Mobile communication network

Abstract

To provide a technique of suppressing the prolongation of a time period from the occurrence of data to be transmitted to a wireless device belonging to the same group to the completion of transmitting the data.SOLUTION: A mobile communication network communicates with a plurality of wireless devices belonging to the same group, and includes a plurality of base stations. Between each of a plurality of first base station in the plurality of base stations and network nodes connected to an external network, connection for the group is maintained. Each of the plurality of first base stations stores a context for the group and an identifier for the context.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to mobile communication networks. [Background technology]

[0002] In order to improve the accommodation efficiency of wireless devices (WDs) for machine type communication (MTC), Non-Patent Document 1 discloses a configuration in which such WDs are grouped and the same international mobile subscriber identity (IMSI) is assigned to multiple WDs in the same group. In the following description, WDs for MTC are also simply referred to as "WDs." [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] M.Ito,et. al.,"Reducing state information by sharing IMSI for cellular IoT devices", IEEE IoT J., 2016. Summary of the Invention [Problem to be solved by the invention]

[0004] Fig. 1 is an explanatory diagram of an outline of the configuration disclosed in Non-Patent Document 1. WD#1 to WD#4 belong to the same group and therefore have the same IMSI. In Fig. 1, WD#1 and WD#2 are in a cell provided by base station (BS)#1, and WD#3 and WD#4 are in a cell provided by BS#2. BS#1 and BS#2 are connected to a core network.

[0005] For example, when data to be transmitted to WD#1 occurs, WD#1 transmits an RRC connection setup request message including a service request message to BS#1. BS#1 transmits the service request message included in the RRC connection setup request message to the access and mobility management function (AMF) of the core network. This triggers the establishment of a protocol data unit (PDU) session between WD#1 and a user plane function (UPF). In order to establish the PDU session, control messages are transmitted and received between the AMF, the session management function (SMF), and the UPF. After the PDU session is established, WD#1 transmits data via the PDU session. After the data transmission is completed, WD#1 transitions to an idle state.

[0006] In addition, since WD#1 to WD#4 share the same IMSI, when WD#1 is communicating, WD#2 to WD#4 cannot communicate. However, since the communication frequency and communication period of the WD for MTC are short, the probability of communication collision is low.

[0007] However, in the configuration of non-patent document 1, when data to be transmitted to a WD occurs, as described above, a PDU session needs to be established by transmitting and receiving control messages between the BS, AMF, SMF and UPF, which results in a long time between the occurrence of data to be transmitted and the actual transmission of the data.

[0008] The present disclosure provides a technique for preventing a long time from increasing between the occurrence of data to be transmitted to wireless devices belonging to the same group and the transmission of the data. [Means for solving the problem]

[0009] According to one aspect of the present disclosure, a mobile communication network that communicates with multiple wireless devices belonging to the same group includes multiple base stations, and maintains a connection for the group between each of multiple first base stations among the multiple base stations and a network node connected to an external network, and each of the multiple first base stations stores a context of the group and an identifier of the context. Effect of the Invention

[0010] According to the present disclosure, it is possible to prevent a long time from increasing between when data to be transmitted to wireless devices belonging to the same group occurs and when the data is transmitted. [Brief description of the drawings]

[0011] [Figure 1] FIG. [Diagram 2] 1 is a configuration diagram of a mobile communication network according to an embodiment. [Diagram 3] FIG. 13 is an explanatory diagram of information stored in the WD and the BS. [Figure 4] FIG. 11 is a sequence diagram when data to be sent to the WD occurs. [Diagram 5] Configuration diagram for setting up an N3 tunnel between a BS and a UPF. [Figure 6] Sequence diagram for setting up an N3 tunnel between the BS and the UPF. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the invention according to the claims, and not all combinations of features described in the embodiments are essential to the invention. Two or more features among the multiple features described in the embodiments may be arbitrarily combined. In addition, the same reference numbers are used for the same or similar configurations, and duplicated descriptions are omitted.

[0013] FIG. 2 is an explanatory diagram of a mobile communication network according to the present embodiment. In FIG. 2, WD#A1, #A2, #A3, and #A4 belong to the same group #A and have the same IMSI#A. Also, in FIG. 2, WD#B1 and #B2 belong to the same group #B and have the same IMSI#B. According to FIG. 2, WD#A1, #A2, and WD#B1 are in a cell provided by BS#1, and WD#A3, #A4, and WD#B2 are in a cell provided by BS#2. WD#A1 to #A4 and WD#B1 and #B2 may be wireless devices such as machine type communication (MTC) or IOT (Internet of Things) devices. The groups are determined based on the business operators who provide services using each WD, the service contents, and the like. For example, group #A is a group of wireless devices that are attached to an electric meter and report electricity usage, and group #B is a group of wireless devices that are attached to a gas meter and report gas usage. The groups can be further classified by area, such as the Kanto region, the Kinki region, etc.

[0014] In this embodiment, each WD belonging to a group is configured to transition between a connected state (RRC_CONNCTED) and an inactive state (RRC_INACTIVE), but not to transition to an idle state (RRC_IDLE). In FIG. 2, WDs #A1 to #A4 belonging to group #A and WDs #B1 and #B2 belonging to group #B are all in the inactive state.

[0015] In response to the WDs belonging to a group not being transitioned to the idle state, the mobile communication network also establishes and maintains an N3 tunnel for each group between the UPF and each BS. The N3 tunnel is a "connection" set in a section between the UPF and the BS that connects to the data network (DN) in the PDU session. The UPF is a network node of the user plane, and the DN is an external network seen from the mobile communication network such as the Internet. According to FIG. 2, the N3 tunnel #A1 is used for a PDU session for WDs #A1 and #A2 of group #A camped in a cell that is an area where the BS #1 provides services, and the N3 tunnel #B1 is used for a PDU session for WDs #B1 of group #B camped in a cell provided by the BS #1. Similarly, the N3 tunnel #A2 is used for a PDU session for WDs #A3 and #A4 of group #A camped in a cell provided by the BS #2, and the N3 tunnel #B2 is used for a PDU session for WDs #B2 of group #B camped in a cell provided by the BS #2.

[0016] In FIG. 2, BS#1 and BS#2 establish an N3 tunnel with the same UPF, but the UPF that establishes the N3 tunnel may be different for each BS. That is, the UPF that establishes the N3 tunnel #A1 with BS#1 may be different from the UPF that establishes the N3 tunnel #A2 with BS#2. Furthermore, the UPF that sets the N3 tunnel may be different for each group. For example, the UPF that establishes the N3 tunnel #A1 with BS#1 may be different from the UPF that establishes the N3 tunnel #B1 with BS#1.

[0017] When a WD transitions from a connected state to an inactive state, the BS (last BS) that was connected to the WD notifies the WD of an I-RNTI (inactive-radio network temporary identifier) ​​and a MAC-I (message authentication code-integrity), and holds the user equipment (UE) context of the WD. The WD in the inactive state holds the I-RNTI and MAC-I.

[0018] The I-RNTI is a combination of the WD identifier and the last BS identifier. The MAC-I is an authentication code generated based on the UE context of the WD maintained in the last BS. When the WD transitions from an inactive state to a connected state, it transmits an RRC resume request including the MAC-I and I-RNTI to the BS. The BS that receives the RRC resume request determines the last BS based on the I-RNTI and obtains the UE context of the WD from the last BS. It then authenticates the WD based on the obtained UE context and the MAC-I received from the WD.

[0019] In this embodiment, a UE context for multiple WDs belonging to the same group and an I-RNTI for identifying the UE context are determined in advance. Furthermore, a MAC-I for the group is obtained based on the UE context determined for the group. For example, as shown in FIG. 3, for group #A, a context #A is generated as a UE context, an I-RNTI #A is assigned as an I-RNTI for identifying context #A, and a MAC-I #A is generated based on context #A. Similarly, for group #B, a context #B is generated as a UE context, an I-RNTI #B is assigned as an I-RNTI for identifying context #B, and a MAC-I #B is generated based on context #B.

[0020] Then, WDs #A1 to #A4 belonging to group #A store MAC-I #A and I-RNTI #A in advance, and WDs #B1 and #B2 belonging to group #B store MAC-I #B and I-RNTI #B in advance.

[0021] Furthermore, BS #1 and #2 providing services to cells (areas) in which WDs #A1 to #A4 belonging to group #A are located store the context #A of group #A in association with I-RNTI #A, which is an identifier of the context #A. Similarly, BS #1 and #2 providing services to cells (areas) in which WDs #B1 and #B2 belonging to group #B are located store the context #B for WDs of group #B in association with I-RNTI #B, which is an identifier of the context #B.

[0022] In summary, the mobile communication network always maintains an N3 tunnel for a group that connects a BS in whose cell a WD belonging to the group and a UPF, and stores the UE context of the group in association with the I-RNTI of the group in the BS in whose cell a WD belonging to the group is located. Also, the WD belonging to the group stores the I-RNTI and MAC-I of the group.

[0023] In this embodiment, the BS in which the WD belonging to the group is located in the cell stores the UE context and I-RNTI of the group and sets up the N3 tunnel, but for example, in consideration of the addition or movement of the WD belonging to the group, the BS in which the WD belonging to the group is not located in the cell may also store the UE context and I-RNTI of the group and set up the N3 tunnel. In other words, the BS that establishes the N3 tunnel for the group and stores the UE context and I-RNTI of the group includes at least the BS that provides services to the cell in which the WD belonging to the group is located, but may additionally include a BS in which the WD is not located in the cell. The BS that establishes the N3 tunnel for the group and stores the UE context and I-RNTI of the group may be determined based on the service area (e.g., metering, etc.) provided by the WD of the group.

[0024] As described above, the I-RNTI is originally generated based on the identifier of the WD and the identifier of the final BS, but in this embodiment, the I-RNTI can be generated regardless of the identifiers of the WD and the BS. In other words, the BS treats the I-RNTI received from the WD belonging to the group as a UE context stored in the BS, and does not perform a process of determining the final BS based on the received I-RNTI. The I-RNTI of the group is determined so as not to overlap with a normal I-RNTI generated based on the identifier of the WD and the identifier of the final BS. The I-RNTI of the group can be configured so that the BS can determine from its value that it is the I-RNTI of the group, not the I-RNTI generated based on the identifier of the WD and the identifier of the final BS.

[0025] FIG. 4 is a sequence diagram when transmission data occurs in WD#A1 in FIG. 2. In S1, WD#A1 transmits an RRC connection setup request message to BS#1. The RRC connection setup request message includes I-RNTI#A and MAC-I#A stored in WD#A1, and transmission data. In response to the RRC connection setup request message, BS#1 determines the context#A, which is the UE context of WD#A1, based on I-RNTI#A in S2, and authenticates WD#A1 based on the context#A and MAC-I#A. Here, it is assumed that the authentication is successful. In this case, BS#1 transmits the transmission data toward UPF using N3 tunnel#A1 in S3, and transmits an RRC Resume message to WD#A1 in S4.

[0026] The sequence in Fig. 4 is basically the same as the sequence at the time of transition from an inactive state to a connected state defined by 3GPP (registered trademark). The difference is that in S2, BS#1 does not determine the final BS based on I-RNTI#A, but determines the UE context stored in its own device.

[0027] As is clear from the sequence in Fig. 4, in this embodiment, when a WD transmits data, it is not necessary to transmit and receive control signaling involving the BS, AMF, SMF, and UPF. Therefore, it is possible to prevent the time from when data to be transmitted to a WD occurs until the data is transmitted to the WD from becoming too long.

[0028] As described above, in this embodiment, an N3 tunnel for a group is set in advance in a BS in an area where a service is provided, and a UE context and I-RNTI for the group are stored. For this reason, in this embodiment, a control node is provided in a core network of a mobile communication network, as shown in Fig. 5. The control node stores the I-RNTI and UE context of the group, and inputs information for identifying the BS for setting up the N3 tunnel.

[0029] Fig. 6 is a sequence diagram of a process of setting up an N3 tunnel between a BS and a UPF and storing the I-RNTI and UE context of a group in the BS. Note that Fig. 6 shows the process for one BS. The control node performs the process of Fig. 6 for each BS for which an N3 tunnel is set up.

[0030] In S10, the control node transmits a configuration request message to the BS. The configuration request message includes the UE context and I-RNTI to be stored in the BS. In response to receiving the configuration request message, the BS transmits a request to establish a PDU session to the AMF in S11. As a result, the AMF, the SMF, and the UPF transmit and receive control signaling to set up the N3 tunnel. The BS also stores the UE context and I-RNTI. When the configuration of the N3 tunnel section is completed, the BS transmits an RRC Reconfiguration message to the control node in S12. In response to the RRC reconfiguration message, the control node transmits an RRC Reconfiguration Complete message to the BS in S12. The processes of S11 to S13 are basically the same as the processes of establishing a PDU session for the WD. The difference is that the control node acting as the WD transmits the UE context and I-RNTI to be stored in the BS to the BS.

[0031] Then, in S14, the BS transmits an RRC Release message including information indicating that the WD is suspended to the control node. The process of S14 is similar to the process performed by the BS to transition the WD from a connected state to an inactive state. The difference is that the RRC Release message does not need to notify the UE of the I-RNTI and MAC-I.

[0032] The purpose of the sequence in Fig. 6 is to set up an N3 tunnel between the BS and the UPF and to store the I-RNTI and UE context of the group in the BS. Therefore, the processes in S12 to S14 in Fig. 6 may be omitted.

[0033] In addition, the I-RNTI and MAC-I of the group are stored in advance in each WD belonging to the group, and this can be done by any method at any timing before using the WD for a service, for example, before shipping the WD, or immediately before using the WD for a service, etc. For example, the MAC-I of the group can be stored in the control node, and the control node can transmit the MAC-I and I-RNTI of the group to each WD in the group that is configured to be able to communicate with the control node.

[0034] According to this embodiment, it is possible to suppress the time from when data to be transmitted to wireless devices belonging to the same group occurs until the transmission of the data. Therefore, it is possible to contribute to Goal 9 of the Sustainable Development Goals (SDGs) led by the United Nations, "Build resilient infrastructure, promote sustainable industrialization and foster innovation."

[0035] The invention is not limited to the above-described embodiment, and various modifications and variations are possible within the scope of the gist of the invention.

Claims

1. A mobile communication network for communicating with a plurality of wireless devices belonging to the same group, comprising: It has multiple base stations, maintaining a connection for the group between each of a first plurality of base stations of the plurality of base stations and a network node connected to an external network; A mobile communication network, wherein each of the plurality of first base stations stores a context of the group and an identifier of the context.

2. The mobile communication network according to claim 1 , wherein the plurality of wireless devices are in an inactive state when not communicating, and transition to a connected state when communicating.

3. The mobile communications network of claim 2 , wherein the plurality of wireless devices do not transition to an idle state.

4. The mobile communication network according to claim 1 , wherein the plurality of wireless devices are devices performing machine-type communication or Internet of Things (IoT) devices.

5. The mobile communication network of claim 1 , wherein the network node is a node implementing a User Plane Function (UPF).

6. The mobile communication network of claim 1 , wherein the connection is an N3 tunnel.

7. The mobile communication network of claim 1 , wherein the first plurality of base stations includes at least one of the plurality of base stations that serves an area in which the plurality of wireless devices are located.

8. each of the plurality of wireless devices having the identifier of the context of the group and an authentication code generated based on the context of the group; The mobile communication network according to any one of claims 1 to 7, wherein the plurality of first base stations are configured, when receiving transmission data, the identifier, and the authentication code from a first wireless device among the plurality of wireless devices, to determine the context of the group to which the first wireless device belongs based on the identifier, to authenticate the first wireless device based on the determined context and the authentication code, and, if authentication is successful, to transmit the transmission data to the connection.

9. 8. The mobile communication network according to claim 1 , further comprising a control node configured to inform each of the first base stations of the context of the group and the identifier of the context, thereby establishing the connection between each of the first base stations and the network node.

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