Server equipment, communication control method, terminal equipment, and base station

Abstract

This invention provides a server device, terminal device, base station, and their respective communication control methods for notifying safety-related warning messages between V2X (vehicle-to-vehicle) terminals located in different geographical areas that exceed the communication range of V2X communication. [Solution] In the V2X communication system 1, the server device 100 includes a communication unit that communicates with one or more terminal devices that operate as clients of the V2X application, and a server processing unit that operates as a server of the V2X application. The server processing unit sets each of the one or more terminal devices 200 to receive road safety warning messages via the side link 40, receives location information of the first terminal device via the communication unit, determines that the first terminal device is located within a first geographic area based on the location information, and instructs the first terminal device to relay warning messages received in the first geographic area via the side link.

Description

Technical Field

[0001] The present invention relates to a server device, a communication control method, a terminal device, and a base station.

Background Art

[0002] In the fourth-generation cellular communication technology, also called Long-Term Evolution (LTE) standardized by the Third Generation Partnership Project (3GPP), it is assumed that a sidelink, which is a direct wireless link between terminals, is used for Vehicle-to-Everything (V2X) communication (see Section 5.6 of Non-Patent Document 1). Non-Patent Document 2 explains that V2X can include the following four types of concepts: · V2V: Vehicle-to-Vehicle · V2I: Vehicle-to-Infrastructure · V2N: Vehicle-to-Network · V2P: Vehicle-to-Pedestrian

[0003] In the fifth-generation cellular communication technology, also called New Radio (NR), the radio access network (RAN) is supposed to support both the 4G V2X sidelink and the 5G NR sidelink (see Section 16.9 of Non-Patent Document 3). For example, a terminal (also referred to as a user equipment (UE)) that performs sidelink communication establishes a wireless link called a PC5 interface with a communication partner terminal, and performs V2X communication on a communication resource scheduled by the RAN or a communication resource autonomously selected from a pre-allocated resource pool. In the 4G V2X sidelink, only the broadcast of V2X messages is supported, whereas in the 5G NR sidelink, the broadcast, groupcast, and unicast of V2X messages are supported.

[0004] Patent Document 1 discloses a technique in which a V2X communication-capable terminal device mounted on a vehicle evaluates the safety on the road in real time and issues an alert to the user of the vehicle or other users when it is determined that there is some threat.

[0005] Non-patent document 4 discloses the results of a test that verified the communication range of V2V message exchange using 4G V2X sidelinks on actual roads. According to the test results, when a clear line of sight was maintained between vehicles, message exchange with good quality was possible at a maximum vehicle distance of 1000m, whereas when obstacles were present between vehicles, the maximum vehicle distance at which message exchange with good quality could be performed was 400m. [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] 3GPP TS36.300 v16.7.0, December 23, 2021 [Non-Patent Document 2] 3GPP TS22.185 v16.0.0, July 16, 2020 [Non-Patent Document 3] 3GPP TS38.300 v16.8.0, December 23, 2021 [Non-Patent Document 4] Qualcomm Technologies, Inc., "Cellular-V2X Technology Overview", [online], 2019, 80-PE732-63 Rev B, [Retrieved May 9, 2022], Internet,<URL:https: / / www.qualcomm.com / media / documents / files / c-v2x-technology-overview.pdf> [Patent Documents]

[0007] [Patent Document 1] U.S. Patent Application Publication No. 2020 / 0312142 [Overview of the project] [Problems that the invention aims to solve]

[0008] As disclosed in Patent Document 1, V2X terminals can notify each other of the presence of security threats, thereby improving user security. However, the limitations of the communication range of V2X communication are one constraint on improving security.

[0009] In light of the points mentioned above, this disclosure aims to provide a mechanism that can further improve the safety of users involved in road traffic. [Means for solving the problem]

[0010] According to this disclosure, A communication unit that communicates with one or more terminal devices acting as clients for a V2X (Vehicle-to-Everything) application, A server processing unit that operates as a server for the aforementioned V2X application, Equipped with, The server processing unit can access a database that shows the adjacency relationships between geographical areas for a plurality of geographical areas predefined for the V2X application. The first geographical area and the second geographical area are indicated as adjacent areas in the database, The server processing unit, Each of the one or more terminal devices is configured to receive road safety warning messages transmitted from other terminal devices via side links. The location information of the first terminal device is received via the communication unit. Based on the location information, it is determined that the first terminal device is located within the first geographical area. By instructing the first terminal device to relay the alarm message received in the first geographic area via the side link, a second terminal device located in the second geographic area is made able to receive the relayed alarm message. Server equipment will be provided. A corresponding communication control method, terminal device, and base station are also provided.

Advantages of the Invention

[0011] According to the present disclosure, the safety of users related to road traffic can be further improved.

Brief Description of the Drawings

[0012] [Figure 1] Reproduction of Figure 16.9.1-1 of 3GPP TS38.300 v16.8.0. [Figure 2] Reproduction of Figure 6.2-2 of 3GPP TS23.286 v17.3.0. [Figure 3] Schematic diagram showing an example of the configuration of a V2X communication system according to an embodiment. [Figure 4] Block diagram showing an example of the configuration of a server device according to an embodiment. [Figure 5] Explanatory diagram for explaining an example of the definition of a geographical area according to an embodiment. [Figure 6A] Explanatory diagram showing a first example of a message format for relay indication. [Figure 6B] Explanatory diagram showing a second example of a message format for relay indication. [Figure 6C] Explanatory diagram showing a third example of a message format for relay indication. [Figure 6D] Explanatory diagram showing a fourth example of a message format for relay indication. [Figure 7] Block diagram showing an example of the configuration of a UE according to an embodiment. [Figure 8] Block diagram showing an example of the configuration of a base station according to an embodiment. [Figure 9] Sequence diagram showing an example of the processing flow according to the first embodiment. [Figure 10] Sequence diagram showing an example of the processing flow according to the second embodiment.

Modes for Carrying Out the Invention

[0013] The embodiments will be described in detail below with reference to the attached drawings. Note that the following embodiments do not limit the invention as defined in the claims, and not all combinations of features described in the embodiments are essential to the invention. Two or more features from the multiple features described in the embodiments may be combined arbitrarily. Furthermore, identical or similar configurations will be given the same reference numeral, and redundant descriptions will be omitted.

[0014] <1. Basic System Architecture for V2X Services> Figure 1 is a reproduction of Figure 16.9.1-1 from 3GPP TS38.300 v16.8.0 and shows an example of the NG-RAN architecture of a 5G system. A gNB is a 5G base station connected to the 5G core network (not shown). An ng-eNB is a 4G base station connected to the 5G core network. The gNB and ng-eNB are connected to each other via the Xn interface. User equipment (UE) is terminal equipment serviced by the gNB or ng-eNB. The radio link for sending and receiving user data between the UE and the gNB or ng-eNB is called the Uu interface. The PC5 interface is a communication link established between two UEs. Such direct communication links between UEs that do not pass through a base station are also called sidelinks. NG (Next Generation)-RAN (Radio Access Network) supports these PC5 interfaces. A PC5 interface can be identified by a pair of Layer 2 IDs: a Source Layer-2 ID assigned to the transmitting UE and a Destination Layer-2 ID assigned to the receiving UE. Resources used for communication are either scheduled by the base station (scheduled resource allocation) or autonomously selected by the UE from a pre-configured resource pool (autonomous resource selection). In 5G systems, such PC5 interfaces can be utilized for V2X services.

[0015] Figure 2 is a replica of Figure 6.2-2 from 3GPP TS23.286 v17.3.0 and shows a layered functional model of a V2X application. In the functional model of Figure 2, the UE acts as a client (V2X UE) of the V2X application. On the other hand, the server of the V2X application is typically deployed on an IP (Internet Protocol) network and communicates with one or more V2X UEs via a 3GPP network system consisting of a RAN and a core network. A V2X UE located inside the NG-RAN coverage (V2X UE1 in Figure 2) can communicate with a V2X UE located outside the coverage (V2X UE2 in Figure 2) via a sidelink.

[0016] The functional model in Figure 2 has a hierarchical structure consisting of, from top to bottom in the figure, a V2X application-specific layer, a V2X application enabler (VAE) layer, and a service enabler architecture layer (SEAL).

[0017] SEAL is a layer that provides basic services common to various applications, including V2X and other types of applications. Services related to V2X applications provided in SEAL include, for example, location management, group management, configuration management, identity management, key management, and network resource management. A V2X UE includes a SEAL client, and a V2X application server includes a SEAL server. SEAL-PC5 is the interface between V2X UEs in SEAL. SEAL-UU is the interface between V2X UEs and V2X application servers in SEAL. Detailed information on the functions of SEAL clients and SEAL servers is described in 3GPP TS23.434 v17.5.0.

[0018] The VAE layer is a layer that supports the V2X application-specific layer by interpreting the services provided by SEAL for use in V2X applications. A V2X UE includes a VAE client, and a V2X application server includes a VAE server. Functions provided by the VAE client may include, for example, registering the VAE client with the VAE server for receiving V2X messages, providing application-level location information to the VAE server, receiving communication configuration information from the VAE server, and supporting dynamic group management. Functions provided by the VAE server may include, for example, accepting registration of VAE clients, tracking the location of application-level V2X UEs, providing communication configuration information, and supporting the delivery of V2X messages. V5-AE is the interface between V2X UEs in the VAE layer. V1-AE is the interface between V2X UEs and V2X application servers in the VAE layer.

[0019] The V2X application-specific layer is a layer that, with support from the VAE layer, provides functionality specific to individual V2X applications. The V2X UE includes V2X application-specific clients, and the V2X application server includes V2X application-specific servers. The V5-APP is the interface between V2X UEs in the V2X application-specific layer. The V1-APP is the interface between the V2X UE and the V2X application server in the V2X application-specific layer.

[0020] The functions of the V2X UE and V2X application server that may have such a hierarchical structure in the embodiments of the technology described herein will be described in detail later.

[0021] As can be seen from Figure 2, V2X communication is treated at the application level as end-to-end communication between the V2X UE and the V2X application server, and the contents of the V2X communication are transparent to base stations and other network nodes along the communication path.

[0022] Section 7 of 3GPP TS23.286 v17.3.0 describes various deployment models for V2X application-specific servers and VAE servers. The V2X application-specific servers and VAE servers may be co-located in a single physical device or they may be located in separate devices. Each of these servers may belong to either the V2X service provider's domain or the network operator's domain.

[0023] <2. Embodiments of V2X Communication Systems> <2-1. System Overview> Figure 3 is a schematic diagram showing an example of the configuration of a V2X communication system 1 according to one embodiment. Referring to Figure 3, the V2X communication system 1 includes a server device 100, UEs 200a, 200b, 200c, 200d, and base stations 300a, 300b.

[0024] In the following explanation, when it is not necessary to distinguish between UE200a, 200b, 200c, and 200d, the alphabet at the end of the code will be omitted, and they will be collectively referred to as UE200. The same applies to base stations 300a, 300b (base station 300), and other components.

[0025] The server device 100 is a V2X application server that provides V2X services aimed at improving safety on roads. The server device 100 is connected to multiple base stations, including base stations 300a and 300b, via the network 10. The network 10 may be, for example, a 5G core network, or a combination of a 5G core network and an IP network.

[0026] UE200 is a terminal device that utilizes the V2X service provided by the server device 100. In the example in Figure 3, UE200a is an in-vehicle terminal mounted on vehicle 20a, UE200c is an in-vehicle terminal mounted on vehicle 20c, and UE200d is an in-vehicle terminal mounted on vehicle 20d. UE200b is a pedestrian terminal carried by pedestrian 21b. For example, UE200a located within cell 30a can establish a wireless link with base station 300a to receive downlink data from base station 300a and transmit uplink data to base station 300a. In addition, with the support of base station 300a (e.g., resource scheduling or pre-allocation of resource pools), UE200a can communicate with other nearby V2X UEs via sidelinks. For example, Figure 3 shows sidelink 40b between UE200a and UE200b and sidelink 40c between UE200a and UE200c. Naturally, UE200 units other than the UE200a can also communicate with nearby V2X UEs via sidelinks.

[0027] The base station 300 may be, for example, a gNB or an ng-eNB, and relays communication between the UE200 and the server device 100. In the example in Figure 3, base station 300a serves the UE200 in cell 30a, and base station 300b serves the UE200 in a different cell from cell 30a. Broadcasting of information from base station 300 to multiple UE200s in a cell takes place over the physical broadcast channel (PBCH). Transmission of downlink data from base station 300 to a specific UE200 takes place over the physical downlink shared channel (PDSCH). Transmission of uplink data from a specific UE200 to base station 300 takes place over the physical uplink shared channel (PUSCH). Control signaling to control these data transmissions (e.g., downlink allocation, scheduling requests, uplink permission, and retransmission control) takes place over various control channels, including the physical downlink control channel (PDCCH) and the physical uplink control channel (PUCCH).

[0028] In this embodiment, at least some UE200s are capable of transmitting a warning message on the sidelink when a road safety threat is detected. The UE200s may detect safety threats using any known method. For example, a UE200 mounted on a vehicle may recognize one or more of the following as threats: • The speed or acceleration of your vehicle or another vehicle exceeds the standard value. • Deviation of one's own vehicle / other vehicles from the correct lane • Physiological abnormalities of the driver of the vehicle • Detection of alcohol components from the driver's breath • Detection of contact or collision • Abnormal driving conditions (e.g., presence of fallen objects, decrease in road surface temperature) When a UE200 detects such a security threat, it sends an alarm message, for example, over a sidelink shared channel (SL-SCH). The alarm message may include type information indicating the type of threat detected. The server device 100 configures each UE200 to receive alarm messages sent from other UE200s via sidelinks. When a UE200 receives an alarm message, it alerts the user via the user interface, allowing the user to recognize the threat early and take appropriate action to ensure security.

[0029] However, only UE200 units located within the communication range of the sidelink can receive the warning messages transmitted on the sidelink. According to the results of verification experiments disclosed in Non-Patent Literature 4, the radius of the sidelink communication range is a maximum of 1000m when a line of sight is available, and a maximum of 400m when there are obstacles between the vehicles. For example, in the situation shown in Figure 3, suppose the UE200c of vehicle 20c detects that vehicle 20d is traveling at a speed exceeding a standard value and transmits a warning message. The UE200a of vehicle 20a receives this warning message via the sidelink 40c. On the other hand, UE200b cannot receive the warning message transmitted by UE200c because it is far away from UE200c or because there are obstacles between UE200b and UE200c. Therefore, UE200b does not warn the user, pedestrian 21b, about the threat posed by vehicle 20d, leaving pedestrian 21b at risk. In this embodiment, in order to eliminate or mitigate these inconveniences, the V2X communication system 1 incorporates a mechanism that substantially extends the reach of alarm messages by having the UE200 that receives the alarm message relay the received message.

[0030] <2-2. Example of Server Device Configuration> Figure 4 is a block diagram showing an example of the configuration of the server device 100 according to this embodiment. Referring to Figure 4, the server device 100 includes a communication interface (I / F) 101, memory 102, database 110, and server processing unit 150.

[0031] The communication interface 101 is a communication unit for the server device 100 to communicate with one or more UE200s that act as clients of a V2X application. The communication interface 101 is connected to the network 10 and can communicate with UE200s connected to the base station 300 via one or more network nodes and base stations 300 within the network 10.

[0032] Memory 102 may include any combination of non-volatile storage media such as ROM (Read Only Memory) and volatile storage media such as RAM (Random Access Memory). For example, ROM pre-stores computer programs for several server modules, which will be described later. RAM provides a temporary storage area for calculations performed by the server processing unit 150.

[0033] Database 110 is a database that stores various data required for the server device 100 to provide V2X applications. In this embodiment, database 110 includes area definition data 120, risk level data 130, and UE location data 140. Although this example describes a server device 100 that includes database 110, database 110 may be implemented on a separate device (e.g., a database server or cloud server) from the server device 100, as long as it is accessible by the server processing unit 150.

[0034] Area definition data 120 is data that indicates the definition of multiple geographic areas for a V2X application provided by the server device 100. For example, area definition data 120 may include the following four data items for each geographic area: • "Area ID" • "Area Definition" • "Related base stations" • "Adjacent area" "Area ID" is an identifier that uniquely identifies each geographic area. "Area Definition" is a set of parameters that define the geographical location and shape of each geographic area. For example, for a polygonal geographic area, the "Area Definition" indicates a set of coordinate values ​​(e.g., latitude and longitude) for N vertices (where N is an integer greater than or equal to 3). For a circular geographic area, the "Area Definition" indicates the coordinate value of the center point and the radius. "Associated Base Station" indicates at least one address (or other identifying information) for communication with the base station serving each geographic area. "Adjacent Area" is data that indicates the adjacency relationship between geographic areas. For example, if the first geographic area is adjacent to the second and third geographic areas, the "Adjacent Area" in the record for the first geographic area may indicate a list of area IDs for the second and third geographic areas.

[0035] Figure 5 is an explanatory diagram illustrating an example of a geographic area definition. Referring to Figure 5, the boundaries of four geographic areas 121-1, 121-2, 121-3, and 121-4 are shown as dashed lines superimposed on a road map of the area where base station 300a is installed. Here, the shape of these geographic areas is roughly rectangular. Geographic areas 121-2, 121-3, and 121-4 are adjacent areas to geographic area 121-1. Therefore, in this case, the area definition data 120 may include a record that associates the respective area IDs of geographic areas 121-2, 121-3, and 121-4 as "adjacent areas" with the "area ID" that identifies geographic area 121-1. Two adjacent geographic areas may partially overlap. Figure 5 also shows the boundaries of cell 30a of base station 300a. Geographic areas are typically defined considering the purpose of the V2X application, independently of cell coverage. For example, in this embodiment, a region may be divided into multiple geographical areas based on differences in the characteristics of the wireless communication environment (e.g., density of obstacles such as buildings, noise level, etc.), road characteristics (e.g., speed limit, number of lanes, etc.), or traffic trends (e.g., amount of pedestrians, frequency of congestion, etc.).

[0036] Risk data 130 is data indicating the risk level determined for each of the multiple geographic areas defined by area definition data 120. Risk data 130 may include, for example, the following three data items: • "Management Area" • "Danger level" ·"Last updated" The "Management Area" identifies each geographic area subject to risk management using the "Area ID" registered in the area definition data 120. The "Risk Level" is a parameter indicating the risk level determined for the geographic area identified by the "Management Area". In this embodiment, the "Risk Level" is evaluated in three stages, representing one of the following values: "Low" (meaning the lowest risk), "Medium" (meaning a moderate risk), or "High" (meaning the highest risk). In other embodiments, the "Risk Level" may be evaluated in two or four or more stages. The "Last Updated" indicates the date and time when the "Risk Level" value for each geographic area was last updated.

[0037] UE location data 140 is data for managing the location of V2X UEs that utilize V2X applications provided by the server device 100. UE location data 140 may include, for example, the following four data items: • "UE ID" • "Location" • "Area of ​​Stay" ·“Final report” "UE ID" is an identifier that uniquely identifies each V2X UE. "Location" indicates the last location reported by each V2X UE. "Area of ​​Stay" identifies the geographic area corresponding to the last location reported by each V2X UE using the "Area ID" registered in the area definition data 120. "Last Report" indicates the date and time when the location was last reported by each V2X UE.

[0038] Note that the configuration of database 110 is not limited to the configuration described herein. Database 110 may store additional data, and some of the data items mentioned above may be omitted. For example, database 110 may store user IDs and authentication information (e.g., passwords or authentication keys) for authenticating users who use the V2X application provided by server device 100.

[0039] The server processing unit 150 is a functional module that operates as a server for a V2X application. The functions of the server processing unit 150 can be realized by one or more processors (e.g., a CPU (Central Processing Unit)) executing a computer program stored in memory 102. As shown in Figure 4, the server processing unit 150 consists of three server modules: a V2X application-specific server, a VAE server, and a SEAL server. The division of functions among these server modules may be as explained using Figure 2.

[0040] When the UE200, which acts as a client for the V2X application, connects to the base station 300, the server processing unit 150 performs authentication procedures as necessary, and then sets up a communication link (V1-APP / V1-AE / SEAL-UU) for V2X communication with the UE200.

[0041] Furthermore, the server processing unit 150 configures each UE200 to receive road safety warning messages transmitted from other V2X UEs via the sidelink. For example, if a warning message is broadcast on the PC5 interface, the server processing unit 150 configures the UE200 to monitor the sidelink resource for messages with a destination Layer 2 ID for broadcast reception. If a warning message is groupcast on the PC5 interface, the server processing unit 150 assigns a group ID for receiving warning messages to the UE200 and configures the UE200 to monitor the sidelink resource for messages with a destination Layer 2 ID corresponding to that group ID. The group ID may be different for each geographic area, may be common across multiple geographic areas, or may be common across the entire system. Warning messages may be sent by unicast, but broadcast or groupcast is more advantageous than unicast, which requires the establishment of individual PC5 interfaces, in terms of rapid transmission of warning messages.

[0042] Furthermore, the server processing unit 150 manages the risk level of each geographic area indicated by the risk level data 130. For example, the initial value of the "risk level" in the risk level data 130 is predetermined based on static conditions such as the characteristics of the wireless communication environment and road characteristics in the corresponding geographic area. The server processing unit 150 may update the "risk level" value based on temporal conditions that may include season or time of day, or sunlight conditions (for example, increasing the risk level by one level during the evening hours when visibility deteriorates). In addition, in this embodiment, the server processing unit 150 updates the "risk level" value of the risk level data 130 based on V2X messages received via the communication I / F 101 from one or more terminal devices. Each of the terminal devices here may be the UE200 described with reference to Figure 3, or other types of terminal devices (for example, roadside units with sensors or cameras). For example, if the server processing unit 150 determines, based on a V2X message received from a terminal device, that the following event is occurring in a certain geographical area, it may temporarily increase the "risk level" value of that geographical area until it is determined that the event has been resolved: • Presence of a vehicle that meets the threat detection conditions described above. • Stopping vehicles on the road ·traffic jam • Abnormal driving conditions

[0043] Furthermore, the server processing unit 150 also tracks the location of the connected UE200. Specifically, the server processing unit 150 periodically receives location information of the connected UE200 via the communication I / F 101. Based on the received location information, the server processing unit 150 determines which geographic area the UE200 is located in and updates the "Location," "Area of ​​Stay," and "Final Report" in the corresponding record of the UE location data 140. The location information may also indicate the geographic coordinates obtained as a result of positioning in the UE200 as the location of the UE200. In this case, the server processing unit 150 can determine which geographic area the geographic location indicated by the location information belongs to based on the "Area Definition" in the area definition data 120. If the size of the geographic area is equal to or greater than the size of the cell serviced by the base station 300, the location information may indicate the cell ID of the cell to which the UE200 is connected as the location. In this case, the server processing unit 150 can determine which geographic area the cell to which the UE200 is connected belongs, based on a known mapping between the cell ID indicated by the location information and the area ID of the corresponding geographic area.

[0044] In this embodiment, when the area definition data 120 indicates that the first and second geographic areas are adjacent areas, the server processing unit 150 instructs the UE 200 located in the first geographic area to relay the received alarm message via a side link so that the alarm message transmitted in the first geographic area can also be received in the second geographic area.

[0045] In the first embodiment, relay instructions are given by sending a control message to the UE200 via the communication I / F101 instructing it to relay alarm messages received in the first geographic area via a sidelink, in response to a determination that the UE200 is located within the first geographic area. That is, in the first embodiment, relay instructions are given at the application level. The server processing unit 150 may also send the control message to the UE200 if it is determined that the UE200 is located within the first geographic area and also within or near the second geographic area. When the UE200 that receives such a control message relays the alarm message, the range of the alarm message is substantially expanded, and other UE200s located within the second geographic area adjacent to the first geographic area can receive the relayed alarm message.

[0046] In the second embodiment, the server processing unit 150, when the first and second geographic areas are adjacent areas, sends a request message to the base station 300 serving the first geographic area via the communication I / F 101, requesting that control information be broadcast indicating that a V2X UE located within the first geographic area and within or near the second geographic area should relay the alarm message. That is, in the second embodiment, the relay instruction is made at the radio link level, not at the application level. Upon receiving this request message from the server device 100, the base station 300 broadcasts the control information for instructing the relay of the alarm message, for example, by including it in a system information block (SIB) on the PBCH.

[0047] The server processing unit 150 may determine that if the risk level of the second geographic area indicated by the risk level data 130 meets a predetermined criterion, then alarm messages received in the adjacent first geographic area should also be receivable in the second geographic area. The predetermined criterion here may include the risk level being above a predetermined threshold (for example, "high," or "high" or "medium"). For example, among the three adjacent areas 121-2, 121-3, and 121-4 adjacent to geographic area 121-1 shown in Figure 5, the risk level of adjacent area 121-4 is "high" (for example, due to the lack of a separate sidewalk next to the roadway), while the risk levels of adjacent areas 121-2 and 121-3 are "low." In this case, the server processing unit 150 instructs the relay of alarm messages only to UE200s located within geographic area 121-1 whose location is within or near adjacent area 121-4. This relay control makes it possible to selectively extend the range of alarm messages in a specific direction.

[0048] The server processing unit 150 may determine that alarm messages received in the first geographic area should also be receivable in the second geographic area if the risk level of the first geographic area, as well as the risk level of the second geographic area, meets the predetermined criteria. For example, suppose that among the four geographic areas shown in Figure 5, geographic areas 121-1 and 121-4 have a "high" risk level, while geographic areas 121-2 and 121-3 have a "low" risk level. In this case, the server processing unit 150 instructs UE200 located near the boundary between geographic area 121-1 and geographic area 121-4 to relay alarm messages, while not instructing UE200 located near the boundary between geographic area 121-1 and geographic area 121-2 or 121-3 to relay alarm messages. This relay control makes it possible to selectively extend the reach of alarm messages generated in areas with relatively high risk levels.

[0049] Figure 6A shows a first example of the format of a control message sent to a UE200 for relay instructions. In the first example, format 160a includes a V2X UE ID 161, a dwelling area 162, and a relay flag 163. The V2X UE ID 161 is a UE ID that identifies the UE200 to which the control message is destined. The dwelling area 162 is an area ID that identifies the geographical area where the UE200 identified by the V2X UE ID 161 is determined to be located. The relay flag 163 is a control parameter that indicates whether the UE200 identified by the V2X UE ID 161 should relay the alarm message. For example, a value of "0" for the relay flag 163 indicates that the UE200 receiving this control message should not relay the alarm message, and a value of "1" for the relay flag 163 indicates that the UE200 receiving this control message should relay the alarm message.

[0050] Figure 6B shows a second example of the format of a control message sent to the UE200 for relay instructions. In the second example, format 160b includes the V2X UE ID 161 and the relay flag 163.

[0051] Figure 6C shows a third example of the format of a control message sent to the UE200 for relay instructions. In the third example, format 160c includes the V2X UE ID 161, the dwelling area 162, and the adjacent area 164. The adjacent area 164 indicates one or more geographic areas adjacent to the geographic area identified by the dwelling area 162 that are near the location of the UE200 identified by the V2X UE ID 161. Since format 160c does not indicate whether the UE200 that receives this control message should relay the alarm message, it can be used in combination with format 160d, which is described below.

[0052] Figure 6D shows a fourth example of the format of a control message sent to the UE200 for relay instructions. In the fourth example, format 160d includes area number 165 and K pairs of area IDs 166-k and relay area lists 167-k (k=1,2,...,K). Area number 165 indicates the number K of area ID-relay area list pairs included in the control message. Area ID 166-k indicates an area ID that identifies the k-th geographical area. Relay area list 167-k indicates a list of area IDs that identify the geographical areas to which alarm messages from the k-th geographical area should be relayed. Upon receiving control messages in both formats 160c and 160d, the UE200 looks up the area ID indicated by the dwelling area 162 of the former control message in the K area IDs 166-k of the latter control message. If the relay area list 167-k paired with the discovered area ID 166-k contains the area ID indicated by the adjacent area 164 of the former control message, the UE200 can recognize that relaying of the alarm message is instructed.

[0053] In the first embodiment described above, the control message that the server processing unit 150 can send to the UE200 may be one of the following options: Message A (Format 160a) Message B (Format 160b) • Message C (format 160c) and Message D (format 160d) Messages A, B, or C may be sent each time the UE200's location changes. Message D, on the other hand, does not need to be sent again to the same UE200 once it has been sent, unless the risk level of one or more geographic areas changes. Each message may, of course, include additional control parameters not shown. If the UE200 can autonomously determine its current geographic area and its adjacent areas based on its location (for example, by referring to pre-downloaded area definitions), only message D (format 160d) may be sent to the UE200.

[0054] In the second embodiment described above, the control information that the UE200 may receive may be one of the following options: • System information broadcast from the base station (format 160d) and message C received from the server device 100 (format 160c) • System information broadcast from the base station (format 160d) The second option may be adopted if the UE200 can autonomously determine the geographical area in which it is currently located and its adjacent areas based on its own location. Broadcasting system information from the base station can be done, for example, by including the system information in a system information block provided for controlling V2X communication.

[0055] In the first embodiment, if multiple UE200s are located near the boundary between the first and second geographical areas, the server processing unit 150 may instruct only some of those multiple UE200s to relay the alarm message. The server processing unit 150 may decide which UE200 should relay the alarm message by considering one or more of the capabilities, location, processing performance, and remaining power of each UE200. For example, by instructing only the UE200 with the highest processing performance among the UE200s located close to each other to relay the message, the range of the alarm message can be effectively extended while avoiding message collisions caused by multiple UE200s relaying the alarm message.

[0056] <2-3. Example of terminal device configuration> Figure 7 is a block diagram showing an example of the configuration of the UE200 according to this embodiment. Referring to Figure 7, the UE200 includes a wireless I / F 201, memory 202, storage 203, sensor group 204, camera 205, positioning module 206, input device 207, output device 208, power supply 209, and control unit 210.

[0057] The wireless interface 201 is the wireless communication unit for the UE 200 to perform wireless communication. In this embodiment, the wireless interface 201 can communicate via a wireless link established with the base station 300, and can also communicate with other V2X UEs via a side link.

[0058] Memory 202 may include any combination of non-volatile storage media such as ROM and volatile storage media such as RAM. For example, ROM pre-stores computer programs for several client modules that operate in the control unit 210. RAM provides a temporary storage area for calculations performed by the control unit 210.

[0059] Storage 203 is a storage device for storing large amounts of data. Storage 203 may be, for example, an HDD (Hard Disk Drive) or an SSD (Solid State Drive).

[0060] Sensor group 204 is a collection of various sensors mounted on the UE200. If the UE200 is a pedestrian terminal, sensor group 204 may include an accelerometer, a gyroscope, and a compass sensor. If the UE200 is an in-vehicle terminal, sensor group 204 may include, in addition to the sensors mentioned above, further sensors such as a distance measuring sensor (e.g., LiDAR or millimeter-wave radar) and a biometric information sensor.

[0061] Camera 205 is an imaging module capable of capturing images of the surroundings of UE200. Sensor group 204 and camera 205 may be used to detect road safety threats in accordance with the threat detection conditions described above.

[0062] The positioning module 206 is a module for measuring the position of the UE200. The positioning module 206 may be capable of obtaining the latitude, longitude, and altitude of the UE200's current position using a GNSS (Global Navigation Satellite System), such as GPS (Global Positioning System). Alternatively or additionally, the positioning module 206 may be capable of estimating the UE200's current position based on the known absolute position of the connected base station and its relative position from said base station.

[0063] The input device 207 is a device for the UE200 to receive instructions and information input from the user. The input device 207 includes, for example, one or more of the following: a touch sensor, a button, a switch, a keypad, and a microphone.

[0064] Output device 208 is a device that the UE200 uses to output information or signals to the user. Output device 208 includes, for example, one or more of the following: a display, a speaker, a light, and a vibrator.

[0065] Power supply 209 is a rechargeable battery that supplies power to various parts of UE200 via power lines partially shown in the diagram. The power supply from power supply 209 is controlled by control unit 210.

[0066] The control unit 210 includes one or more processors and controls the overall functions of the UE200 by executing computer programs stored in memory 202. For example, the control unit 210 functions as a client processing unit 220 that acts as a client for a V2X application. The client processing unit 220 consists of three client modules: a V2X application-specific client, a VAE client, and a SEAL client. The division of functions among these client modules may be as explained using Figure 2. The control unit 210 may also have various other functions that a typical pedestrian terminal or in-vehicle terminal has, but for the sake of simplicity, the functions of the client processing unit 220 will be described here.

[0067] The client processing unit 220 connects to the server device, which operates as a server for the V2X application, via a radio link between the radio interface 201 and the base station 300. The client processing unit 220 sets up the radio interface 201 to receive road safety warning messages transmitted from other V2X UEs via the sidelink, according to settings signaled by the server processing unit 150 of the server device 100. For example, the radio interface 201 monitors messages with a destination Layer 2 ID for warning messages on the sidelink resource and receives such warning messages when they are transmitted from nearby V2X UEs. When the client processing unit 220 receives a warning message via the sidelink, it alerts the user via the user interface of the UE 200 so that the user can take appropriate action to ensure their safety. For example, the alert may be displayed as warning text or an icon on the display of the output device 208, output as a warning sound or voice from a speaker, or sounded by a vibrator.

[0068] The client processing unit 220 may detect security threats based on sensor data input from the sensor group 204 or video data input from the camera 205, in accordance with one or more of the threat detection conditions described above. When the client processing unit 220 detects a security threat, it issues an alert to the user and causes the wireless I / F 201 to transmit an alert message over the sidelink communication resource. As described above, the alert message may be transmitted by broadcast, groupcast, or unicast. Not all UE200 client processing units 220s necessarily have the function to transmit alert messages.

[0069] The client processing unit 220 periodically reports location information to the server device 100, indicating the latest location of the UE 200 acquired by the positioning module 206. A V2X message for reporting location information is transmitted to the server device 100 via the wireless I / F 201 and the connected base station 300. As described above, the server processing unit 150 of the server device 100 determines which geographic area the UE 200 is located in in response to this location information report. The V2X message transmitted to the server device 100 may also include information for updating the risk level for each geographic area managed by the server processing unit 150. For example, the client processing unit 220 may transmit sensor data input from the sensor group 204 to the server device 100. The client processing unit 220 may also notify the server device 100 that a safety threat has been detected according to any of the threat detection conditions. Furthermore, the client processing unit 220 may perform more advanced processing, such as determining whether a parked vehicle is present, whether there is congestion, or whether there is an abnormality in the driving environment, and notify the server device 100 of the determination results.

[0070] In this embodiment, the client processing unit 220 receives instructions from the server device 100, either directly at the application level or indirectly at the wireless link level, regarding the relaying of alarm messages received from other V2X UEs via sidelinks.

[0071] For example, suppose the location information of the UE200 reported to the server device 100 indicates a location within a first geographic area and within or near an adjacent second geographic area. In this case, the client processing unit 220 may receive an instruction to relay alarm messages received from other V2X UEs via a sidelink. Alternatively, such an instruction may be received when the risk data 130 indicates that the risk level of the second geographic area (or the risk level of both the first and second geographic areas) is high. When the client processing unit 220 receives an instruction to relay alarm messages, it relays alarm messages received from other V2X UEs in the first geographic area to the wireless I / F 201 via a sidelink. This makes it possible for a V2X UE located in the second geographic area adjacent to the first geographic area to receive the relayed alarm message.

[0072] In the first embodiment, instructions regarding the relaying of alarm messages are included in a control message received from the server device 100 via the wireless link of the wireless I / F 201 as a response to the transmission of location information. For example, if it is determined that the UE 200 is located in a location where relaying of alarm messages is required, the control message includes a control parameter (e.g., a relay flag 163 indicating a value of "1") that instructs the relaying of alarm messages. On the other hand, if it is determined that the UE 200 is located in a location where relaying of alarm messages is not required, the control parameter includes a control parameter (e.g., a relay flag 163 indicating a value of "0") that indicates that the alarm messages do not need to be relayed.

[0073] In the second embodiment, instructions regarding the relaying of alarm messages are included in control information broadcast from the base station 300 serving the geographic area where the UE200 is located and received by the radio I / F 201. For example, if relaying of alarm messages is required near the boundary between the first geographic area and the second geographic area, the control information broadcast from the base station 300 includes an association between the area IDs of the first and second geographic areas (e.g., a combination of area ID 166-k and relay area list 167-k). The client processing unit 220 may, for example, monitor a system information block for controlling V2X communication (e.g., SIB 13 or SIB 14) periodically broadcast from the base station 300 to obtain control information including such instructions regarding the relaying of alarm messages. The client processing unit 220 may receive a control message from the server device 100 that includes the area ID of the geographic area where the UE200 is located, or it may autonomously determine which geographic area the UE200 is located in.

[0074] In the first and second embodiments, the control messages or control information that the UE200 can receive may have the format described above with reference to Figures 6A to 6D.

[0075] In this embodiment, the alarm messages transmitted and received via the sidelink may include a control parameter for distinguishing between the original alarm message sent by the V2X UE that detected the threat and an alarm message that has been relayed at least once. This control parameter may be, for example, a flag that shows different values ​​for the original alarm message and the relayed alarm message, or a counter that shows the number of times it has been relayed. The client processing unit 220 may refrain from relaying an alarm message that indicates this control parameter has been relayed at least once, regardless of instructions from the server device 100. This prevents message congestion or excessive expansion of the reach range caused by relaying alarm messages across multiple hops.

[0076] <2-4. Example of base station configuration> Figure 8 is a block diagram showing an example of the configuration of a base station 300 according to this embodiment. Referring to Figure 8, the base station 300 includes a wireless I / F 301, a network I / F 302, a memory 303, a storage 304, and a communication control unit 310.

[0077] The radio interface 301 is a radio communication unit for the base station 300 to provide radio access to one or more UEs 200 within cell 30. For example, if the coverage of cell 30 of the base station 300 includes a first geographic area, the base station 300 can radio communicate with at least one UE 200 located within the first geographic area via the radio interface 301.

[0078] The network interface 302 is a network communication unit for the base station 300 to communicate with network nodes in the network 10 and other devices connected to the network 10. For example, the base station 300 can communicate with the server device 100 via the network interface 302.

[0079] Memory 303 may include any combination of non-volatile storage media such as ROM and volatile storage media such as RAM. For example, ROM pre-stores computer programs executed by the communication control unit 310. RAM provides a temporary storage area for calculations performed by the communication control unit 310. Storage 304 is a storage device for storing large amounts of data. Storage 304 may be, for example, an HDD or an SSD.

[0080] The communication control unit 310 includes one or more processors and controls wireless communication via the wireless interface 301 and network communication via the network interface 302 by executing computer programs stored in the memory 303. For example, when the communication control unit 310 receives a connection request from the UE200 via the wireless interface 301, it establishes a wireless link between the UE200 and the wireless interface 301. The communication control unit 310 also mediates application-level communication between the UE200 and the server device 100 when the UE200 uses a V2X application provided by the server device 100. Furthermore, the communication control unit 310 schedules sidelink resources or allocates a resource pool for sidelinks for the UE200, which is a V2X UE. This enables the UE200 to communicate wirelessly via the wireless link to the base station 300 and sidelinks to other V2X UEs.

[0081] In one embodiment, the communication control unit 310 is involved in controlling the relaying of alarm messages by the UE 200. For example, if the server device 100 determines that the first geographic area and the second geographic area are adjacent areas and that the risk level of the second geographic area (or both the risk levels of the first and second geographic areas) meets a predetermined standard, it sends a request message to the base station 300 requesting the broadcast of control information indicating that the UE 200 located near the boundary between these two geographic areas should relay alarm messages received from other V2X UEs via a sidelink. When the communication control unit 310 receives this request message via the network I / F 302, it causes the wireless I / F 301 to broadcast control information indicating that the UE 200 located near the boundary should relay alarm messages via a sidelink. The format of the broadcasted control information may be the format described above in relation to the second embodiment. The wireless I / F 301 may broadcast the control information in a system information block for controlling V2X communication. In this case, terminal devices not involved in V2X communication can ignore the system information block.

[0082] <3. Processing Flow> This section will explain an example of the processing flow that can be executed in the V2X communication system 1 described above, using the sequence diagrams in Figures 9 and 10. In the following explanation, a processing step will be abbreviated as S (step).

[0083] <3-1. First Example> Figure 9 is a sequence diagram showing an example of the processing flow according to the first embodiment. The illustrated processing mainly involves the server device 100, UE200a, UE200b, UE200c, and base station 300. However, several V2X UEs other than UE200a to 200c also exchange V2X messages with the server device 100.

[0084] First, in S11, the server device 100 receives V2X messages from multiple V2X UEs. Each received V2X message may contain arbitrary information, such as the speed or acceleration of a moving vehicle, its position on the road, the driver's physiological parameters, or the state of the driving environment. In S13, the server processing unit 150 of the server device 100 updates the risk level of each geographic area indicated by the risk level data 130 based on the received V2X messages. Such updates may be performed periodically or intermittently while the server device 100 is operating.

[0085] Next, when the UE200a enters coverage of cell 30 served by the base station 300, a radio link is established between the UE200a and the base station 300 in S15. Then, in S17, the communication control unit 310 of the base station 300 schedules sidelink resources or allocates a resource pool for sidelinks for the UE200a, which is a V2X UE.

[0086] Next, in S21, the UE200a's client processing unit 220 accesses the server device 100 using, for example, the URL of the server device 100 pre-stored in memory 202, and participates in the V2X service provided by the server device 100. In S23, the server processing unit 150 of the server device 100 registers the UE200a as a connected client (if authentication of the UE200a is successful). Then, in S25, the server processing unit 150 sets up a communication link with the UE200a. For example, the UE200a's client processing unit 220 sets up the wireless I / F 201 to receive alarm messages transmitted from other V2X UEs via the sidelink, according to the settings from the server processing unit 150.

[0087] Next, in S31, the client processing unit 220 of the UE200a transmits location information indicating the latest location of the UE200a to the server device 100. Upon receiving the location information, the server processing unit 150 of the server device 100 determines in S33 whether the UE200a is located in a place where alarm messages on the sidelink should be relayed. Here, it is determined that the UE200a is located in a place where alarm messages should be relayed because it is located near the boundary between the first and second geographic areas, which are indicated to be high-risk by the risk data 130. In S35, the server processing unit 150 transmits a control message to the UE200a indicating that if an alarm message has been received via the sidelink, the alarm message should be relayed via the sidelink. The client processing unit 220 of the UE200a receives this control message via the wireless I / F 201.

[0088] Subsequently, in S41, UE200c, which is participating in the same V2X service, detects a road safety threat. In S43, the UE200c's client processing unit 220 transmits an alarm message (e.g., broadcast or groupcast) over the sidelink communication resources. The UE200a's wireless I / F 201 continuously monitors the sidelink resources for broadcast or groupcast and receives the alarm message transmitted from UE200c. Meanwhile, UE200b also continuously monitors the sidelink resources for broadcast or groupcast, but because UE200b is located outside the range of the alarm message from UE200c, UE200b does not receive the alarm message. In S45, in response to receiving the alarm message, the UE200a's client processing unit 220 alerts the user via the user interface so that the user can take appropriate action to ensure their safety.

[0089] The UE200a's client processing unit 220 receives an instruction in S35 to relay the alarm message, and therefore, in S47, relays the alarm message received from UE200c over the sidelink communication resource. The UE200b's wireless I / F 201 then receives the alarm message transmitted (relayed) from UE200a. Then, in S49, the UE200b's client processing unit 220 alerts the user via the user interface so that the user can take appropriate action to ensure their safety, in response to receiving the relayed alarm message.

[0090] <3-2. Second Example> Figure 10 is a sequence diagram showing an example of the processing flow according to the second embodiment. The illustrated processing mainly involves the server device 100, UE200a, UE200b, UE200c, and base station 300. However, several V2X UEs other than UE200a to 200c also exchange V2X messages with the server device 100.

[0091] The processing steps S11 to S33 may be the same as the corresponding processing steps in the first embodiment described with reference to Figure 9. Therefore, the explanation of those processing steps will be omitted here.

[0092] In S33, the server processing unit 150 of the server device 100, which has determined the location of the UE200a, sends a control message to the UE200a in S34 that includes an area ID identifying the geographic area where the UE200a is located and its adjacent areas. Note that if the UE200a can autonomously determine the area, the area notification in S34 may be omitted. Here, it is assumed that the UE200a is located near the boundary between the first and second geographic areas, which are indicated to be high-risk by the risk data 130, and is therefore determined to be located in a place where an alarm message should be relayed. Next, in S36, the server processing unit 150 requests the base station 300 serving the first geographic area where the UE200a is located to broadcast control information to instruct the V2X UE within the first geographic area to relay the alarm message. Upon receiving this broadcast request, the communication control unit 310 of the base station 300 instructs the radio I / F 301 in S38 to broadcast control information indicating that V2X UEs located within the first geographic area and within or near the second geographic area should relay alarm messages via sidelink. The client processing unit 220 of the UE 200a receives this control information via the radio I / F 201.

[0093] The subsequent processing steps S41 to S49 may be the same as the corresponding processing steps in the first embodiment described with reference to Figure 9. Therefore, the explanation of those processing steps will be omitted here.

[0094] <4. Summary of Embodiments> The above embodiment discloses at least the following server device, communication control method, terminal device, and base station.

[0095] 1. The server device (100) of the above embodiment is A communication unit (101) that communicates with one or more terminal devices (200) that act as clients for a V2X (Vehicle-to-Everything) application, A server processing unit (150) that operates as a server for the aforementioned V2X application, Equipped with, The server processing unit can access a database (110) that shows the adjacency relationships (120) between geographical areas (121-1, 121-2, 121-3, 121-4) that are predefined for the V2X application. The first geographical area and the second geographical area are indicated as adjacent areas in the database, The server processing unit, Each of the one or more terminal devices is configured to receive road safety warning messages transmitted from other terminal devices via the side link (S25), The location information of the first terminal device is received via the communication unit (S31), Based on the location information, it is determined that the first terminal device is located within the first geographical area (S33), By instructing the first terminal device to relay the alarm message received in the first geographical area via the side link (S35, S36), a second terminal device located in the second geographical area is made able to receive the relayed alarm message. According to this embodiment, the range over which a threat alert message can reach can be extended by relaying it using a side link on a terminal device. Since the relayed alert message is transmitted from a first geographic area to a second geographic area without going through a base station, the latency associated with relaying is small. Therefore, threats can be notified to a wide range of V2X UE users in a timely manner, further improving the safety of users involved in road traffic.

[0096] 2. In the above embodiment, Instructing the first terminal device to relay the aforementioned alarm message is: In response to the determination that the first terminal device is located within the first geographical area and within or near the second geographical area, a control message instructing the relay of the alarm message is transmitted to the first terminal device via the communication unit (S35). Includes. According to this embodiment, communication for controlling the relay operation of terminal devices is performed at the application level between the server and client of the V2X application. In other words, the content of the communication is transparent to base stations located along the communication path. Therefore, regardless of the placement of base stations, multiple geographical areas can be defined based on road traffic conditions, and relay operation control can be realized on a unit basis for each geographical area.

[0097] 3. In the above embodiment, Instructing the first terminal device to relay the aforementioned alarm message is: A terminal device operating as a client of the V2X application, located within the first geographic area and within or near the second geographic area, is requested by a base station serving the first geographic area to broadcast control information indicating that the terminal device should relay the alarm message (S36). Includes. According to this embodiment, one or more terminal devices that receive control information broadcast from a base station relay the alarm message, thereby enabling a wider and more efficient extension of the range to which the alarm message can reach.

[0098] 4. In the above embodiment, The database further indicates the risk level (130) for each of the aforementioned geographical areas, The server processing unit determines that if the risk level of the second geographic area, as indicated by the database, meets a predetermined standard, the alarm message received in the first geographic area should also be received in the second geographic area. According to this embodiment, the range in which warning messages can reach areas where user safety is easily threatened, such as areas with many obstacles that obstruct the line of sight, or areas with many pedestrians. Therefore, sufficient safety can be achieved while avoiding excessive consumption of communication resources caused by relaying warning messages.

[0099] 5. In the above embodiment, The server processing unit determines that if both the risk level of the first geographic area and the risk level of the second geographic area, as indicated by the database, meet the predetermined criteria, the alarm message received in the first geographic area should also be received in the second geographic area. According to this embodiment, the reachable range of alarm messages generated in relatively high-risk areas can be adaptively extended towards areas that are also relatively high-risk and therefore more likely to threaten user safety.

[0100] 6. The communication control method of the above embodiment is: A communication control method performed by a server device (100) acting as a server for a V2X (Vehicle-to-Everything) application, for controlling V2X communication by a terminal device (200) acting as a client for the V2X (Vehicle-to-Everything) application, wherein the server device (100) acting as a server for the V2X application controls V2X communication by the terminal device (200) acting as a client for the V2X (Vehicle-to-Everything) application, The server device can access a database (110) that shows the adjacency relationships (120) between geographic areas (121-1, 121-2, 121-3, 121-4) that are predefined for the V2X application. The first geographical area and the second geographical area are indicated as adjacent areas in the database, The aforementioned communication control method is: Each of one or more terminal devices is configured to receive road safety warning messages transmitted from other terminal devices via the side link (S25), Receiving location information of the first terminal device (S31), Based on the location information, it is determined that the first terminal device is located within the first geographical area (S33), By instructing the first terminal device to relay the alarm message received in the first geographic area via the side link (S35, S36), a second terminal device located in the second geographic area is made able to receive the relayed alarm message, Includes. According to this embodiment, the range over which a threat alert message can reach can be extended by relaying it using a side link on a terminal device. Since the relayed alert message is transmitted from a first geographic area to a second geographic area without going through a base station, the latency associated with relaying is small. Therefore, threats can be notified to a wide range of V2X UE users in a timely manner, further improving the safety of users involved in road traffic.

[0101] 7. The terminal device (200) of the above embodiment is A wireless communication unit (201) that wirelessly communicates via a wireless link between the terminal device and a base station (300) and a side link between the terminal device and other terminal devices (200), A client processing unit (220) that operates as a client for a V2X (Vehicle-to-Everything) application and connects to a server device (100) that operates as a server for the V2X application via the wireless link of the wireless communication unit, Equipped with, The server device can access a database (110) that shows the adjacency relationships (120) between geographic areas (121-1, 121-2, 121-3, 121-4) that are predefined for the V2X application. The first geographical area and the second geographical area are indicated as adjacent areas in the database, The aforementioned client processing unit, The wireless communication unit is set up to receive road safety warning messages transmitted from the other terminal device via the side link (S25), The location information of the terminal device is transmitted to the server device (S31), If the server device determines, based on the location information, that the terminal device is located within the first geographical area, it receives an instruction to relay the alarm message via the side link (S35, S38), The alarm message received in the first geographical area is relayed via the sidelink of the wireless communication unit (S47), thereby enabling terminal devices located in the second geographical area to receive the relayed alarm message. According to this embodiment, when a terminal device is located within a first geographic area adjacent to a second geographic area, it relays an alert message notifying of the presence of a threat via a sidelink, in accordance with control from the server device. This extends the range to which the alert message can reach to span both the first and second geographic areas. Since the alert message is relayed without going through a base station, the latency associated with the relay is small. Therefore, the presence of a threat can be notified to a wide range of V2X UE users in a timely manner, further improving the safety of users related to road traffic.

[0102] 8. In the above embodiment, The client processing unit receives a control message from the server device via the wireless link of the wireless communication unit in response to the transmission of the location information, instructing it to relay the alarm message (S35). According to this embodiment, control messages for controlling the relay operation of terminal devices are received from the server device via application-level communication. Therefore, relay operation can be controlled on a geographical area basis, regardless of the placement of base stations.

[0103] 9. In the above embodiment, The client processing unit receives the control message from the server device when the server device determines that the terminal device is located within the first geographical area and within or near the second geographical area. According to this embodiment, the range in which alarm messages can reach areas where user safety is particularly vulnerable can be adaptively extended. Therefore, sufficient security can be achieved while avoiding excessive consumption of communication resources caused by relaying alarm messages.

[0104] 10. In the above embodiment, The wireless communication unit receives control information broadcast by a base station serving the first geographic area in response to a request from the server device (S38), The control information indicates that a terminal device operating as a client of the V2X application, located within the first geographical area and within or near the second geographical area, should relay the alarm message. According to this embodiment, there is no need to send individual control messages from the server device to each terminal device in order to extend the range to which alarm messages can reach, thus enabling efficient range expansion.

[0105] 11. The communication control method of the above embodiment is: A communication control method performed by a terminal device (200) that operates as a client for a V2X (Vehicle-to-Everything) application, for controlling V2X communication by the terminal device, The terminal device includes a wireless communication unit (201) that wirelessly communicates via a wireless link between the terminal device and a base station (300) and a side link between the terminal device and other terminal devices (200). The wireless communication unit connects to a server device (100) that operates as a server for the V2X application via the wireless link of the wireless communication unit. The server device can access a database (110) that shows the adjacency relationships (120) between geographic areas (121-1, 121-2, 121-3, 121-4) that are predefined for the V2X application. The first geographical area and the second geographical area are indicated as adjacent areas in the database, The aforementioned communication control method is: Setting up the wireless communication unit to receive road safety warning messages transmitted from the other terminal device via the side link (S25), Transmitting the location information of the terminal device to the server device (S31), When the server device determines, based on the location information, that the terminal device is located within the first geographical area, it receives an instruction to relay the alarm message via the side link (S35, S38), The alarm message received in the first geographical area is relayed via the side link of the wireless communication unit (S47), thereby enabling a terminal device located in the second geographical area to receive the relayed alarm message. Includes. According to this embodiment, when a terminal device is located within a first geographic area adjacent to a second geographic area, it relays an alert message notifying of the presence of a threat via a sidelink, in accordance with control from the server device. This extends the range to which the alert message can reach to span both the first and second geographic areas. Since the alert message is relayed without going through a base station, the latency associated with the relay is small. Therefore, the presence of a threat can be notified to a wide range of V2X UE users in a timely manner, further improving the safety of users related to road traffic.

[0106] 12. The base station (300) of the above embodiment is A wireless communication unit (301) that performs wireless communication in at least one of several predefined geographic areas (121-1, 121-2, 121-3, 121-4) for V2X (Vehicle-to-Everything) applications, A network communication unit (302) that communicates with a server device (100) that operates as a server for the V2X application, A control unit (310) that controls the communication performed by the wireless communication unit and the network communication unit, Equipped with, The server device is able to access a database (110) that shows the adjacency relationships (120) between geographic areas for a plurality of geographic areas predefined for the V2X application. The first geographical area and the second geographical area are indicated as adjacent areas in the database, In response to a request from the server device, the control unit causes the wireless communication unit to broadcast control information indicating that, if a terminal device (200) operating as a client of the V2X application is located within the first geographic area and within or near the second geographic area, it should relay a road safety warning message transmitted from another terminal device via the side link (S38). According to this embodiment, through the broadcast of control information from the base station, one or more terminal devices located near the boundaries of the first and second geographical areas can be configured to relay warning messages notifying of the presence of a threat. This extends the range to which the warning message can reach to a wider range spanning the two geographical areas. Therefore, the presence of a threat can be notified to a wide range of V2X UE users in a timely manner, further improving the safety of users related to road traffic.

[0107] 13. In the above embodiment, The control unit causes the wireless communication unit to broadcast the control information, including it in a system information block for controlling V2X communication. According to this embodiment, terminal devices not involved in V2X communication can ignore the system information block that carries the control information. Therefore, the addition of control information broadcast from the base station does not increase the processing load on terminal devices that do not benefit from alarm messages.

[0108] 14. The communication control method of the above embodiment is: A communication control method performed by a base station (300) for controlling V2X communication by a terminal device (200) acting as a client of a V2X (Vehicle-to-Everything) application, The base station comprises a wireless communication unit (301) that performs wireless communication in at least a first geographic area among a plurality of geographic areas (121-1, 121-2, 121-3, 121-4) predefined for the V2X application, and a network communication unit (302) that communicates with a server device (100) that operates as a server for the V2X application. The server device is able to access a database (110) that shows the adjacency relationships (120) between the geographical areas. The first geographical area and the second geographical area are indicated as adjacent areas in the database, The aforementioned communication control method is: The server device receives a request message via the network communication unit (S36), In response to receiving the request message, control information is broadcast to the wireless communication unit indicating that terminal devices located within the first geographic area and within or near the second geographic area should relay road safety warning messages received from other terminal devices via the side link (S38). Includes. According to this embodiment, through the broadcast of control information from the base station, one or more terminal devices located near the boundaries of the first and second geographical areas can be configured to relay warning messages notifying of the presence of a threat. This extends the range to which the warning message can reach to a wider range spanning the two geographical areas. Therefore, the presence of a threat can be notified to a wide range of V2X UE users in a timely manner, further improving the safety of users related to road traffic.

[0109] Although embodiments of the invention have been described above, the invention is not limited to the above embodiments, and various modifications and changes are possible within the scope of the gist of the invention. [Explanation of symbols]

[0110] 1 V2X communication system, 100 server device, 101 communication unit, 110 database, 120 area definition data, 121-1, 121-2, 121-3, 121-4 geographical area, 130 risk level data, 140 UE location data, 150 server processing unit, 200 UE (terminal device), 201 wireless communication unit, 220 client processing unit, 300 base station, 301 wireless communication unit, 302 network communication unit, 310 communication control unit

Claims

1. A communication unit that communicates with one or more terminal devices acting as clients for a V2X (Vehicle-to-Everything) application, A server processing unit that operates as a server for the aforementioned V2X application, Equipped with, The server processing unit can access a database that shows the adjacency relationships between geographical areas for a plurality of geographical areas predefined for the V2X application. The first geographical area and the second geographical area are indicated as adjacent areas in the database, The server processing unit, Each of the one or more terminal devices is configured to receive road safety warning messages transmitted from other terminal devices via side links. The location information of the first terminal device is received via the communication unit. Based on the location information, it is determined that the first terminal device is located within the first geographical area. By instructing the first terminal device to relay the alarm message received in the first geographic area via the side link, a second terminal device located in the second geographic area is made able to receive the relayed alarm message. Server device.

2. Instructing the first terminal device to relay the aforementioned alarm message is: In response to the determination that the first terminal device is located within the first geographical area and within or near the second geographical area, a control message instructing the relay of the alarm message is transmitted to the first terminal device via the communication unit. The server device according to claim 1, including the following:

3. Instructing the first terminal device to relay the aforementioned alarm message is: A terminal device operating as a client of the V2X application, located within the first geographic area and within or near the second geographic area, requests a base station serving the first geographic area to broadcast control information indicating that the terminal device should relay the alarm message. The server device according to claim 1, including the following:

4. The aforementioned database further indicates the risk level for each of the aforementioned geographical areas, The server processing unit determines that if the risk level of the second geographic area indicated by the database meets a predetermined standard, the alarm message received in the first geographic area should also be received in the second geographic area. A server device according to any one of claims 1 to 3.

5. The server device according to claim 4, wherein the server processing unit determines that the alarm message received in the first geographic area should also be received in the second geographic area if both the risk level of the first geographic area and the risk level of the second geographic area, as indicated by the database, satisfy the predetermined criteria.

6. A communication control method performed by a server device acting as a server for a V2X (Vehicle-to-Everything) application, for controlling V2X communication by a terminal device acting as a client for the V2X (Vehicle-to-Everything) application, The server device is capable of accessing a database that shows the adjacency relationships between geographical areas for a plurality of geographical areas predefined for the V2X application. The first geographical area and the second geographical area are indicated as adjacent areas in the database, The aforementioned communication control method is: Configure each of one or more terminal devices to receive road safety warning messages transmitted from other terminal devices via side links, Receiving location information of the first terminal device, Based on the location information, it is determined that the first terminal device is located within the first geographical area, By instructing the first terminal device to relay the alarm message received in the first geographic area via the side link, a second terminal device located in the second geographic area is made able to receive the relayed alarm message. A communication control method, including a communication control method.

7. A terminal device, A wireless communication unit that wirelessly communicates via a wireless link between the terminal device and the base station and a side link between the terminal device and other terminal devices, A client processing unit that operates as a client for a V2X (Vehicle-to-Everything) application and connects to a server device that operates as a server for the V2X application via the wireless link of the wireless communication unit, Equipped with, The server device is capable of accessing a database that shows the adjacency relationships between geographical areas for a plurality of geographical areas predefined for the V2X application. The first geographical area and the second geographical area are indicated as adjacent areas in the database, The aforementioned client processing unit, The wireless communication unit is set up to receive road safety warning messages transmitted from the aforementioned other terminal devices via the side link. The location information of the terminal device is transmitted to the server device. When the server device determines, based on the location information, that the terminal device is located within the first geographical area, it receives an instruction to relay the alarm message via the side link. The alarm message received in the first geographical area is relayed via the side link of the wireless communication unit, thereby enabling terminal devices located in the second geographical area to receive the relayed alarm message. Terminal device.

8. The terminal device according to claim 7, wherein the client processing unit receives a control message from the server device via the wireless link of the wireless communication unit instructing the relay of the alarm message as a response to the transmission of the location information.

9. The terminal device according to claim 8, wherein the client processing unit receives the control message from the server device when the server device determines that the terminal device is located within the first geographical area and within or near the second geographical area.

10. The wireless communication unit receives control information broadcast by a base station serving the first geographic area in response to a request from the server device. The control information indicates that a terminal device operating as a client of the V2X application, located within the first geographical area and within or near the second geographical area, should relay the alarm message. The terminal device according to claim 7.

11. A communication control method performed by a terminal device for controlling V2X communication by a terminal device acting as a client for a V2X (Vehicle-to-Everything) application, The terminal device comprises a wireless communication unit that wirelessly communicates via a wireless link between the terminal device and a base station and a side link between the terminal device and other terminal devices. The wireless communication unit connects to a server device that operates as a server for the V2X application via the wireless link of the wireless communication unit. The server device is capable of accessing a database that shows the adjacency relationships between geographical areas for a plurality of geographical areas predefined for the V2X application. The first geographical area and the second geographical area are indicated as adjacent areas in the database, The aforementioned communication control method is: The wireless communication unit is set up to receive road safety warning messages transmitted from the other terminal device via the side link, The location information of the terminal device is transmitted to the server device, When the server device determines, based on the location information, that the terminal device is located within the first geographical area, it receives an instruction to relay the alarm message via the side link, The alarm message received in the first geographical area is relayed via the side link of the wireless communication unit, thereby enabling terminal devices located within the second geographical area to receive the relayed alarm message. A communication control method, including a communication control method.

12. A wireless communication unit that performs wireless communication in at least one of several geographic areas predefined for a V2X (Vehicle-to-Everything) application, A network communication unit that communicates with a server device that operates as a server for the aforementioned V2X application, A control unit that controls the communication performed by the wireless communication unit and the network communication unit, Equipped with, The server device is capable of accessing a database that shows the adjacency relationships between geographical areas for a plurality of geographical areas predefined for the V2X application. The first geographical area and the second geographical area are indicated as adjacent areas in the database, The control unit, in response to a request from the server device, broadcasts control information to the wireless communication unit indicating that, when a terminal device operating as a client of the V2X application, located within the first geographic area and within or near the second geographic area, receives a road safety warning message transmitted from another terminal device via the side link, the warning message should be relayed via the side link. Base station.

13. The base station according to claim 12, wherein the control unit causes the wireless communication unit to broadcast the control information in a system information block for controlling V2X communication.

14. A communication control method performed by a base station for controlling V2X communication by a terminal device acting as a client for a V2X (Vehicle-to-Everything) application, The base station comprises a wireless communication unit that performs wireless communication in at least a first geographic area among a plurality of geographic areas predefined for the V2X application, and a network communication unit that communicates with a server device that operates as a server for the V2X application. The server device is capable of accessing a database that shows the adjacency relationships between the geographical areas. The first geographical area and the second geographical area are indicated as adjacent areas in the database, The aforementioned communication control method is: The server device receives a request message via the network communication unit, In response to receiving the request message, the wireless communication unit broadcasts control information indicating that terminal devices located within the first geographic area and within or near the second geographic area should relay road safety warning messages received from other terminal devices via sidelink. A communication control method, including a communication control method.

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