Communication device and communication method

Abstract

To provide a communication device that reduces one or both of a communication load and a processing load in message processing.SOLUTION: A communication device 21 is configured to be capable of communicating a message including target information. A communication device 20 includes: a grouping unit 31 that determines whether or not to group a plurality of targets perceived by using a sensor; a message generation unit 32 for generating a message including aggregated information obtained by aggregating a plurality of targets into a target group based on grouping; and a message transmission unit 33 for transmitting the message including the aggregated information.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] TECHNICAL FIELD This disclosure relates to techniques for communicating messages containing target information. [Background technology]

[0002] Patent Document 1 discloses communicating a message containing information about individual targets perceived by a sensor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6844642 Summary of the Invention [Problem to be solved by the invention]

[0004] For example, in densely populated urban areas where there are a large number of road users, such as pedestrians, the number of targets detected by sensors increases. However, when communicating messages containing information about each individual target, the amount of information or the number of messages increases according to the number of targets, raising concerns about the communication load or the processing load in message processing.

[0005] An object of the disclosure of this specification is to provide a communication device and a communication method that reduce one or both of the communication load and the processing load in message processing. [Means for solving the problem]

[0006] An aspect disclosed herein is a communication device configured to be able to communicate a message including target information, the communication device comprising: a grouping unit (31) that determines whether or not to group a plurality of targets perceived by a sensor; a message generating unit (32) that generates a message including aggregated information that aggregates a plurality of targets into a target group based on the grouping; a message sending unit (33) that sends a message including the aggregated information; 、 The aggregated information is aggregated so that information on one target group can be stored in one perceived target container that is configured to store information on one ungrouped target. do. Another disclosed aspect is a communication device configured to be able to communicate a message including target information, a grouping unit (31) that determines whether or not to group a plurality of targets perceived by a sensor; a message generating unit (32) that generates a message including aggregated information that aggregates a plurality of targets into a target group based on the grouping; a message sending unit (33) that sends a message including the aggregated information; The grouping section is determining whether to group the plurality of targets based on the initial grouping conditions; Modifying the grouping conditions according to the total number of targets and target groups after aggregation or the message size after aggregation in the grouping based on the initial grouping conditions; Based on the modified grouping conditions, it is again determined whether or not to group the multiple targets. Another disclosed aspect is a communication device configured to be able to communicate a message including target information, a grouping unit (31) that determines whether or not to group a plurality of targets perceived by a sensor; a message generating unit (32) that generates a message including aggregated information that aggregates a plurality of targets into a target group based on the grouping; a message sending unit (33) that sends a message including the aggregated information; the message generation unit expresses the dimensions of the target group included in the aggregated information as the dimensions of a rectangular parallelepiped that includes all of the multiple targets aggregated in the target group; Under a transmission condition in which the message transmission unit transmits a message at a predetermined first interval, When it is determined that the dimensions of the group of targets aggregated in the previously transmitted message have changed by more than a preset threshold, the message transmission unit changes the message transmission interval to a second interval that is shorter than the first interval. Another disclosed aspect is a communication device configured to be able to communicate a message including target information, a grouping unit (31) that determines whether or not to group a plurality of targets perceived by a sensor; a message generating unit (32) that generates a message including aggregated information that aggregates a plurality of targets into a target group based on the grouping; a message sending unit (33) that sends a message including the aggregated information; If multiple targets of the same type are not grouped in the grouping, the message generation unit generates a message to which information indicating whether the targets that are not grouped are vulnerable road users is added.

[0007] Yet another disclosed aspect is a communication method executed by at least one processor for communicating a message including target information, the method comprising: determining whether to group a plurality of targets perceived using a sensor; generating a message including aggregated information that aggregates a plurality of targets into a target group based on the grouping; sending a message including the aggregate information; fruit, The aggregated information is aggregated so that information about one target group can be stored in one perceived target container configured to store information about one ungrouped target. . Yet another disclosed aspect is a communication method executed by at least one processor for communicating a message including target information, the method comprising: determining whether to group a plurality of targets perceived using a sensor; generating a message including aggregated information that aggregates a plurality of targets into a target group based on the grouping; sending a message including the aggregate information; In determining whether to group, determining whether to group the plurality of targets based on the initial grouping conditions; Modifying the grouping conditions according to the total number of targets and target groups after aggregation or the message size after aggregation in the grouping based on the initial grouping conditions; Based on the modified grouping conditions, it is again determined whether or not to group the multiple targets. Yet another disclosed aspect is a communication method executed by at least one processor for communicating a message including target information, the method comprising: determining whether to group a plurality of targets perceived using a sensor; generating a message including aggregated information that aggregates a plurality of targets into a target group based on the grouping; sending a message including the aggregate information; generating the message includes expressing dimensions of the target group included in the aggregated information by dimensions of a rectangular parallelepiped that includes all of the multiple targets aggregated in the target group; Under a transmission condition in which a message is transmitted at every predetermined first interval, When it is determined that the dimensions of the group of targets aggregated in the previously transmitted message have changed by more than a preset threshold, transmitting the message includes changing the message transmission interval to a second interval that is shorter than the first interval. Yet another disclosed aspect is a communication method executed by at least one processor for communicating a message including target information, the method comprising: determining whether to group a plurality of targets perceived using a sensor; generating a message including aggregated information that aggregates a plurality of targets into a target group based on the grouping; sending a message including the aggregate information; Generating a message includes, when multiple targets of the same type are not grouped in the grouping, generating a message with information indicating whether the targets that were not grouped are vulnerable road users.

[0008] According to these aspects, the transmitted message includes aggregated information of a group of targets based on grouping of multiple targets perceived using a sensor. By aggregating target information that can be grouped into a target group, it is possible to suppress an increase in the amount of information or the number of messages compared to when multiple targets are transmitted as individual information. Therefore, it is possible to reduce one or both of the communication load and the processing load in message processing.

[0009] Another disclosed aspect is a communication device configured to be able to communicate a message including target information, a grouping unit (31) that determines whether or not to group a plurality of targets perceived by a sensor; a message generation unit (32) that determines whether or not information on each target and each target group after aggregation based on the grouping should be included in a message, excludes targets and target groups that are determined not to be included in the message, and generates a message including information on targets and target groups that are determined to be included in the message; A message sending unit (33) that sends the generated message. 、 The message includes aggregated information that aggregates multiple targets into a target group based on the grouping, The aggregated information is aggregated so that information on one target group can be stored in one perceived target container that is configured to store information on one ungrouped target. do.

[0010] According to this aspect, the transmitted message excludes targets and target groups that are determined not to be included in the message among the multiple targets detected by the sensor. Furthermore, this determination is made for the information of each target and each target group after aggregation based on grouping. In other words, by aggregating target information and determining the necessity of transmission, it is possible to suppress an increase in the amount of information or the number of messages. Therefore, it is possible to reduce one or both of the communication load and the processing load in message processing.

[0011] The reference numerals in parentheses are intended to exemplify the correspondence with the parts of the embodiments described later, and are not intended to limit the technical scope. [Brief explanation of the drawings]

[0012] [Figure 1] 1 illustrates an example architecture of a V2X communication device. [Figure 2] FIG. 1 is a diagram illustrating a V2X message. [Figure 3] FIG. 1 illustrates the logical interfaces for the CPS and other layers. [Figure 4] Functional block diagram of CPS. [Figure 5] A diagram showing the basic structure of CPM. [Figure 6] FIG. 1 shows the configuration of a POC. [Figure 7] FIG. 4 is a diagram illustrating a method for extracting target data. [Figure 8] System configuration diagram. [Figure 9] FIG. [Figure 10] 10 is a flowchart showing a process for generating and transmitting a CPM. [Figure 11]11 is a flowchart showing detailed processing of S3 in FIG. 10; [Figure 12] 12 is a flowchart showing the processing executed subsequent to FIG. 11. [Figure 13] 11 is a flowchart showing detailed processing of S4 in FIG. 10; [Figure 14] 11 is a flowchart showing detailed processing of S6 in FIG. 10. [Figure 15] 11 is a flowchart showing detailed processing of S3 in FIG. 10; [Figure 16] 11 is a flowchart showing detailed processing of S6 in FIG. 10. [Figure 17] 11 is a flowchart showing detailed processing of S6 in FIG. 10. [Figure 18] 11 is a flowchart showing a process executed before S1 in FIG. 10. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, several embodiments will be described with reference to the drawings. Note that corresponding components in each embodiment are given the same reference numerals, and redundant description may be omitted. When only a portion of the configuration is described in each embodiment, the configuration of another embodiment described previously can be applied to the remaining portion of the configuration. Furthermore, in addition to the combinations of configurations explicitly stated in the description of each embodiment, configurations of several embodiments can also be partially combined together even if not explicitly stated, as long as there is no particular problem with the combination.

[0014] (First embodiment) The communication device of the present disclosure is configured to be capable of communicating messages including target information. In one embodiment, the communication device is mounted on a vehicle. The communication device can also be called a V2X communication device. The V2X communication device may perform communication between vehicles, between a vehicle and a bicycle, between a vehicle and a mobile terminal, between a vehicle and a roadside device, etc. The V2X communication device may correspond to an on-board device of a vehicle, or may be included in the on-board device. The on-board device may be called an OBU (On-Board Unit).

[0015] The communication device may correspond to a roadside unit that constitutes an infrastructure, and the roadside unit may sometimes be called an RSU (Road Side Unit). The communication device can also be an element that constitutes an ITS (Intelligent Transport System). When it is an element of the ITS, the communication device may correspond to an ITS station (ITS-S) or may be included in the ITS-S. The ITS-S is a device that performs information exchange, and it can be any of an OBU, an RSU, and a mobile terminal, or may be included in them. The mobile terminal is, for example, a PDA (Personal Digital Assistant) or a smartphone.

[0016] The communication device may correspond to a WAVE (Wireless Access in Vehicular) device disclosed in IEEE 1609 or may be included in the WAVE device.

[0017] In this embodiment, it is assumed that the communication device is a V2X communication device. This V2X communication device has a function of providing a Collective Perception Service (hereinafter referred to as CPS). In CPS, the V2X communication device communicates a Collective Perception Message (hereinafter referred to as CPM). Even if the communication device is an RSU or a mobile terminal, the same or similar method as that disclosed below is applicable.

[0018] <Regarding V2X communication> FIG. 1 shows an exemplary architecture of a V2X communication device according to an embodiment of the present disclosure. The architecture shown in FIG. 1 is based on the reference architecture of an ITS-S according to EU standards. The architecture shown in FIG. 1 is a configuration including an application layer 110, a facility layer 120, a network & transport layer 140, an access layer 130, a management layer 150, and a security layer 160.

[0019] The application layer 110 implements or supports various applications 111. In Fig. 1, examples of the applications 111 include a traffic safety application 111a, an efficient traffic information application 111b, and other applications 111c.

[0020] The facility layer 120 supports the execution of various use cases defined in the application layer 110. The facility layer 120 can support functions that are the same as or similar to those of the top three layers (application layer, presentation layer, and session layer) in the OSI reference model. Note that facility means providing a function, information, or data. The facility layer 120 may provide the functions of a V2X communication device. For example, the facility layer 120 may provide the functions of application support 121, information support 122, and communication support 123 shown in FIG. 1.

[0021] The application support 121 has a function to support a basic application set or message set. An example of a message is a V2X message. The V2X message can include a periodic message such as a Cooperative Awareness Message (CAM) and an event message such as a Decentralized Environmental Notification Message (DENM). The facility layer 120 can also support CPM.

[0022] The information support 122 has the function of providing common data or databases used for a basic application set or message set. One example of a database is a local dynamic map (LDM).

[0023] The communication support 123 has a function for providing services for communication and session management, such as address mode and session support.

[0024] In this way, the facility layer 120 supports an application set or a message set. That is, the facility layer 120 generates a message set or a message based on the information to be transmitted or the service to be provided by the application layer 110. The messages generated in this way may be called V2X messages.

[0025] The access layer 130 includes an external IF (Interface) 131 and an internal IF 132, and can transmit messages / data received by the upper layer via a physical channel. For example, the access layer 130 can perform or support data communication using the following communication technologies: communication technology based on the IEEE 802.11 and / or 802.11p standards, ITS-G5 wireless communication technology based on the physical transmission technology of the IEEE 802.11 and / or 802.11p standards, 2G / 3G / 4G (LTE) / 5G wireless mobile communication technology including satellite / broadband wireless mobile communication, wideband terrestrial digital broadcasting technology such as DVB-T / T2 / ATC, GNSS communication technology, and WAVE communication technology.

[0026] The network and transport layer 140 can use various transport protocols and network protocols to configure a network for vehicle communication between homogeneous and heterogeneous networks. The transport layer is a connection layer between upper and lower layers. Upper layers include the session layer, presentation layer, and application layer 110. Lower layers include the network layer, data link layer, and physical layer. The transport layer can manage transmitted data to ensure it arrives at its destination correctly. At the sender side, the transport layer processes data into packets of appropriate size for efficient data transmission. At the receiver side, the transport layer restores the received packets to the original file. Transport protocols include, for example, TCP (Transmission Control Protocol), UDP (User Datagram Protocol), and BTP (Basic Transport Protocol).

[0027] The network layer can manage logical addresses. The network layer may also determine packet delivery routes. The network layer may receive packets generated in the transport layer and add destination logical addresses to network layer headers. Packet transmission routes may include unicast / multicast / broadcast between vehicles, between vehicles and fixed stations, and between fixed stations. Geo-networking, mobility support, or IPv6 networking related to geo-networking may be considered as network protocols.

[0028] As shown in Fig. 1, the architecture of the V2X communication device may further include a management layer 150 and a security layer 160. The management layer 150 manages data transmission and interaction between layers. The management layer 150 includes a management information base 151, a regulatory management 152, an inter-layer management 153, a station management 154, and an application management 155. The security layer 160 manages security for all layers. The security layer 160 includes a firewall and intrusion detection management 161, an authentication, authorization, and profile management 162, and a security management information base 163.

[0029] 2 illustrates an example of a V2X message. A V2X message may also be referred to as an ITS message. A V2X message may be generated by the application layer 110 or the facility layer 120. Examples of V2X messages are CAM, DENM, and CPM.

[0030] The transport layer in the network and transport layer 140 generates a BTP packet. The network layer in the network and transport layer 140 can encapsulate the BTP packet to generate a geo-networking packet. The geo-networking packet is encapsulated in a Logical Link Control (LLC) packet. In Figure 2, the data may include a message set. The message set is, for example, a basic safety message.

[0031] BTP is a protocol for transmitting V2X messages generated in the facility layer 120 to lower layers. There are two types of BTP headers: A type and B type. A type BTP header may include the destination port and source port required for sending and receiving packets in bidirectional packet transmission. A type B BTP header may include the destination port and destination port information required for transmission in non-bidirectional packet transmission.

[0032] The following describes the fields contained in the BTP header. The destination port identifies the facility entity corresponding to the destination of the data contained in the BTP packet (BTP-PDU). The BTP-PDU is a unit of transmission data in BTP.

[0033] The source port is a field generated for the BTP-A type. The source port indicates the port of the protocol entity in the facility layer 120 at the source of the corresponding packet. This field can have a size of 16 bits.

[0034] Destination port information is a field generated for BTP-B type. It provides additional information if the destination port is a well-known port. This field can have a size of 16 bits.

[0035] The geo-networking packet includes a basic header and a common header according to the network layer protocol, and optionally includes an extension header according to the geo-networking mode. The geo-networking header will be described later.

[0036] An LLC packet is a geonetworking packet with an LLC header added. The LLC header provides the ability to distinguish between IP data and geonetworking data before transmission. IP data and geonetworking data can be distinguished by the SNAP (Subnetwork Access Protocol) Ethertype.

[0037] When IP data is transmitted, the Ethertype may be set to x86DD and included in the LLC header. When geo-networking data is sent, the Ethertype may be set to 0x86DC and included in the LLC header. The receiver can check the Ethertype field in the LLC packet header and forward and process the packet to the IP data path or the geo-networking path depending on the value of the Ethertype field in the LLC packet header.

[0038] The LLC header contains a Destination Service Access Point (DSAP) and a Source Service Access Point (SSAP). Following the SSAP in the LLC header are the control field (Control in Figure 2), protocol ID, and Ethertype.

[0039] The V2X communication device may provide various services for traffic safety and traffic efficiency improvement. One of the services may be a Cooperative Awareness (CA) service. Cooperative awareness in road traffic means that road users and roadside infrastructure can know each other's positions, dynamics, and attributes. Road users refer to all users on and around the road who perform traffic safety and control, such as automobiles, trucks, motorcycles, bicycles, pedestrians, etc., and roadside infrastructure refers to facilities such as road signs, signal lights, barriers, and entrances. Among these, pedestrians, people moving in wheelchairs, etc. can be said to be vulnerable road users.

[0040] Recognizing each other is fundamental to applications such as traffic safety and traffic efficiency improvement. Mutual recognition can be achieved through regular information exchange among road users such as vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), infrastructure-to-vehicle (I2V), and object-to-object (X2X) based on a wireless network called the V2X network.

[0041] In applications for cooperative safe driving and traffic efficiency improvement, it is required to develop situation awareness including the presence and actions of road users around the V2X communication device. For example, the V2X communication device can perform situation awareness through its own sensors and communication with other V2X communication devices. In this case, the CA service can specify a method for the V2X communication device to notify its position, behavior, and attributes by transmitting a CAM.

[0042] In this way, in the CA service, the V2X communication device can support traffic safety by periodically providing its position and status to surrounding V2X communication devices. However, the CA service has a limitation that it can only share the information of the corresponding V2X communication device itself. To overcome this limitation, service development such as CPS124 is necessary.

[0043] <CPS and CPM> The CPS 124 can specify how the V2X communication device notifies other V2X communication devices about the positions, behaviors, and attributes of detected surrounding road users and other targets. For example, the CPS 124 can share the information contained in the CPM with other V2X communication devices by transmitting the CPM. Note that the CPS 124 may be a function that can be added to all types of target information communication devices participating in road traffic.

[0044] CPMs are messages exchanged between V2X communication devices over a V2X network. CPMs can be used to generate collective perceptions of road users and other targets detected and / or recognized by the V2X communication devices. The recognized road users or targets may include, but are not limited to, road users or targets that are not equipped with V2X communication devices.

[0045] As mentioned above, V2X communication devices that share information via CAM only share information about their own perception state with other V2X communication devices for cooperative perception. In this case, road users without V2X communication devices are not part of the system, and therefore have a limited view of the situation related to safety and traffic management.

[0046] One way to improve this is for a system equipped with a V2X communication device that can recognize road users and targets that are not equipped with a V2X communication device to notify other V2X communication devices of the presence and status of road users and targets that are not equipped with a V2X communication device. In this way, the CPS 124 cooperatively recognizes the presence of road users and targets that are not equipped with a V2X communication device, making it possible to easily improve the safety and traffic management performance of systems equipped with V2X communication devices.

[0047] 3, the CPS 124 may be an entity in the facilities layer 120 that operates the CPM protocol. For example, the CPS 124 may be part of the application support domain of the facilities layer 120.

[0048] The CPS 124 may provide two services, for example, CPM transmission and reception, which may fundamentally differ from the CA service in that the CPS 124 may not receive input data about the host V2X communications device, for example, from a Vehicle Data Provider (VDP) 125 or a position and time (POTI) unit 126.

[0049] The transmission of the CPM includes generating and transmitting the CPM. In the process of generating the CPM, the originating V2X communication device generates the CPM, and then the CPM is sent to the network and transport layer 140 for transmission. The originating V2X communication device may be referred to as an originating V2X communication device, a host V2X communication device, etc.

[0050] CPS 124 may interface with other entities in facility layer 120 and V2X applications in facility layer 120 to collect relevant information for CPM generation and distribute received CPM content for further processing. In a V2X communications device, the entity for data collection may be the function providing target detection in the host target detector.

[0051] Furthermore, to distribute (or transmit) the CPM, the CPS 124 may use services provided by protocol entities in the Network & Transport Layer 140. For example, the CPS 124 may connect to the Network & Transport Layer 140 through an NF-SAP to exchange CPMs with other V2X communication devices. The NF-SAP is a service access point between the Network & Transport Layer 140 and the Facilities Layer 120.

[0052] Furthermore, CPS 124 may connect with a secure entity through an SF-SAP, which is an SAP between security layer 160 and facility layer 120, to access security services for sending and receiving CPMs. CPS 124 may also connect with a management entity through an MF-SAP, which is an SAP between management layer 150 and facility layer 120. CPS 124 may also connect with application layer 110 through an FA-SAP, which is an SAP between facility layer 120 and application layer 110, to provide received CPM data directly to an application.

[0053] The distribution of CPM may vary depending on the applied communication system. For example, in an ITS-G5 network as defined in ETSI EN 302 663, CPM may be transmitted from the originating V2X communication device to all V2X communication devices within direct communication range. Communication range may be particularly influenced by the originating V2X communication device by varying its transmission power depending on the relevant region.

[0054] Furthermore, the CPM may be generated periodically at a frequency controlled by the CPS 124 in the originating V2X communication device. The generation frequency may be determined taking into account the wireless channel load determined by distributed congestion control. The generation frequency may also be determined taking into account the state of the detected non-V2X target, for example, dynamic behavior of the position, speed, or direction, and the transmission of CPMs for the same perceived target by other V2X communication devices.

[0055] Additionally, when the receiving V2X communications device receives the CPM, the CPS 124 makes the contents of the CPM available for use by functions within the receiving V2X communications device, such as the V2X application and / or the LDM 127. For example, the LDM 127 may be updated with the received CPM data. The V2X application may retrieve this information from the LDM 127 for further processing.

[0056] As shown in FIG. 4, the CPS 124 can provide the following sub-functions for CPM transmission and reception: The CPM encoder 1241 configures or generates a CPM according to a predefined format. The latest in-vehicle data may be included in the CPM. The CPM decoder 1242 decodes the received CPM. The CPM transmission manager 1243 performs protocol operations for the source V2X communication device. Operations performed by the CPM transmission manager 1243 may include starting and ending the CPM transmission operation, determining the CPM generation frequency, and triggering CPM generation. The CPM reception manager 1244 can perform protocol operations for the recipient V2X communication device. Specifically, these operations may include triggering a CPM decoding function upon CPM reception, providing received CPM data to the LDM 127 or a V2X application in the recipient V2X communication device, and checking the information of the received CPM.

[0057] The modulation and coding scheme (MCS) in CPM affects the resulting channel usage. In scenarios where large packets are required, using a higher MCS increases bandwidth efficiency and reduces channel congestion. For example, a modulation scheme such as QAM16 or higher may be employed.

[0058] Next, CPM distribution will be described in detail. Specifically, the requirements for CPM distribution, activation and termination of the CPS 124, CPM trigger conditions, CPM generation cycle, constraints, etc. will be described. Point-to-multipoint communication specified in ETSI EN 302 663 may be used for CPM distribution. For example, if ITS-G5 is used for CPM distribution, a control channel (G5-CCH) may be used. CPM generation may be triggered and managed by the CPS 124 while the CPS 124 is operating. The CPS 124 may be activated when the V2X communication device is activated and may be terminated when the V2X communication device is terminated.

[0059] The host V2X communication device may transmit a CPM each time at least one object with sufficient reliability to be exchanged with nearby V2X communication devices is detected. Regarding including the detected object, the CPS should consider the trade-off between the lifetime of the object and the channel utilization rate. For example, from the perspective of an application that uses the information received by the CPM, it is necessary to provide updated information as frequently as possible. However, from the perspective of the ITS-G5 stack, since it is necessary to minimize the channel usage rate, a low transmission period is required. Therefore, it is desirable for the V2X communication device to consider this point and appropriately include the detected object and object information in the CPM. The transmission period (also referred to as T_GenCpm) may be restricted to a range greater than 100 ms and less than 1000 ms. The transmission period may be changed dynamically, and in this case, the transmission period may also be referred to as the transmission interval. Also, in order to reduce the message size, it is necessary to evaluate the object before transmission.

[0060] <Structure of CPM> Figure 5 shows the structure of the CPM. As described above, the CPM may be a message exchanged between V2X communication devices in the V2X network. Also, the CPM may be used to generate a collective perception of road users and / or other objects detected and / or perceived by the V2X communication device. That is, the CPM may be an ITS message for generating a collective perception of the object detected by the V2X communication device.

[0061] The CPM may include the state information and attribute information of the road users and objects detected by the source V2X communication device. The content may vary according to the type of the detected road user or object and the detection performance of the source V2X communication device. For example, when the object is a vehicle, the state information may include at least information regarding the actual time, position, and motion state. The attribute information may include attributes such as dimensions, vehicle type, and role in road traffic.

[0062] The CPM may complement and function similarly to the CAM, i.e., to enhance cooperative awareness. The CPM may include externally observable information about detected road users or objects. The CPS 124 may include a method for verifying CPMs transmitted by other stations to reduce duplication or overlap of CPMs transmitted by different V2X communication devices.

[0063] Upon receiving the CPM, the receiving V2X communication device may recognize the presence, type, and status of road users or targets detected by the originating V2X communication device. The received information may be used by the receiving V2X communication device to support V2X applications to enhance safety and improve traffic efficiency and travel time. For example, by comparing the received information with the status of the detected road users or targets, the receiving V2X communication device can estimate the risk of a collision with the road users or targets. Furthermore, the receiving V2X communication device may notify the user via the receiving V2X communication device's human-machine interface (HMI) or automatically take corrective action.

[0064] The general format of a CPM will be described with reference to Figure 5. This format may be presented as an ASN (Abstract Syntax Notation).1 Data elements (DE) and data frames (DF) not defined in this disclosure may be derived from the common data dictionary specified in ETSI TS 102 894-2. As shown in Figure 5, a CPM may include a common ITS protocol unit header / ITS packet data unit (hereinafter ITS PDU header) and multiple containers.

[0065] The ITS PDU header contains information about the protocol version, message type, and the ITS ID of the originating V2 communication device. The ITS PDU header is a common header used in ITS messages and is located at the beginning of the ITS message. The ITS PDU header is also called a common header.

[0066] The multiple containers may include a Management Container, a Station Data Container, a Sensor Information Container, a Perceived Object Container, and a Free Space Addendum Container.

[0067] The sensor information container is sometimes called a field-of-view container. The field-of-view container is sometimes written as FOC. The perceived target container is sometimes written as POC. The CPM includes a management container as a required container, and the station data container, sensor information container, perceived target container, and free space adjunct container may be optional containers. The sensor information container, perceived target container, and free space adjunct container may be multiple containers. The upper limit of the number of sensor information containers, perceived target containers, and free space adjunct containers that can be included in one CPM message may be set jointly or individually. The upper limit of the number of containers may be, for example, 128.

[0068] Each container is described below. In the following, DF stands for data frame, and DE stands for data element. Each container consists of a sequence of optional or mandatory DE and / or DF.

[0069] The management container provides basic information about the originating ITS-S, regardless of whether it is a vehicle or roadside unit type station. The management container may also include information about the station type, reference location, and optionally the current message segment. The station type indicates the type of ITS-S. The reference location is the location of the originating ITS-S. The information about the message segment describes the division information when the CPM is divided into multiple messages due to message size constraints.

[0070] The station data container provides more specific information about the originating ITS-S in addition to the common information provided by the management container. If the originating ITS-S is a vehicle, the station data container includes an Originating Vehicle Container (OVC). The OVC may contain information that overlaps to some extent with the CAM. An ITS-S that receives a CPM from an origin also receives a CAM from the same origin. Furthermore, the OVC may contain additional parameters not provided by the CAM. The additional optional parameters may include at least one of vehicle heading angle, pitch angle, roll angle, vehicle height, and trailer data.

[0071] If the originating ITS-S is an RSU, it contains an Originating RSU Container, which contains an ID for the road or intersection where the RSU is located. The Originating RSU Container may contain optional parameters to refer to the road infrastructure provided by the road lane topology service.

[0072] The sensor information container lists information about individual sensors attached to the vehicle or RSU to detect surrounding targets. If the V2X communication device is equipped with multiple sensors, multiple sensor information containers may be added. All sensors listed in the sensor information container are assigned a temporary ID (sensor ID) that is used in turn in the perceived target container to associate perceived target information with a specific sensor.

[0073] Each sensor information DF may contain a sensor type indicating the type of sensor system. This may be a specific sensor type that fuses target information fused from multiple sensors. An ITS-S can be equipped with different types of sensors, e.g. radar, lidar, or multi-sensor fusion systems. Thus, the sensor information container offers different possibilities for describing the characteristics of the sensor system.

[0074] Sensors attached to a moving station, such as a vehicle, are described using the vehicle sensor description DF. Stationary sensors attached to an RSU are described using the stationary sensor variant DF. Thus, the descriptions of the two sensor types may be different. Both sensor types can be used to describe the detection performance of the ITS-S, which may be actual parameters of the perception system. The actual parameters may be, for example, the actual perception range or the applicable perception area of ​​the perception system, i.e., the area in which targets are detected by the perception system.

[0075] The sensor type indicates the type of sensor. The sensor types are listed below. The number in parentheses is a flag corresponding to the type. For example, sensor types are undefined (0), radar (1), LiDAR (2), mono video (3), stereo vision (4), night vision (5), ultrasonic (6), pmd (7), fusion (8), induction loop (9), spherical camera (10), and a combination of these (11). pmd is a photo mixing device. A spherical camera is also called a 360-degree camera.

[0076] The Perceived Target Container is used to describe targets perceived by a sensor associated with the originating V2X communication device. A Perceived Target Container can be added for every target perceived by the ITS-S. The Perceived Target Container can also provide classification and location matching road data.

[0077] 6 is a configuration example of a perceptual target container in CPM. The DF and DE defined in the perceptual target container will be described with reference to Table 1.

[0078] The target ID shown in Table 1 is an identifier assigned to a detected target. The target ID remains constant as long as the target is perceived by the distributed ITS-S.

[0079] The sensor ID list is a list of sensor IDs that provided measurement data. This list is used to reference the sensor IDs in the sensor information container.

[0080] The measurement time provides the time difference from the message's generated delta time to the measurement time. A negative value indicates that the specified target state refers to a point in time after the generated delta time was calculated, i.e., after the most recent ITS-S position update used to calculate the generated delta time.

[0081] The target age provides the age of the target that was detected and described.

[0082] Target confidence is the confidence associated with a target. Target confidence indicates the reliability of the target's existence and its characteristics. The target confidence value may be expressed as a percentage between 1 and 100. A target confidence value of 0 may indicate that the target's confidence is unknown. A target confidence value of 101 may indicate that the confidence cannot be calculated and the required confidence level defined by the corresponding standard that applies the DE is not applicable.

[0083] The absolute distance is the absolute distance from the reference point of the ITS-S to the detected target at the time of measurement. The absolute distance may be provided by three DFs: x-distance, y-distance, and z-distance. The x-distance is the absolute distance in the x-direction from the reference point of the ITS-S to the detected target at the time of measurement. The y-distance is the absolute distance in the y-direction from the reference point of the ITS-S to the detected target at the time of measurement. The z-distance is the absolute distance in the z-direction from the reference point of the ITS-S to the detected target at the time of measurement. When the ITS-S is a vehicle, the x-, y-, and z-directions follow the coordinate system specified in ISO 8855. When the ITS-S is an RSU, a coordinate system is adopted in which y indicates north, x indicates east, and z indicates vertical.

[0084] The relative velocity is the relative velocity of the detected target from the reference point of the ITS-S at the time of measurement. The relative velocity may be provided by three DFs: x velocity, y velocity, and z velocity. The x velocity is the relative velocity of the detected target in the x direction from the reference point of the ITS-S at the time of measurement. The y velocity is the relative velocity of the detected target in the y direction from the reference point of the ITS-S at the time of measurement. The z velocity is the relative velocity of the detected target in the z direction from the reference point of the ITS-S at the time of measurement.

[0085] Relative acceleration is the relative velocity of the detected target from the reference point of the ITS-S at the time of measurement. Relative acceleration may be provided by three DFs: x acceleration, y acceleration, and z acceleration. x acceleration is the relative acceleration of the detected target in the x direction from the reference point of the ITS-S at the time of measurement. y acceleration is the relative acceleration of the detected target in the y direction from the reference point of the ITS-S at the time of measurement. z acceleration is the relative acceleration of the detected target in the z direction from the reference point of the ITS-S at the time of measurement.

[0086] The yaw angle is the relative yaw angle of the target from the reference point of the ITS-S. If the ITS-S is a vehicle, the yaw angle corresponds to the x direction of the vehicle in the coordinate system specified by ISO 8855. If the ITS-S is an RSU, the yaw angle is measured as a positive value that takes into account the target's direction rotating counterclockwise from the x direction in a coordinate system where y indicates north, x indicates east, and z indicates vertical. The confidence in the yaw angle may be described with a predefined 95% confidence level for the component.

[0087] The dimensions are the dimensions of the target provided by the sensor or environmental model. The dimensions may be provided by three DFs: the first planar dimension, the second planar dimension, and the vertical dimension. The first planar dimension is the first dimension of the target provided by the sensor or environmental model. The first planar dimension is always contained in a plane perpendicular to the direction of the angle indicated by the yaw angle and containing the target's reference point. The second planar dimension is the second dimension of the target provided by the sensor or environmental model. The second planar dimension is always contained in a plane containing the direction of the angle indicated by the yaw angle and the target's reference point. The vertical dimension is the vertical dimension of the target provided by the sensor or environmental model. The dimensions may be described with a predefined 95% confidence level for the component. The DF of the dimension may store the target's dimension value, which can be estimated as the mean of the current distribution, and the dimension accuracy associated with the specified value.

[0088] The reference point is a reference point on the perceived target for which measurement data is provided. If the reference point on the target cannot be identified, the reference point is considered to be the center point of the detected target. The reference point is included in a plane perpendicular to the direction of the yaw angle.

[0089] Dynamic status is the classification of a perceived target according to its movement ability. Dynamic status indicates whether the detected target is classified as a dynamic target. If this value is stored as 0, the dynamic status indicates that the target is generally moving. If this value is stored as 1, the dynamic status indicates that the target was previously dynamic. If this value is stored as 2, the dynamic status indicates that the target has not moved during previous observations.

[0090] The classification provides a classification of the described target. Multidimensional classifications may be provided along with confidence levels. Classifications are performed with a certain confidence level. The classification DF may include the class that best describes the detected target. Each class may provide optional subclasses and confidence levels associated with the subclasses.

[0091] Targets may be classified into five categories: unknown, vehicle, human, animal, and other. That is, the class must be set to one of vehicle, human, animal, and other. For vehicles, the following subclass types may be described: unknown (0), moped (1), motorcycle (2), passenger car (3), bus (4), light truck (5), heavy truck (6), trailer (7), special vehicle (8), tram (9), emergency vehicle (10), and agricultural vehicle (11). The numbers in parentheses here are flag values ​​stored as subclass values.

[0092] For humans, the following subclass types may be described: unknown (0), pedestrian (1), human using a wheelchair (2), cyclist (3), human walking while pushing or pulling a stroller (4), human skating (5), and human group (6). The numbers in parentheses here are flag values ​​stored as subclass values.

[0093] The map matching location is an optionally provided map matching location of the object. The map matching location may be the location of the object on the LDM. The DF of the map matching location may provide a lane ID and longitudinal lane location indicating the lane on the road where the object is located.

[0094] The free space add container is a container that indicates information about the free space recognized by the source V2X communication device (i.e., free space information). Free space is an area that is not considered to be occupied by road users or obstacles, and can also be referred to as an empty space. Free space can also be referred to as a space in which a moving object traveling with the source V2X communication device can move.

[0095] 7 conceptually illustrates sensor data extraction by a V2X communication device providing a CPS 124. More specifically, FIG. 7(a) illustrates how the V2X communication device extracts sensor data at a low level, and FIG. 7(b) illustrates how the V2X communication device extracts sensor data at a high level.

[0096] The source of the sensor data transmitted as part of the CPM needs to be selected according to the requirements of the future data fusion process in the receiving V2X communication device. In general, the transmitted data should be as close as possible to the original sensor data. However, simply transmitting the original sensor data, e.g., raw data, is not practical, as it imposes very high requirements on data rate and transmission period.

[0097] Figures 7(a) and 7(b) show possible embodiments for selecting data to be transmitted as part of a CPM. In the embodiment of Figure 7(a), sensor data is acquired from different sensors and processed as part of a low-level data management entity. This entity can select object data to be inserted as part of the next CPM and can also calculate the validity of detected objects. In Figure 7(a), transmitting data from each sensor increases the amount of data transmitted over the V2X network. However, this allows the receiving V2X communication device to efficiently utilize the sensor information.

[0098] In the embodiment of FIG. 7(b), sensor data or object data provided by a data fusion unit specific to the V2X communication equipment manufacturer is transmitted as part of the CPM.

[0099] In Figure 7(b), the integrated sensor data collected via the data fusion unit is transmitted, which has the advantage of reducing the amount of data transmitted via the V2X network. However, it has the disadvantage of being dependent on the collection method used by the V2X communication device to collect sensor information. In addition, different manufacturers may implement different data fusion processes.

[0100] <System configuration example> An example configuration of a system 20 for realizing ITS-S is shown in Fig. 8. The system 20 may be an in-vehicle system or a roadside system. The communication device 21 included in the system 20 has the functions and configurations described below in addition to the functions and configurations of the communication devices such as the V2X communication device described above.

[0101] The system 20 includes a sensor 40, a target object detection unit 41, a road data storage unit 42, and a communication device 21. When the system 20 is an in-vehicle system, the system 20 may further include a self-position estimation unit 43. The sensor 40 is provided to detect and recognize targets. When the system 20 is an in-vehicle system, the sensor 40 is mounted on a vehicle. A plurality of sensors 40 may be provided on one vehicle. When the system 20 is a roadside system, one or a plurality of sensors 40 are provided and fixed to a road, a building, a pole, etc. The sensor 40 may be a camera, a millimeter-wave radar, a sonar, a LiDAR, etc.

[0102] Targets can include dynamic and static objects. Dynamic objects include, for example, four-wheeled vehicles, two-wheeled vehicles such as motorcycles, pedestrians, and animals. Static objects include, for example, pylons, warning triangles, utility poles, and fallen objects.

[0103] The target detection unit 41 acquires signals including sensor data information from the sensor 40 and detects various targets present around the sensor 40. The target detection unit 41 may be realized by a dedicated computer. The dedicated computer may have at least one memory and one processor. The memory may be a non-transitory tangible storage medium that non-temporarily stores programs, data, etc. that can be read by the processor. Furthermore, a rewritable volatile storage medium such as a RAM (Random Access Memory) may be provided as the memory.

[0104] Information on targets detected and perceived by the sensor 40 and the target detection unit 41 is associated with information necessary for generating a CPM, i.e., information such as a sensor ID included in a sensor information container, and provided to the communication device 21. Note that the target detection unit 41 may be included in the sensor 40 itself as a component of the sensor 40.

[0105] The road data storage unit 42 stores and holds road map data. The road data storage unit 42 may be realized by a database equipped with a storage medium. The road map data is data that represents road shapes. The road map data may include high-precision map data. The road map data may include LDM data. The road map data may be data that makes it possible to distinguish lanes on a road. The road map data may be configured to be updated by update map data distributed from a road map distribution center.

[0106] The self-position estimation unit 43 estimates the self-position of the vehicle equipped with the system 20. For example, the self-position estimation unit 43 includes a GNSS receiver that receives navigation signals transmitted by navigation satellites included in GNSS (Global Navigation Satellite Systems). The self-position estimation unit 43 successively estimates the current self-position based on the navigation signals received by the GNSS receiver. The current self-position is expressed by coordinates including latitude and longitude. The coordinates may also include altitude. The current self-position may be used, for example, to identify the reference point of the ITS-S described above.

[0107] The communication device 21 is configured to be capable of wireless communication with another communication device. The other communication device may be another ITS-S, or may be a V2X communication device mounted on the other ITS-S. The other communication device may be a V2X communication device mounted on another vehicle, or may be a V2X communication device mounted on an RSU.

[0108] The communication device 21 may be realized by a dedicated short range communications (DSRC) communication device, a cellular V2X (C-V2X) communication device, etc. The communication device 21 includes a communication circuit 22 and a control unit 23.

[0109] The communication circuit 22 includes a modulation circuit, a demodulation circuit, an amplifier circuit, and the like. The communication circuit 22 modulates and amplifies a message provided from the control unit 23 and transmits the message from the antenna 22a. The communication circuit 22 also demodulates and amplifies a message received via the antenna 22a and provides the message to the control unit 23. The frequency used for communication may be, for example, the 5 GHz band or the 700 MHz band. When the communication device 21 is a V2X communication device, the communication performed by the communication device 21 is V2X communication.

[0110] The control unit 23 controls the communication device 21. As shown in FIG. 9, the control unit 23 may be realized by a dedicated computer 24. The dedicated computer 24 constituting the control unit 23 may have at least one memory 24a and one processor 24b. The memory 24a may be at least one type of non-transitory tangible storage medium, such as a semiconductor memory, a magnetic medium, or an optical medium, that non-temporarily stores programs and data readable by the processor 24b. Furthermore, the memory 24a may be provided with a rewritable volatile storage medium, such as a random access memory (RAM). The processor 24b includes at least one type of core, such as a central processing unit (CPU), a graphics processing unit (GPU), or a reduced instruction set computer (RISC)-CPU.

[0111] The control unit 23 includes a message acquisition unit 30, a grouping unit 31, a message generation unit 32, and a message transmission unit 33 as functional blocks realized by the processor 24b that executes a program.

[0112] The message acquisition unit 30 acquires messages transmitted by other communication devices via the antenna 22a and the communication circuit 22. The messages transmitted by other communication devices include CAM, CPM, DENM, etc. The CPM may include at least one of information on targets perceived by sensors provided in a vehicle or RSU on which the other communication device is mounted, and information on perceived targets further acquired by the vehicle or RSU from another vehicle or RSU.

[0113] When the communication device 21 is mounted in a vehicle, the message acquired by the message acquisition unit 30 may be provided to other systems in the same vehicle through an in-vehicle network. The in-vehicle network may be, for example, Ethernet, CAN (Controller Area Network), LIN (Local Interconnect Network), CXPI (Clock Extension Peripheral Interface), FlexRay, or MOST (Media Oriented Systems Transport). Ethernet, CAN, CXPI, FlexRay, and MOST are registered trademarks. The message acquired by the message acquisition unit 30 is provided to the grouping unit 31.

[0114] The grouping unit 31 determines whether to group multiple targets based on at least one of the target information provided by the message acquisition unit 30 and the target information provided by the target detection unit 41. This determination may include determining assignment of the multiple targets to one or more groups. A target group generated by grouping may be composed of two or more arbitrary targets. A maximum number of targets that can be included in a target group generated by grouping may be set based on message format constraints.

[0115] The multiple targets referred to here are multiple targets perceived by a sensor. The multiple targets perceived by a sensor may include targets perceived by a sensor 40 included in the system 20. The multiple targets perceived by a sensor may include targets perceived by a sensor not included in the system 20 belonging to the communication device 21 but mounted on a vehicle or RSU in which the communication device 21 is mounted, and capable of acquiring sensor data via a network. The multiple targets perceived by a sensor may also include targets perceived by a sensor mounted on a vehicle or RSU in which another communication device is mounted, and information about which is provided by a message received from the other communication device.

[0116] The grouping unit 31 may perform grouping based on predefined grouping conditions. The grouping conditions may be commonly used between the ITS-Ss that transmit and receive the CPM. A plurality of grouping conditions may be defined. In this case, the grouping unit 31 may select a grouping condition to be adopted from the plurality of grouping conditions depending on the road environment, communication congestion, etc. The grouping conditions may be referred to as aggregation conditions for detected targets, or simply as aggregation conditions. Furthermore, the grouping conditions may be considered as a type of redundancy mitigation rules for reducing the message size of the CPM.

[0117] One grouping condition may be one of the conditions described below. On the other hand, one grouping condition may be a composite combination of the conditions described below. In the following, making something a target for grouping includes making it a candidate for grouping, and may also include excluding it from the final grouping in combination with other conditions.

[0118] The grouping conditions may include conditions related to the positions of the targets. For example, the grouping unit 31 may group two targets if the absolute distance between the two targets is equal to or less than a predetermined distance. The grouping unit 31 may exclude two targets from being grouped if the absolute distance between the two targets is greater than the predetermined distance.

[0119] Here, the absolute distance may be calculated by referring to at least one of the information on the distance of the target provided by the target detection unit 41 and the information on the absolute distance of the detected target container in the CPM received from another communication device. A uniquely defined value may be used as the value of the predetermined distance. The value of the predetermined distance may also be changed depending on the road environment, communication congestion, etc. On the other hand, the grouping conditions do not need to include a condition related to the position of the target.

[0120] The grouping condition may include a condition related to the type of target. The type of target may be a class or subclass in the CPM classification. For example, the grouping unit 31 may group multiple targets of the same type. The grouping unit 31 may exclude multiple targets of different types from the grouping target. Multiple targets of the same class but different subclasses may be grouped. Multiple targets of the same class but different subclasses may be excluded from the grouping target. On the other hand, the grouping condition does not have to include a condition related to the type of target.

[0121] The condition related to the target position and the condition related to the target type may be applied in combination. For example, the grouping unit 31 may group two targets if the absolute distance between them is equal to or less than a predetermined distance and the two targets are of the same type. The grouping unit 31 may exclude two targets from grouping if the absolute distance between the two targets is equal to or less than the predetermined distance but the two targets are of different types. Note that the predetermined distance here is a preset threshold value, and a common value may be used between vehicles and RSUs performing V2X communication. The predetermined distance may be a different value depending on the type (e.g., class, subclass) of targets to be grouped. For example, if the targets to be grouped are pedestrians, a first distance may be used as the predetermined distance, and if the targets are vehicles, a second distance may be used as the predetermined distance. The second distance may be smaller than the first distance. The second distance may be larger than the first distance.

[0122] The grouping conditions may include a condition regarding the identity of the sensors. For example, the grouping unit 31 may group multiple targets perceived by the same sensor. The grouping unit 31 may exclude targets perceived by different sensors from the grouping targets. The determination of whether the sensors are the same may be performed by referring to the sensor ID in the sensor information container of the CPM. For example, if two cameras with the same model number (or specifications) are installed on a vehicle, the two cameras may be treated as different sensors. In other words, only multiple targets perceived by one of the two cameras may be grouped.

[0123] The grouping unit 31 may also group multiple targets perceived by sensors of the same type. The grouping unit 31 may exclude targets perceived by sensors of different types from the targets to be grouped. The determination of whether the sensor types are the same may be performed by referring to the sensor type in the sensor information container of the CPM.

[0124] Furthermore, the grouping unit 31 may group a plurality of targets of the same type that are perceived by the same sensor. On the other hand, the grouping conditions do not necessarily have to include a condition regarding the identity of the sensor.

[0125] The grouping condition may include a condition related to the behavior of the target. The condition related to the behavior of the target may be a condition related to the similarity of the behavior. The similarity of the behavior may be determined based on the dynamic status, moving direction, instability of the moving direction, speed, acceleration, or a combination thereof of the target.

[0126] For example, similarity in behavior may be recognized for multiple targets whose speeds fall within a predefined common speed range and whose movement directions fall within a predefined common angle range. If the common speed range is a range indicating small speeds that includes a speed of 0, the movement direction does not need to be included in the parameters for determining similarity in behavior.

[0127] The grouping unit 31 may group multiple targets that are recognized to have similar behaviors. The grouping unit 31 may exclude multiple targets that are recognized to have no similar behaviors or that are recognized to have different behaviors from the targets to be grouped.

[0128] Here, a further specific example of grouping using similarity in behavior will be given. For example, in a densely populated urban area, when a crosswalk changes from a stop signal (e.g., red) to a go signal (e.g., green), a large number of pedestrians start crossing the crosswalk all at once. In this case, similarities in behavior regarding speed and direction of movement are observed among the large number of pedestrians. On the other hand, there may be cases where the distance between pedestrians at both ends is large and it is not appropriate to aggregate them into one target group. In this case, it may be possible to attempt to cluster the large number of pedestrians into two or more target groups using other factors.

[0129] For example, the grouping unit 31 may detect whether there is a gap in a large number of pedestrians where the distance between pedestrians increases, and may cluster the large number of pedestrians into two or more target groups using the gap as a boundary. Other factors may be pedestrian subclasses in CPM target classification, similarities in pedestrian clothing, etc. On the other hand, the grouping conditions may not include conditions related to target behavior.

[0130] The grouping conditions may include a condition regarding the importance of a target. The importance of a target may be set according to the possibility that a vehicle that is expected to receive a message including target information will collide with the target (so-called collision probability). The importance of a target that is located in a position that is directly visible from a vehicle that is expected to receive a message including target information may be set to be relatively low. The importance of a target that is located in a position that is not directly visible from the vehicle (i.e., an obstructed area) may be set to be relatively high.

[0131] For example, the grouping unit 31 may group targets whose importance is lower than a predetermined value. The grouping unit 31 may exclude targets whose importance is higher than a predetermined value from the grouping conditions. On the other hand, the grouping conditions do not need to include a condition regarding the importance of the targets.

[0132] The grouping conditions may include conditions related to road shape. To determine these conditions, the grouping unit 31 may refer to road map data stored in the road data storage unit 42. Furthermore, the grouping unit 31 may also refer to the lane ID and longitudinal lane position in the DF of the map matching position in the detected target container of the received CPM. For example, the grouping unit 31 may group multiple vehicles that exist in the same lane on the road. The grouping unit 31 may exclude vehicles that exist in different lanes on the road from being grouped.

[0133] Here, the grouping conditions may include conditions related to prediction of future behavior of the target object in addition to conditions related to the road shape. For example, the grouping unit 31 may perform grouping by referring to blinker information of other vehicles detected by the sensor 40, blinker information of other vehicles acquired from received messages, or lane change schedule information. The grouping unit 31 may exclude from grouping, even among multiple vehicles existing in the same lane on the road, vehicles that are activating their blinkers or that are planning to change lanes.

[0134] On the other hand, the grouping conditions do not have to include a condition related to the road shape, and in this case, the grouping conditions may include a condition related to the prediction of the future behavior of the target.

[0135] The grouping conditions may include a condition regarding the vulnerability of the target. For example, if the grouping unit 31 determines that the target is not a vulnerable road user, the grouping unit 31 may include the target in the grouping. If the grouping unit 31 determines that the target is a vulnerable road user, the grouping unit 31 may exclude the target from the grouping. On the other hand, the grouping conditions may not include a condition regarding the vulnerability of the target.

[0136] The grouping conditions may include conditions related to the communication congestion status around the communication device 21. For example, the grouping unit 31 may target each target for grouping when the communication congestion level exceeds a predetermined level. The grouping unit 31 may decide not to group each target or aggregate each target into a target group when the communication congestion level is equal to or lower than a predetermined level. The congestion level may be, for example, the usage rate of wireless resources available for short-range communication. Communication load, traffic condition data, etc. may be used together with or instead of the congestion level as a factor for determining whether to group.

[0137] As described above, the grouping unit 31 determines the grouping mode for multiple targets and provides the result to the message generation unit 32. Note that if the number of targets that can be handled by the message is sufficiently small, the processing by the grouping unit 31 may be skipped, and the message may be generated and transmitted without aggregating information on each target.

[0138] The message generator 32 generates a new message to be transmitted. The message generated by the message generator 32 is a message including target information, such as a CPM. The message generator 32 may aggregate multiple received messages into a new message. The message generator 32 may aggregate one or more received messages and target information perceived using the sensors 40 of the system 20 into a new message. The message to be aggregated may include a CAM, a DENM, etc. in addition to a CPM.

[0139] Aggregating messages may include generating aggregated information that aggregates multiple targets into a single target group. The aggregated information that aggregates multiple targets into a single target group may include aggregated information in which multiple targets, each with their own individual information, are aggregated into a single target group. The aggregated information that aggregates multiple targets into a single target group may include aggregated information in which one or more aggregated aggregated information items and one or more targets with their own individual information are aggregated into a single target group. The aggregated information that aggregates multiple targets into a single target group may include aggregated information in which multiple aggregated aggregated information items are aggregated into a single target group. Furthermore, the aggregated information that aggregates multiple targets into a single target group may include aggregated information in which some targets are extracted from one or more aggregated aggregated information items and then re-aggregated. Here, the aggregated information may include information indicating the number of aggregated targets, i.e., the number of targets that make up a single target group.

[0140] The message generation unit 32 generates a message including aggregated information in which targets to be aggregated among the multiple targets are aggregated into target groups based on the group assignments determined by the grouping unit 31. The aggregated information may be stored in a perceived target container of the CAM. For information on targets that have not been grouped or aggregated, one perceived target container may be assigned to one target. For aggregated information on target groups that have been grouped and aggregated, one perceived target container may be assigned to one target group. An example of how aggregated information is handled in a perceived target container is described below.

[0141] The target ID may be newly assigned to the aggregated target group, or may be a list of the target IDs of all targets that make up the target group.

[0142] The sensor ID list may be a list of sensor IDs for all sensors that provided measurement data for each target that constitutes the target group.

[0143] The target reliability may be a reliability associated with the aggregated target group, an average reliability of the reliability of each target constituting the target group, or the minimum reliability of the reliability of each target constituting the target group.

[0144] The absolute distance may be the absolute distance from the reference point of the ITS-S at the time of measurement to the reference point of the target group. The relative velocity may be the relative velocity at which the reference point of the target group moves as viewed from the reference point of the ITS-S at the time of measurement. The relative acceleration may be the relative acceleration at which the reference point of the target group moves as viewed from the reference point of the ITS-S at the time of measurement.

[0145] The dimensions may be expressed by the dimensions of an imaginary rectangle or rectangular parallelepiped that includes all of the targets that make up the target group, and the reference point in the target group may be the center point of this rectangle or rectangular parallelepiped.

[0146] The classification may be based on the type of target if all targets in the target group are of the same type. If targets of different types are mixed in the target group, the classification may be based on another classification, or an additional classification indicating the mixed type. A flag indicating whether the target is an individual target or a target group may be optionally provided in the classification DF.

[0147] Optionally, a DF and / or DE may be provided to provide the number of targets constituting the target group, the density of targets in the target group, etc. The density of targets in the target group may be the density of targets within a rectangle or rectangular parallelepiped that defines the above-mentioned dimensions.

[0148] Furthermore, for a single target that has not been grouped, an optional DF and / or DE may be provided that provides information on whether the target is a vulnerable road user. In particular, when targets of the same type are not grouped in the grouping, it is preferable to provide information on the vulnerability of the target, which is the reason for not grouping.

[0149] The message sending unit 33 converts messages such as CPMs generated by the message generating unit 32 into data suitable for transmission and sends the data to the surrounding area. The CPMs can be transmitted by point-to-multipoint communication. However, the CPMs may also be transmitted by communication methods other than point-to-multipoint communication, such as point-to-point communication.

[0150] If the size of the encoded CPM exceeds the maximum transmission unit, the message sending unit 33 divides the CPM into multiple parts and sends them. When the CPM is divided, the receiving communication device may combine the data of the CPM into one after completing reception of all the divided CPMs.

[0151] Messages containing aggregated information are processed by the receiving vehicle and RSU after being transmitted. For example, the receiving vehicle may use the aggregated information for autonomous driving or driving assistance. In autonomous driving, the information of the target group included in the aggregated information may be used for speed planning and vehicle trajectory planning to ensure safety for the target group. In driving assistance, the information of the target group included in the aggregated information may be used for applications such as the PCS system (Pre-Crash Safety System) and AES system (Automatic Emergency Steering System) to avoid collisions with the target group. Also, in driving assistance, it may be used to notify the driver of the vehicle about the presence of the target group. The receiving RSU may use the aggregated information to further share it with other vehicles or to generate statistical data.

[0152] Here, the correspondence between the configuration diagram of the CPS shown in FIG. 4 and the functions of the control unit 23 shown in FIG. 8 will be described. The function of the message acquisition unit 30 is at least part of the functions of the CPM decoding unit 1242 and the CPM reception management unit 1244. The function of generating and transmitting CPM by the grouping unit 31 and the message generation unit 32 is at least part of the function of the CPM transmission management unit 1243. The function of finally generating and transmitting data by the message transmission unit 33 is at least part of the function of the CPM encoding unit 1241.

[0153] <CPM Generation Process and Transmission Process> Next, an example of the processing method for generating and transmitting CPM will be described using the flowchart of FIG. 10. This processing method can also be said to be a communication method. The series of processes shown in FIG. 10 is executed at a predetermined execution cycle or based on a predetermined trigger. The predetermined cycle may be shorter than T_GenCpm described later. The series of processes may be executed by at least one processor 24b provided in the control unit 23 so that the functions of the message acquisition unit 30, the grouping unit 31, the message generation unit 32, and the message transmission unit 33 are realized.

[0154] In S1, it is determined whether T_Now-T_LastCpm is greater than or equal to T_GenCpm. T_Now is the current time. T_LastCpm is the time when the last CPM was transmitted. T_GenCpm is the cycle for generating CPMs. Therefore, in S1, it is determined whether the cycle for transmitting CPMs has passed since the last CPM was transmitted.

[0155] In S2, T_GenEvent is set to T_Now. T_GenEvent means the time when the event that generates the CPM occurs. By setting T_GenEvent to T_Now, the time when the CPM is generated becomes the current time.

[0156] In S3, candidates for perceived targets are selected. A perceived target means a target whose target characteristics are included in the perceived target container. Details of the process in S3 are shown in Figure 11.

[0157] In S4, a sensor information container is generated. Details of the process in S4 are shown in FIG.

[0158] In S5, it is determined whether POC (i.e., perceived object container) or SIC (i.e., sensor information container) data has been generated. If neither POC nor SIC has been generated, the determination result in S5 is NO. If the determination result in S5 is NO, the processing in FIG. 10 ends without transmitting the CPM. If the determination result in S5 is YES, proceed to S6.

[0159] In S6, an OVC (when the entity transmitting the CPM is a vehicle) and a management container are generated. The process of S6 is shown in FIG.

[0160] In S7, T_LastCpmtimestamp is set in T_GenEvent. T_LastCpmtimestamp indicates the time when the last CPM was generated.

[0161] In S8, the next CPM is obtained. In S9, the CPM obtained in S8 is transmitted.

[0162] In S10, it is determined whether there are any untransmitted CPM segments. If the determination result in S10 is YES, the process returns to S8, where the untransmitted CPM segments are acquired and transmitted. If the determination result in S10 is NO, the series of processes in FIG. 10 is terminated.

[0163] Next, the processing method for selecting a perception target candidate in S3 will be described in detail with reference to the flowcharts of FIGS.

[0164] In S301 shown in FIG. 11, a list of targets is acquired from the environmental model and stored in a target list. The environmental model may be generated by the control unit 23. The control unit 23 may acquire an environmental model generated by another device inside or outside the system 20. The environmental model is an example of a representation form of the results of estimating the characteristics of various targets. The target list is a list for selecting candidates for perceived targets in the processing of FIG. 11. The target list may include information on target reliability. Targets included in the environmental model may include targets perceived by the sensor 40. Targets included in the environmental model may be targets included in the target information of the CPM acquired by the message acquisition unit 30.

[0165] In S302, it is determined whether or not a target exists in the target list. If the determination result in S302 is NO, the process of S3 is terminated and the process proceeds to S4. If the determination result in S302 is YES, the process proceeds to S303.

[0166] In S303, the next target is acquired from the target list. In S304, it is determined whether the target reliability is equal to or greater than a preset threshold. Note that S304 may be omitted and the process proceeds to S305. For example, if the target reliability has not been determined, S304 may be omitted. If the determination result in S304 is NO, the process proceeds to S311 in FIG. 12. If the determination result in S304 is YES, the process proceeds to S305.

[0167] In S305, it is determined whether the target has been stored in a predetermined area of ​​the internal memory. For example, the internal memory is memory 24a provided in control unit 23, and the predetermined area is an area for saving data for generating a CPM. If the determination result in S305 is NO, that is, if the target acquired in S303 has already been stored in the internal memory, the process proceeds to S310 in FIG. 12. If the determination result in S305 is YES, the process proceeds to S306.

[0168] In S306, it is determined whether the target acquired in S303 belongs to the human or animal class. In other words, it is determined whether the target acquired in S303 is classified as a human or an animal. If the determination result in S306 is NO, the process proceeds to S307. In S307, it is determined whether at least one of the distance, speed, direction, and elapsed time of the target has changed by more than a predetermined threshold value since the last CPM transmission. If the determination result in S307 is YES, the process proceeds to S310 in FIG. 12. On the other hand, if the determination result in S307 is NO, the process proceeds to S311 in FIG. 12.

[0169] If the determination result in S306 is YES, the process proceeds to S308. In S308, it is determined whether 500 ms or more have passed since the target acquired in S303 was included in the CPM. If the determination result in S308 is NO, the process also proceeds to S311 in FIG. 12. If the determination result in S308 is YES, the process proceeds to S309. In S309, all people and animals are included in the CPM to be generated. Thereafter, the process proceeds to S310 in FIG. 12.

[0170] 12, it is determined whether or not to group the targets in the target list based on the grouping conditions. In S311, multiple targets are aggregated into target groups based on the grouping determined in S310.

[0171] In S312, the target ID and T_GenEvent are stored in internal memory, and the stored information is marked for transmission.

[0172] In S313, it is determined whether the target or group of targets is the last in the target list. If the determination result in S311 is NO, the process returns to S303. If the determination result in S313 is YES, the process proceeds to S314. In S314, a list of candidates for perceived target containers is created based on the mark. After executing S314, the process proceeds to S4 in FIG. 10.

[0173] Next, the processing method for generating the sensor information container in S4 will be described in detail with reference to the flowchart in FIG.

[0174] In S41, it is determined whether the value obtained by subtracting T_LastSensorInfoContainer from T_Now is greater than or equal to T_AddSensorInformation. T_LastSensorInfoContainer is the time when the last sensor information container was generated. T_AddSensorInformation indicates the period for adding sensor information containers. If the determination result in S41 is NO, the processing in FIG. 13 is terminated and the process proceeds to S5 in FIG. 10. If the determination result in S41 is YES, the process proceeds to S42.

[0175] In S42, the sensor parameters are obtained by querying a database that stores the sensor parameters. In S43, a sensor information container is generated using the sensor parameters obtained in S42. In S44, T_LastSensorInfoContainer is set to T_GenEvent. In other words, the time when the sensor information container was generated is set to the time when S2 is executed when the next CPM is created. When the processing in FIG. 13 is completed, proceed to S5 in FIG. 10.

[0176] Next, the processing method for generating the OVC and management container in S6 will be described in detail with reference to the flowchart in FIG.

[0177] In S61, the station type is selected. If the station type is a vehicle, the process proceeds to S62. In S62, an OVC is generated. After S62 is executed, the process proceeds to S65.

[0178] If the determination in S61 indicates that the station type is an RSU, proceed to S63. In S63, determine whether to transmit a MAP message. A MAP message is a message that provides the shape of an intersection or road segment around the RSU. If the determination result in S63 is YES, proceed to S64. In S64, generate a source RSU container that includes the MAP message. Then, proceed to S65. If the determination result in S63 is NO, proceed to S65 without executing S64.

[0179] In S65, a management container for an undivided CPM is generated. The management container generated here may include station types, reference points, segmentation information, and the number of perceived object targets. The management container may also include information on grouping conditions used to determine the groupings. The information on grouping conditions may be flags indicating the grouping conditions, or may be actual conditions.

[0180] In S66, the encoding size of the CPM including all the generated containers is calculated. Note that the CPM can include a free space additional container. If a free space additional container is generated, the encoding size of the CPM is calculated including the size of the free space additional container.

[0181] In S67, it is determined whether the size of the encoded CPM exceeds MTU_CPM. MTU_CPM is the maximum transmission unit of one CPM and is set in advance. MTU_CPM is determined depending on the maximum transmission unit of the access stratum 130.

[0182] If the determination result in S67 is NO, proceed to S68. In S68, a CPM including all of the generated containers is generated. Then, proceed to S7 in FIG. 10. On the other hand, if the determination result in S67 is YES, proceed to S69. In S69, message segments are determined in order to divide the message. Then, proceed to S7 in FIG. 10.

[0183] (Action and effect) The effects of the first embodiment described above will be explained below.

[0184] According to the first embodiment, the transmitted message includes aggregated information of a target group based on grouping of multiple targets perceived by a sensor. By aggregating target information that can be grouped into a target group, it is possible to suppress an increase in the amount of information or the number of messages compared to when multiple targets are transmitted as individual information. Therefore, it is possible to reduce one or both of the communication load and the processing load in message processing.

[0185] Furthermore, according to the first embodiment, targets of the same type are grouped together. By configuring the target group in this manner, when a display device mounted on a vehicle notifies or warns the driver about target information, the target group can be explained in a simple and concise manner. Furthermore, it is possible to more easily predict the behavior of the target group, such as its speed.

[0186] Furthermore, according to the first embodiment, targets of the same type perceived by the same type of sensor are grouped together. When a target group is configured in this way, the information in the CPM perceived target container and the information in the sensor information container referenced by it can be simply associated, making it easier to use the information.

[0187] Furthermore, according to the first embodiment, whether or not to group multiple targets is determined depending on the positions of the targets. For example, by grouping targets whose positions are within a preset distance into a target group, a vehicle that receives a message can easily plan a response, such as collision avoidance, for the target group.

[0188] Furthermore, according to the first embodiment, whether or not to group multiple targets is determined depending on the similarity of the behaviors of the multiple targets. By grouping multiple targets with similar behaviors into a target group, the behavior of the target group can be easily represented.

[0189] Furthermore, according to the first embodiment, whether or not to group the multiple targets is determined based on the reliability of the sensor's perception. In particular, by grouping targets with similar sensor reliability, it is easy to handle the target group even if the receiving ITS-S is designed to change the way it handles target groups based on the sensor reliability.

[0190] Furthermore, according to the first embodiment, whether to group multiple targets is determined depending on the importance of the targets. In particular, targets with high importance are not grouped into a target group, but are transmitted as individual target information, which makes it easier to respond appropriately to the targets.

[0191] Furthermore, according to the first embodiment, whether or not to group multiple targets is determined depending on the lane on the road the targets are in. In particular, by not grouping vehicles in different lanes into the same target group, lane ID information can be stored appropriately in the CPM.

[0192] Furthermore, according to the first embodiment, whether to group multiple targets is determined based on the prediction of the future behavior of the targets. By grouping targets with similar predictions of future behavior into a target group, it is possible to reduce the possibility that the target group will be separated in the future and will have to be handled separately.

[0193] Furthermore, according to the first embodiment, whether to group multiple targets is determined depending on the communication congestion situation around the communication device 21. When communication is congested, further strain on the communication load can be avoided by grouping multiple targets into a small number of target groups.

[0194] Furthermore, according to the first embodiment, information indicating the grouping conditions determined in the grouping is added to the message. By sharing the grouping conditions with the receiving ITS-S, the receiving ITS-S can use the grouping conditions as reference information when grouping and aggregating targets.

[0195] Furthermore, according to the first embodiment, the dimensions of a target group are expressed by the dimensions of a rectangular parallelepiped that encompasses all of the targets aggregated in the target group. This allows the dimensions of the target group to be stored in a DF similar to the perceived target container that stores individual targets in a CPM.

[0196] Furthermore, according to the first embodiment, when multiple targets of the same type are not grouped in the grouping, information indicating whether the ungrouped targets are vulnerable road users is added to the message, which makes it easier to respond appropriately to the ungrouped targets.

[0197] (Second embodiment) 15 and 16, the second embodiment is a modification of the first embodiment. The second embodiment will be described, focusing on the differences from the first embodiment.

[0198] The grouping unit 31 of the second embodiment determines whether to group multiple targets based on initial grouping conditions. Thereafter, the grouping unit 31 modifies the grouping conditions according to the total number of targets and target groups or the expected message size after aggregation in the grouping based on the initial grouping conditions. Then, the grouping unit 31 again determines whether to group multiple targets based on the modified grouping conditions.

[0199] For example, if the total number of targets and target groups based on the initial grouping conditions exceeds a predetermined number, the grouping unit 31 may modify the grouping conditions. On the other hand, if the total number of targets and target groups based on the initial grouping conditions is equal to or less than the predetermined number, the grouping unit 31 may ultimately adopt the grouping under the initial grouping conditions without modifying the grouping conditions. The predetermined number here may be the maximum number of perceived target containers that can be formatted and stored in one CPM. In other words, in order to avoid splitting the CPM, the initial grouping conditions are modified to conditions that provide a higher degree of aggregation.

[0200] An example of a processing method based on the total number will now be described with reference to the flowchart of Fig. 15. The processing of Fig. 15 can be used in place of the processing of Fig. 12 in the first embodiment.

[0201] 15, it is determined whether or not to group the targets in the target list based on the initial grouping conditions. In S1311, multiple targets are aggregated into target groups based on the grouping determined in S1310.

[0202] In S1313, it is determined whether the total number of targets after aggregation and the total number of targets exceeds a predetermined number. If the determination result in S1313 is YES, the process proceeds to S1314. If the determination result in S1313 is NO, the process proceeds to S1316.

[0203] In S1314, the initial grouping conditions are modified to conditions that increase the degree of aggregation, and grouping is performed again based on the modified grouping conditions. In S1315, multiple targets are aggregated into target groups based on the grouping determined in S1314. The processes of S1316 to S1318 are the same as the processes of S312 to S314 in FIG. 12.

[0204] Instead of processing based on the total number, processing based on the message size can be adopted. For example, if the message size after aggregation in grouping based on the initial grouping conditions exceeds the above-mentioned maximum transmission unit, the grouping unit 31 may modify the grouping conditions. On the other hand, if the message size is equal to or smaller than the maximum transmission unit, the grouping unit 31 may ultimately adopt the grouping based on the initial grouping conditions without modifying the grouping conditions. In other words, in order to avoid splitting the CPM, the initial grouping conditions are modified to conditions that result in a higher degree of aggregation.

[0205] An example of a processing method based on the message size will now be described with reference to the flowchart in Fig. 16. The processing in Fig. 16 can be used in place of the processing in Fig. 14 in the first embodiment. In this case, the processing in Fig. 12 similar to that in the first embodiment can be used for the processing of S3.

[0206] The processes of S2061 to S2068 in Fig. 16 are the same as the processes of S61 to S68 in Fig. 14. On the other hand, if it is determined in S2067 that the size of the encoded CPM exceeds MTU_CPM, i.e., the maximum transmission unit, the message is not divided in S2069.

[0207] In S2069, the initial grouping conditions are modified to conditions that increase the degree of aggregation, and grouping is performed again based on the modified grouping conditions. The modified grouping conditions are preferably conditions that allow messages to be transmitted without being divided reliably. In S2070, multiple targets are aggregated into target groups based on the grouping determined in S2069.

[0208] (Third embodiment) As shown in Fig. 17, the third embodiment is a modification of the first embodiment. The third embodiment will be described, focusing on the differences from the first embodiment.

[0209] The message generator 32 aggregates multiple targets into targets and target groups based on the grouping by the grouping unit 31. The message generator 32 then determines whether or not to include information about each aggregated target and each target group in a message. The message generator 32 excludes targets and target groups that are determined not to be included in the message. The message generator 32 generates a message that includes information about targets and target groups that are determined to be included in the message.

[0210] This determination may be based on predefined redundancy mitigation rules, which may include frequency-based redundancy mitigation rules, such that if the number of historical CPMs containing identical target and target group information exceeds a predefined threshold, targets and target groups perceived by local sensors may be excluded from the CPM being generated.

[0211] The redundancy mitigation rules may include dynamic-based redundancy mitigation rules, i.e., a target or group of targets may be excluded if the difference between the current estimated position (or estimated velocity) of the reference point of the target or group of targets included in the last received CPM and the current estimated position (or estimated velocity) of the target or group of targets as perceived by the local sensor is less than or equal to a preset threshold.

[0212] The redundancy mitigation rules may include confidence-based redundancy mitigation rules, i.e., if historical CPMs contain information about the same target or group of targets, and the confidence of this target or group of targets in these historical CPMs is higher than the confidence in local sensor perception, then this target or group of targets may be excluded.

[0213] Other redundancy mitigation rules may include entropy-based redundancy mitigation rules, target self-declaration redundancy mitigation rules, distance-based redundancy mitigation rules, and the like.

[0214] An example of the processing method will now be described with reference to the flowchart of Fig. 17. The processing of Fig. 17 can be used in place of the processing of Fig. 14 in the first embodiment.

[0215] The processes of S3061 to S3068 in Fig. 17 are the same as the processes of S61 to S68 in Fig. 14. On the other hand, if it is determined in S3067 that the size of the encoded CPM exceeds MTU_CPM, i.e., the maximum transmission unit, the message is not divided in S3069.

[0216] In S3069, targets and target groups to be included in the CPM are selected. In S3070, a CPM is generated that includes containers for the targets and target groups selected in S3069.

[0217] According to the third embodiment described above, the message to be transmitted excludes targets and target groups that are determined not to be included in the message among multiple targets detected by the sensor. Furthermore, this determination is made for the information of each target and each target group after aggregation based on grouping. In other words, by aggregating target information and determining the necessity of transmission, it is possible to suppress an increase in the amount of information or the number of messages. Therefore, it is possible to reduce one or both of the communication load and the processing load in message processing.

[0218] (Fourth embodiment) The fourth embodiment is a modification of the first embodiment, and the fourth embodiment will be described focusing on the differences from the first embodiment.

[0219] The message transmitter 33 transmits a CPM at a predetermined first interval. Under this transmission condition, the message generator 32 considers a case where it is determined that the dimensions of the aggregated targets in the previously transmitted CPM have changed by a predetermined threshold or more. In this case, the message transmitter 33 changes the CPM transmission interval to a second interval that is shorter than the first interval.

[0220] That is, under normal circumstances, the CPM is transmitted at a first interval that is sufficiently larger than 100 ms, and when there is a large change in the characteristics of the target group, such as the shape, the transmission interval is changed to a second interval that is close to the minimum value of 100 ms. In this way, by transmitting information about a target group that tends to change dynamically at short intervals, the receiving vehicle or RSU can more easily respond to dynamic changes in the target group.

[0221] An example of a processing method for setting a transmission cycle will now be described with reference to the flowchart in Fig. 18. The processing in Fig. 18 can be inserted before the processing of S1 in Fig. 10 in the first embodiment.

[0222] In S100 shown in Fig. 18, it is determined whether the dimensions of the target group have changed by more than a threshold value in the target group information included in the previously transmitted CPM. If the determination result in S100 is NO, the process proceeds to S101. If the determination result in S100 is YES, the process proceeds to S102.

[0223] In S101, T_GenCpm is set to T1, which is a value corresponding to the first interval. After S101 is executed, the process proceeds to S1 in FIG.

[0224] In S102, T_GenCpm is set to T2. T2 is a value corresponding to the second interval and is smaller than T1. After S102 is executed, the process proceeds to S1 in FIG.

[0225] (Other embodiments) Although multiple embodiments have been described above, the present disclosure should not be construed as being limited to those embodiments, and can be applied to various embodiments and combinations within the scope that does not deviate from the gist of the present disclosure.

[0226] As a first modification, if the size of the encoded CPM exceeds the maximum transmission unit as a result of the processing in S2069 and S2070 in FIG. 15, the CPM may be divided.

[0227] As a second modification, if the size of the encoded CPM exceeds the maximum transmission unit as a result of the processing in S3069 and S3070 in FIG. 16, the CPM may be divided.

[0228] As a third modification, the architecture and messages for communicating target information may be those conforming to US standards. The architecture and messages for communicating target information may be those conforming to Japanese standards. The grouping function or the function of aggregating multiple targets into target groups according to the present disclosure may be applied to various architectures and messages adopted in each country or region.

[0229] As a fourth modification, the system 20 may be an autonomous driving system or a driving assistance system as an in-vehicle system. In this case, the system 20 may further include an autonomous driving planning function, a driving function, and driving assistance functions such as emergency braking.

[0230] As a fifth variant, the shape of the target group defined in the perceived target container may be expressed by a shape other than a rectangle or a rectangular parallelepiped. For example, the shape of the target group may be expressed by a plurality of points, such as a polygon. In other words, the area surrounded by the plurality of points that represent the polygon may be an area that includes all of the targets that make up the target group. The plurality of points may be expressed by relative position coordinates from a reference point of the ITS-S. The plurality of points may be expressed by relative position coordinates from a reference point of the target group. When the shape of the target group is expressed by a polygon, the dimensions of the perceived target container may be replaced by the coordinates of the plurality of points.

[0231] The message generator 32 may calculate the similarity of the perceived target group to the actual shape of a rectangle or a cuboid, and select whether to represent the shape of the target group as a rectangle or a cuboid or as a polygon based on the similarity. That is, if the similarity is higher than a preset threshold, the shape of the target group may be represented as a rectangle or a cuboid. If the similarity is equal to or lower than the threshold, the shape of the target group may be represented as a polygon.

[0232] The controller and methods described herein may be implemented by a special-purpose computer comprising a processor programmed to perform one or more functions embodied in a computer program. Alternatively, the apparatus and methods described herein may be implemented by special-purpose hardware logic circuitry. Alternatively, the apparatus and methods described herein may be implemented by one or more special-purpose computers comprising a processor executing a computer program in combination with one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by a computer on a computer-readable non-transitory storage medium.

[0233] (Disclosure of technical ideas) This specification discloses multiple technical ideas described in the following multiple clauses. Some clauses may be written in a multiple dependent form, where the subsequent clause alternatively refers to the preceding clause. These multiple dependent clauses define multiple technical ideas.

[0234] <Technical philosophy 1> A communication device configured to be able to communicate a message including target information, a grouping unit (31) that determines whether or not to group a plurality of targets perceived by a sensor; a message generating unit (32) that generates a message including aggregated information that aggregates the plurality of targets into a target group based on the grouping; A communication device comprising: a message sending unit (33) that sends a message including the aggregated information.

[0235] <Technical philosophy 2> The communication device according to Technical Idea 1, wherein the grouping unit groups targets of the same type.

[0236] <Technical philosophy 3> The communication device according to Technical Idea 2, wherein the grouping unit groups targets of the same type perceived by the same sensor.

[0237] <Technical philosophy 4> The communication device according to any one of Technical Ideas 1 to 3, wherein the grouping unit determines whether to group the plurality of targets depending on the positions of the targets.

[0238] <Technical philosophy 5> The communication device according to any one of Technical Ideas 1 to 4, wherein the grouping unit determines whether to group the plurality of targets according to similarity in behavior among the plurality of targets.

[0239] <Technical philosophy 6> The communication device according to any one of Technical Ideas 1 to 5, wherein the grouping unit determines whether to group the plurality of targets depending on the reliability of the sensor's perception.

[0240] <Technical philosophy 7> The communication device according to any one of Technical Ideas 1 to 6, wherein the grouping unit determines whether to group the plurality of targets according to the importance of the targets.

[0241] <Technical philosophy 8> The communication device according to any one of Technical Ideas 1 to 7, wherein the grouping unit determines whether to group the plurality of targets depending on a lane on a road on which the targets are located.

[0242] <Technical philosophy 9> The communication device according to any one of Technical Ideas 1 to 8, wherein the grouping unit determines whether to group the plurality of targets according to a prediction of future behavior of the targets.

[0243] <Technical Thought 10> The communication device according to any one of technical ideas 1 to 9, wherein the grouping unit determines whether to group the plurality of targets depending on a communication congestion situation around the communication device.

[0244] <Technical Thought 11> The grouping unit determining whether to group the plurality of targets based on an initial grouping condition; modifying the grouping conditions in accordance with the total number of targets and target groups after aggregation or the message size after aggregation in the grouping based on the initial grouping conditions; The communication device according to any one of Technical Ideas 1 to 10, wherein whether or not to group the plurality of targets is determined again based on the modified grouping conditions.

[0245] <Technical Thought 12> The communication device described in any one of Technical Ideas 1 to 11, wherein the message generation unit expresses the dimensions of the target group included in the aggregated information by the dimensions of a rectangular parallelepiped that includes all of the multiple targets aggregated in the target group.

[0246] <Technical Thought 13> Under a transmission condition in which the message transmitter transmits the message at a predetermined first interval, The communication device described in Technical Idea 12, wherein when it is determined that the dimensions of the target group aggregated in the previously transmitted message have changed by more than a preset threshold, the message transmitting unit changes the transmission interval of the message to a second interval that is shorter than the first interval.

[0247] <Technical Thought 14> The communication device according to any one of Technical Ideas 1 to 13, wherein the message generation unit generates a message including information indicating a grouping condition determined in grouping.

[0248] <Technical Thought 15> The communication device according to any one of technical ideas 1 to 14, wherein the message generation unit generates a message including information indicating whether the ungrouped targets are vulnerable road users when the multiple targets of the same type are not grouped in the grouping.

[0249] <Technical Thought 16> A communication device configured to be able to communicate a message including target information, a grouping unit (31) that determines whether or not to group a plurality of targets perceived by a sensor; a message generation unit (32) that determines whether or not information on each target and each target group after aggregation based on the grouping is to be included in a message, excludes targets and target groups that are determined not to be included in the message, and generates a message including information on targets and target groups that are determined to be included in the message; a message sending unit (33) that sends the generated message.

[0250] <Technical Thought 17> 1. A communication method executed by at least one processor for communicating a message including target information, comprising: determining whether to group a plurality of targets perceived using a sensor; generating a message including aggregated information that aggregates the plurality of targets into a target group based on the grouping; and sending a message including the aggregated information.

[0251] <Technical Thought 18> A V2X communication system mounted on a vehicle or a roadside unit for communicating messages including target information with other vehicles or other roadside units, a sensor (40) for detecting a target and generating target information relating to the detected target; a processing system (33) having at least one processor (34b) and at least one storage medium (34a); a communication circuit (32) having an antenna (32a), the storage medium stores grouping conditions; At least one processor receiving a message including the target information about the target transmitted from another vehicle or another roadside unit through the communication circuit; acquiring the target information from the sensor; determining whether to group a plurality of targets based on the target information included in the message and the target information from the sensor based on the grouping conditions; generating a new message including aggregated information that aggregates the plurality of targets into a target group based on the grouping; A V2X communication system that transmits a message including the aggregated information to another vehicle or another roadside unit through the communication circuit.

[0252] <Technical Thought 19> 1. A V2X communication method for communicating messages including target information with other vehicles or other roadside units, comprising: receiving a message including the target information about the target transmitted from another vehicle or another roadside unit through a communication circuit; acquiring target information from a sensor that detects targets and generates the target information regarding the detected targets; determining whether to group a plurality of targets based on the target information included in the message and the target information from the sensor based on a grouping condition stored in at least one storage medium; generating a new message including aggregated information that aggregates the plurality of targets into a target group based on the grouping; A V2X communication method, wherein a message including the aggregated information is transmitted to another vehicle or another roadside unit through the communication circuit. [Explanation of symbols]

[0253] 21: communication device, 31: grouping unit, 32: message generation unit, 33: message transmission unit

Claims

1. A communication device configured to be able to communicate a message including target information, a grouping unit (31) for determining whether or not to group a plurality of targets sensed by a sensor; a message generating unit (32) that generates a message including aggregated information that aggregates the plurality of targets into a target group based on the grouping; a message sending unit (33) that sends a message including the aggregated information, The aggregated information is aggregated so that information of one group of targets can be stored in one perceived target container configured to store information of one ungrouped target.

2. The communication device according to claim 1 , wherein the grouping unit groups targets of the same type.

3. The communication device according to claim 2 , wherein the grouping unit groups the targets of the same type perceived by the same sensor.

4. The communication device according to claim 1 , wherein the grouping unit determines whether to group the plurality of targets according to positions of the targets.

5. The communication device according to claim 1 , wherein the grouping unit determines whether to group the plurality of targets according to similarities in behavior among the plurality of targets.

6. The communication device according to claim 1 , wherein the grouping unit determines whether to group the plurality of targets according to a reliability of perception by the sensor.

7. The communication device according to claim 1 , wherein the grouping unit determines whether to group the plurality of targets according to the importance of the targets.

8. The communication device according to claim 1 , wherein the grouping unit determines whether to group the plurality of targets depending on a lane on a road where the targets are located.

9. The communication device according to claim 1 , wherein the grouping unit determines whether to group the plurality of targets in accordance with a prediction of future behavior of the targets.

10. The communication device according to claim 1 , wherein the grouping unit determines whether to group the plurality of targets depending on a communication congestion state around the communication device.

11. The grouping unit determining whether to group the plurality of targets based on an initial grouping condition; modifying the grouping conditions in accordance with the total number of targets and target groups after aggregation or the message size after aggregation in the grouping based on the initial grouping conditions; The communication device according to claim 1 , further comprising: a step of determining again whether or not to group the plurality of targets based on the modified grouping condition.

12. A communication device configured to be able to communicate a message including target information, a grouping unit (31) for determining whether or not to group a plurality of targets sensed by a sensor; a message generating unit (32) that generates a message including aggregated information that aggregates the plurality of targets into a target group based on the grouping; a message sending unit (33) that sends a message including the aggregated information, The grouping unit determining whether to group the plurality of targets based on an initial grouping condition; modifying the grouping conditions in accordance with the total number of targets and target groups after aggregation or the message size after aggregation in the grouping based on the initial grouping conditions; The communication device again determines whether or not to group the plurality of targets based on the modified grouping conditions.

13. The communication device according to claim 1 , wherein the message generator expresses the dimensions of the target group included in the aggregated information by the dimensions of a rectangular parallelepiped that includes all of the targets aggregated in the target group.

14. Under a transmission condition in which the message transmitter transmits the message at predetermined first intervals, 14. The communication device according to claim 13, wherein, when it is determined that dimensions of the group of targets aggregated in the previously transmitted message have changed by a predetermined threshold or more, the message transmitter changes the transmission interval of the message to a second interval shorter than the first interval.

15. A communication device configured to be able to communicate a message including target information, a grouping unit (31) for determining whether or not to group a plurality of targets sensed by a sensor; a message generating unit (32) that generates a message including aggregated information that aggregates the plurality of targets into a target group based on the grouping; a message sending unit (33) that sends a message including the aggregated information, the message generator expresses the dimensions of the target group included in the aggregated information by the dimensions of a rectangular parallelepiped that includes all of the targets aggregated in the target group; Under a transmission condition in which the message transmitter transmits the message at predetermined first intervals, when it is determined that the dimensions of the target group aggregated in the previously transmitted message have changed by a predetermined threshold or more, the message transmitting unit changes the transmission interval of the message to a second interval shorter than the first interval.

16. The communication device according to claim 1 , wherein the message generating unit generates a message including information indicating a grouping condition determined in the grouping.

17. 2. The communication device according to claim 1, wherein, when the plurality of targets of the same type are not grouped in the grouping, the message generation unit generates a message to which information indicating whether the targets that are not grouped are vulnerable road users is added.

18. A communication device configured to be able to communicate a message including target information, a grouping unit (31) for determining whether or not to group a plurality of targets sensed by a sensor; a message generating unit (32) that generates a message including aggregated information that aggregates the plurality of targets into a target group based on the grouping; a message sending unit (33) that sends a message including the aggregated information, The message generation unit generates a message including information indicating whether the targets that are not grouped are vulnerable road users when the multiple targets of the same type are not grouped in the grouping.

19. A communication device configured to be able to communicate a message including target information, a grouping unit (31) for determining whether or not to group a plurality of targets sensed by a sensor; a message generation unit (32) that determines whether or not information on each target and each target group after aggregation based on the grouping is to be included in a message, excludes targets and target groups that are determined not to be included in the message, and generates a message including information on targets and target groups that are determined to be included in the message; a message sending unit (33) that sends the generated message, the message includes aggregated information in which the plurality of targets are aggregated into a target group based on the grouping, The aggregated information is aggregated so that information of one group of targets can be stored in one perceived target container configured to store information of one ungrouped target.

20. 1. A communication method executed by at least one processor for communicating a message including target information, comprising: determining whether to group a plurality of targets perceived using a sensor; generating a message including aggregated information that aggregates the plurality of targets into a target group based on the grouping; sending a message including the aggregated information; The aggregated information is aggregated so that information of one group of targets can be stored in one perceived target container configured to store information of one ungrouped target.

21. 1. A communication method executed by at least one processor for communicating a message including target information, comprising: determining whether to group a plurality of targets perceived using a sensor; generating a message including aggregated information that aggregates the plurality of targets into a target group based on the grouping; sending a message including the aggregated information; In determining whether to group, determining whether to group the plurality of targets based on an initial grouping condition; modifying the grouping conditions in accordance with the total number of targets and target groups after aggregation or the message size after aggregation in the grouping based on the initial grouping conditions; a communication method in which it is determined again whether or not to group the plurality of targets based on the modified grouping conditions.

22. 1. A communication method executed by at least one processor for communicating a message including target information, comprising: determining whether to group a plurality of targets perceived using a sensor; generating a message including aggregated information that aggregates the plurality of targets into a target group based on the grouping; sending a message including the aggregated information; generating the message includes expressing dimensions of the target group included in the aggregated information by dimensions of a rectangular parallelepiped that includes all of the targets aggregated in the target group; Under a transmission condition in which the message is transmitted at a predetermined first interval, the step of transmitting the message when it is determined that the dimensions of the group of targets aggregated in the previously transmitted message have changed by a predetermined threshold or more includes changing the transmission interval of the message to a second interval that is shorter than the first interval.

23. 1. A communication method executed by at least one processor for communicating a message including target information, comprising: determining whether to group a plurality of targets perceived using a sensor; generating a message including aggregated information that aggregates the plurality of targets into a target group based on the grouping; sending a message including the aggregated information; The communication method, wherein generating the message includes, when the plurality of targets of the same type are not grouped in the grouping, generating a message to which information indicating whether the targets that were not grouped are vulnerable road users is added.

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