateway that transmits and receives user data to and from the mobile terminal. A control method executed by a communication system having a change request for changing a pre-change gateway, which is a control plane gateway used for communication with the mobile terminal, to another control plane gateway, Transmitting to a selection device that selects a gateway after change as the other gateway for the control plane; selecting the gateway after change in response to the selection device receiving the change request; After the selection device selects the changed gateway, the changed gateway and the user are selected. And a step of establishing a communication path with the plane gateway.

  According to the present invention, it is possible to change the CPlane gateway independently.

It is a figure which shows the structure of the communication system S of this embodiment. It is a figure which shows a communication sequence in case MME3 is used as a selection apparatus. It is a figure which shows a communication sequence in case PGW6 is used as a selection apparatus. It is a figure which shows a communication sequence in case U-SGW5 is used as a selection apparatus.

[Configuration of Communication System S]
FIG. 1 is a diagram illustrating a configuration of a communication system S according to the present embodiment. The communication system S includes a mobile terminal 1, an eNB 2, an MME 3, a plurality of C-SGWs 4, a U-SGW 5, and a PGW 6. A solid line in FIG. 1 indicates a path through which user data such as voice / data is transmitted, and a broken line indicates a path through which control data is transmitted. Moreover, the dashed-dotted line between C-SGW4 and U-SGW5 has shown the path | route in which control information is transmitted / received between C-SGW4 and U-SGW5.

  The portable terminal 1 is a terminal that can communicate with a portable telephone network such as LTE (Long Term Evolution) and 3GPP (Third Generation Partnership Project). The portable terminal 1 transmits / receives user data such as control data and voice / data to / from the eNB 2 via a radio channel.

  eNB2 is an LTE base station. The eNB 2 transfers the control data received from the mobile terminal 1 to the MME 3 and transfers the control data received from the MME 3 to the mobile terminal 1. Also, the eNB 2 transfers user data received from the mobile terminal 1 to the U-SGW 5 and transfers user data received from the U-SGW 5 to the mobile terminal 1.

  The MME 3 is a mobility management device that manages location registration of the mobile terminal 1, calling, and handover between base stations. MME3 relays control data between eNB2 and C-SGW4.

  The C-SGW 4 is a control data gateway for CPlane that processes control data. The C-SGW 4 transmits / receives control data to / from the mobile terminal 1. The communication system S includes a plurality of C-SGWs 4 corresponding to the number and type of mobile terminals 1. Each of the plurality of C-SGWs 4 is connected to the MME 3, the U-SGW 5, and the PGW 6.

  The U-SGW 5 is a user data gateway for UPlane that processes user data. The U-SGW 5 transmits and receives user data to and from the mobile terminal 1. U-SGW5 is connected with eNB2, some C-SGW4, and PGW6.

  The PGW 6 is a gateway for the mobile terminal 1 to access an external network such as the Internet. The PGW 6 is connected to a plurality of C-SGW 4 and U-SGW 5.

  In the communication system S, the C-SGW 4 in which the mobile terminal 1 is accommodated among the plurality of C-SGWs 4 can be changed. In this specification, it is assumed that the C-SGW 4 in which the mobile terminal 1 is accommodated before the change is the C-SGW 4a, and the C-SGW 4 in which the mobile terminal 1 is accommodated after the change is the C-SGW 4b.

  When changing the C-SGW 4 in which the portable terminal 1 is accommodated, it is necessary to select which C-SGW 4 to change to among the plurality of C-SGWs 4. Therefore, the communication system S responds to the reception of the change request for requesting the C-SGW 4a used for the communication with the mobile terminal 1 to change the other C-SGW 4 before the change. A selection device for selecting the post-change gateway C-SGW 4b as another C-SGW 4 is provided. The selection device is, for example, MME3, U-SGW5, or PGW6. Communication system S may be provided with devices other than MME3, U-SGW5, or PGW6 as a selection device.

In the procedure for changing the C-SGW 4, the following processing is mainly performed.
The information of C-SGW 4a before the change associated with the mobile terminal 1 (mainly information related to the mobile terminal 1) is notified to the C-SGW 4b of the change destination.
Establish a CPlane bearer among MME3, C-SGW4, and PGW6.
Notify U-SGW 5 that C-SGW 4 has been changed.
Hereinafter, a procedure for changing the C-SGW 4 in which the mobile terminal 1 is accommodated will be specifically described.

<First Embodiment>
[Communication sequence when the selection device is MME3]
FIG. 2 is a diagram illustrating a communication sequence when the MME 3 is used as a selection device. A solid arrow in FIG. 2 indicates a message that is also used in 3GPP, and a broken arrow is a message that is a characteristic of the present embodiment and has not been used conventionally.

  The changing process from the C-SGW 4a to the C-SGW 4b is started by an operation of an operator who manages the C-SGW 4a, for example. Specifically, C-SGW4a changes C-SGW4 which accommodates the specific portable terminal 1, for example based on the instruction | indication received via the management terminal (not shown) which manages several C-SGW4. A C-SGW change request is transmitted to the selection device.

  The changing process from the C-SGW 4a to the C-SGW 4b may be activated by other factors. For example, the C-SGW 4a transmits a C-SGW change request to the selection device when its communication state satisfies a predetermined condition. Specifically, the C-SGW 4a may activate the change process in response to the load on the C-SGW 4a exceeding a predetermined magnitude.

  As illustrated in FIG. 2, when the C-SGW 4 a starts the change process, the C-SGW change request (SGW_C Change Request), which is a request to change the process communicating with the mobile terminal 1 to another C-SGW 4, is sent to the MME 3. Transmit (S11). This C-SGW change request includes the IP address of the control U-SGW 5, the selection method of the switching destination C-SGW 4 and the information of the selection destination. Here, as a selection method, there are a method for uniquely designating C-SGW4, a method for designating C-SGW4 in pool units, and a method of not designating.

  In addition, MME3 discriminate | determines the portable terminal 1 used as the object which changes C-SGW4 based on the header of the received C-SGW change request, According to the selection method designated by the received C-SGW change request, The C-SGW 4b after the change is determined (S12). MME3 selects C-SGW4b from C-SGW4 other than C-SGW4 which received the notification that the load became more than predetermined amount, for example. The MME 3 may inquire the C-SGW 4b about the magnitude of the load and select the C-SGW 4 whose load is smaller than a predetermined value.

  Subsequently, the MME 3 creates a session establishment request (Create session request) including terminal identification information (for example, user information of the mobile terminal 1 registered in itself) for identifying the mobile terminal 1 with which the C-SGW 4a communicated. ). The MME 3 assigns the control address for the U-SGW 5 to the session establishment request, and transmits the session establishment request to which the U-SGW 5 control address is assigned to the C-SGW 4b determined in step S12 (S13).

  In response to receiving the session establishment request, the C-SGW 4b transmits a C-SGW modification message (Modify SGW_C Message) to the U-SGW 5 of the address included in the received session establishment request. A communication path is established (S14). The C-SGW change request is a change notification for notifying that the control plane gateway has been changed, including the terminal identification information of the mobile terminal 1.

  In response to receiving the C-SGW change message, the U-SGW 5 stores the terminal identification information included in the C-SGW change message and the address of the C-SGW 4b in association with each other. Specifically, the U-SGW 5 changes the IP address of the C-SGW 4a before the change stored in the storage medium such as a hard disk to the IP address of the C-SGW 4b (S15). Thereafter, the U-SGW 5 selects the C-SGW 4b based on the address of the C-SGW 4b included in the C-SGW change message, and the C-SGW change response (Modify) indicating that the change of the C-SGW 4 is completed. SGW_C Response) is transmitted to C-SGW 4b (S16).

  Subsequently, in order to create a CPlane bearer between the C-SGW 4 and the PGW 6, the C-SGW 4b transmits a bearer change request (Modify Bearer Request) for requesting a change of the CPlane bearer to the PGW 6 (S17). . When the change of the CPlane bearer is completed, the PGW 6 transmits a bearer change response (Modify bearer Response) indicating that the change of the CPlane bearer is completed to the C-SGW 4 (S18).

  Thereafter, the C-SGW 4b transmits a session establishment response (Create Session Response) to establish a CPlane bearer with the MME 3 (S19). The MME 3 recognizes the completion of the change of the bearer from the C-SGW 4a to the C-SGW 4b by receiving the session establishment response, and notifies the C-SGW 4a of a C-SGW change completion response (SGW_C Change Complete) (S20).

<Second Embodiment>
[Communication sequence when the selection device is PGW 6]
FIG. 3 is a diagram illustrating a communication sequence when the PGW 6 is used as a selection device. When the C-SGW 4a starts the change process, the C-SGW 4a transmits a C-SGW change request (SGW_C Change Request), which is a request to change the process communicating with the mobile terminal 1 to another C-SGW 4 (S31). This C-SGW change request includes the user ID of the mobile terminal 1, the IP address of the control U-SGW 5, the selection method of the switching destination C-SGW 4, and the information of the selection destination. Here, as a selection method, there are a method of uniquely designating C-SGW 4, a method of designating C-SGW 4 in pool units, and a method of not designating.

  Subsequently, the PGW 6 determines the mobile terminal 1 that is the target of changing the C-SGW 4 based on the received header of the C-SGW change request, and changes according to the selection method specified by the received C-SGW 4 After determining the C-SGW 4b after the change, the PGW 6 transmits a session establishment request trigger (Create Session Request Trigger) to the C-SGW 4b (S33). The session establishment request trigger includes the user ID of the mobile terminal 1 accommodated in the C-SGW 4a and the information of the MME 3 to which the user is connected.

  When receiving the session establishment request trigger, the C-SGW 4b transfers the received session establishment request trigger to the MME 3 (S34). The MME 3 creates a session establishment request (Create Session Request) using the user information registered in itself. The MME 3 gives an address for U-SGW5 control to the created session establishment request, and transmits it to the C-SGW 4b determined in step S32 (S35).

  When the C-SGW 4b receives the session establishment request (Create Session Request), the C-SGW 4b transmits a C-SGW modification message (Modify SGW_C Message) to the U-SGW 5 of the address included in the received session establishment request ( S36). When the U-SGW 5 receives the C-SGW change message, the U-SGW 5 changes the IP address of the C-SGW 4 corresponding to the mobile terminal 1 included in the C-SGW change message (S37).

  When the IP address of the C-SGW 4 is changed, the U-SGW 5 transmits a C-SGW change response (Modify SGW_C Response) indicating that the C-SGW 4 change is completed to the C-SGW 4b (S38). When the C-SGW 4b receives the C-SGW change response, the C-SGW 4b transmits a bearer change request (Modify Bearer Request) to the PGW 6 in order to create a CPlane bearer between the C-SGW 4 and the PGW 6 (S39). When the bearer change is completed, the PGW 6 transmits a bearer change response (Modify Bearer Response) indicating that the change of the CPlane bearer is completed to the C-SGW 4 (S40).

  When the C-SGW 4b receives the bearer change response, the C-SGW 4b transmits a session establishment response (Create Session Response) to establish a CPlane bearer with the MME 3 (S41). The MME 3 recognizes that the bearer change from the C-SGW 4a to the C-SGW 4b is completed by receiving the session establishment response, and indicates that the change to the C-SGW 4b is completed (SGW_C Change Complete) is notified (S42).

<Third Embodiment>
FIG. 4 is a diagram illustrating a communication sequence when the U-SGW 5 is used as a selection device. When starting the change process, the C-SGW 4a transmits a C-SGW change request (SGW_C Change Request) to the U-SGW 5 (S51). This C-SGW change request includes the ID of the user of the mobile terminal 1, the selection method of the C-SGW 4 to be switched to, and information on the selection destination. Here, as the selection method, as in the second embodiment, there are a method of uniquely designating C-SGW 4, a method of designating C-SGW 4 in pool units, and a method of not designating.

  Upon receiving the C-SGW change request, the U-SGW 5 determines the changed C-SGW 4b according to the selection method included in the received C-SGW change request (S52). When the U-SGW 5 determines the C-SGW 4b, the U-SGW 5 transmits a session establishment request trigger (Create Session Request Trigger) to the C-SGW 4b (S53). The session establishment request trigger includes the user ID of the mobile terminal 1 accommodated in the C-SGW 4a and the information of the MME 3 to which the user is connected.

  Upon receiving the session establishment request trigger, the C-SGW 4b transfers the received session establishment request trigger to the MME 3 (S54). The MME 3 creates a session establishment request (Create Session Request) using the user information registered in itself. The MME 3 gives an address for U-SGW5 control to the created session establishment request, and transmits it to the C-SGW 4b determined in step S52 (S55).

  When the C-SGW 4b receives the session establishment request, the C-SGW 4b transmits a bearer change request (Modify Bearer Request) to the PGW 6 in order to create a CPlane bearer between the C-SGW 4 and the PGW 6 (S56). When the bearer change is completed, the PGW 6 transmits a bearer change response (Modify Bearer Response) indicating that the change of the CPlane bearer is completed to the C-SGW 4 (S57).

  When the C-SGW 4b receives the bearer change response, the C-SGW 4b transmits a session establishment response (Create Session Response) to establish a CPlane bearer with the MME 3 (S58). The MME 3 recognizes that the bearer change from the C-SGW 4a to the C-SGW 4b is completed by receiving the session establishment response, and indicates that the change to the C-SGW 4b is completed (SGW_C Change Complete) is notified (S59).

[Effects of Communication System S of Embodiment of Present Invention]
As described above, according to the communication system S, when it is necessary to change the C-SGW 4 accommodating the mobile terminal 1, the C-SGW 4 transmits a change request to the selection device. C-SGW4 can be changed independently without changing U-SGW5. By doing in this way, when performing maintenance of C-SGW4 or when the load of a specific C-SGW4 increases, only C-SGW4 that needs to be changed is changed, and U-SGW5 is the same device as it is Can be used. Therefore, since C-SGW4 can be changed easily, it becomes easy to maintain. Moreover, when the load of C-SGW4 increases, it becomes possible to respond quickly to the increase in load.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above embodiment. In particular, the specific embodiments of the distribution / integration of the devices are not limited to those illustrated above, and all or a part thereof may be added in arbitrary units according to various additions or according to functional loads. It can be configured functionally or physically distributed and integrated.

1 mobile terminal 2 eNB
3 MME
4 C-SGW
5 U-SGW
6 PGW
S communication system

Claims (8)

A plurality of control plane gateways for transmitting and receiving control data to and from a mobile terminal;
A user plane gateway for transmitting and receiving user data to and from the portable terminal;
In response to receiving a change request for changing the gateway before change, which is a gateway for control plane used for communication with the portable terminal, to another gateway for control plane, for the other control plane A selection device for selecting the gateway after the change as a gateway; and
Have
The selection device , after selecting the changed gateway, transmits a session establishment request including terminal identification information for identifying the portable terminal with which the pre-change gateway communicated to the changed gateway. ,
The post-change gateway transmits a change notification notifying that the control plane gateway has been changed, including the terminal identification information, to the user plane gateway in response to receiving the session establishment request. By establishing a communication path between the changed gateway and the user plane gateway by
In response to receiving the change notification, the user plane gateway associates and stores the terminal identification information and the address of the changed gateway.
Communications system. A plurality of control plane gateways for transmitting and receiving control data to and from a mobile terminal;
A user plane gateway for transmitting and receiving user data to and from the portable terminal;
Included in the change request in response to receiving a change request for changing a pre-change gateway, which is a control plane gateway used for communication with the mobile terminal, to another control plane gateway A selection device that selects the changed gateway as the other control plane gateway based on the address of the changed gateway,
Have
After the selection device selects the changed gateway, a communication path is established between the changed gateway and the user plane gateway.
Communications system.   A plurality of control plane gateways for transmitting and receiving control data to and from a mobile terminal;
  A user plane gateway for transmitting and receiving user data to and from the portable terminal;
  Based on an instruction received via a management terminal that manages the plurality of control plane gateways, the gateway before change, which is the control plane gateway used for communication with the mobile terminal, is changed to another control plane gateway. The pre-change gateway sending a change request requesting to change;
  In response to receiving the change request, a selection device that selects the changed gateway as the other control plane gateway;
  Have
  After the selection device selects the changed gateway, a communication path is established between the changed gateway and the user plane gateway.
  Communications system.   A plurality of control plane gateways for transmitting and receiving control data to and from a mobile terminal;
  A user plane gateway for transmitting and receiving user data to and from the portable terminal;
  When the communication state of the device satisfies a predetermined condition, a change request for requesting to change the pre-change gateway, which is the control plane gateway used for communication with the mobile terminal, to another control plane gateway The pre-change gateway to send;
  In response to receiving the change request, a selection device that selects the changed gateway as the other control plane gateway;
  Have
  After the selection device selects the changed gateway, a communication path is established between the changed gateway and the user plane gateway.
  Communications system. A control method executed by a communication system having a plurality of control plane gateways for transmitting / receiving control data to / from a mobile terminal and a user plane gateway for transmitting / receiving user data to / from the mobile terminal,
A change request requesting to change a gateway before change which is a gateway for control plane used for communication with the mobile terminal to another gateway for control plane, and a gateway after change as the gateway for other control plane Transmitting to a selection device that selects
Selecting the post-change gateway in response to the selection device receiving the change request;
After the selection device selects the post-change gateway , the selection device transmits a session establishment request including terminal identification information for identifying the mobile terminal with which the pre-change gateway communicated to the post-change gateway. Steps,
In response to the reception of the session establishment request, the post-change gateway transmits a change notification that notifies the user plane gateway that the control plane gateway has been changed, including the terminal identification information. establishing a communication path between said after-gateway and the user plane gateways by,
The user plane gateway, in response to receiving the change notification, associating and storing the terminal identification information and the address of the changed gateway;
A control method.   A control method executed by a communication system having a plurality of control plane gateways for transmitting / receiving control data to / from a mobile terminal and a user plane gateway for transmitting / receiving user data to / from the mobile terminal,
  A change request requesting to change a gateway before change which is a gateway for control plane used for communication with the mobile terminal to another gateway for control plane, and a gateway after change as the gateway for other control plane Transmitting to a selection device that selects
  Selecting the post-change gateway based on the address of the post-change gateway included in the change request in response to the selection device receiving the change request;
  Establishing a communication path between the changed gateway and the user plane gateway after the selection device has selected the changed gateway;
  A control method.   A control method executed by a communication system having a plurality of control plane gateways for transmitting / receiving control data to / from a mobile terminal and a user plane gateway for transmitting / receiving user data to / from the mobile terminal,
  Based on the instruction received by the pre-change gateway, which is the control plane gateway used for communication with the mobile terminal, via the management terminal that manages the plurality of control plane gateways, the pre-change gateway Transmitting a change request for changing to a control plane gateway to a selection device that selects the changed gateway as the other control plane gateway; and
  Selecting the post-change gateway in response to the selection device receiving the change request;
  Establishing a communication path between the changed gateway and the user plane gateway after the selection device has selected the changed gateway;
  A control method.   A control method executed by a communication system having a plurality of control plane gateways for transmitting / receiving control data to / from a mobile terminal and a user plane gateway for transmitting / receiving user data to / from the mobile terminal,
  When the pre-change gateway, which is a control plane gateway used for communication with the mobile terminal, satisfies the predetermined condition of the pre-change gateway, the pre-change gateway is changed to another control plane gateway. Transmitting a change request for changing to a selection device that selects the changed gateway as the gateway for the other control plane; and
  Selecting the post-change gateway in response to the selection device receiving the change request;
  Establishing a communication path between the changed gateway and the user plane gateway after the selection device has selected the changed gateway;
  A control method.

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