Terminal device and communication control method

Abstract

This terminal device comprises a wireless communication unit that communicates wirelessly via a wireless link between the terminal device and a base station and a sidelink between the terminal device and another terminal device, and a control unit that controls the wireless communication of the wireless communication unit. The control unit can be operated in a DRX mode during wireless communication via the sidelink, and in accordance with a predetermined condition, the control unit generates an emergency message including emergency information of which the other terminal device is to be notified in a geographical area where the terminal device is located. In accordance with the generation of the emergency message, the control unit uses a request field provided at the head of a transmission frame section corresponding to an ON section of a DRX cycle, and transmits, via the sidelink, a transmission request for transmitting the emergency message to the other terminal device within the same DRX cycle.

Description

Technical Field

[0005] , , ,

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

Background Art

[0002] In the 3rd Generation Partnership Project (3GPP (registered trademark)), technologies for two user equipments (UEs) in a cellular communication system to perform Vehicle-to-Everything (V2X) communication through sidelink have been standardized. For example, a UE performing sidelink communication establishes a wireless link called a PC5 interface with a communication partner UE, and performs V2X communication on communication resources scheduled by a radio access network (RAN) or communication resources autonomously selected from a pre-assigned resource pool (Non-Patent Document 1).

[0003] Patent Document 1 discloses a technology 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. In Non-Patent Document 2, in a scenario of V2X communication in which messages regarding road safety are transmitted and received, when discontinuous reception (DRX) operation for reducing power consumption in a terminal device is performed, in order to enable message transmission and reception, synchronization of the timing of an on-interval for performing a reception operation for each geographical area is being considered.

Prior Art Documents

Non-Patent Documents

[0004]

Non-Patent Document 1

Non-Patent Document 2

Patent Documents

[0005] [Patent Document 1] U.S. Patent Application Publication No. 2020 / 0312142 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] When the ON segments of the DRX cycle are synchronized between terminal devices within the same geographical area, there is a possibility of message transmission collisions via sidelinks between terminal devices. However, for urgent messages (e.g., messages informing of the presence of road safety threats), it is required that they be transmitted to other terminal devices more reliably.

[0007] Therefore, this disclosure provides a technology that enables terminal devices performing DRX operation to more reliably transmit urgent messages. [Means for solving the problem]

[0008] According to one aspect of the present disclosure, a terminal device is provided comprising: wireless communication means for wirelessly communicating via a wireless link between the terminal device and a base station and a side link between the terminal device and other terminal devices; and control means for controlling the wireless communication by the wireless communication means, wherein the control means is capable of operating in DRX mode in the wireless communication via the side link, generates an emergency message containing emergency information to be notified to other terminal devices in the geographic area where the terminal device is located, according to predetermined conditions, and, in response to the generation of the emergency message, transmits a transmission request via the side link to transmit the emergency message to the other terminal devices within the same DRX cycle, using a request field provided at the beginning of a transmission frame section corresponding to the ON section of the DRX cycle. [Effects of the Invention]

[0009] According to this disclosure, terminal devices performing DRX operation will be able to transmit urgent messages more reliably.

Brief Description of the Drawings

[0010] [Figure 1] Copy of Figure 16.9.1-1 in 3GPP TS38.300 v16.8.0 [Figure 2] Copy of Figure 6.2-2 in 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 6] Block diagram showing an example of the configuration of a UE according to an embodiment [Figure 7] Block diagram showing an example of the configuration of a base station according to an embodiment [Figure 8] Explanatory diagram for explaining the transmission process of an emergency message by a UE according to an embodiment [Figure 9] Flowchart showing an example of a processing procedure by a UE according to an embodiment [Figure 10] Sequence diagram showing an example of the flow of processing in a V2X communication system according to an embodiment

Embodiments for Carrying Out the Invention

[0011] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the invention according to the claims, and not all combinations of the features described in the embodiments are essential for the invention. Two or more of the features described in the embodiments may be arbitrarily combined. Also, the same or similar configurations are given the same reference numerals, and duplicate descriptions are omitted.

[0012] <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.

[0013] Figure 2 is a reproduction of Figure 6.2-2 in 3GPP TS23.286 v17.3.0, showing a hierarchical functional model of V2X applications. In the functional model of Figure 2, the UE operates as a client (V2X UE) of the V2X application. On the other hand, the server of the V2X application is typically deployed on the 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 (V2X UE1 in Figure 2) located inside the coverage of the NG-RAN can communicate with a V2X UE (V2X UE2 in Figure 2) located outside the coverage via a sidelink.

[0014] The functional model of Figure 2 has a hierarchical structure consisting of, in order from top to bottom in the figure, the V2X application specific layer, the V2X application enabling (VAE) layer, and the service enabling architecture layer (SEAL).

[0015] 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. The V2X UE includes a SEAL client, and the V2X application server includes a SEAL server. SEAL-PC5 is the interface between V2X UEs in SEAL. SEAL-UU is the interface between a V2X UE and a V2X application server in SEAL. Details of the functions of the SEAL client and SEAL server are described in 3GPP TS23.434 v17.5.0.

[0016] The VAE layer is a layer that supports the V2X application-specific layer by interpreting the services provided by SEAL for the purposes of V2X applications. The V2X UE includes a VAE client, and the V2X application server includes a VAE server. The functions provided by the VAE client may include, for example, registration of the VAE client with the VAE server for receiving V2X messages, provision of application-level location information to the VAE server, reception of communication configuration information from the VAE server, and support for dynamic group management. The functions provided by the VAE server may include, for example, acceptance of registration of the VAE client, tracking of the location of the V2X UE at the application level, provision of communication configuration information, and support for delivery of V2X messages. V5-AE is an interface between V2X UEs in the VAE layer. V1-AE is an interface between a V2X UE and a V2X application server in the VAE layer.

[0017] The V2X application-specific layer is a layer that provides functionality specific to individual V2X applications with the support from the VAE layer. The V2X UE includes a V2X application-specific client, and the V2X application server includes a V2X application-specific server. V5-APP is an interface between V2X UEs in the V2X application-specific layer. V1-APP is an interface between a V2X UE and a V2X application server in the V2X application-specific layer.

[0018] The functions of the V2X UE and the V2X application server that may have such a hierarchical structure in embodiments of the technology according to the present disclosure will be described in detail later.

[0019] As can be understood from FIG. 2, at the application level, V2X communication is treated as end-to-end communication between a V2X UE and a V2X application server, and the content of V2X communication is transparent to the base stations and other network nodes in the middle of the communication path.

[0020] Section 7 of 3GPP TS23.286 v17.3.0 describes various deployment models of V2X application-specific servers and VAE servers. The V2X application-specific server and the VAE server may be co-located on a physically single device, or may be deployed on separate devices. Each of these servers may belong to either the domain of the V2X service provider or the domain of the network operator.

[0021] <Overview of V2X Communication System> FIG. 3 is a schematic diagram showing an example of the configuration of a V2X communication system 1 according to an embodiment. Referring to FIG. 3, the V2X communication system 1 includes a server device 100, UEs 200a, 200b, 200c, 200d, and base stations 300a, 300b.

[0022] In the following description, when there is no need to distinguish between UEs 200a, 200b, 200c, 200d from each other, these are collectively referred to as UE200 by omitting the alphabet at the end of the reference numeral. The same applies to base stations 300a, 300b (base station 300) and other components.

[0023] The server device 100 is a V2X application server that provides V2X services for the purpose of improving road safety. The server device 100 is connected to a plurality of base stations including base stations 300a, 300b via a 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.

[0024] UE200 is a terminal device that utilizes the V2X service provided by the server device 100. In the example in Figure 3, UE200a and UE200b are pedestrian terminals, and UE200c and UE200d are in-vehicle terminals. 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 via sidelinks with other nearby V2X UEs. For example, Figure 3 shows sidelink 40b between UE200a and UE200b, and sidelink 40c between UE200a and UE200c. Naturally, UE200s other than UE200a can also communicate via sidelinks with nearby V2X UEs.

[0025] 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).

[0026] In this embodiment, the UE200 can operate in one of several operating modes, including Continuous Reception mode and Discontinuous Reception (DRX) mode. The operating mode may be a mode relating to all downlink, uplink, and sidelink, or a mode relating only to sidelink. For example, when operating in Continuous Reception mode, the UE200 monitors all candidate resources on the sidelink and receives broadcast, groupcast, or unicast V2X messages addressed to the device. On the other hand, when operating in DRX mode, the UE200 monitors only candidate resources included in ON intervals that arrive periodically according to the DRX cycle and receives V2X messages transmitted over those candidate resources. By operating in DRX mode, the UE200 can reduce power consumption and extend battery life.

[0027] Furthermore, in this embodiment, at least some UE200s are configured to transmit urgent messages on the sidelink when they generate messages that should be notified to other terminal devices. For example, at least some UE200s are configured to transmit warning messages (urgent messages) on the sidelink when a road safety threat is detected or when a threat is expected to occur in the near future. The UE200s may detect safety threats using any known method. For example, a UE200 installed in 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 or another vehicle 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.

[0028] However, a scenario is envisioned in which the on-periods of the DRX cycle are synchronized to enable V2X communication via sidelinks between multiple UE200s operating in DRX mode within the same geographical area. In this case, if one UE200 transmits an alarm message (emergency message) via sidelink during the on-period of the DRX cycle, a collision may occur with message transmissions from other UE200s. Therefore, as will be described later, the V2X communication system 1 according to this embodiment incorporates a mechanism to ensure that highly urgent messages (for example, messages informing of the presence of a threat to road safety) can be transmitted more reliably to other terminal devices (UEs).

[0029] <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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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 three data items for each geographic area: • "Area ID" • "Area Definition" • "Related base stations" The "Area ID" is an identifier that uniquely identifies each geographic area. The "Area Definition" is a set of parameters that define the geographic 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. The "Associated Base Station" indicates at least one address (or other identifying information) for communication with the base station serving each geographic area.

[0034] Figure 5 is an explanatory diagram illustrating an example of the definition of a geographic area. 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 the 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. 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 geographic areas based on differences in road characteristics (e.g., speed limits, number of lanes, etc.) and traffic trends (e.g., pedestrian volume, frequency of congestion, etc.).

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] Furthermore, the server processing unit 150 configures the UE200 to receive alarm messages sent from other V2X UEs via the sidelink. For example, if an alarm 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 an alarm message is groupcast on the PC5 interface, the server processing unit 150 assigns the UE200 a group ID for receiving alarm messages and configures the UE200 to monitor the sidelink resource for messages with a destination Layer 2 ID corresponding to that group ID. Alarm messages may be sent by unicast, but from the standpoint of rapid transmission of alarm messages, broadcast or groupcast is more advantageous than unicast, which requires the establishment of individual PC5 interfaces.

[0041] Furthermore, the server processing unit 150 manages the hazard level of each geographic area indicated by the hazard data 130. For example, the initial value of the "hazard level" in the hazard data 130 is predetermined based on static road characteristics in the corresponding geographic area, such as speed limits, number of lanes, curvature, separation of roadways and sidewalks, and the presence of steps. The server processing unit 150 may update the "hazard level" value based on temporal conditions, which may include seasons or time of day, or sunlight conditions (for example, increasing the hazard level by one level during the evening hours when visibility deteriorates). In addition, in this embodiment, the server processing unit 150 updates the "hazard level" value of the hazard data 130 based on V2X messages received from one or more terminal devices via the communication I / F 101. 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

[0042] 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 "Last 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.

[0043] <Example of terminal device configuration> Figure 6 is a block diagram showing an example of the configuration of the UE200 according to this embodiment. Referring to Figure 6, 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.

[0044] 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. Furthermore, the wireless interface 201 can operate in one of several operating modes, including continuous reception mode and discontinuous reception (DRX) mode.

[0045] 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.

[0046] 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).

[0047] 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.

[0048] Camera 205 is an imaging module capable of capturing images of the surroundings of UE200. The sensor group 204 and camera 205 may be used to detect road safety threats in accordance with the threat detection conditions described above.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] Power supply 209 is a rechargeable battery that supplies power to various parts of the UE200 via power lines partially shown in the diagram. The power supply from power supply 209 is controlled by the control unit 210. For example, when the wireless interface 201 is operating in DRX mode, the power supplied from power supply 209 to the wireless interface 201 is reduced during periodically occurring off-periods.

[0053] 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.

[0054] The client processing unit 220 is configured by the server processing unit 150 of the server device 100 to receive road safety warning messages transmitted from other V2X UEs via the side link. When the client processing unit 220 receives a warning message via the side link, 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 the speaker, or sounded by a vibrator.

[0055] 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.

[0056] The client processing unit 220 periodically reports location information indicating the latest location of the UE200, acquired by the positioning module 206, to the server device 100. A V2X message for reporting the 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 UE200 is located within in response to this location information report.

[0057] The V2X message sent to the server device 100 may 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 send 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.

[0058] In this embodiment, the client processing unit 220 receives a control message from the server device 100 via the wireless I / F 201 as a response to the transmission of location information. This control message may include an area ID that identifies the geographic area in which the UE200 is determined to be located, from among a plurality of geographic areas predefined for the V2X application.

[0059] <Example of base station configuration> Figure 7 is a block diagram showing an example of the configuration of a base station 300 according to this embodiment. Referring to Figure 7, 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.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] <Processing to send an emergency message> Next, with reference to Figure 8, an example of the emergency message transmission process performed by a UE200 according to one embodiment will be described. Here, we assume a scenario in which the on-intervals of the DRX cycle are synchronized so that V2X communication via sidelinks is possible between multiple UE200s operating in DRX mode within the same geographical area. In DRX mode, one period is defined as a DRX cycle consisting of an on-interval and an off-interval, and the on-intervals and off-intervals are repeated alternately and periodically. A UE200 operating in DRX mode monitors only candidate resources included in the on-intervals that arrive periodically according to the DRX cycle and receives V2X messages transmitted on the candidate resources. Furthermore, when a message to be transmitted arises, the UE200 transmits the message using the sidelink communication resources in the on-interval of the DRX cycle.

[0065] Figure 8 shows an example of a transmit frame (wireless frame) transmitted and received between UE200s via a sidelink during the ON-period of the DRX cycle. In this example, the length of the transmit frame matches the length of the ON-period of the DRX cycle, but the length of the transmit frame may differ from the length of the ON-period of the DRX cycle (for example, it may be shorter than the length of the ON-period). Furthermore, the transmit frame used during the ON-period of the DRX cycle may be configured as a subframe of a wireless frame.

[0066] As shown in Figure 8, the transmit frame section corresponding to the ON section of the DRX cycle includes at least a "transmit request field" and a "message transmit field". One or more other fields or a transmit gap may be provided between the transmit request field and the message transmit field, or the transmit request field and the message transmit field may be placed consecutively.

[0067] The Send Request field is located at the beginning of the transmit frame section corresponding to the ON section of the DRX cycle and is used for requesting the transmission of an emergency message. The Send Request field is used by UE200 to send a Send Request to another UE via a sidelink, requesting that they transmit an emergency message within the same DRX cycle. By sending a Send Request, the UE notifies other UEs that the message transmit field contained within the same DRX cycle should be used preferentially for transmitting emergency messages. During the ON section of the DRX cycle, other UEs that receive a Send Request from UE200 using the Send Request field will act to refrain from using the message transmit field contained within the same DRX cycle. This prevents a conflict between the transmission of an emergency message from UE200 and the transmission of a normal message from another UE in the message transmit field. Although it is not possible to completely avoid a conflict between the transmission of an emergency message from UE200 and the transmission of an emergency message from another UE in the message transmit field, the probability of such a conflict occurring is very low.

[0068] When UE200 sends an emergency message, it first uses the Send Request field to send a Send Request to another UE via a sidelink. In this case, the Send Request field stores information indicating the Send Request. For example, the UE200's identification information is stored in the Send Request field. The UE200's identification information may also be information indicating the address assigned to that UE (e.g., Layer 2 ID).

[0069] The message sending field can be used to send emergency messages or regular messages other than emergency messages. After sending a send request using the send request field, UE200 uses the message sending field to send an emergency message to another UE via sidelink within the same DRX cycle. In this way, it becomes possible to send an emergency message within the same DRX cycle in which the send request was sent. This makes it possible to quickly notify other UEs located within the same geographical area as UE200 via sidelink of emergency messages.

[0070] The transmission of a transmission request using the transmission request field, and the transmission of an urgent message using the message transmission field, are performed by broadcast or groupcast using the sidelink communication resources. The transmission request field may use the communication resources of the control area in the wireless frame (or subframe), and the message transmission field may use the communication resources of the data area in the wireless frame (or subframe).

[0071] <Processing flow> Figure 9 is a flowchart showing an example of the processing procedure by UE200 in a V2X communication system 1 according to one embodiment. When data to be transmitted (message) is generated, UE200 starts processing according to the procedure in Figure 9.

[0072] In S901, UE200 determines whether the message to be sent is an urgent message. If the message to be sent is an urgent message, UE200 proceeds to S902. In S902, UE200 uses a transmission request field located at the beginning of the transmission frame section corresponding to the ON section of the DRX cycle to send an urgent message transmission request to another UE (within the same geographic area) via the sidelink. For example, UE200 sets its own address information as a transmission request in the transmission request field and sends it using the sidelink communication resources.

[0073] Subsequently, in S903, UE200 transmits the generated emergency message to another UE via a sidelink using the message transmission field within the corresponding transmission frame segment within the same DRX cycle.

[0074] Furthermore, if the message to be sent is not an urgent message (it is a normal message), UE200 proceeds from S901 to S904. In S904, UE200 determines whether it has received a send request using a send request field from another UE via the sidelink during the ON section of the DRX cycle in which it is attempting to send the message. If UE200 has received a send request using a send request field, it proceeds to S906. In S906, UE200 acts to refrain from sending data in the current DRX cycle.

[0075] Specifically, UE200 operates to wait for the next DRX cycle before sending a message. In this case, if UE200 does not receive a send request using the send request field from another UE during the ON section of the next DRX cycle, it will send a message (transmit data) via the sidelink using the message send field in the transmit frame section corresponding to the ON section of that next DRX cycle.

[0076] On the other hand, if UE200 has not received a transmit request using the transmit request field, it proceeds from S904 to S905. In S905, UE200 transmits a message (transmit data) via the sidelink using the message transmit field in the transmit frame section corresponding to the ON section of the current DRX cycle.

[0077] Figure 10 is a sequence diagram showing an example of the processing flow in a V2X communication system 1 according to one embodiment. The illustrated processing mainly involves the server device 100, UE200c, UE200a, and base station 300. As shown in Figure 3, UE200a is a pedestrian terminal (pedestrian UE), and UE200c is an in-vehicle terminal (in-vehicle UE). In this example, the server device 100 (server processing unit 150) operates as a server for the V2X application, and UE200a and 200c operate as clients (V2X UE) for the V2X application. In addition, both UE200a and 200c are operating in DRX mode.

[0078] First, in S11, when the UE200c enters cell 30a, which is served by the base station 300, it establishes a radio link with the base station 300. Once the radio link between the UE200c and the base station 300 is established, in S12, the base station 300 (communication control unit 310) schedules sidelink resources for the UE200c, which is a V2X UE, or allocates a resource pool for sidelinks.

[0079] Next, in S13, the UE200c (client processing unit 220) accesses the server device 100 using, for example, the URL of the server device 100 which is pre-stored in memory 202, and participates in the V2X service provided by the server device 100. In S14, the server device 100 (server processing unit 150) registers the UE200c as a connected client (if authentication of the UE200c is successful). Furthermore, in S15, the server device 100 sets up a communication link with the UE200c. For example, the UE200c sets up the wireless I / F 201 to receive alarm messages (emergency messages) transmitted from other V2X UEs via the sidelink, according to the settings from the server device 100.

[0080] Here, UE200a is located within cell 30a of base station 300. Furthermore, UE200a and 200b are located within the same geographical area managed by server device 100 and participate in the same V2X service. UE200a and 200b are capable of V2X communication via sidelinks with other UEs within the same geographical area, and with server device 100. In the geographical area where UE200a and 200b are located, base station 300 controls the DRX cycle ON phases to synchronize among UEs within that area. Therefore, UEs operating in DRX mode within this geographical area (UE200a and 200b in this example) can perform V2X communication with other UEs via sidelinks during the DRX cycle ON phase.

[0081] Subsequently, in S21, the in-vehicle terminal UE200c detects a road safety threat. In response to the detection of a road safety threat, the UE200c performs a transmission process to send an emergency message to other UEs via the side link.

[0082] Specifically, in S22, when the ON section of the DRX cycle arrives, UE200c sends a transmission request using the transmission request field located at the beginning of the transmission frame (wireless frame) section corresponding to that ON section. The transmission request is sent to another UE (V2X UE) via the sidelink within the same DRX cycle to request the transmission of an emergency message. After sending the transmission request, in S23, UE200c sends the emergency message (e.g., broadcast or groupcast) over the sidelink communication resource using the message transmission field within the transmission frame (wireless frame) section within the same DRX cycle.

[0083] When UE200a receives a request to send an urgent message from UE200c in the request to send field at the beginning of the corresponding transmit frame during the ON section of a DRX cycle, it operates to prioritize the use of the subsequent message transmit field by UE200c. That is, even if there is transmit data that should be sent via the sidelink, UE200a will not send that data during the ON section of the DRX cycle in which the request to send was received, but will postpone the transmission to the next DRX cycle. In the DRX cycle in which the request to send was received, UE200a will receive the urgent message sent by UE200c in the message transmit field that follows the request to send field.

[0084] When the UE200a receives an emergency message, it notifies the user via the user interface in S24 based on the emergency information contained in the message. The emergency message includes emergency information indicating that the UE200c has detected a road safety threat. The notification to the user prompts the user to take appropriate action to ensure their safety.

[0085] As described above, the UE200 (terminal device) of this embodiment is capable of operating in DRX mode and includes a wireless I / F201 that wirelessly communicates via a wireless link between the UE200 and the base station 300 and a side link between the UE200 and other UEs, and a control unit 210 that controls the wireless communication by the wireless I / F201. The control unit 210 generates an emergency message containing emergency information to be notified to other UEs in the geographic area where the UE200 is located, according to predetermined conditions. In response to the generation of the emergency message, the control unit 210 uses a transmission request field provided at the beginning of the transmission frame section corresponding to the ON section of the DRX cycle to send a transmission request to other UEs via the side link for sending the emergency message within the same DRX cycle. In this way, by sending a transmission request, it is possible to notify other UEs that the message transmission field included in the same DRX cycle should be used preferentially for sending the emergency message. Therefore, according to this embodiment, it becomes possible to more reliably transmit highly urgent messages in a UE (terminal device) performing DRX operation.

[0086] <Summary of Embodiments> The above embodiment discloses at least the following terminal device and communication control method.

[0087] (Item 1) Terminal device (200), Wireless communication means (201) 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, The system includes a control means (210) for controlling wireless communication by the wireless communication means, The control means is In wireless communication via the aforementioned side link, it is possible to operate in DRX mode. In accordance with predetermined conditions, an emergency message containing emergency information to be notified to other terminal devices in the geographical area where the terminal device is located is generated. A terminal device that, in response to the generation of the emergency message, sends a transmission request via the sidelink to another terminal device within the same DRX cycle, using a request field provided at the beginning of the transmission frame section corresponding to the ON section of the DRX cycle. According to this item, terminal devices performing DRX operation will be able to transmit urgent messages more reliably.

[0088] (Item 2) The terminal device according to item 1, wherein the control means (210) stores the identification information of the terminal device in the request field as information indicating the transmission request and transmits it. According to this section, requests to send emergency messages can be implemented using the identification information of the terminal device.

[0089] (Item 3) The terminal device described in item 2, wherein the identification information includes address information indicating an address assigned to the terminal device. According to this section, requests to send emergency messages can be made using the address assigned to the terminal device.

[0090] (Item 4) The terminal device according to any one of items 1 to 3, wherein the control means (210) transmits the emergency message to the other terminal device using the transmission field within the transmission frame interval in the same DRX cycle after the transmission of the transmission request. According to this item, by sending an emergency message to other terminal devices within the same DRX cycle, the emergency message can be quickly transmitted to other terminal devices.

[0091] (Item 5) The terminal device according to item 4, wherein the control means (210) broadcasts the emergency message via the side link. According to this section, it is possible to transmit emergency messages to other terminal devices using broadcasting.

[0092] (Item 6) The terminal device according to any one of items 1 to 5, wherein the control means (210) refrains from transmitting the transmission data in the DRX cycle if it receives a transmission request using the request field from another terminal device during the ON section of the DRX cycle when transmission data to be transmitted via the side link is generated. According to this item, it is possible to avoid conflicts between the transmission of urgent messages from other terminal devices and the transmission of data, and to receive urgent messages from other terminal devices.

[0093] (Item 7) The terminal device according to item 6, wherein the control means (210) refrains from transmitting the transmission data, and if it does not receive the transmission request using the request field from another terminal device in the ON section of the next DRX cycle, it transmits the transmission data via the side link using the transmission field in the transmission frame section corresponding to the ON section of the next DRX cycle. According to this item, it becomes possible to transmit data via a sidelink while avoiding conflicts between the transmission of urgent messages from other terminal devices and the transmission of data.

[0094] (Item 8) The terminal device according to any one of items 1 to 7, wherein the control means (210) transmits the transmission data via the side link using the transmission field in the transmission frame section corresponding to the on section of the DRX cycle if, when transmission data to be transmitted via the side link is generated, the terminal device does not receive the transmission request using the request field from another terminal device during the ON section of the DRX cycle. According to this item, it becomes possible to transmit data via a sidelink while avoiding conflicts between the transmission of urgent messages from other terminal devices and the transmission of data.

[0095] (Item 9) The aforementioned predetermined condition is that a threat to road safety has been detected. The emergency message includes information indicating the detection of the threat. A terminal device as described in any one of items 1 through 8. According to this item, the detection results of road safety threats can be quickly transmitted to other terminal devices as emergency messages.

[0096] (Item 10) Terminal device (200), Wireless communication means (201) 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, The system includes a control means (210) for controlling wireless communication by the wireless communication means, The control means (210) is In wireless communication via the aforementioned side link, it is possible to operate in DRX mode. A transmission request sent from another terminal device using a request field provided at the beginning of a transmission frame section corresponding to the ON section of a DRX cycle, and which is a transmission request for sending an emergency message within the same DRX cycle, is received via the side link. A terminal device that, upon receiving the aforementioned transmission request, refrains from transmitting transmission data via the sidelink in the same DRX cycle. According to this item, terminal devices performing DRX operation can avoid collisions between the transmission of urgent messages from other terminal devices and the transmission of data, and can receive urgent messages from other terminal devices.

[0097] (Item 11) The terminal device according to item 10, wherein the control means (210) receives the emergency message from the other terminal device via the side link in the transmission field within the transmission frame interval in the same DRX cycle. According to this item, it will be possible to receive urgent messages more reliably from other terminal devices.

[0098] (Item 12) The terminal device according to item 10 or 11, wherein the control means (210) refrains from transmitting the transmission data and, if it does not receive the transmission request using the request field in the ON section of the next DRX cycle, transmits the transmission data via the side link using the transmission field in the transmission frame section corresponding to the ON section of the next DRX cycle. According to this item, it becomes possible to transmit data via a sidelink while avoiding conflicts between the transmission of urgent messages from other terminal devices and the transmission of data.

[0099] (Item 13) A communication control method performed by a terminal device, comprising wireless communication means for wireless communication 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 via the aforementioned side link is capable of operating in DRX mode, To generate an emergency message containing emergency information to be notified to other terminal devices in the geographical area where the terminal device is located, in accordance with predetermined conditions, In response to the generation of the emergency message, a transmission request for sending the emergency message to the other terminal device within the same DRX cycle is transmitted via the side link, using a request field provided at the beginning of the transmission frame section corresponding to the ON section of the DRX cycle. A communication control method, including a communication control method. According to this item, terminal devices performing DRX operation will be able to transmit urgent messages more reliably.

[0100] (Item 14) A communication control method performed by a terminal device, comprising wireless communication means for wireless communication 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 via the aforementioned side link is capable of operating in DRX mode, Receiving, via the sidelink, a transmission request sent from another terminal device using a request field provided at the beginning of a transmission frame section corresponding to the ON section of a DRX cycle, which is a transmission request for sending an emergency message within the same DRX cycle. In response to the receipt of the aforementioned transmission request, the transmission of transmission data via the side link in the same DRX cycle will be refrained from, A communication control method, including a communication control method. According to this item, terminal devices performing DRX operation can avoid collisions between the transmission of urgent messages from other terminal devices and the transmission of data, and can receive urgent messages from other terminal devices.

[0101] 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]

[0102] 1: V2X communication system, 100: Server device, 101: Communication unit, 150: Server processing unit, 200: UE (Terminal device), 201: Wireless I / F, 220: Client processing unit, 300: Base station

Claims

1. A terminal device, Wireless communication means for wireless communication 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 system comprises control means for controlling wireless communication by the wireless communication means, The control means is In wireless communication via the aforementioned side link, it is possible to operate in DRX mode. In accordance with predetermined conditions, an emergency message containing emergency information to be notified to other terminal devices in the geographical area where the terminal device is located is generated. A terminal device that, in response to the generation of the emergency message, uses a request field provided at the beginning of the transmission frame section corresponding to the ON section of the DRX cycle to send a transmission request to the other terminal device within the same DRX cycle via the side link.

2. The terminal device according to claim 1, wherein the control means stores the identification information of the terminal device in the request field as information indicating the transmission request and transmits it.

3. The terminal device according to claim 2, wherein the identification information includes address information indicating an address assigned to the terminal device.

4. The terminal device according to any one of claims 1 to 3, wherein the control means transmits the emergency message to the other terminal device using the transmission field within the transmission frame section in the same DRX cycle after the transmission of the transmission request.

5. The terminal device according to claim 4, wherein the control means broadcasts the emergency message via the side link.

6. The terminal device according to any one of claims 1 to 3, wherein the control means, when transmission data to be transmitted via the side link is generated, receives the transmission request using the request field from another terminal device during the ON section of the DRX cycle, refrains from transmitting the transmission data in the DRX cycle.

7. The terminal device according to claim 6, wherein the control means, after refraining from transmitting the transmission data, transmits the transmission data via the sidelink using the transmission field in the transmission frame section corresponding to the on section of the next DRX cycle if it does not receive the transmission request using the request field from another terminal device in the on section of the next DRX cycle.

8. The terminal device according to any one of claims 1 to 3, wherein the control means transmits the transmission data via the side link using the transmission field in the transmission frame section corresponding to the on section of the DRX cycle if, when transmission data to be transmitted via the side link is generated, the control means transmits the transmission data via the side link using the transmission field in the transmission frame section corresponding to the on section of the DRX cycle, unless the control means has not received the transmission request using the request field from another terminal device during the ON section of the DRX cycle.

9. The aforementioned predetermined condition is that a threat to road safety has been detected. The emergency message includes information indicating the detection of the threat. The terminal device according to any one of claims 1 to 3.

10. A terminal device, Wireless communication means for wireless communication 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 system comprises control means for controlling wireless communication by the wireless communication means, The control means is In wireless communication via the aforementioned side link, it is possible to operate in DRX mode. A transmission request sent from another terminal device using a request field provided at the beginning of a transmission frame section corresponding to the ON section of the DRX cycle, and which is a transmission request for sending an emergency message within the same DRX cycle, is received via the side link. A terminal device that, upon receiving the aforementioned transmission request, refrains from transmitting transmission data via the sidelink in the same DRX cycle.

11. The terminal device according to claim 10, wherein the control means receives the emergency message from the other terminal device via the side link in the transmission field within the transmission frame section in the same DRX cycle.

12. The terminal device according to claim 10 or 11, wherein the control means, after refraining from transmitting the transmission data, transmits the transmission data via the sidelink using the transmission field in the transmission frame section corresponding to the on section of the next DRX cycle if it does not receive the transmission request using the request field in the on section of the next DRX cycle.

13. A communication control method performed by a terminal device, comprising wireless communication means for wireless communication 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 via the aforementioned side link is capable of operating in DRX mode, To generate an emergency message containing emergency information to be notified to other terminal devices in the geographical area where the terminal device is located, in accordance with predetermined conditions, In response to the generation of the emergency message, a transmission request for sending the emergency message to the other terminal device within the same DRX cycle is transmitted via the side link using a request field provided at the beginning of the transmission frame section corresponding to the ON section of the DRX cycle. A communication control method, including a communication control method.

14. A communication control method performed by a terminal device, comprising wireless communication means for wireless communication 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 via the aforementioned side link is capable of operating in DRX mode, Receiving a transmission request sent from another terminal device using a request field provided at the beginning of a transmission frame section corresponding to the ON section of the DRX cycle, and a transmission request for sending an emergency message within the same DRX cycle, via the side link, In response to receiving the aforementioned transmission request, the transmission of transmission data via the sidelink in the same DRX cycle will be refrained from. A communication control method, including a communication control method.

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