JP7018884B2 - Communication method - Google Patents

Description

The present invention relates to a communication method.

Conventionally, when moving a cell in which a user terminal is located, a process of changing the route of a communication path provided from the user terminal via a base station device and a gateway device is performed. For example, Patent Document 1 discloses a configuration in which a redundant communication path is corrected via a plurality of gateway devices due to the movement of a user terminal.

Republished Patent No. 2011/118196

In recent years, it has been studied to reduce communication delay by distributedly arranging gateway devices, which were conventionally arranged collectively for a large number of base station devices. However, as shown in Patent Document 1, if the movement of the user terminal is allowed while providing the communication path via the plurality of gateway devices according to the movement of the user terminal, it is considered that the communication delay increases. On the other hand, if an attempt is made to secure an appropriate communication path when a movement between cells that requires a change in the gateway device occurs, it is necessary to reset the communication path or the like, and the communication may be interrupted momentarily.

The present invention has been made in view of the above, and an object of the present invention is to provide a communication method capable of suitably continuing communication when a user terminal moves between cells.

In order to achieve the above object, the communication method according to one embodiment of the present invention includes a user terminal, a first base station device included in a plurality of base station devices provided for each cell in which the user terminal can be located, and a first base station device. Two base station devices, a plurality of networked packet gateway devices associated with the base station device and responsible for transmitting data of the user terminal, and externally associated with the base station device and the network packet gateway device. Via a plurality of network gateway devices that control the transmission and reception of data of the user terminal to and from the network, one of the plurality of base station devices, and one of the plurality of regional packet gateway devices. In a communication system including a network gateway device included in the plurality of network gateway devices and a connection control device for performing processing related to establishment and disconnection of a communication path provided between the user terminal and the user terminal, the user. It is a communication method when a terminal moves from a cell under the control of the first base station device to a cell under the control of the second base station device, and the connection control device is associated with the base station device. It has a control information storage unit that stores information that identifies the network gateway device, and the user terminal is provided between the user terminal and the network gateway device associated with the first base station device, and the first base is provided. It has a first communication path via the station device and the area packet gateway device associated with the first base station device, and the connection control device has the first communication path from the first base station device. With reference to the route change request receiving step for receiving the request to change to the route via the second base station device, and the information stored in the control information storage unit by the connection control device, the first 2. A network gateway device determination step for determining whether or not the network gateway device associated with the base station device matches the network gateway device associated with the first base station device, and the network gateway device. In the determination step, when it is determined that the network gateway device associated with the second base station device does not match the network gateway device associated with the first base station device, the connection control device is used. However, with respect to the first communication path, the in-zone packet gateway associated with the second base station apparatus and the second base station apparatus. After the first communication route change step for changing to a route via the way device and the first communication route change step, the connection control device is associated with the user terminal and the second base station device. A second communication path via the zoned packet gateway device associated with the second base station device and the second base station device is provided between the network gateway device and the communication used by the user terminal. After the second communication path new establishment step of switching the route to the second communication path and the second communication path new establishment step, the connection control device disconnects the first communication path. With steps.

INDUSTRIAL APPLICABILITY According to the present invention, there is provided a communication method capable of suitably continuing communication when a user terminal moves between cells.

It is a figure explaining the schematic structure of the communication system in which the communication method which concerns on one embodiment of this invention is executed. It is a figure explaining the functional block of eNB and MME. It is a figure explaining the hardware configuration of each apparatus included in a communication system. It is a figure explaining the outline of the communication method of this embodiment. It is a figure explaining the example of the information used in the communication method of this embodiment. It is a sequence diagram explaining the communication method of this embodiment.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are designated by the same reference numerals, and duplicate description will be omitted.

FIG. 1 is a diagram illustrating a schematic configuration of a communication system 1 in which a communication method according to an embodiment of the present invention is executed. As shown in FIG. 1, the communication system 1 conforms to a communication standard (communication protocol) of an LTE (Long Term Evolution) network, and provides communication such as VoLTE (Voice over LTE) to a terminal device. It is a system. The communication system 1 includes a first eNB (eNodeB) 20A, a second eNB 20B, an MME (Mobility Management Entity) 30, a first SGW (Serving Gateway) 41A, a second SGW 41B, a first PGW (Packet Data Network Gateway) 42A, a second PGW 42B, and a first edge. It is configured to include a server 50A and a second edge server 50B. The UE (User Equipment) 10 (user terminal) realized by a smartphone, a tablet terminal, or the like is a mobile communication terminal capable of communicating by communicating with the communication system 1. FIG. 1 shows a case where the UE 10 is being moved by the moving means, so the vehicle is shown as the UE 10. In the drawings, the first eNB, the second eNB, the first SGW, the first PGW, the second SGW, and the second PGW are indicated as eNB1, eNB2, SGW1, PGW1, SGW2, and PGW2, respectively.

The first eNB 20A (first base station device) and the second eNB 20B (second base station device) are radio base stations connected to the MME 30 and are base station devices having a radio access control function. The first eNB 20A and the second eNB 20B each manage cells in which the UE 10 can be located, and have a reception control function when a call is made from the UE 10 in the cell, or when an incoming call is received from another UE 10 or the like. It has a paging function to call the UE 10 as a basic function.

The MME 30 (communication control device) has a function of performing position management and authentication control of the UE 10 in the network. Further, the MME 30 is a part that sets a communication path of user data that reaches the edge server 50 from the eNB 20 via the first SGW 41A, the first PGW 42A, the second SGW 41B, the second PGW 42B, and the like. The MME 30 holds information related to the setting process of the communication path (PDN connection) between the UE 10 under the eNB 20 and the first SGW 41A, the first PGW 42A, the second SGW 41B, and the second PGW 42B, and establishes the PDN connection based on the route information. Controls the release. That is, the MME 30 functions as a connection control device in this embodiment.

The SGW (1st SGW 41A, 2nd SGW 41B) functions as an exchange that transmits / receives user data to / from PGW and is also connected to UE 10 via eNB to transmit data to / from UE 10. In this embodiment, this SGW is referred to as a territorial packet gateway device.

The PGW (1st PGW42A, 2nd PGW42B) is made connectable to the SGW and functions as a gateway (exchange) which is a connection point with a packet data network (external network) that provides communication services such as voice service and Internet connection service. .. In this embodiment, the PGW is referred to as a network gateway device.

There are a plurality of the above SGWs and PGWs, respectively. There is also a device called S / PGW in which the SGW and the PGW are integrated. In this case as well, if the function as the SGW and the function as the PGW are separated, it corresponds to the SGW and the PGW shown in the present embodiment. Further, in the following description, SGW and PGW may be collectively displayed as S / PGW for simplification. The above-mentioned MME, SGW and PGW are nodes constituting EPC (Evolved Packet Core) in the LTE network.

In this embodiment, the first SGW 41A can communicate with the first eNB 20A, and the second SGW 41B can communicate with the second eNB 20B. That is, the first eNB 20A and the second eNB 20B can communicate with SGWs different from each other. In the present embodiment, it is said that the first SGW 41A is associated with the first eNB 20A and the second SGW 41B is associated with the second eNB 20B, respectively.

Further, the first PGW 42A can communicate with the first SGW 41A and also with the second SGW 41B. However, the nearest SGW to the first PGW 42A is the first SGW 41A. When viewed from the first SGW 41A side, it is the first PGW 41A that can suppress delay in communication and has high communication efficiency and the like. Therefore, when the first SGW 41A communicates with the PGW, the first PGW 41A is preferentially selected. In the present embodiment, it is said that the first SGW 41A and the first PGW 42A are associated with each other based on the relationship between the first PGW 42A and the first SGW 41A. As described above, the first SGW 41A is associated with the first eNB 20A. Therefore, when these are combined, it can be said that the first PGW 42A is associated with the first eNB 20A.

Similarly, the second PGW 42B can communicate with the second SGW 41B and also with the first SGW 41A. However, the nearest SGW to the second PGW 42B is the second SGW 41B. Therefore, when viewed from the second SGW 41B side, it is the second PGW 41B that can suppress the delay in communication and has high communication efficiency and the like. Therefore, when the second SGW 41B communicates with the PGW, the second PGW 41B is preferentially selected. In the present embodiment, it is said that the second SGW 41B and the second PGW 42B are associated with each other based on the relationship between the second PGW 42B and the second SGW 41B. As described above, the second SGW 41B is associated with the second eNB 20B. Therefore, when these are combined, it can be said that the second PGW 42B is associated with the second eNB 20B.

The first edge server 50A and the second edge server 50B are edge servers that communicate and connect to the first PGW 42A and the second PGW 42B, respectively. The edge server can communicate with an external application server and has a function of providing a service provided by the application server to the UE 10. Examples of the service provided by the application server include control of automatic driving of the vehicle. In the present embodiment, the edge server is one of the devices related to the application server that provides the service, and in the present embodiment, it may be treated as the service providing device on the side that provides the service. The service providing device capable of communicating with the application server may be a device different from the edge server.

The communication connection of the UE 10 in the communication system 1 will be described. When the UE 10 uses the service provided by the application server, a PDN (Packet Data Network) connection (communication path) for transmitting / receiving data between the UE 10 and the edge server (for example, the first edge server 50A) is provided. It will be provided. The PDN connection reaches the edge server (eg, first edge server 50A) from the UE 10 via the eNB (eg, first eNB 20A), SGW (eg, first SGW 41A), and PGW (eg, first PGW 42A). It is provided as follows. It is the MME 30 that controls the processing related to the connection and disconnection of the PDN connection. Further, the eNB has a function of requesting the MME 30 to change (handover) the PDN connection corresponding to the movement between cells when the movement between cells becomes necessary due to the movement of the UE 10.

Therefore, as shown in FIG. 2, the eNBs (first eNB 20A, second eNB 20B) have a route control unit 21 that monitors and controls PDN connections. Further, the MME 30 has a control request receiving unit 31 that receives a PDN connection change request or the like from the eNB, and a control processing unit that performs processing such as connection (establishment), disconnection, and change of the PDN connection based on the request from the eNB. It has 32 and a control information storage unit 33 in which information for connecting a PDN connection or the like by the control processing unit 32 is stored. The control information storage unit 33 stores, for example, information related to the SGW / PGW connected to the UE 10, information indicating the correspondence between the SGW / PGW and the cell (eNB), and the like, but the control information storage unit 33 stores the information. The information to be provided will be described later.

The PDN connection is a communication path for transmitting and receiving user data between the UE 10 and a service providing device such as a MEC server, but is actually controlled between the UE 10 and the MME 30 via an eNB. A control connection is also provided as a communication path for control of transmitting and receiving signals. The control connection is connected to the MME 30 via the same eNB as the PDN connection. The control connection is provided between the UE 10 and the MME 30 via the eNB when the UE 10 first connects to the network (Attach), and the connection is maintained while changing (handovering) the eNB passing through with the movement of the UE 10. Communication path.

The block diagram used in the description of the above embodiment shows a block of functional units. These functional blocks (components) are realized by any combination of hardware and / or software. Further, the means for realizing each functional block is not particularly limited. That is, each functional block may be realized by one physically and / or logically coupled device, or directly and / or indirectly by two or more physically and / or logically separated devices. (For example, wired and / or wireless) may be connected and realized by these plurality of devices.

For example, the first eNB 20A, the second eNB 20B, the MME 30, the first SGW 41A, the second SGW 41B, the first PGW 42A, the second PGW 42B, and the like in one embodiment of the present invention are used as computers for performing the respective processes in the communication system 1 of the present embodiment, respectively. It may work. FIG. 3 is a diagram showing an example of the hardware configuration of each of the above-mentioned devices according to the present embodiment. Each of the above-mentioned devices may be physically configured as a computer device including a processor 1001, a memory 1002, a storage 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, and the like.

In the following description, the word "device" can be read as a circuit, a device, a unit, or the like. The hardware configuration of each of the above devices may be configured to include one or more of the devices shown in the figure, or may be configured not to include some of the devices.

Each function in the first eNB 20A, the second eNB 20B, the MME 30, the first SGW 41A, the second SGW 41B, the first PGW 42A, and the second PGW 42B is a processor by loading predetermined software (program) on the hardware such as the processor 1001 and the memory 1002. It is realized by 1001 performing an operation and controlling communication by the communication device 1004 and reading and / or writing of data in the memory 1002 and the storage 1003.

Processor 1001 operates, for example, an operating system to control the entire computer. The processor 1001 may be configured by a central processing unit (CPU) including an interface with a peripheral device, a control device, an arithmetic unit, a register, and the like. For example, the route control unit 21 of the first eNB 20A and the second eNB 20B, the control processing unit 32 of the MME 30, and the like may be realized by the processor 1001.

Further, the processor 1001 reads a program (program code), a software module and data from the storage 1003 and / or the communication device 1004 into the memory 1002, and executes various processes according to these. As the program, a program that causes a computer to execute at least a part of the operations described in the above-described embodiment is used. For example, the route control unit 21 of the first eNB 20A and the second eNB 20B, the control processing unit 32 of the MME 30, and the like may be stored in the memory 1002 and realized by a control program operated by the processor 1001, and the same applies to other functional blocks. It may be realized. Although it has been described that the various processes described above are executed by one processor 1001, they may be executed simultaneously or sequentially by two or more processors 1001. Processor 1001 may be mounted on one or more chips. The program may be transmitted from the network via a telecommunication line.

The memory 1002 is a computer-readable recording medium, and is composed of at least one such as a ROM (Read Only Memory), an EPROM (Erasable Programmable ROM), an EEPROM (Electrically Erasable Programmable ROM), and a RAM (Random Access Memory). May be done. The memory 1002 may be referred to as a register, a cache, a main memory (main storage device), or the like. The memory 1002 can store a program (program code), a software module, and the like that can be executed to implement the wireless communication method according to the embodiment of the present invention.

The storage 1003 is a computer-readable recording medium, for example, an optical disk such as a CD-ROM (Compact Disc ROM), a hard disk drive, a flexible disk, an optical magnetic disk (for example, a compact disk, a digital versatile disk, a Blu-ray). It may consist of at least one (registered trademark) disk), smart card, flash memory (eg, card, stick, key drive), floppy (registered trademark) disk, magnetic strip, and the like. The storage 1003 may be referred to as an auxiliary storage device. The storage medium described above may be, for example, a database, server or other suitable medium containing memory 1002 and / or storage 1003.

The communication device 1004 is hardware (transmission / reception device) for communicating between computers via a wired and / or wireless network, and is also referred to as, for example, a network device, a network controller, a network card, a communication module, or the like. For example, the control request receiving unit 31 of the MME 30 described above may be realized by the communication device 1004.

The input device 1005 is an input device (for example, a keyboard, a mouse, a microphone, a switch, a button, a sensor, etc.) that receives an input from the outside. The output device 1006 is an output device (for example, a display, a speaker, an LED lamp, etc.) that performs output to the outside. The input device 1005 and the output device 1006 may have an integrated configuration (for example, a touch panel).

Further, each device such as the processor 1001 and the memory 1002 is connected by a bus 1007 for communicating information. The bus 1007 may be composed of a single bus or may be composed of different buses between the devices.

Further, the first eNB 20A, the second eNB 20B, the MME 30, the first SGW 41A, the second SGW 41B, the first PGW 42A, and the second PGW 42B are a microprocessor, a digital signal processor (DSP: Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), and a PLD (Programmable). It may be configured to include hardware such as Logic Device) and FPGA (Field Programmable Gate Array), and a part or all of each functional block may be realized by the hardware. For example, the processor 1001 may be implemented on at least one of these hardware.

Here, in the communication system 1 according to the present embodiment, it is assumed that SGW and PGW are provided for each of a plurality of eNBs and a plurality of edge servers are provided as a premise. Specifically, as shown in FIG. 1, it is assumed that a plurality of eNBs including the first eNB 20A are provided under the control of the first SGW 41A, and the first PGW 42A is connected to the first edge server 50A. Further, it is assumed that a plurality of eNBs including the second eNB 20B are provided under the second SGW 41B, and the second PGW 42 is connected to the second edge server 50B. The PGW and the SGW may have a one-to-one relationship, or a plurality of SGWs (or PGWs) may be provided for one PGW (or SGW).

Conventionally, SGWs, PGWs, edge servers, etc. are often geographically integrated, and while a large number of eNBs are connected to one SGW, PDN connection wrapping and the like occur. There was a possibility that communication delays would occur due to the large number of occurrences. The communication system 1 according to the present embodiment attempts to suppress communication delay by arranging SGWs, PGWs, and service providing devices in a distributed manner in order to cope with the above-mentioned conventional problem of delay.

Here, it is assumed that the UE 10 moves from the cell under the control of the first eNB 20A to the cell under the control of the second eNB 20B. When the SGW / PGW is aggregated as in the conventional case, the handover is performed when the UE 10 moves between the cells. That is, a process of changing the base station apparatus via which one PDN connection is maintained is performed. On the other hand, in the case of a movement in which the SGW and PGW (particularly PGW) corresponding to the eNB are changed, such as the movement of the UE 10 from the first eNB 20A to the second eNB 20B, the PDN connection used so far is disconnected and the PDN is connected. It is necessary to establish a new connection, that is, to reconnect the PDN. In the example shown in FIG. 1, when the UE 10 tries to receive the service provided by the service providing device even at the destination second eNB 20B, the first PDN connection (PDN1 in FIG. 1) on the first eNB 20A side is disconnected and the UE 10 is disconnected. , It is necessary to provide a second PDN connection (PDN2 in FIG. 1) on the second eNB 20B side. In general, reconnection of a PDN connection involves a process of disconnecting and connecting the PDN connection, which may increase the time during which the PDN connection cannot be used and delay the process. The processing delay may not be able to favorably receive the service from the service providing device.

Therefore, in the communication method by the communication system 1 according to the present embodiment, the above problem, that is, the movement between cells that require reconnection of the PDN connection, that is, the network gateway devices corresponding to the base station devices are different from each other. It has a configuration for preventing communication delays when moving between devices. That is, by devising the processing related to the disconnection and connection of the PDN connection, the time during which the PDN connection cannot be used is reduced, and a configuration capable of appropriately receiving the service from the service providing device is realized. The specific procedure will be described below.

The communication method according to the present embodiment will be described with reference to FIG. The communication method according to the present embodiment is a method of performing a handover of the PDN connection previously provided and providing a new PDN connection while maintaining the PDN connection. In this method, the first eNB 20A and the second eNB 20B use the X2 interface to use the X2 handover in which the information related to the UE 10 to be handed over is transmitted and received. Further, the above-mentioned communication method is characterized in that the MME determines the handover of the PDN connection and the connection of a new PDN connection.

Specifically, as shown in FIG. 4A, when the UE 10 moves from the cell under the control of the first eNB 20A to the cell under the control of the second eNB 20B, the first eNB 20A, the first SGW 41A, and the first PGW 42A are moved from the UE 10. Handover is performed for the first PDN connection (PDN1) that reaches the first edge server 50A via the device. The first PDN connection after the handover reaches the first edge server 50A from the UE 10 via the second eNB 20B, the second SGW 41B, and the first PGW 42A.

Then, as shown in FIG. 4B, after the UE 10 connects the second PDN connection (PDN2) used in the destination cell, the first PDN connection is deleted. The second PDN connection reaches the second edge server 50B from the UE 10 via the second eNB 20B, the second SGW 41B, and the second PGW 42B.

In order to execute the process shown in FIG. 4, when the handover request accompanying the movement of the UE 10 is received from the first eNB 20A, among the SGWs and PGWs corresponding to the destination eNBs in the MME 30, the PGW is particularly before the movement. It is necessary to determine whether it is the same as the connected PGW. That is, if the PGW corresponding to the destination eNB is different from the PGW connected before the movement, the process shown in FIG. 4 above, that is, the reconnection of the PDN connection is required.

Therefore, the control information storage unit 33 of the MME 30 holds the information shown in FIGS. 5A to 5C. FIG. 5A stores information for specifying the aread packet gateway device (SGW) and the network gateway device (PGW) to which the UE is connected in association with the information for specifying the UE. With the information shown in FIG. 5A, the SGW and PGW to which the UE is connected can be specified. In the example shown in FIG. 5A, the integrated S / PGW is shown, but when it is not the integrated S / PGW, only the SGW and the PGW are shown. FIG. 5B is information showing the correspondence between the in-service packet gateway device and the cell, and specifies the information for specifying the in-service packet gateway device (here, the information for specifying the SGW) and the cell. Information (ie, corresponding to information that identifies the eNB) is associated with. Since the MME 30 can specify the destination cell (eNB), it is possible to specify the SGW corresponding to the eNB by using the information shown in FIG. 5 (B). Further, FIG. 5C is information showing the correspondence relationship between the in-service packet gateway device (SGW) and the network gateway device (PGW). SGW and PGW may not have a one-to-one relationship as described above. Therefore, by holding the information as shown in FIG. 5C as the information for specifying the PGW corresponding to the SGW, the eNB to which the UE 10 is connected changes with the movement of the UE 10, and the eNB of the movement destination is changed. The MME 30 can grasp whether or not the PGW corresponding to the above is changed. Then, when the PGW is changed, the process related to the reconnection of the PDN connection as shown in FIG. 4 above occurs.

A series of flows related to the above method will be described with reference to the sequence diagram of FIG. In FIG. 6, the first SGW 41A and the first PGW 42A are integrally shown for simplification. Further, the second SGW 41B and the second PGW 42B are integrally shown.

First, as a premise, as shown in FIG. 4A, it is assumed that the UE 10 is provided with a first PDN connection (PDN1) via the first eNB 20A, the first SGW 41A, and the first PGW 42A (S01). Next, it is assumed that the first eNB 20A determines that the UE 10 needs a handover as a result of the communication quality measurement or the like in the UE 10 (Handover Decision: S02). With this as an opportunity, the processing related to the handover is started between the UE 10, the first eNB 20A, and the second eNB 20B (S02). After that, a change request (handover request) for the first PDN connection is transmitted from the second eNB 20B to the MME 30 (Path Switch Request: S03: route change request reception step). The PDN connection change request (handover request) includes information indicating the destination cell of the UE 10 based on the communication quality measurement result from the UE 10.

When the control request receiving unit 31 of the MME 30 receives the request from the second eNB 20B, the control processing unit 32 receives the information related to the destination cell of the UE 10 transmitted from the second eNB 20B and the information stored in the control information storage unit 33. Based on the above, it is determined whether the PGW corresponding to the eNB to which the UE 10 is moved is changed, that is, whether the process related to the reconnection of the PDN connection is necessary (S04: network gateway device determination step). Specifically, based on the information stored in the control information storage unit 33, whether or not the PGW corresponding to the eNB of the handover destination cell matches the PGW corresponding to the eNB of the cell before the movement is determined. Determine if the PDN connection needs to be reconnected. It is also possible that there are a plurality of PGWs corresponding to the eNB to which the UE 10 is moved. In that case, an appropriate PGW is selected by the MME 30 based on a predetermined policy or the like.

In the communication method according to the present embodiment, the handover of the first PDN connection itself is performed regardless of the determination result, so that the processing related to the handover is performed so as to go through the second eNB 20B (S05: change of the first communication route). Step). The process related to handover is an existing process. As a result of the handover, the first PDN connection (PDN1) becomes a connection via the second eNB 20B, the second SGW 41B, and the first PGW 41A (S06: However, to be exact, it is the route shown in FIG. 4 (A)).

At the same time as the handover of the first PDN connection, the handover of the control connection is also performed. Since the handover of the control connection is a known process, detailed description thereof will be omitted.

If, as a result of the determination (S04) regarding the necessity of the process related to the reconnection of the PDN connection, it is determined that the process related to the reconnection is unnecessary (S04-NO), the process up to this point ends. do. On the other hand, when it is determined that the process related to the reconnection is necessary (S04-YES) as a result of the determination (S04) regarding the necessity of the process related to the reconnection of the PDN connection, the following process is performed. .. If the PGW corresponding to the eNB of the handover destination cell does not match the PGW corresponding to the eNB of the cell before the movement, the process is performed in order to establish a PDN connection via the new PGW. First, a process related to the establishment of a communication path is performed between the MME 30 and the second PGW 42B (Session Request / Session Response: S07: Second communication path new establishment step).

After that, the MME 30 transmits information related to the establishment of the communication path to the second eNB 20B and the UE 10 (RRC Connec. Reconf. NAS: SM on-demand: S08: second communication path new establishment step). At this time, the information specifying the second PGW 42B via the newly provided PDN connection is notified from the MME 30 to the second eNB 20B and the UE 10. The information that identifies the second PGW 42B is, for example, the IP address of the second PGW 42B. As a result, the UE 10 can transmit information to the second edge server 50B via the second eNB 20B, the second SGW 41B, and the second PGW 42B (First Uplink Packet: S09: second communication path new establishment step). ..

After that, the UE 10 notifies the MME 30 via the second eNB that an instruction relating to the establishment of the communication path has been received (RRC Connec. Reconf. Complete NAS: SM on-demand ack: S10: second communication. Route new establishment step). After that, the UE 10 notifies the application server that provides the service of the IP address of the second PGW 42B (S11). This makes it possible to transmit information from the application server to the UE 10 via the second edge server 50B, the second PGW 42B, the second SGW 41B, and the second eNB 20B (First Downlink Packet: S12: new establishment of the second communication path). Step). That is, the second PDN connection (PDN2) is established, and the communication path used by the UE 10 is switched to the second PDN connection.

After that, the MME 30 performs a disconnection process of the first PDN connection (PDN1) (S13: the first communication path disconnection step after the change). The first PDN connection disconnection process is a known process.

By the above processing, the newly provided second PDN connection (PDN2) is used for transmitting and receiving data of the UE 10 after moving the cell, and the first PDN connection (PDN1) is disconnected.

In the above, in the control processing unit 32 of the MME 30, the movement destination of the UE 10 is based on the information related to the cell of the movement destination of the UE 10 transmitted from the first eNB 20A and the information stored in the control information storage unit 33. It is determined whether the PGW corresponding to the eNB is changed, that is, whether the process related to the reconnection of the PDN connection is necessary (S04), but the process of this determination is the process related to the handover of the first PDN connection. I explained the case where it is done on the way. However, the above determination may be made after the processing related to the handover of the first PDN connection is completed (S06). With the reception of the Path Switch Request from the first eNB 20A (S03) as an opportunity, the MME 30 can make the above determination (S04). That is, the determination regarding the necessity of reconnecting the PDN connection in the MME 30 may be made at any timing after the reception of the Path Switch Request (S03) from the first eNB 20A.

As described above, according to the communication method according to the present embodiment, when the UE 10 moves between cells in which the corresponding network gateway devices (PGWs) are different from each other, first, the first PDN connection is handed over without changing the PGW. After changing to a route that goes through the base station device (eNB) of the destination cell and the packet gateway device (SGW) above it, the second PDN connection that goes through the base station device and network gateway device of the move destination. Is provided. Then, after switching the communication path used by the UE 10 to the second PDN connection, the first PDN connection is disconnected. That is, in the above communication method, the second PDN connection is provided in the state where the first PDN connection after the handover exists, and then the first PDN connection is disconnected. With such a configuration, it is possible to prevent the time when the communication is interrupted when switching from the first PDN connection to the second PDN connection, so that the communication between the UE 10 and the service providing device (edge server) is more preferable. Can be continued to.

Further, in order to realize the above configuration, the MME 30 stores the information of the network gateway device (PGW) associated with the base station device (eNB) in the control information storage unit 33. In the above method, since the MME 30 aggregates and holds the information of the network gateway device (PGW) associated with the base station device (eNB), the MME 30 takes the lead in establishing the communication path (PDN connection). And control the disconnection.

Further, as a method for preventing the above-mentioned communication delay and the like, the UE 10 itself has been studied to provide a plurality of PDN connections. However, conventionally, a connection corresponding to the second PDN connection is provided in advance before the UE 10 moves to the cell under the second eNB 20B, that is, in the state of being in the cell under the first eNB 20A. Then, a method of handing over the PDN connection used with the movement of the UE 10 has been considered. However, in this case, there is a problem that the amount of communication related to the PDN connection provided in advance increases.

For example, in the present embodiment, the case where the UE 10 moves from the cell under the first eNB 20A to the cell under the second eNB 20B is described, but in reality, it corresponds to the second eNB 20B as a cell close to the cell under the first eNB 20A. There may also be cells under the eNB that correspond to a PGW different from the second PGW 42B. Here, when the UE 10 is in the cell under the first eNB 20A and a connection corresponding to the second PDN connection is provided in advance, it is not known in advance which cell the UE 10 will move to, so communication is performed. In order to continue, it is necessary to provide PDN connections corresponding to all adjacent cells in advance. Therefore, in some cases, it is necessary to establish two or more PDN connections in advance. Further, when the UE 10 actually moves across cells, processing related to the handover of the PDN connection provided in advance, processing for disconnecting an unnecessary PDN connection, and the like occur, so that control signals are also transmitted and received. do. As described above, when the PDN connection corresponding to the destination PGW is provided in advance, a new problem of increasing the communication amount may occur.

On the other hand, according to the above method, the PGW corresponding to the eNB of the destination cell is obtained after the first PDN connection is handed over by using the conventional handover method instead of providing the second PDN connection in advance. Will be provided as needed. As a result, communication between the UE 10 and the service providing device (edge server) can be more preferably continued while suppressing the amount of communication for providing the second PDN connection. In the above method, the MME 30 can specify the destination eNB when the handover request related to the UE 10 is received from the eNB, and the MME 30 can specify the PGW corresponding to the eNB. It is a configuration that utilizes a certain point.

As described above, the communication method according to one embodiment of the present invention includes a user terminal and a first base station device and a second base station included in a plurality of base station devices provided for each cell in which the user terminal can be located. The device, a plurality of in-situ packet gateway devices associated with the base station device and responsible for transmitting data of the user terminal, and an external network associated with the base station device and the in-situ packet gateway device. The said via a plurality of network gateway devices which are devices for controlling transmission / reception of data of the user terminal between the devices, one of the plurality of base station devices, and one of the plurality of in-service packet gateway devices. In a communication system including a network gateway device included in a plurality of network gateway devices and a connection control device for performing processing related to establishment and disconnection of a communication path provided between the user terminal and the user terminal, the user terminal is the user terminal. A communication method for moving from a cell under the control of the first base station device to a cell under the control of the second base station device, wherein the connection control device is the network gateway associated with the base station device. It has a control information storage unit that stores information that identifies the device, and the user terminal is provided between the user terminal and the network gateway device associated with the first base station device, and is provided with the first base station device and the first base station device. The connection control device has a first communication path via the zoned packet gateway device associated with the first base station device, and the connection control device from the first base station device to the first communication path. The second base station refers to the route change request receiving step for receiving the request to change to the route via the second base station device and the information stored in the control information storage unit by the connection control device. In the network gateway device determination step for determining whether or not the network gateway device associated with the device matches the network gateway device associated with the first base station device, and the network gateway device determination step. When it is determined that the network gateway device associated with the second base station device does not match the network gateway device associated with the first base station device, the connection control device determines that the network gateway device does not match. The first communication path passes through the second base station device and the in-zone packet gateway device associated with the second base station device. After the first communication route change step for changing to the route and the first communication route change step, the connection control device is associated with the user terminal and the network gateway device associated with the second base station device. A second communication path is provided between the second base station device and the in-service packet gateway device associated with the second base station device, and the communication path used by the user terminal is the first. A second communication path new establishment step for switching to the two communication paths, and a modified first communication path disconnection step in which the connection control device disconnects the first communication path after the second communication path new establishment step. Have.

According to the above communication method, when the user terminal moves between cells in which the corresponding network gateway devices are different from each other, first, the route of the first communication path corresponds to the destination cell without changing the network gateway device. The route is changed to pass through the second base station device and the in-service packet gateway device associated with the second base station device. After that, the second communication path reaches the network gateway device associated with the second base station device via the second base station device and the in-service packet gateway device associated with the second base station device at the destination. Is provided. Then, after switching the communication path used by the user terminal to the second communication path, the first communication path is disconnected. With such a configuration, it is possible to shorten the time during which communication is interrupted due to switching from the first communication path to the second communication path, so that communication when the user terminal moves between cells is suitable. You can continue.

The present invention has been described in detail above based on the embodiments thereof. However, the present invention is not limited to the above embodiment. The present invention can be modified in various ways as described below without departing from the gist thereof.

For example, each device included in the communication system 1 described in the above embodiment may be configured by combining a plurality of devices. Further, a plurality of devices included in the communication system 1 may be realized by one device.

Further, the signal name used in the processing of establishing and disconnecting the communication path (PDN connection) described in the above embodiment is an example. That is, in the series of processes related to the establishment and disconnection of the communication path (PDN connection), the signals transmitted and received between the devices of the communication system 1 are not limited to those described in the above embodiment. In addition, the order of processing may be changed as needed.

Further, in the above embodiment, the case where the communication system 1 is a system compliant with the communication standard of the LTE network has been described, but the communication method by the communication system according to the present invention can be applied to other wireless networks. .. In that case, each device included in the communication system 1 described in the above embodiment can be changed to a device corresponding to each wireless system. Further, the communication system 1 may support a plurality of wireless systems, and in that case, one type of network can be controlled by the base station device between the first base station device and the second base station device. The parts may be different.

Although the present embodiment has been described in detail above, it is clear to those skilled in the art that the present embodiment is not limited to the embodiments described in the present specification. This embodiment can be implemented as an amendment or modification without departing from the spirit and scope of the present invention as determined by the description of the scope of claims. Therefore, the description herein is for purposes of illustration only and has no limiting implications for this embodiment.

The notification of information is not limited to the embodiments / embodiments described herein, and may be performed by other methods. For example, information notification includes physical layer signaling (eg, DCI (Downlink Control Information), UCI (Uplink Control Information)), higher layer signaling (eg, RRC (Radio Resource Control) signaling, MAC (Medium Access Control) signaling, etc. It may be carried out by broadcast information (MIB (Master Information Block), SIB (System Information Block)), other signals, or a combination thereof. Further, the RRC signaling may be referred to as an RRC message, and may be, for example, an RRC Connection Setup message, an RRC Connection Reconfiguration message, or the like.

Each aspect / embodiment described herein includes LTE (Long Term Evolution), LTE-A (LTE-Advanced), SUPER 3G, IMT-Advanced, 4G, 5G, FRA (Future Radio Access), W-CDMA. (Registered Trademarks), GSM (Registered Trademarks), CDMA2000, UMB (Ultra Mobile Broadband), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, UWB (Ultra-WideBand), It may be applied to Bluetooth®, other systems that utilize suitable systems and / or next-generation systems that are extended based on them.

The processing procedures, sequences, flowcharts, and the like of each aspect / embodiment described in the present specification may be rearranged in order as long as there is no contradiction. For example, the methods described herein present elements of various steps in an exemplary order and are not limited to the particular order presented.

In some cases, the specific operation performed by a specific device in the present specification may be performed by an upper node thereof. For example, when a specific device is a base station, various operations performed for communication with a terminal in a network consisting of one or more network nodes having the base station may be performed. It is clear that it can be done by a base station and / or other network nodes other than the base station, such as, but not limited to, MME or S-GW. Although the case where there is one network node other than the base station is illustrated above, it may be a combination of a plurality of other network nodes (for example, MME and S-GW).

Information and the like can be output from the upper layer (or lower layer) to the lower layer (or upper layer). Input / output may be performed via a plurality of network nodes.

The input / output information and the like may be stored in a specific place (for example, a memory) or may be managed by a management table. Information to be input / output may be overwritten, updated, or added. The output information and the like may be deleted. The input information or the like may be transmitted to another device.

The determination may be made by a value represented by 1 bit (0 or 1), by a boolean value (Boolean: true or false), or by comparing numerical values (for example, a predetermined value). It may be done by comparison with the value).

Each aspect / embodiment described in the present specification may be used alone, in combination, or may be switched and used according to the execution. Further, the notification of predetermined information (for example, the notification of "being X") is not limited to the explicit one, but is performed implicitly (for example, the notification of the predetermined information is not performed). May be good.

Software, whether referred to as software, firmware, middleware, microcode, hardware description language, or other names, is an instruction, instruction set, code, code segment, program code, program, subprogram, software module. , Applications, software applications, software packages, routines, subroutines, objects, executable files, execution threads, procedures, features, etc. should be broadly interpreted.

Further, software, instructions, and the like may be transmitted and received via a transmission medium. For example, the software may use wired technology such as coaxial cable, fiber optic cable, twisted pair and digital subscriber line (DSL) and / or wireless technology such as infrared, wireless and microwave to website, server, or other. When transmitted from a remote source, these wired and / or wireless technologies are included within the definition of transmission medium. The information, signals, etc. described herein may be represented using any of a variety of different techniques. For example, data, instructions, commands, information, signals, bits, symbols, chips, etc. that may be referred to throughout the above description are voltages, currents, electromagnetic waves, magnetic fields or magnetic particles, light fields or photons, or any of these. It may be represented by a combination of.

The terms described herein and / or the terms necessary for understanding the present specification may be replaced with terms having the same or similar meanings. For example, the channel and / or symbol may be a signal. Also, the signal may be a message. Further, the component carrier (CC) may be referred to as a carrier frequency, a cell, or the like.

The terms "system" and "network" used herein are used interchangeably.

Further, the information, parameters, etc. described in the present specification may be represented by an absolute value, a relative value from a predetermined value, or another corresponding information. .. For example, the radio resource may be indexed.

The names used for the parameters described above are not limited in any way. Further, mathematical formulas and the like using these parameters may differ from those expressly disclosed herein. Since the various channels (eg, PUCCH, PDCCH, etc.) and information elements (eg, TPC, etc.) can be identified by any suitable name, the various names assigned to these various channels and information elements are in any respect. However, it is not limited.

A base station can accommodate one or more (eg, three) cells (also referred to as sectors). When a base station accommodates multiple cells, the entire base station coverage area can be divided into multiple smaller areas, each smaller area being a base station subsystem (eg, a small indoor base station RRH: Remotee). Communication services can also be provided by Radio Head). The term "cell" or "sector" refers to a part or all of the coverage area of a base station and / or base station subsystem that provides communication services in this coverage. In addition, the terms "base station," "eNB," "cell," and "sector" may be used interchangeably herein. A base station may also be referred to by terms such as fixed station, NodeB, eNodeB (eNB), access point, femtocell, and small cell.

Mobile communication terminals may be subscriber stations, mobile units, subscriber units, wireless units, remote units, mobile devices, wireless devices, wireless communication devices, remote devices, mobile subscriber stations, access terminals, mobile terminals, etc. It may also be referred to as a wireless terminal, remote terminal, handset, user agent, mobile client, client, or some other suitable term.

The terms "determining" and "determining" as used herein may include a wide variety of actions. "Judgment" and "decision" are, for example, judgment, calculation, computing, processing, deriving, investigating, looking up (for example, table). , Searching in a database or another data structure), ascertaining can be considered as a "judgment" or "decision". Also, "judgment" and "decision" are receiving (for example, receiving information), transmitting (for example, transmitting information), input (input), output (output), and access. It may include (for example, accessing data in memory) to be regarded as "judgment" or "decision". In addition, "judgment" and "decision" are considered to be "judgment" and "decision" when the things such as solving, selecting, choosing, establishing, and comparing are regarded as "judgment" and "decision". Can include. That is, "judgment" and "decision" may include considering some action as "judgment" and "decision".

The terms "connected", "coupled", or any variation thereof, mean any direct or indirect connection or connection between two or more elements and each other. It can include the presence of one or more intermediate elements between two "connected" or "combined" elements. The connection or connection between the elements may be physical, logical, or a combination thereof. As used herein, the two elements are by using one or more wires, cables and / or printed electrical connections, and, as some non-limiting and non-comprehensive examples, radio frequencies. By using electromagnetic energies such as electromagnetic energies with wavelengths in the region, microwave region and light (both visible and invisible) regions, they can be considered to be "connected" or "coupled" to each other.

The phrase "based on" as used herein does not mean "based on" unless otherwise stated. In other words, the statement "based on" means both "based only" and "at least based on".

As used herein by designations such as "first", "second", etc., any reference to that element does not generally limit the quantity or order of those elements. These designations can be used herein as a convenient way to distinguish between two or more elements. Thus, references to the first and second elements do not mean that only two elements can be adopted there, or that the first element must somehow precede the second element.

As long as "include", "comprising", and variations thereof are used herein or within the scope of the claims, these terms are similar to the term "comprising". In addition, it is intended to be inclusive. Moreover, the term "or" as used herein or in the claims is intended to be non-exclusive. In the present specification, a plurality of devices shall be included unless the device has only one device apparently in context or technically.

The entire disclosure is intended to include more than one, unless the context clearly indicates the singular.

1 ... Communication system, 10 ... UE, 20A ... 1st eNB, 20B ... 2nd eNB, 30 ... MME, 41A ... 1st SGW, 41B ... 2nd SGW, 42A ... 1st PGW, 42B ... 2nd PGW, 50A ... 1st edge server, 50B ... Second edge server.

Claims (1)

The user terminal, the first base station device and the second base station device included in a plurality of base station devices provided for each cell in which the user terminal can be located, and the user terminal associated with the base station device. A device that controls the transmission and reception of data of the user terminal between a plurality of in-service packet gateway devices that are responsible for transmitting the data of the above, and a device that is associated with the base station device and the in-service packet gateway device and that is connected to an external network. A network gateway device included in the plurality of network gateway devices via a plurality of network gateway devices, any of the plurality of base station devices, and any of the plurality of in-service packet gateway devices, and the user. In a communication system including a connection control device provided between a terminal and a connection control device for performing processing related to establishment and disconnection of a communication path, the user terminal moves from a cell under the control of the first base station device to the second base station device. It is a communication method when moving to a cell under
The connection control device has a control information storage unit that stores information that identifies the network gateway device associated with the base station device.
The user terminal is provided between the network gateway device associated with the first base station device, and is associated with the first base station device and the first base station device. It has a first communication path via the device and has a first communication path.
A route change request receiving step in which the connection control device receives a request from the first base station device to change the first communication path to a route via the second base station device.
The connection control device refers to the information stored in the control information storage unit, and the network gateway device associated with the second base station device is associated with the first base station device. A network gateway device determination step for determining whether or not the information matches the network gateway device, and
When it is determined in the network gateway device determination step that the network gateway device associated with the second base station device does not match the network gateway device associated with the first base station device. The first communication route change step in which the connection control device changes the first communication path to a route via the second base station device and the zoned packet gateway device associated with the second base station device. When,
After the first communication path change step, the connection control device is associated with the user terminal and the network associated with the second base station device while maintaining the first communication path provided earlier. A second communication path via the zoned packet gateway device associated with the second base station device and the second base station device is provided between the gateway device and the communication path used by the user terminal. The second communication path new establishment step for switching to the second communication path, and
After the second communication path new establishment step, the connection control device disconnects the first communication path, and the modified first communication path disconnection step.
Communication method with.

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