Improvement of simultaneous notification

Abstract

A communication method includes a determination process, a selection process, and a transmission process. The determination process includes determining to transmit a notification to a user device, located in a first macro cell covered by a first macro base station, by broadcasting the notification. The selection process includes selecting one or more target small base stations among a plurality of small base stations located in the first macro cell. The transmission process includes transmitting a notification to a user device, connected to the one or more target small base stations, by broadcasting the notification via the one or more target small base stations.

Description

Mass notification improvements

[0001] The present disclosure relates to improvements in broadcasting notifications to user devices.

[0002] A system has been developed that sends a simultaneous notification to user devices such as mobile terminals to warn of danger in the event of a natural disaster such as an earthquake. For example, Patent Document 1 discloses an emergency warning system that can send a simultaneous notification of an emergency situation from a base station to each mobile terminal.

[0003] Japanese Patent Application Laid-Open No. 2008-158599

[0004] The coverage range (communication range) of a base station as described in the above document is generally a radius of 100 m to several km, and a broadcast notification is made within that coverage range. On the other hand, there is a demand to limit the broadcast notification to a narrower range, or to divide the coverage range into smaller ranges and make notifications within those divided ranges. Furthermore, in conventional systems, a base station operated by one of multiple carriers (telecommunications operators) makes a broadcast notification to user devices subscribed to that carrier, but there is also a demand to be able to receive a broadcast notification from user devices subscribed to any carrier.

[0005] In view of the above-mentioned problems, the present disclosure aims to provide a technique for improving simultaneous notifications to user devices.

[0006] In order to solve the above problems, a communication method according to one aspect of the present disclosure comprises a decision process, a selection process, and a transmission process. The decision process includes deciding to transmit, by broadcast, a notification to user equipment located in a first macro cell covered by a first macro base station. The selection process includes selecting one or more target small base stations from among a plurality of small base stations located in the first macro cell. The transmission process includes transmitting, by broadcast, a notification to user equipment connected to the one or more target small base stations via the one or more target small base stations.

[0007] In order to solve the above problems, a communication system according to one aspect of the present disclosure includes one or more devices and executes a decision process, a selection process, and a transmission process. The decision process includes deciding to transmit, by broadcast, a notification to user equipment located in a first macro cell covered by a first macro base station. The selection process includes selecting one or more target small base stations from among a plurality of small base stations located in the first macro cell. The transmission process includes transmitting, by broadcast, a notification to user equipment connected to the one or more target small base stations via the one or more target small base stations.

[0008] The techniques of the present disclosure provide techniques related to improved broadcast notifications to user devices.

[0009] FIG. 1A is a diagram illustrating an example of the configuration of a communication system according to an embodiment. FIG. 1B is a diagram illustrating an example of the configuration of a communication system according to an embodiment. FIG. 2 is a diagram illustrating an example of a network configuration conforming to the 5G standard. FIG. 3 is a conceptual diagram illustrating a procedure for forced connection switching. FIG. 4A is a conceptual diagram of a network configuration for forced connection switching using network sharing. FIG. 4B is a conceptual diagram of inter-node connections for forced connection switching using network sharing. FIG. 5A is a conceptual diagram of a network configuration for forced connection switching using roaming. FIG. 5B is a conceptual diagram of inter-node connections for forced connection switching using roaming. FIG. 6A shows an example of a communication sequence for forced connection switching and broadcast notification by small base stations. FIG. 6B shows another example of a communication sequence for forced connection switching and broadcast notification by small base stations. FIG. 7 shows example hardware configurations of an MEC server, a macro base station, and a management device. FIG. 8 shows an example functional configuration of an MEC server. FIG. 9 shows example functional configurations of a macro base station and a management device.

[0010] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Among the components disclosed below, components having the same functions are designated by the same reference numerals, and their description will be omitted. Note that the embodiment disclosed below is one form of the present disclosure, and should be appropriately modified or changed depending on the configuration of the device and various conditions, and is not limited to the following embodiment. Furthermore, not all of the combinations of features described in the present embodiment are necessarily essential to solving the above-mentioned problems.

[0011] In the embodiments disclosed below, a network to which the technology according to the present disclosure is applied is assumed to be a network (5G network) conforming to the fifth generation (5G) standardized by the Third Generation Partnership Project (3GPP (registered trademark)). Note that the network here also includes user equipment. Note that the technology according to the present disclosure may also be applied to networks other than 5G networks.

[0012] [Outline of Use Case in Embodiment] An outline of a use case in this embodiment will be described with reference to Figures 1A and 1B. Figures 1A and 1B are diagrams showing an example of the configuration of a communication system in this embodiment. Components common to Figures 1A and 1B are given the same reference numerals. A base station 10 includes at least a device that executes an RU (Radio Unit) that performs part of the functions of a RAN (Radio Access Network). The base station 10 forms a macrocell 100 within the coverage area of ​​the base station 10. The macrocell 100 forms an area (coverage area) with a radius of 100 m to several km.

[0013] Multiple base stations (N is a natural number greater than 1) are deployed within the macrocell 100. In Figures 1A and 1B, three base stations 11, 12, and 13 are deployed. Like base station 10, base stations 11, 12, and 13 include at least a device that executes an RU that performs part of the functions of the RAN. Base stations 11, 12, and 13 form small cells (also called microcells, picocells, or femtocells) 101, 102, and 103 within their respective coverage areas. Small cells 101, 102, and 103 each form an area (coverage area) with a radius ranging from several meters to several tens of meters. The areas of small cells 101, 102, and 103 only need to be smaller than the area of ​​macrocell 100, and are not limited to the above numerical ranges. To prevent radio waves from interfering between the small cells 101, 102, and 103 and the macro cell 100, different frequencies are used by the small cells 101, 102, and 103 and the macro cell 100. In the following description, in order to distinguish between the base station 10 that forms the macro cell 100 and the base stations 11, 12, and 13 that form the small cells 101, 102, and 103, respectively, the base station 10 will also be referred to as a macro base station, and the base stations 11, 12, and 13 will also be referred to as small base stations 11, 12, and 13.

[0014] In such a communication environment, vehicles V1 to V7 are traveling on roads within macrocell 100. Each of vehicles V1 to V7 is equipped with user equipment (UE) 21 to 27, which is a communication device having a communication function compliant with 5G. Each of UE 21 to 27 is incorporated, for example, as part of a navigation device installed in each of vehicles V1 to V7. Alternatively, each of UE 21 to 27 may be a UE carried by or attached to a user (e.g., a driver or a passenger) in each of vehicles V1 to V7.

[0015] 1 , when UE21 to 23 enter the small cell 101, they are switched to a connection with the small base station 11, and while they belong to (are in the coverage area of) the small cell 101, they maintain their connection to the small base station 11. When UE21 to 23 leave the small cell 101, their connection to the small base station 11 is released. Similarly, when UE24 and 25 enter the small cell 102, they are switched to a connection with the small base station 12, and while they belong to the small cell 102, they maintain their connection to the small base station 12. When UE24 and 25 leave the small cell 102, their connection to the small base station 12 is released. Furthermore, when UEs 26 and 27 enter the small cell 103, their connection is switched to the small base station 13, and the connection to the small base station 13 is maintained while they belong to the small cell 103. When UEs 26 and 27 leave the small cell 103, their connection to the small base station 13 is released. UEs 21 to 27 that have been released from any of the small base stations 11, 12, and 13 can be reconnected to the macro base station 10 depending on the radio wave conditions.

[0016] The macro base station 10 and the small base stations 11, 12, and 13 are connected to a mobile communication network 104. The mobile communication network 104 includes a core network 105 and an MEC system 106. The configuration of the core network 105 will be described later. The MEC system 106 also includes a UPF (User Plane Function) node 107 and an MEC (Multiaccess Edge Computing) server 108. The UPF node 107 has functions to control routing and forwarding (including duplicating and forwarding) packets containing information and data, interconnection with other data networks, connection with the MEC server 108, and the like. The MEC server 108 is a server device (edge ​​server) for edge computing (MEC in this embodiment).

[0017] The UEs 21 to 27 can transmit a notification including specific information (hereinafter also referred to as a specific notification) to the external system 109 via a base station to which they are connected (the macro base station 10 or any of the small base stations 11, 12, and 13) and the mobile communication network 104. The specific notification is, for example, a notification including information about the time and place where an accident occurred when at least one of the vehicles V1 to V7 has been involved in an accident (such as a collision between vehicles).

[0018] The external system 109 is connected to the mobile communication network 104. The external system 109 may be connected to the mobile communication network 104 via an external network (not shown). When the external system 109 receives a specific notification, it can analyze the content of the notification and generate necessary information (information on the time and location of the accident, instructions to slow down, instructions to take a detour, etc.). For example, when the external system 109 receives a specific notification from any of the UEs 21 to 27 via the macro base station 10, it can transmit the generated information as area information of the macro cell 100 (area information related to the macro cell 100) to at least any of the UEs 21 to 27 via the mobile communication network 104 and the macro base station 10.

[0019] The mobile communication network 104 controls the transmission of the specific notification. For example, the mobile communication network 104 can change the destination of the specific notification from the external system 109 and transmit the specific notification to a system other than the external system 109 (this is referred to as destination change here). Furthermore, for example, the mobile communication network 104 can copy the specific notification and transmit the original specific notification to the external system 109, while changing the destination of the copied specific notification and transmitting it to a system other than the external system 109 (this is referred to as copy and forward here). In this embodiment, the mobile communication network 104 performs destination change or copy and forward for the specific notification transmitted to the small base stations 11, 12, and 13. As a result, the specific notification with the changed destination or the copied specific notification is received by the MEC system 106 in the mobile communication network 104. The destination change and copy and forward can be performed by implementing known technologies including a UPF function and the like defined as a standard technology for 5G. Furthermore, all packets destined for the external system 109 may be subject to destination change or duplication and forwarding, or packets that meet a predetermined condition may be subject to destination change or duplication and forwarding.

[0020] When the MEC system 106 receives a specific notification via the small base stations 11, 12, and 13, it can decide to send a simultaneous notification based on that notification. Furthermore, when the MEC system 106 receives a specific notification, it can analyze the contents of that notification and generate necessary information (information on the time and location of the accident, instructions to slow down, instructions to take a detour, etc.). For example, when the MEC system 106 receives a specific notification from any of the UEs 21 to 27 via any of the small base stations 11, 12, and 13, it can transmit the generated information to at least one of the UEs 21 to 27 via at least one of the small base stations 11, 12, and 13 as area information of any of the small cells 101, 102, and 103 (area information related to any of the small cells 101, 102, and 103).

[0021] In this embodiment, the mobile communication network 104 is operated by a specific carrier (telecommunications operator), as will be described later. However, the external system 109 is not necessarily connected only to networks operated by a specific carrier. For example, each carrier provides a public land mobile network (PLMN), and the external system 109 may be connected to all of them.

[0022] 1B , consider a scene in which an accident occurs at an intersection within the small cell 101, in which vehicles V1 and V2 collide. At least one of UEs 21 and 22 of vehicles V1 and V2, which have switched to a connection to the small base station 11, transmits a specific notification (including, for example, information about the time and location of the accident) to the mobile communication network 104 via the small base station 11 in response to the occurrence of the accident. In this case, it would be beneficial if area information about the small cell 101 could be quickly notified to users near the collision site or users of vehicles heading toward the collision site, in order to avoid danger and obtain information about the collision accident. Therefore, in the example of FIG. 1B , the MEC server 108 of the MEC system 106 in the mobile communication network 104 receives the specific notification and generates area information about the small cell 101 based on the specific notification. The MEC server 108 then transmits the area information of the small cell 101 to UEs 21 to 23, which have switched to a connection to the small base station 11, via the small base station 11. Furthermore, because small cell 102 is adjacent to small cell 101, the MEC server 108 transmits area information of small cell 101 to UEs 24 and 25 that have switched their connection to small base station 12 via small base station 12. Note that small cell 103 is a certain distance away from the collision location in small cell 101. For this reason, the value of area information of small cell 101 is considered to be low for UEs 26 and 27 that are located inside small cell 103. Therefore, in the example of FIG. 1B , the MEC server 108 does not transmit area information of small cell 101 to UEs 26 and 27 that have switched their connection to small base station 13 via small base station 13.

[0023] Broadcast notification via a macro base station is not suitable for information that is not beneficial to all UEs within the macro cell 100 but that should be transmitted to UEs located only within a portion of the area of ​​the macro cell 100. However, if it is attempted to check for each UE whether it is located in that portion of the area, it would be impossible to quickly transmit urgent information. For this reason, as described above, it is preferable to change the connection destination of the UE from a macro base station to a small base station, and to transmit broadcast notification only via the necessary small base stations.

[0024] Specific processing procedures for realizing such a use case will be described below. First, a procedure (forced connection switching procedure) for forcibly switching a connection to one of the small base stations 11, 12, 13 that form the small cell when a UE connected to the macro base station 10 and belonging to the macro cell 100 enters a small cell 101, 102, 103 will be described. In this embodiment, connection switching is performed so that even if the UE is connected to a macro base station operated by a carrier (communications operator) different from the carrier that operates the macro base station 10, the connection is forcibly switched to one of the small base stations 11, 12, 13. Next, a procedure for broadcast notification by the small base stations that is performed after forced connection switching will be described.

[0025] [Procedure for Forced Connection Switching] Here, two methods, (1) network sharing and (2) roaming, will be described as methods for forcibly switching the connection of a UE from one base station (in this embodiment, a macro base station) to another base station (in this embodiment, a small base station). Network sharing is a method in which a base station operated by a specific carrier among a plurality of carriers is shared among the plurality of carriers. Roaming is a method in which a base station operated by a specific carrier among a plurality of carriers is shared among the plurality of carriers via a network operated by the specific carrier.

[0026] To specifically explain the network sharing and roaming techniques, the core network 105 and the MEC system 106 shown in Figures 1A and 1B will first be described with reference to Figure 2. Figure 2 is a diagram showing an example of a network configuration that complies with the 5G standard. The core network 105 includes a User Plane Function (UPF) 203, an Authentication Server Function (AUSF) 205, an Access and Mobility Management Function (AMF) 206, a Session Management Function (SMF) 207, a Network Exposure Function (NEF) 208, a Network Repository Function (NRF) 209, a Policy Control Function (PCF) 210, and a Unified Data Management Function (UDM). 2, the RAN 202 includes a UE 201 and a RAN Management 211, and is connected to the UE 201 and the RAN 202. The UPF 203 is connected to the MEC 204. The UPF 203 is also connected to a DN (Data Network) 212. The UE 201 corresponds to the UEs 21 to 27 in FIGS. 1A and 1B. The UPF 203 and the MEC 204 correspond to the UPF node 107 and the MEC server 108 in FIGS. 1A and 1B, and form the MEC system 106. The RAN 202 includes the macro base station 10 and the small base stations 11, 12, and 13 in FIGS. 1A and 1B. As can be seen from FIG. 2, the macro base station 10 and the small base stations 11, 12, and 13 in FIGS. 1A and 1B are connected to the core network 105 and the MEC system 106, respectively.

[0027] In this embodiment, in order to explain the procedure for forced connection switching, it is assumed that four carriers (telecommunications operators) operate mobile networks to provide 5G communication services, and the four carriers are referred to as Carrier-A, Carrier-B, Carrier-C, and Carrier-D. Note that, for the purpose of explaining the procedure, components having similar functions to the components described in Figures 1A, 1B, and 2 are given the same reference numerals, and further, components with "A," "B," "C," or "D" at the end of the reference numeral indicate components operated by Carrier-A, Carrier-B, Carrier-C, or Carrier-D, respectively.

[0028] FIG. 3 is a conceptual diagram illustrating the procedure for forced connection switching. FIG. 3 shows communication systems of carrier A and carrier B, and the configuration of the communication system of each carrier is the same as the configuration shown in FIG. 1A and FIG. 1B, except for a management device 301, which will be described later. The procedure described with reference to FIG. 3 is also applicable to FIG. 1A and FIG. 1B. In FIG. 3, a macro base station 10A and a small base station 11A are operated by carrier A and form a macro cell 100A and a small cell 101, respectively. The macro base station 10A and the small base station 11A are also connected to a mobile communication network 104A having a core network 105A and an MEC system 106A operated by carrier A. On the other hand, the macro base station 10B is operated by carrier B and forms a macro cell 100B. The macro base station 10B is also connected to a mobile communication network 104B having a core network 105B and an MEC system 106B operated by carrier B. 3, the mobile communication network 104A has a management device 301 that manages connections between carriers A to D. Note that the management device 301 may be installed in a network other than the mobile communication network 104A and manage connections between carriers A to D.

[0029] Here, assume that UE21 is connected to the macro base station 10A operated by carrier A, and UE23 is connected to the macro base station 10B operated by carrier B. In this case, when UE23 enters the small cell 101, it is triggered to switch its connection from the macro base station 10B to the small base station 11A by the network sharing or roaming method described below. In other words, UE23 connects to the small base station 11A across carriers. Furthermore, when UE21 connected to the macro base station 10A enters the small cell 101, it is also triggered to switch its connection to the small base station 11A.

[0030] The macro base station 10B can detect that the UE 23 is entering the small cell 101. For example, the macro base station 10B can detect that the UE 23 is entering the small cell 101 based on the radio wave strength from the UE 23 (for example, Received Signal Strength Indicator (RSSI) or Reference Signal Received Power (RSRP)) or location information (for example, latitude and longitude information) acquired from the UE 23. Similarly, the macro base station 10A can detect that the UE 21 is entering the small cell 101.

[0031] (1) Network Sharing The procedure for forced connection switching using network sharing will be described with reference to Figures 4A and 4B. Figure 4A is a conceptual diagram of a network configuration for forced connection switching using network sharing. Network sharing is a technique in which a base station operated by a specific carrier among multiple carriers is shared. Here, an example will be described in which a small base station 11A operated by carrier A is shared in the use case shown in Figure 3.

[0032] As shown in Fig. 4A, the small base station 11A is connected to a core network 105A and an MEC system 106A operated by carrier A. Furthermore, in order to realize network sharing, the small base station 11A is connected to an MEC system 106B operated by carrier B, an MEC system 106C operated by carrier C, and an MEC system 106D operated by carrier D. The MEC systems 106B, 106C, and 106D are connected to the macro base stations 10B, 10C, and 10D, respectively. Therefore, the UE 23 connected to the macro base station 10B in Fig. 3 can connect to the small base station 11A via the MEC system 106B.

[0033] 4B is a conceptual diagram of inter-node connections for forced connection switching using network sharing. As shown in FIG. 4B, a UPF 203B in an MEC system 106B is connected to a RAN 202A. Similarly, a UPF 203C in an MEC system 106C is connected to a RAN 202A, and a UPF 203D in an MEC system 106D is connected to the RAN 202A. Also, as shown in FIG. 4B, core networks 105B, 105C, and 105D are connected to UPFs 203B, 203C, and 203D, respectively.

[0034] 3, when the macro base station 10B detects that the UE 23 has entered the small cell 101, it uses this as a trigger to perform control so that a connection between the UE 23 and the small base station 11A is established via the MEC system 106B. Alternatively, the management device 301 may perform control so that a connection between the UE 23 and the small base station 11A is established via the MEC system 106B. Alternatively, the core network 105A or the core network 105B may perform control so that a connection between the UE 23 and the small base station 11A is established via the MEC system 106B. This enables the UE 23 to communicate with the small base station 11A via the MEC system 106A. Furthermore, when the macro base station 10A or the management device 301 detects that the UE 21 has entered the small cell 101, it performs control so that a connection between the UE 21 and the small base station 11A is established.

[0035] 3, when the small base station 11A detects that UE23 is leaving the small cell 101, this triggers the release of the connection between UE23 and the MEC system 106B. In other words, the release of UE23 from the small cell 101 triggers the release of the forced connection switching. Furthermore, when the small base station 11A detects that UE21 is leaving the small cell 101, this triggers the release of the connection with UE21. Note that the small base station 11A can detect that UE21 and UE23 are leaving the area of ​​the small cell 101 from the radio wave strength from UE21 and UE23 and the location information of UE21 and UE23.

[0036] (2) Roaming Next, a procedure for forced connection switching using roaming will be described with reference to Figures 5A and 5B. Figure 5A is a conceptual diagram of a network configuration for forced connection switching using roaming. Roaming is a technique for using a core network operated by another carrier and sharing a base station connected to that core network. Here, an example will be described in which a small base station 11A operated by carrier A is shared in the use case shown in Figure 3.

[0037] As shown in Fig. 5A, the small base station 11A is connected to a core network 105A operated by carrier A and an MEC system 106A. Furthermore, to achieve roaming, the core network 105A is connected to a core network 105B operated by carrier B, a core network 105C operated by carrier C, and a core network 105D operated by carrier D. The core networks 105B, 105C, and 105D are connected to the macro base stations 10B, 10C, and 10D, respectively. Therefore, the UE 23 connected to the macro base station 10B in Fig. 3 can connect to the small base station 11A via the core network 105B and the core network 105A.

[0038] 5B is a conceptual diagram of inter-node connections for forced connection switching using roaming. As shown in FIG. 5B, UDM 211B in core network 105B is connected to RAN 202A via core network 105A. Specifically, UDM 211B in core network 105B is connected to UDM 211A in core network 105A, and is connected to RAN 202A via SMF 207A and UPF 203A. Similarly, UDM 211C in core network 105C is connected to RAN 202A via core network 105A, and UDM 211D in core network 105D is connected to RAN 202A via core network 105A.

[0039] 3, when the macro base station 10B detects that the UE 23 has entered the small cell 101, it triggers control so that a connection between the UE 23 and the small base station 11A is established via the core networks 105B and 105A. Alternatively, the management device 301 may perform control so that a connection between the UE 23 and the small base station 11A is established via the core networks 105B and 105A. Alternatively, the core network 105A or the core network 105B may perform control so that a connection between the UE 23 and the small base station 11A is established via the core networks 105B and 105A. This enables the UE 23 to communicate with the small base station 11A via the core networks 105B and 105A. Furthermore, when the macro base station 10A detects that the UE 21 has entered the small cell 101, it performs control so that a connection between the UE 21 and the small base station 11A is established.

[0040] 3, when the small base station 11A detects that UE23 is leaving the small cell 101, it uses this as a trigger to request the core network 105A to release the connection between the core networks 105A and 105B. The core network 105A then releases the connection with the core network 105B. In other words, the release of UE23 from the small cell 101 is used as a trigger to release the forced connection switching. Also, when the small base station 11A detects that UE21 is leaving the small cell 101, it uses this as a trigger to release the connection with UE21. As described above, the small base station 11A can detect that UE21 and UE23 are leaving the area of ​​the small cell 101 based on radio wave strength and location information.

[0041] As described above, in this embodiment, by using either the network sharing or roaming method described above, in the example of Fig. 3, UE 23 entering the small cell 101 has its connection forcibly switched to the small base station 11A. Also, UE 21 entering the small cell 101 has its connection forcibly switched to the small base station 11A.

[0042] 3, the entry of UE21 and 23 into the small cell 101 triggers a forced switchover of the connection to the small base station 11A, but such forced connection switching may also be performed when a predetermined condition is met. With reference to FIG. 3, the macro base station 10B that detects that UE23 is entering the small cell 101 may control the UE23 to connect to the small base station 11A when a predetermined condition is met. Similarly, the macro base station 10A that detects that UE21 is entering the small cell 101 may control the UE23 to connect to the small base station 11A when a predetermined condition is met. Alternatively, the management device 301 or the core network 105A or 105B may perform such control. The predetermined condition may be set in advance in the macro base stations 10A and 10B, the management device 301, or the core network 105A or 105B. Alternatively, the predetermined condition may be instructed from a system (not shown) to the macro base stations 10A and 10B, the management device 301, or the core network 105A or 105B.

[0043] The predetermined condition will be described here using an example in Fig. 3 in which the macro base station 10B forcibly switches the connection of the UE 23 to the small base station 11A. The determination of whether the predetermined condition is met is not limited to when the UE 23 enters the small cell 101, but may be made at any timing during communication with the macro base station 10B. In this embodiment, the predetermined condition is a condition for determining the UE to which area information of the small cell 101 should be notified when an accident such as that shown in Fig. 1B occurs, but is not limited to this.

[0044] The predetermined condition may be a condition related to time. For example, the predetermined condition may be a predetermined time period in a day based on the fact that traffic accidents are more likely to occur during certain time periods, such as times of relatively heavy traffic or in the evening. In this case, when the macro base station 10B detects that the UE 23 is entering the small cell 101, it may obtain the detected time and time period, and if the detected time and time period are included in the predetermined time period, it may control the UE 23 to connect to the small base station 11A.

[0045] Furthermore, the predetermined condition may be a condition related to traffic volume in the small area to which the UE belongs. For example, the predetermined condition may be a predetermined threshold value for the volume of at least one of vehicles, bicycles, and pedestrians passing through per unit time. In this case, when the macro base station 10B detects that the UE 23 is entering the small cell 101, it may obtain information about traffic volume in the small cell 101, and if the traffic volume is equal to or greater than the threshold value, it may control the UE 23 to connect to the small base station 11A.

[0046] Furthermore, the predetermined condition may be a condition related to the attributes of the UE (for example, demographic information). The macro base station 10B can, for example, acquire the UE attributes directly from the UE. Furthermore, the macro base station 10B can acquire the UE attributes as information registered with a predetermined web service by the user of the UE. Demographic information is information indicating demographic user attributes such as gender, age, residential area, occupation, and family structure. For example, if the predetermined condition is a predetermined age or older, the macro base station 10B may control the UE 23 to connect to the small base station 11A when it detects that the UE 23 has entered the small cell 101 and the user age included in the attributes of the UE 23 is the predetermined age or older.

[0047] Furthermore, the predetermined condition may be a condition related to the movement speed of the UE. For example, the predetermined condition may be one or more thresholds for the movement speed of the UE. In this case, the macro base station 10B acquires location information of the UE 23 at predetermined time intervals and compares the movement speed derived from the location information with the threshold, thereby being able to identify whether the object on which the UE 23 is mounted or carried is a vehicle, a bicycle, or a pedestrian. Then, when the macro base station 10B detects that the UE 23 is entering the small cell 101, it may perform control so as to connect the UE 23 to the small base station 11A based on the movement speed of the UE 23. Furthermore, the predetermined condition may be a combination of the above conditions. Furthermore, the predetermined condition may be derived based on the results of learning by machine learning using conditions at the time of an accident occurrence.

[0048] In this way, by limiting the UEs that are targets of forced connection switching, forced connection switching is performed only on UEs that should be targets of simultaneous notification, rather than on all UEs that have entered the small cell 101. For example, UEs that are not relevant to simultaneous notification (for example, IoT (Internet of Things) devices attached to animals) can be excluded from the UEs that are targets of forced connection switching. This makes it possible to prevent wasteful use of communication resources.

[0049] [Broadcast procedure by small base station] The procedure for broadcasting to UEs that belong to the small cell formed by a small base station, which is carried out after a forced connection switch to the small base station as described above, will now be described. Refer to Figure 1B for an explanation of this procedure. In Figure 1B, UEs 21 to 27 are able to communicate with any of small base stations 11, 12, and 13 in any of small cells 101, 102, and 103 as shown in the figure, due to the forced connection switch.

[0050] The MEC server 108 in the MEC system 106 recognizes the installation locations of the small base stations 11, 12, and 13. The MEC server 108 can control the transmission of area information of any of the small cells 101, 102, and 103 to the UEs 21 to 27 via any of the small base stations 11, 12, and 13.

[0051] 1B , when UE21 or UE22 transmits a specific notification to the small base station 11 toward the external system 109, the UPF node 107 in the MEC system 106 receives the specific notification and transmits the specific notification to the MEC server 108 by redirecting the destination or by copying and forwarding. The MEC server 108 decides to perform a broadcast notification based on the received specific notification. The MEC server 108 also generates area information for the small cell 101 based on the received specific notification. The MEC server 108 also selects one or more small cells as communication ranges for which area information should be notified based on the received specific notification, and selects small base stations that cover the selected one or more small cells as target small base stations. In the example of FIG. 1B , the MEC server 108 decides to notify the small cells 101 and 102 of the area information, and selects the small base stations 11 and 12 as target base stations. Subsequently, the MEC server 108 transmits the area information to the small base stations 11 and 12. In response to this, small base station 11 transmits area information of small cell 101 to UEs connected to small base station 11, and small base station 12 transmits area information of small cell 101 to UEs connected to small base station 12. As a result, the area information of small cell 101 is not notified to UEs 26 and 27 that are present in macro cell 100 but are not thought to need it, but is notified to UEs 23 to 25 that are thought to need it. Therefore, it is possible to reduce dissatisfaction among users who receive unnecessary notifications, compared to when simultaneous notifications are made via base station 10 that forms macro cell 100.

[0052] It is assumed that the simultaneous notification in this embodiment uses a method such as Cell Broadcast Service (CBS) to perform broadcast transmission to all UEs connected to the small base station. However, it is also possible to manage the UEs connected to the small base station and send notification by unicast to specific UEs connected to the small base station. For example, broadcast and unicast may be used depending on the content of the area information, etc.

[0053] 1B , the MEC system 106 has notified the area information of the small cell 101. However, the information notified by the MEC system 106 is not limited to the area information of any of the small cells 101, 102, and 103. For example, another system such as the external system 109 may transmit a specific notification to the MEC system 106, and the MEC server 108 may generate notification information to be notified based on the received specific notification and transmit this notification information to UEs 21 to 27 via the small base stations 11, 12, and 13. In this case, the MEC server 108 may select one or more small base stations (target small base stations) from among the small base stations 11, 12, and 13 to transmit the notification information based on the specific notification. Then, the MEC server 108 may transmit the notification information to UEs connected to the selected one or more small base stations via the selected one or more small base stations.

[0054] <Processing Flow> The processing flow executed by this embodiment will be described with reference to Figures 6A and 6B. Figure 6A shows an example of a communication sequence for forced connection switching and simultaneous notification by small base stations. The communication sequence shown in Figure 6A is a communication sequence related to processing executed to realize the use case shown in Figure 1B.

[0055] In S601, for UEs 21 to 23, entry into small cell 101 is used as a trigger to perform forced connection switching to small base station 11. For UEs 24 and 25, entry into small cell 102 is used as a trigger to perform forced connection switching to small base station 12. The procedure for forced connection switching is as described above.

[0056] If UE 21 and 22 collide after the forced connection switching, at least one of UE 21 and 22 transmits a specific notification to the external system 109 (S602). The specific notification includes, for example, information about the time and location of the accident. The small base station 11 that receives the specific notification transmits it to the MEC system 106 (S603). The UPF node 107 of the MEC system 106 receives the specific notification, duplicates the notification (S604), and transfers it to the MEC server 108 (S605). Based on the specific notification, the UPF node 107 may decide to send a simultaneous notification to one or more UEs located within the macro cell 100 covered by the macro base station 10. The UPF node 107 may or may not transmit the specific notification to the external system 109 via the core network 105.

[0057] The MEC server 108 that has received the duplicated specific notification may decide, based on the specific notification, to send a broadcast notification to one or more UEs located within the macro cell 100 covered by the macro base station 10. Furthermore, in S606, the MEC server 108 generates area information for the small cell 101 based on the specific notification and selects small base stations to transmit the area information. Here, the MEC server 108 selects small base stations 11 and 12. In other words, the MEC server 108 decides to transmit the area information of the small cell 101 to the small base stations 11 and 12. In response to this, the MEC server 108 transmits the area information of the small cell 101 to the small base station 11 (S607), and the small base station 11 transmits the area information to UEs 21 to 23 that are connected to the small base station 11 (S608). Furthermore, the MEC server 108 transmits area information of the small cell 101 to the small base station 12 (S609), and the small base station 12 transmits this area information to UEs 24 and 25 that are connected to the small base station 12 (S610). When UEs 21 to 23 leave the area of ​​the small cell 101, their connection to the small base station 11 is released, and when UEs 24 and 25 leave the area of ​​the small cell 102, their connection to the small base station 12 is released (S611).

[0058] 1B , there may be cases where the small cells 101 and 102 partially overlap, and for example, the UE 24 enters the small cell 101 at the same time as it leaves the small cell 102. In such cases, the management device 301 may switch the connection of the UE 24 from the small base station 12 to the small base station 11.

[0059] In this way, when at least one of the UEs 21 and 22 transmits a specific notification toward the external system 109, the UPF node 107 that receives the specific notification forwards the notification to the MEC server 108. The MEC server 108 that receives the specific notification generates area information for the small cell 101 based on the contents of the specific notification, and performs a broadcast notification via the small base stations 11 and 12 selected to transmit the area information. In other words, the MEC server 108 performs a broadcast notification in a communication range that is narrower than the coverage area of ​​the macro base station 10. The time required for communication with the small base station 11 is shorter for the MEC server 108 than for the external system 109 that is located outside the mobile communication network 104. For this reason, when the UPF node 107 forwards the specific notification to the MEC server 108 and the MEC server 108 controls the broadcast notification of the area information in this way, information that urgently needs to be broadcast is more quickly notified than when the external system 109 that receives the specific notification requests a broadcast notification. In other words, when a report is made by at least one of UEs 21 and 22, area information corresponding to the report is quickly notified to all users, and the user of the UE that receives the area information can take appropriate action based on the area information.

[0060] Fig. 6B shows another example of a communication sequence for forced connection switching and broadcast notification by small base stations. Fig. 6A shows the flow of a process for broadcasting area information based on a specific notification transmitted from a UE. Fig. 6B shows a communication sequence related to a process for broadcasting notification information based on a specific notification transmitted from an external system 109. For the explanation of Fig. 6B, refer to Fig. 1A. In the following explanation of Fig. 6B, explanations common to Fig. 6A will be omitted.

[0061] In S611, for UEs 21 to 23, entry into small cell 101 is triggered to cause a forced connection switch to be made to small base station 11. For UEs 24 and 25, entry into small cell 102 is triggered to cause a forced connection switch to be made to small base station 12. For UEs 26 and 27, entry into small cell 103 is triggered to cause a forced connection switch to be made to small base station 13. The procedure for forced connection switch is as described above.

[0062] After the forced connection switching, if information that should be notified to the UEs belonging to the small cells 101, 102, and 103 occurs in the external system 109, the external system 109 transmits a specific notification including the information to the UPF node 107 in the MEC system 106 (S612). The UPF node 107 that receives the specific notification duplicates the notification (S604) and transfers it to the MEC server 108 (S605).

[0063] In S613, the MEC server 108, which has received the duplicated specific notification, decides to send a broadcast notification based on the specific notification, generates notification information, and selects the small base stations to which to send the notification information. Here, the MEC server 108 selects small base stations 11, 12, and 13. In other words, the MEC server 108 decides to send the notification information to the small base stations 11, 12, and 13. In response to this, the MEC server 108 sends the notification information to the small base station 11 (S614), and the small base station 11 sends the notification information to UEs 21 to 23 that are connected to the small base station 11 (S615). Furthermore, the MEC server 108 sends the notification information to the small base station 12 (S616), and the small base station 12 sends the notification information to UEs 24 and 25 that are connected to the small base station 12 (S617). Furthermore, the MEC server 108 transmits the notification information to the small base station 13 (S618), and the small base station 13 transmits the notification information to UEs 26 and 27 that are connected to the small base station 13 (S619). When UEs 21 to 23 leave the area of ​​the small cell 101, their connection to the small base station 11 is released, when UEs 24 and 25 leave the area of ​​the small cell 102, their connection to the small base station 12 is released, and when UEs 26 and 27 leave the area of ​​the small cell 102, their connection to the small base station 13 is released (S620).

[0064] In this way, the forced connection switching procedure makes it possible to simultaneously notify any information, not limited to information based on notifications transmitted from the UEs, to UEs connected to any of the small cells 101, 102, and 103. By using the MEC server 108, the processing load on the external system 109 related to the simultaneous notification and on the core network 105 operated by any carrier can be reduced.

[0065] [Modification] In the above embodiment, the small base stations 11, 12, and 13 are connected to the MEC system 106, but each of the small base stations 11, 12, and 13 may be connected to an MEC system that has a UPF node (referred to as a local UPF node) and an MEC node (referred to as a local MEC node) similar to the MEC system 106. Furthermore, such an MEC system may be set up in the vicinity of each of the small base stations 11, 12, and 13. In this case, for example, when the UE 21 transmits a specific notification to the external system 109 via the small base station 11, the local UPF node in the MEC system set up in the vicinity of the small base station 11 receives the specific notification and forwards it to the local MEC server. The local MEC server can generate area information of the small cell 101 from the specific notification and transmit this area information to one or more UEs connected to the small base station 11 via the small base station 11. Furthermore, a local MEC server near the small base station 11 may control the small base stations 12 and 13 to transmit the area information to one or more UEs connected to the small base stations 12 and 13. With such a configuration, it is possible to more quickly generate area information in response to a specific notification and to more quickly notify the same simultaneously.

[0066] [Hardware Configurations of MEC Server, Macro Base Station, and Management Device] Fig. 7 shows an example of the hardware configuration of the MEC server 108 according to this embodiment. Note that the macro base station 10 and the management device 301 also have similar hardware configurations. As shown in Fig. 7 , the MEC server 108 includes, as an example of a hardware configuration, a CPU (Central Processing Unit) 71, a ROM (Read Only Memory) 72, a RAM (Random Access Memory) 73, a HDD (Hard Disk Drive) 74, a communication I / F (Interface) 75, and a system bus 76. The MEC server 108 may also include an external memory. The CPU 71 is configured with one or more processors and performs overall control of the operations of the MEC server 108. The CPU 71 controls each component (72 to 75) via a system bus 76, which is a data transmission path. At least one of the one or more CPUs 71 may be replaced by one or more processors such as an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a digital signal processor (DSP), a graphics processing unit (GPU), or the like.

[0067] The ROM 72 is a non-volatile memory that stores control programs and the like necessary for the CPU 71 to execute processing. Note that these programs may be stored in a non-volatile memory such as the HDD 74 or an SSD (Solid State Drive) or in an external memory such as a removable storage medium (not shown). The RAM 73 is a volatile memory that functions as the main memory, work area, and the like of the CPU 71. That is, when executing processing, the CPU 71 loads the necessary programs and the like from the ROM 72 into the RAM 73 and executes the programs and the like to realize various functional operations.

[0068] The HDD 74 stores, for example, various data and information required when the CPU 71 performs processing using a program. The HDD 74 also stores, for example, various data and information obtained when the CPU 71 performs processing using a program. Note that this storage may be performed using a non-volatile memory such as an SSD or an external memory such as a removable storage medium together with the HDD 74 or instead of the HDD 74. The communication I / F 75 is an interface that controls communication between the MEC server 108 and external devices.

[0069] The MEC server 108 may be provided with dedicated hardware for executing each of its functions, or may execute some of its functions with hardware and execute the remaining parts with a computer running a program. Alternatively, all of its functions may be executed by a computer and a program. The same applies to the macro base station 10 and the management device 301.

[0070] [Functional Configuration of MEC Server] Fig. 8 shows an example of the functional configuration of the MEC server 108 according to this embodiment. Each function of the MEC server 108 is a logical function realized by the hardware of the MEC server 108 shown in Fig. 7, for example, and can be realized by the CPU 71 executing a program stored in the ROM 72 or the like. In this embodiment, the MEC server 108 has, as its functional configuration, a transmitter 81, a receiver 82, a transmission method determiner 83, an information generator 84, and a base station selector 85.

[0071] The transmitter 81 and the receiver 82 each transmit and receive packets via the communication I / F 75. In this embodiment, the packets include packets containing data of a specific notification, area information, or notification information. The transmission method determination unit 83 determines a method for transmitting a notification to one or more UEs located within the macrocell 100 covered by the macro base station 10. For example, the transmission method determination unit 93 determines to transmit a simultaneous notification to one or more UEs located within the macrocell 100 covered by the macro base station 10 (in this embodiment, to transmit the notification by broadcast). The information generation unit 84 generates area information and notification information based on the received specific notification. In the example of FIG. 1B , the area information may include information on the time and location of the accident, a slow-down instruction, or a detour instruction. Furthermore, the notification information may include information to be simultaneously transmitted from the external system 109. The base station selection unit 85 selects a base station (target base station) to transmit the information generated by the information generation unit 84. 1B , the information generation unit 84 can select, based on the positions of the three small base stations 11, 12, and 13, one or more small base stations that will transmit area information of the small cell 101. Specifically, the information generation unit 84 selects, as target base stations, small base stations 11 and 12, which are one or more small base stations located within a predetermined distance from the small base station 11 from which the specific notification was received.

[0072] <Functional Configuration of Macro Base Station and Management Device> Fig. 9 shows an example of the functional configuration of the macro base station 10 according to this embodiment. Note that only functions related to forced connection switching are shown here, and the management device 301 also has a similar functional configuration. Each function of the macro base station 10 is a logical function realized by the hardware of the macro base station 10 shown in Fig. 7, for example, and can be realized by the CPU 71 executing a program stored in the ROM 72 or the like. In this embodiment, the macro base station 10 has, as its functional configuration, a transmitter 91, a receiver 92, a detector 93, a UE determiner 94, and a connection controller 95.

[0073] The transmitter 91 and receiver 92 transmit and receive packets via the communication I / F 75, respectively. In this embodiment, the packets include packets containing data for specific notifications, area information, or notification information. The detector 93 detects that a UE has entered one of the small cells 101, 102, or 103. The UE determiner 94 determines which UEs that have entered one of the small cells 101, 102, or 103 are to undergo forced connection switching. The UE determiner 94 can determine which UEs are to undergo forced connection switching, using at least one of the following conditions: the time of day, traffic volume in the area including the small cell, UE attributes, and UE movement speed. The connection controller 95 controls the establishment and termination of connections through forced connection switching. Note that the connection controller 95 may also have the functions of the UE determiner 94.

[0074] As described above, according to the embodiment described above, regardless of which carrier's base station the UE is connected to, entry into a specific small cell triggers a forced connection switch to the small base station that forms that small cell. Furthermore, the forced connection switch is not targeted at all UEs that have entered the small cell, but is limited to UEs that are to receive information that should be notified in that small cell. A specific notification issued by a UE that belongs to that small cell is not transmitted to an external system via the core network, but is instead transmitted to the MEC server via the UPF node. The MEC server generates area information to be transmitted to UEs that belong to the small cell from that notification, and transmits it to one or more small base stations to which UEs that are to receive the area information are connected. This configuration not only enables necessary information to be transmitted quickly to UEs that are to receive the information, but also makes it possible to avoid wasteful use of radio resources.

[0075] Although specific embodiments have been described above, these embodiments are merely examples and are not intended to limit the scope of the present disclosure. The devices and methods described herein may be embodied in forms other than those described above. Furthermore, appropriate omissions, substitutions, and modifications may be made to the above-described embodiments without departing from the scope of the present disclosure. Such omissions, substitutions, and modifications are included within the scope of the claims and their equivalents, and belong to the technical scope of the present disclosure.

[0076] (Embodiments of the Present Disclosure) The present disclosure includes the following embodiments: [1] A communication method comprising: a decision process for deciding to transmit, by broadcast, a notification to user equipment located within a first macro cell covered by a first macro base station; a selection process for selecting one or more target small base stations from among a plurality of small base stations located within the first macro cell; and a transmission process for transmitting, by broadcast, a notification to user equipment connected to the one or more target small base stations via the one or more target small base stations.

[0077] [2] The communication method according to [1], further comprising a receiving process for receiving a specific notification from a user equipment via a first small base station that is one of the plurality of small base stations, and the determination process and the selection process are performed based on the specific notification.

[0078] [3] The communication method according to [2], wherein the reception processing includes forwarding the specific notification to an edge server that is not a destination of the specific notification by a UPF (User Plane Function) node in a core network that can communicate with the plurality of small base stations, and receiving the specific notification by the edge server.

[0079] [4] The communication method according to [2] or [3], wherein the selection process includes selecting, from the plurality of small base stations, one or more small base stations that are within a predetermined distance from the first small base station as the one or more target small base stations.

[0080] [5] The communication method according to any one of [1] to [4], wherein each of the plurality of small base stations covers a small cell in an area with a radius of several meters to several tens of meters.

[0081] [6] The communication method according to [2], further comprising: a detection process of detecting that a user equipment connected to a second macro base station has entered a first small cell covered by the first small base station; and a connection switching process of switching the connection of the detected user equipment from the second macro base station to the first small base station, wherein the first small base station and the first macro base station are operated by a first telecommunications carrier, and the second macro base station is operated by a second telecommunications carrier different from the first telecommunications carrier.

[0082] [7] The communication method described in [6], wherein the connection switching process includes switching the connection of the detected user equipment from the second macro base station to the first small base station when a predetermined condition is satisfied.

[0083] [8] The communication method described in [7], wherein the specified conditions include conditions relating to at least one of the time period of the detection, the traffic volume in the area including the first small cell, the attributes of the detected user equipment, and the movement speed of the detected user equipment.

[0084] [9] The communication method according to any one of [6] to [8], wherein the detection process and the connection switching process are performed by the first macro base station.

[0085]

[10] A communication system comprising one or more devices that perform a decision process for deciding to broadcast a notification to user equipment located within a first macro cell covered by a first macro base station, a selection process for selecting one or more target small base stations from among a plurality of small base stations located within the first macro cell, and a transmission process for broadcasting a notification to user equipment connected to the one or more target small base stations via the one or more target small base stations.

[0086] V1 to V7: vehicles, 10: macro base station, 11; 12; 13: small base station, 21 to 27: user equipment (UE), 100: macro cell, 101; 102; 103: small cell, 104: mobile communication network, 105: core network, 106: MEC system, 107: UPF node, 108: MEC server, 109: external system, 71: CPU, 72: ROM, 73: RAM, 74: HDD, 75: communication I / F, 81: transmitter, 82: receiver, 83: transmission method determination unit, 84: information generation unit, 85: base station selection unit, 91: transmitter, 92: receiver, 93: detection unit, 94: UE determination unit, 95: connection control unit

Claims

1. A communications method comprising: a decision process for deciding to broadcast a notification to user equipment located within a first macro cell covered by a first macro base station; a selection process for selecting one or more target small base stations from among a plurality of small base stations located within the first macro cell; and a transmission process for broadcasting a notification to user equipment connected to the one or more target small base stations via the one or more target small base stations.

2. The communication method according to claim 1, further comprising a receiving process of receiving a specific notification from the user equipment via a first small base station that is one of the plurality of small base stations, and the determination process and the selection process are performed based on the specific notification.

3. The communication method according to claim 2, wherein the reception processing includes: forwarding the specific notification to an edge server that is not a destination of the specific notification by a UPF (User Plane Function) node in a core network that can communicate with the plurality of small base stations; and receiving the specific notification by the edge server.

4. The communications method according to claim 2, wherein the selection process includes selecting, from among the plurality of small base stations, one or more small base stations that are within a predetermined distance from the first small base station as the one or more target small base stations.

5. The communication method according to claim 1, wherein each of the plurality of small base stations covers a small cell in an area with a radius of several meters to several tens of meters.

6. The communications method according to claim 2, further comprising: a detection process for detecting that a user equipment connected to a second macro base station has entered a first small cell covered by the first small base station; and a connection switching process for switching the connection of the detected user equipment from the second macro base station to the first small base station, wherein the first small base station and the first macro base station are operated by a first communications carrier, and the second macro base station is operated by a second communications carrier different from the first communications carrier.

7. The communication method according to claim 6, wherein the connection switching process includes switching the connection of the detected user equipment from the second macro base station to the first small base station when a predetermined condition is satisfied.

8. The communication method described in claim 7, wherein the predetermined conditions include conditions related to at least one of the time period of the detection, the traffic volume in the area including the first small cell, the attributes of the detected user equipment, and the movement speed of the detected user equipment.

9. The communication method according to claim 6, wherein the detection process and the connection switching process are performed by the first macro base station.

10. A communications system comprising one or more devices that perform the following: a decision process that decides to broadcast a notification to user equipment located within a first macro cell covered by a first macro base station; a selection process that selects one or more target small base stations from among a plurality of small base stations located within the first macro cell; and a transmission process that broadcasts a notification to user equipment connected to the one or more target small base stations via the one or more target small base stations.

Images