COMMUNICATION DEVICE, COMMUNICATION SYSTEM, CONTROL CIRCUIT, STORAGE MEDIUM, AND COMMUNICATION METHOD

Abstract

To obtain a communication device (101) that is mounted on a vehicle and capable of sharing free space information indicating locations where no vehicles or obstacles exist with communication devices mounted on other vehicles. The communication device includes a free space information sharing unit (103) that collects self-location information and other-party location information including location information of other vehicles and obstacles, and generates host vehicle free space information indicating locations where the vehicle (1) or other vehicles or obstacles do not exist, and a wireless communication unit (104) that receives the other-vehicle free space information generated by the other vehicles and transmits the host vehicle free space information to the other vehicles.

Description

[Technical field]

[0001] The present disclosure relates to a communication device, a communication system, a control circuit, a storage medium, and a communication method mounted on a vehicle. [Background technology]

[0002] In an automatic driving system, a safe driving support system, and the like, it is necessary to share vehicle position information, vehicle speed information, and the like between vehicles in real time. In recent years, with the spread of ITS (Intelligent Transportation System), technological developments have been made to share vehicle position information, vehicle speed information, and the like between vehicles by wireless communication between vehicles, and representative wireless communication systems include DSRC (Dedicated Short-Range Communications) and C-V2X (Cellular-Vehicle-to-Everything). For example, Patent Document 1 discloses a technology in which a communication device mounted on a vehicle periodically broadcasts vehicle position information, and the like to surrounding vehicles, thereby sharing position information, and the like between surrounding vehicles. Patent Document 1 describes that DSRC can be used for communication between vehicles. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2009-278194 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, according to the above conventional technology, the vehicle position information shared between the vehicles indicates the area where the vehicle and other vehicles exist, but does not positively indicate that other vehicles do not exist in the area where the vehicle and other vehicles do not exist. In other words, it is not clear whether other vehicles do not exist in the area where the vehicle position information does not clearly indicate the presence of other vehicles, or whether other vehicles actually exist. Therefore, there is a problem that the vehicle equipped with the communication device cannot actively use the shared position information for lane change to the area where other vehicles do not exist, entering an intersection, etc. For a vehicle that plans to change lanes, enter an intersection, etc., free space information indicating a place where no vehicles or obstacles exist, that is, no vehicles or obstacles exist in a certain area, is important.

[0005] The present disclosure has been made in consideration of the above, and aims to obtain a communication device that is mounted on a vehicle and can share free space information indicating locations where no vehicles or obstacles exist with communication devices mounted on other vehicles. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems and achieve the object, the present disclosure provides a communication device mounted on a vehicle. The communication device includes a free space information sharing unit that collects self-location information, which is vehicle location information of the vehicle, and other-party location information, which includes vehicle location information of other vehicles and location information of obstacles, and generates own-vehicle free space information, which is free space information indicating a location where the vehicle, other vehicles, or obstacles are not present, and a communication unit that receives other-vehicle free space information, which is free space information generated by the other vehicles, and transmits the own-vehicle free space information to the other vehicles. The accuracy and granularity of the free space information that each vehicle can provide is called capability. The communication unit actively or passively searches for the capability of other vehicle free space information that the vehicle wishes to acquire, and receives the other vehicle free space information that the vehicle wishes to acquire. It is characterized by: Effect of the Invention

[0007] The communication device of the present disclosure is mounted on a vehicle and has the effect of being capable of sharing free space information indicating locations where no vehicles or obstacles exist with communication devices mounted on other vehicles. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing a configuration example of a communication system according to a first embodiment; [Diagram 2] FIG. 1 is a diagram illustrating an example of the configuration of a free space information sharing unit included in a communication device according to a first embodiment; [Diagram 3] FIG. 1 is a diagram illustrating an example of the configuration of a free space information generating unit included in a communication device according to a first embodiment. [Figure 4] FIG. 1 is a diagram showing an example of information indicated in free space information handled by a vehicle according to the first embodiment; [Diagram 5] 1 is a flowchart showing an operation of a communication device according to a first embodiment. [Figure 6] FIG. 1 is a diagram showing an example of the configuration of a processing circuit that realizes a communication device according to a first embodiment when the processing circuit is realized by a processor and a memory. [Figure 7] FIG. 1 is a diagram showing an example of a processing circuit for implementing a communication device according to a first embodiment when the processing circuit is configured with dedicated hardware; [Figure 8] FIG. 13 is a diagram showing a state in which free space information is shared by communication devices mounted on four vehicles according to the second embodiment. [Figure 9] FIG. 13 is a diagram showing an example of a capability of a vehicle according to a third embodiment; [Figure 10] FIG. 11 is a sequence diagram showing an operation when a vehicle according to a third embodiment performs discovery. [Figure 11] FIG. 11 is a sequence diagram showing an operation of a vehicle according to a fourth embodiment when free space information is shared with a plurality of vehicles after a notification message is transmitted and received. [Figure 12] A sequence diagram showing an operation when a vehicle that requests free space information starts to actively search for the capabilities of surrounding vehicles in a vehicle according to a fifth embodiment. [Figure 13]A sequence diagram showing the operation of a vehicle according to a sixth embodiment when a vehicle that desires free space information starts to actively search for the capabilities of surrounding vehicles and a plurality of vehicles transmit response messages. [Figure 14] A sequence diagram showing the operation of a vehicle according to a seventh embodiment in which a vehicle that requests free space information starts to actively search for the capabilities of surrounding vehicles, and multiple vehicles transmit response messages and are made targets for sharing free space information with the multiple vehicles based on the contents of the response messages. [Figure 15] FIG. 23 is a sequence diagram showing an operation of a vehicle according to an eighth embodiment when passively searching for a group member who needs free space information. [Figure 16] FIG. 13 is a sequence diagram showing an operation when a vehicle according to a ninth embodiment actively searches for a group member who needs free space information. [Figure 17] FIG. 23 is a diagram showing a configuration example of a communication system according to a tenth embodiment. [Figure 18] A sequence diagram showing an operation in a case where a vehicle according to a twelfth embodiment uses a C-V2X communication unit as a wireless communication unit and uses Model A Discovery in ProSe Direct Discovery for discovery. [Figure 19] A sequence diagram showing an operation in a case where a vehicle according to a twelfth embodiment uses a C-V2X communication unit as a wireless communication unit and uses Model B Discovery in ProSe Direct Discovery for discovery. [Figure 20] A sequence diagram showing an operation in a case where a vehicle according to a thirteenth embodiment uses a C-V2X communication unit as a wireless communication unit and uses Model A Discovery in Group Member Discovery for discovery. [Figure 21] A sequence diagram showing an operation in a case where a vehicle according to a thirteenth embodiment uses a C-V2X communication unit as a wireless communication unit and uses Model B Discovery in Group Member Discovery for discovery. [Figure 22] FIG. 23 is a sequence diagram showing an operation of a vehicle according to a fourteenth embodiment when communication between a vehicle requesting free space information and a vehicle providing the free space information is multi-hop. [Figure 23] FIG. 23 is a sequence diagram showing an operation when a relay vehicle is selected in a vehicle according to the fourteenth embodiment. [Figure 24] FIG. 23 is a sequence diagram showing an operation when a relay vehicle is actively selected in a vehicle according to the fifteenth embodiment. [Diagram 25] FIG. 23 is a sequence diagram showing an operation when a vehicle according to a sixteenth embodiment uses ProSe UE-to-UE Relay Model A Discovery in selecting a relay vehicle. [Figure 26] A sequence diagram showing an operation when a vehicle according to a seventeenth embodiment actively selects a relay vehicle by using ProSe UE-to-UE Relay Model B Discovery in selecting a relay vehicle. [Figure 27] FIG. 23 is a diagram showing an example in which a conflict occurs in free space information shared by a plurality of vehicles according to the eighteenth embodiment; [Figure 28] FIG. 23 is a diagram showing an example of a result of a vehicle according to the eighteenth embodiment combining a plurality of pieces of free space information. [Figure 29] FIG. 23 is a first sequence diagram showing an operation for quickly selecting a vehicle that is to be provided with new free space information when a contention occurs during sharing of free space information in vehicles according to the nineteenth embodiment. [Diagram 30] FIG. 23 is a second sequence diagram showing an operation for quickly selecting a vehicle that is to be provided with new free space information when a contention occurs during sharing of free space information in the vehicles according to the nineteenth embodiment. [Diagram 31] FIG. 23 is a sequence diagram showing the operation of passively selecting a vehicle that is to be provided with new free space information quickly when a contention occurs during sharing of free space information in the vehicles according to the twenty-first embodiment. [Diagram 32]A sequence diagram showing an operation when using a C-V2X communication unit when setting a primary response vehicle, a secondary response vehicle, etc., in the case where a conflict occurs when sharing free space information in a vehicle according to a twenty-second embodiment. [Diagram 33] A sequence diagram showing an operation of a surrounding vehicle estimating absolute position information or relative position information of a vehicle that shares free space information in a vehicle according to a twenty-third embodiment when the surrounding vehicle does not have absolute position information or relative position information of the vehicle. [Diagram 34] FIG. 24 is a sequence diagram showing an operation in which a vehicle capable of positioning performs positioning voluntarily, and a vehicle that desires to obtain free space information passively obtains a positioning result according to the twenty-fourth embodiment. [Diagram 35] A sequence diagram showing the operation of a vehicle according to a 26th embodiment when a vehicle sharing free space information does not have absolute or relative position information of its own vehicle and a surrounding vehicle estimates absolute or relative position information of the vehicle and actively shares free space information. [Diagram 36] A sequence diagram showing an operation in a case where a vehicle that wishes to acquire free space information actively performs discovery in a vehicle according to a twenty-seventh embodiment, and a surrounding vehicle passively estimates absolute position information or relative position information of a vehicle that does not have the absolute position information or relative position information of the vehicle itself. [Figure 37] A sequence diagram showing the operation of a vehicle according to a twenty-eighth embodiment when the vehicle shares free space information and the vehicle does not have absolute or relative position information of the vehicle and the surrounding vehicles estimate the absolute or relative position information of the vehicle by using Ranging / SL Positioning. [Figure 38]A sequence diagram showing an operation when a vehicle that shares free space information in a vehicle according to a twenty-ninth embodiment does not have absolute or relative position information of its own vehicle and a surrounding vehicle estimates the absolute or relative position information of the vehicle by Ranging / SL Positioning, and actively discovers a vehicle that performs Ranging / SL Positioning. [Figure 39] FIG. 32 is a diagram showing an example of a case where free space information in a vehicle according to a 32nd embodiment includes information such as vehicle speed, vehicle movement direction, and time. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A communication device, a communication system, a control circuit, a storage medium, and a communication method according to embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.

[0010] Embodiment 1 FIG. 1 is a diagram showing a configuration example of a communication system 70 according to the first embodiment. The communication system 70 includes a vehicle 1 and a vehicle 2. The communication system 70 is a system for sharing free space information indicating a location where no vehicle or obstacle exists between the vehicle 1 and the vehicle 2. The free space information can also be said to be information indicating an empty space where no vehicle or obstacle exists. The vehicle 1 includes an application execution unit 100 and a communication device 101. The communication device 101 mounted on the vehicle 1 includes a free space information sharing unit 103 and a wireless communication unit 104. The vehicle 2 includes an application execution unit 200 and a communication device 201. The communication device 201 mounted on the vehicle 2 includes a free space information sharing unit 203 and a wireless communication unit 204.

[0011] In the following description, vehicle 1 may be referred to as a first vehicle, vehicle 2 may be referred to as a second vehicle, communication device 101 may be referred to as a first communication device, communication device 201 may be referred to as a second communication device, free space information generated by communication device 101 of vehicle 1 may be referred to as first free space information, and free space information generated by communication device 201 of vehicle 2 may be referred to as second free space information. Also, free space information sharing unit 103 may be referred to as a first free space information sharing unit, free space information sharing unit 203 may be referred to as a second free space information sharing unit, wireless communication unit 104 may be referred to as a first communication unit, and wireless communication unit 204 may be referred to as a second communication unit. Also, when vehicle 1 and communication device 101 are used as references, vehicle 1 may be simply referred to as a vehicle, vehicle 2 may be referred to as another vehicle, the first free space information may be referred to as own vehicle free space information, and the second free space information may be referred to as other vehicle free space information.

[0012] The application execution unit 100 and the application execution unit 200 execute applications such as an automatic driving system and a safe driving support system in each vehicle. Note that the applications executed by the application execution unit 100 and the application execution unit 200 are not limited to these. Also, the number of applications simultaneously executed by the application execution unit 100 and the application execution unit 200 is not limited to one, and may be multiple.

[0013] The communication device 101 and the communication device 201 are communication devices for sharing free space information mounted on each vehicle. The communication device 101 is connected to the application execution unit 100 via an interface 102. The communication device 201 is connected to the application execution unit 200 via an interface 202. In the communication device 101, the free space information sharing unit 103 and the wireless communication unit 104 are connected via an interface 105. In the communication device 201, the free space information sharing unit 203 and the wireless communication unit 204 are connected via an interface 205. The wireless communication unit 104 and the wireless communication unit 204 are connected via an interface 900.

[0014] The wireless communication unit 104 and the wireless communication unit 204 are communication units that perform wireless communication between vehicles. The wireless communication method between the wireless communication unit 104 and the wireless communication unit 204 is not particularly limited as long as it is a wireless communication method that allows wireless communication between vehicles.

[0015] Next, an operation of the communication device 101 when transmitting free space information of the vehicle 1, which is the vehicle itself, to the communication device 201 of the vehicle 2, which is the other vehicle, will be described. Controlled by the application execution unit 100 via the interface 102, the free space information sharing unit 103 generates and analyzes free space information, and transmits the free space information to the wireless communication unit 104 via the interface 105. The wireless communication unit 104 transmits the free space information to the wireless communication unit 204 via the interface 900. The wireless communication unit 204 transmits the free space information to the free space information sharing unit 203 via the interface 205. The free space information sharing unit 203 provides the free space information to the application execution unit 200 via the interface 202.

[0016] Next, a detailed configuration and operation of the free space information sharing unit 103 will be described. The free space information sharing unit 103 and the free space information sharing unit 203 have the same configuration and perform the same operation, so the free space information sharing unit 103 will be described below as an example. FIG. 2 is a diagram showing an example of the configuration of the free space information sharing unit 103 provided in the communication device 101 according to the first embodiment. The free space information sharing unit 103 includes a free space information generating unit 130 and a free space information analyzing unit 131. The free space information generating unit 130 and the free space information analyzing unit 131 are connected via an interface 132, the free space information analyzing unit 131 and the wireless communication unit 104 are connected via an interface 105, and the free space information analyzing unit 131 and the application execution unit 100 are connected via an interface 102.

[0017] Next, the operation of the free space information sharing unit 103 will be described. The free space information generating unit 130 collects vehicle position information of the vehicle itself, which is the vehicle 1 equipped with the communication device 101, which is the own communication device, and vehicle position information of the other vehicle. The other vehicle is, for example, the vehicle 2 equipped with the communication device 201, which is the other communication device, but may be a vehicle not shown in FIG. 1. The other vehicle may be a vehicle that does not have a communication device such as the communication devices 101 and 201 shown in FIG. 1. In the following description, the vehicle position information of the vehicle itself is referred to as the self-position information, and the vehicle position information of the other vehicle is referred to as the other vehicle position information. The other vehicle position information may include obstacles other than the vehicle itself and the other vehicle. That is, the other vehicle position information may include the vehicle position information of the other vehicle as well as the obstacle position information. Note that the subject of the "vehicle" is limited to vehicles equipped with communication devices such as the communication devices 101 and 201 shown in FIG. 1, and vehicles that do not have a communication device such as the communication devices 101 and 201 shown in FIG. 1 may be treated in the same manner as the obstacles described above. The free space information generating unit 130 uses the collected self-position information and other person's position information to generate free space information indicating a location where no vehicle or obstacle exists, and outputs the information to the free space information analyzing unit 131 via the interface 132. The vehicles that are the subject of the free space information are the above-mentioned own vehicle and other vehicles. The operation of the free space information generating unit 130 to generate free space information from the self-position information and other person's position information will be described later in detail.

[0018] The free space information analysis unit 131 analyzes the free space information acquired from the free space information generation unit 130. Since the free space information analysis unit 131 can acquire free space information from other vehicles as described later, for example, in analyzing the free space information, the free space information analysis unit 131 performs processing such as resolving conflicts between free space information, expanding the coverage range of free space information, and merging multiple pieces of free space information using free space information acquired from the vehicle itself and free space information acquired from other vehicles. In a situation in which the free space information analysis unit 131 does not acquire free space information from other vehicles and acquires free space information only from the free space information generation unit 130, the free space information analysis unit 131 may analyze using the current and past several pieces of free space information acquired from the free space information generation unit 130. For example, when the driving conditions of other vehicles in the vicinity can be grasped from the current and past several pieces of free space information, the free space information analysis unit 131 may estimate the driving speed of other vehicles, or may process a detection value detected only from the free space information at a certain point in time as a false detection. As will be described later, in subsequent embodiments, the free space information analysis unit 131, or a free space information analysis unit provided in another communication device, will perform analysis such as processing to resolve conflicts between free space information.

[0019] The free space information analysis unit 131 outputs the free space information to the wireless communication unit 104 via the interface 105. The wireless communication unit 104 transmits the free space information acquired from the free space information analysis unit 131 to the vehicle 2 via the interface 900. In addition, the free space information analysis unit 131 outputs the free space information to the application execution unit 100 via the interface 102. The application execution unit 100 executes an application using the free space information acquired from the free space information analysis unit 131.

[0020] Meanwhile, in the vehicle 1, the wireless communication unit 104 receives free space information transmitted from other vehicles and outputs it to the free space information analysis unit 131 via the interface 105. The free space information analysis unit 131 analyzes both the free space information obtained by the vehicle itself and the free space information obtained from other vehicles. The free space information analysis unit 131 provides the free space information obtained as a result of the analysis to the wireless communication unit 104 and the application execution unit 100.

[0021] Next, a detailed configuration and operation of the free space information generating unit 130 will be described. Fig. 3 is a diagram showing an example of the configuration of the free space information generating unit 130 included in the communication device 101 according to the embodiment 1. The free space information generating unit 130 includes a self-location information collecting unit 133 and an other person's location information collecting unit 134.

[0022] The self-location information collecting unit 133 is a device for acquiring absolute position information or relative position information of the vehicle itself. The self-location information collecting unit 133 is a self-location estimation device that utilizes, for example, a Global Navigation Satellite System (GNSS) such as a Global Positioning System (GPS), a radar, a Light Detection And Ranging (LiDAR), a camera, an infrared sensor, an odometer, or the like.

[0023] The other person's position information collecting unit 134 is a device for acquiring absolute position information or relative position information of other vehicles. The other person's position information collecting unit 134 is, for example, a other person's position estimation device that utilizes a radar, LiDAR, camera, infrared sensor, or the like mounted on the vehicle 1. Note that the other vehicles targeted by the other person's position information collecting unit 134 also include obstacles other than vehicles, as described above.

[0024] Next, the details of the free space information handled in this embodiment will be described. The free space information in this embodiment is information for indicating a place where no vehicle or obstacle exists. FIG. 4 is a diagram showing an example of information indicated by the free space information handled by the vehicles 1 and 2 according to the first embodiment. In FIG. 4, the free space information 1300 is expressed as a two-dimensional area map centered on the position 1301 of the vehicle. The free space information 1300 is composed of three information elements, a free space 1302, an object presence space 1303, and an uncertain space 1304. The free space 1302 is based on information obtained by some means, and is an information element indicating that no object exists at that place. The object presence space 1303 is based on information obtained by some means, and is an information element indicating that an object exists at that place. The uncertain space 1304 is an information element indicating that it is not possible to determine that an object exists at that place. The information obtained by some means is, for example, a detection value of the above-mentioned radar, LiDAR, camera, infrared sensor, etc., but is not limited to these.

[0025] The free space information generating unit 130 specifies the position 1301 of the vehicle in the free space information 1300 from the information obtained by the self-position information collecting unit 133, and determines from the information obtained by the other person's position information collecting unit 134 whether the surrounding area of ​​the position 1301 of the vehicle is a free space 1302, an object presence space 1303, or an uncertain space 1304. For example, based on the detection results of a radar, LiDAR, camera, infrared sensor, etc. collected by the other person's position information collecting unit 134, the free space information generating unit 130 determines an area where it is possible to determine that no vehicle or obstacle exists as a free space 1302, an area where it is possible to determine that a vehicle or obstacle exists as an object presence space 1303, and an area where it is impossible to determine whether a vehicle or obstacle exists as an uncertain space 1304. An area where it is not possible to determine whether a vehicle or an obstacle exists is, for example, an area where the detection values ​​of a radar, LiDAR, camera, infrared sensor, etc., i.e., other person's position information, cannot be collected due to the influence of other vehicles or obstacles, or an area where the detection values ​​of a radar, LiDAR, camera, infrared sensor, etc., i.e., other person's position information, are present but the value is such that it is not possible to clearly determine that a vehicle or an obstacle exists. In this way, the free space information generating unit 130 can generate free space information as shown in FIG. 4 by using the information obtained by the self-position information collecting unit 133 and the other person's position information collecting unit 134.

[0026] In the communication system 70, the communication device 101 mounted on the vehicle 1 and the communication device 201 mounted on the vehicle 2 can mutually share free space information as shown in Fig. 4, thereby making it possible to identify not only locations where vehicles, obstacles, etc. exist, but also locations where no vehicles, obstacles, etc. exist. This allows the application execution unit 100 of the vehicle 1 and the application execution unit 200 of the vehicle 2 to use the free space information to help with route design, for example, when changing lanes, entering an intersection, merging, leaving, etc.

[0027] FIG. 5 is a flowchart showing the operation of the communication device 101 according to the first embodiment. In the communication device 101 mounted on the vehicle 1, the free space information generating unit 130 provided in the free space information sharing unit 103 collects self-location information, which is the vehicle location information of the vehicle 1, and other vehicle location information including the vehicle location information of other vehicles and the location information of obstacles (step S1). The free space information generating unit 130 provided in the free space information sharing unit 103 uses the self-location information and the other vehicle location information to generate first free space information indicating a location where the vehicle 1, other vehicles, or obstacles do not exist (step S2). The wireless communication unit 104 receives second free space information generated by the communication device 201 mounted on the vehicle 2 and transmitted from the communication device 201 mounted on the vehicle 2, indicating a location where the vehicle 2, other vehicles, or obstacles do not exist, and transmits the first free space information to the communication device 201 (step S3). The order of transmission and reception in step S3 may be reversed. The free space information analysis unit 131 included in the free space information sharing unit 103 shares the first free space information and the second free space information with the communication device 201, and analyzes the first free space information and the second free space information (step S4).

[0028] Although the operation of the communication device 101 has been described, the communication device 201 also performs the same operation as above. In this case, in the above description, the components of the communication device 101 are replaced with the components of the communication device 201. When viewed as a communication system 70, the free space information sharing unit 103 included in the communication device 101 and the free space information sharing unit 203 included in the communication device 201 can share the first free space information and the second free space information between the communication device 101 and the communication device 201, and can analyze the first free space information and the second free space information.

[0029] Next, the hardware configuration of the communication device 101 will be described. Since the configuration of the communication device 201 is similar to that of the communication device 101, the communication device 101 will be described as an example. In the communication device 101, the wireless communication unit 104 is a communication device capable of wireless communication. The free space information sharing unit 103 is realized by a processing circuit. The processing circuit may be a processor and memory that executes a program stored in a memory, or may be dedicated hardware. The processing circuit is also called a control circuit.

[0030] FIG. 6 is a diagram showing a configuration example of a processing circuit 90 in the case where the processing circuit for realizing the communication device 101 according to the first embodiment is realized by a processor 91 and a memory 92. The processing circuit 90 shown in FIG. 6 is a control circuit and includes a processor 91 and a memory 92. When the processing circuit 90 is configured with the processor 91 and the memory 92, each function of the processing circuit 90 is realized by software, firmware, or a combination of software and firmware. The software or firmware is described as a program and stored in the memory 92. In the processing circuit 90, each function is realized by the processor 91 reading and executing the program stored in the memory 92. That is, the processing circuit 90 includes a memory 92 for storing a program that results in the processing of the communication device 101 being executed. This program can also be said to be a program for causing the communication device 101 to execute each function realized by the processing circuit 90. This program may be provided by a storage medium in which the program is stored, or may be provided by other means such as a communication medium.

[0031] The above program can also be said to be a program that causes the communication device 101 to execute the following steps: a free space information generation step in which the free space information sharing unit 103 collects self-position information, which is vehicle position information of vehicle 1, and other party position information, which includes vehicle position information of other vehicles as well as position information of obstacles, and generates first free space information, which is free space information indicating locations where vehicle 1, other vehicles, or obstacles are not present; a communication step in which the wireless communication unit 104 receives second free space information, which is free space information indicating locations where vehicle 2, other vehicles, or obstacles are not present, transmitted from a communication device 201, which is a communication device mounted on vehicle 2, and transmits the first free space information to the communication device 201; and a free space information analysis step in which the free space information sharing unit 103 shares the first free space information and the second free space information with the communication device 201 and analyzes the first free space information and the second free space information.

[0032] Here, the processor 91 is, for example, a CPU (Central Processing Unit), a processing device, an arithmetic device, a microprocessor, a microcomputer, or a DSP (Digital Signal Processor), etc. Also, the memory 92 is, for example, a non-volatile or volatile semiconductor memory such as a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an EPROM (Erasable Programmable ROM), an EEPROM (Electrically EPROM), a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, or a DVD (Digital Versatile Disc), etc.

[0033] Fig. 7 is a diagram showing an example of a processing circuit 93 in the case where the processing circuit for realizing the communication device 101 according to the first embodiment is configured with dedicated hardware. The processing circuit 93 shown in Fig. 7 corresponds to, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or a combination of these. The processing circuit may be partially realized with dedicated hardware and partially realized with software or firmware. In this way, the processing circuit can realize each of the above-mentioned functions by dedicated hardware, software, firmware, or a combination of these.

[0034] As described above, according to this embodiment, in the communication device 101 mounted on the vehicle 1, the free space information generating unit 130 of the free space information sharing unit 103 collects the self-location information, which is the vehicle location information of the vehicle 1, and the other vehicle's location information including the location information of an obstacle together with the vehicle location information of the other vehicle, and generates the first free space information indicating a location where the vehicle 1, the other vehicle, or the obstacle does not exist, using the self-location information and the other vehicle's location information. The wireless communication unit 104 receives the second free space information transmitted from the communication device 201 mounted on the vehicle 2, and transmits the first free space information to the communication device 201. The free space information analyzing unit 131 of the free space information sharing unit 103 shares the first free space information and the second free space information with the communication device 201, and analyzes the first free space information and the second free space information.

[0035] This allows the communication device 101 mounted on the vehicle 1 to share the first free space information and the second free space information with the communication device 201 mounted on the other vehicle, the vehicle 2. By sharing the first free space information and the second free space information with the communication device 201, the communication device 101 can expand the coverage area of ​​the free space information, and can improve the accuracy of the free space information by merging the free space information.

[0036] Embodiment 2 In the above-described first embodiment, free space information is shared between two vehicles, i.e., vehicle 1 and vehicle 2, but free space information may be shared between more vehicles. For example, a configuration diagram of a case where free space information is shared between four vehicles is shown in FIG. 8. FIG. 8 is a diagram showing a state where free space information is shared by communication devices 501, 601, 701, and 801 mounted on four vehicles according to the second embodiment. The communication devices 501, 601, 701, and 801 are communication devices similar to the communication devices 101 and 201 shown in FIG. 1 described in the first embodiment.

[0037] By sharing free space information using communication devices 501, 601, 701, and 801, multiple vehicles can further expand the coverage area of ​​the free space information compared to the case in which free space information is shared by two communication devices 101 and 201 in embodiment 1, and can also improve the accuracy of the free space information by merging multiple pieces of free space information.

[0038] Embodiment 3 In the above-mentioned first and second embodiments, free space information is shared between multiple vehicles, but there are generally differences in the accuracy, granularity, etc. of the free space information that can be provided by each vehicle. In this case, a vehicle that acquires free space information can reduce unnecessary communication, unnecessary processing, etc. by grasping in advance the free space information that other vehicles can provide, and then sharing the free space information only with other vehicles that can provide the necessary free space information.

[0039] Hereinafter, the accuracy and granularity of the free space information that each vehicle can provide will be referred to as capability. Fig. 9 is a diagram showing an example of the capability of a vehicle according to the third embodiment. The capability of a certain vehicle is defined as the area range in which free space information can be provided, and is expressed as a combination of the position 1311 of the vehicle relative to the free space information 1310, and the width 1312 and height 1313 of the free space information 1310. The area range may also be expressed as a combination of position information 1314 to 1317 indicating the four corners of the free space information 1310.

[0040] Next, an operation for grasping the capability of each vehicle in advance will be described. Hereinafter, the operation for grasping the capability of each vehicle in advance will be referred to as discovery. Note that discovery may also be referred to as search. FIG. 10 is a sequence diagram showing the operation when a vehicle according to the third embodiment performs discovery. In FIG. 10, a case is considered in which four vehicles 3 to 6 exist. Here, it is assumed that the vehicle 5 is a vehicle that desires to obtain free space information. Each vehicle broadcasts notification messages 1321 to 1324 for notifying surrounding vehicles of information including each capability using the communication device of each vehicle. The communication device mounted on each vehicle is the same communication device as the communication devices 101 and 201 shown in FIG. 1 described in the first embodiment. The vehicle 5 receives notification messages 1321, 1322, and 1324 from other vehicles, that is, the vehicles 3, 4, and 6, and selects a vehicle from which the vehicle can obtain the free space information that it desires to obtain from the capabilities included in the notification messages 1321, 1322, and 1324. If it is assumed that the capability of vehicle 3 matches the desired free space information, vehicle 3 and vehicle 5 use each other's communication device to perform communication 1325 for sharing the free space information.

[0041] In this way, by vehicles informing each other of their capabilities in advance by means of notification messages, it is possible to obtain necessary free space information without conducting unnecessary communication.

[0042] Embodiment 4 In the above-described third embodiment, the free space information is shared between two vehicles 3 and 5 among the four vehicles 3 to 6. However, a vehicle that wishes to acquire free space information from the capability acquired by transmitting and receiving a notification message may end up sharing the free space information with multiple vehicles. FIG. 11 is a sequence diagram showing the operation of a vehicle according to the fourth embodiment when sharing free space information with multiple vehicles after transmitting and receiving a notification message. Note that the operation of each vehicle broadcasting notification messages 1321 to 1324 using a communication device is the same as the operation in the third embodiment shown in FIG. 10. In FIG. 11, the vehicle 5 performs communications 1325 and 1326 for sharing free space information with the vehicles 3 and 6 that have a capability matching the desired free space information.

[0043] As in embodiment 2, multiple vehicles can expand the coverage area of ​​the free space information by sharing the free space information among multiple vehicles, and the accuracy of the free space information can be improved by merging multiple pieces of free space information.

[0044] Embodiment 5. In the above-described third and fourth embodiments, in discovery, each vehicle voluntarily notifies surrounding vehicles of its capabilities by means of a notification message, and vehicles that desire free space information passively utilize this, but it is also possible for a vehicle that desires free space information to act as the starting point and actively search for the capabilities of surrounding vehicles.

[0045] FIG. 12 is a sequence diagram showing an operation when a vehicle according to the fifth embodiment actively searches for the capabilities of surrounding vehicles, starting from a vehicle that desires free space information. In FIG. 12, a case is considered in which four vehicles 7 to 10 exist. Here, it is assumed that the vehicle 9 is a vehicle that desires to acquire free space information. The vehicle 9 includes a capability that allows the vehicle 9 to acquire the free space information that the vehicle 9 desires to acquire in a request message 1330, and broadcasts the request message using a communication device. The communication devices of each vehicle are communication devices similar to the communication devices 101 and 201 shown in FIG. 1 described in the first embodiment. The vehicles 7, 8, and 10 check their own capabilities in response to the request message 1330 received by the communication device, and transmit a response message if they determine that they can acquire the requested free space information. In FIG. 12, the vehicle 7 determines that it can provide the free space information requested by the vehicle 9, and transmits a response message 1331 to the vehicle 9. The vehicle 9 that receives the response message 1331 by the communication device recognizes that the vehicle 9 is a vehicle that can provide the free space information desired by the vehicle 7. Vehicle 7 and vehicle 9 use each other's communication device to perform communication 1332 for sharing free space information.

[0046] In this way, a vehicle that desires free space information can actively send a message and search for vehicles that match the desired capabilities with fewer message sending and receiving compared to embodiment 4.

[0047] Taking into account the contents of embodiments 3 to 5, and explaining using the communication device 101 shown in FIG. 1, it can be said that the wireless communication unit 104 can actively or passively search for the capability of the second free space information that it wishes to acquire, and receive the second free space information that it wishes to acquire.

[0048] Embodiment 6 In the above fifth embodiment, one vehicle transmits a response message during discovery, but a plurality of vehicles may transmit response messages.

[0049] FIG. 13 is a sequence diagram showing the operation of a vehicle according to the sixth embodiment when a vehicle that desires free space information starts to actively search for the capabilities of surrounding vehicles and a plurality of vehicles transmit response messages. In FIG. 13, as in the fifth embodiment, a case is considered in which four vehicles 7 to 10 exist. Here, it is assumed that the vehicle 9 is the vehicle that desires to obtain free space information. The vehicle 9 includes in a request message 1340 a capability that allows the vehicle 9 to obtain the free space information that the vehicle 9 desires to obtain, and broadcasts the request message 1340 using a communication device. The vehicles 7, 8, and 10 check their own capabilities in response to the request message 1340 received by the communication device, and transmit a response message if they determine that they can obtain the requested free space information.

[0050] Here, vehicle 7 judges that the requested free space information can be acquired, and transmits a response message 1341. Vehicle 10 judges that the requested free space information can be acquired, and transmits a response message 1342. Vehicle 9 receives the response message 1341 from vehicle 7, and receives the response message 1342 from vehicle 10, and selects vehicle 7 as the best vehicle based on, for example, each of their capabilities. Here, vehicle 9 transmits a result message 1343 indicating that vehicle 7 has been selected. Vehicle 9 may transmit the result message 1343 by broadcast. Vehicle 7 recognizes that it is necessary to provide free space information to vehicle 9 by receiving the result message 1343. On the other hand, vehicle 10 recognizes that it is not necessary to provide free space information to vehicle 9 by receiving the result message 1343. Thereafter, vehicle 7 and vehicle 9 use each other's communication devices to perform communication 1344 for sharing free space information.

[0051] In this way, by vehicle 9 sending result message 1343 and vehicle 10 receiving result message 1343, vehicle 10 recognizes that it does not need to provide free space information, thereby making it possible to avoid unnecessary waiting for processing, unnecessary message transmission, etc.

[0052] Embodiment 7 In the above-described sixth embodiment, a vehicle desiring free space information selects only one vehicle as a target for sharing the free space information through discovery, but multiple vehicles may also be selected as targets for sharing the free space information based on the contents of the response message.

[0053] FIG. 14 is a sequence diagram showing the operation in the case where a vehicle according to the seventh embodiment actively searches for the capabilities of surrounding vehicles by using a vehicle that desires free space information as a starting point, and multiple vehicles transmit response messages, and multiple vehicles are made targets for sharing free space information based on the contents of the response messages. In FIG. 14, as in the sixth embodiment, a case is considered in which four vehicles 7 to 10 exist. Here, it is assumed that the vehicle 9 is the vehicle that desires to obtain free space information. The vehicle 9 includes a capability that allows it to obtain the free space information that it desires to obtain in a request message 1350, and broadcasts it using a communication device. The vehicles 7, 8, and 10 check their own capabilities in response to the request message 1350 received by the communication device, and transmit a response message if they determine that they can obtain the requested free space information.

[0054] Here, vehicle 7 judges that it can obtain the requested free space information and transmits a response message 1351. Vehicle 10 judges that it can obtain the requested free space information and transmits a response message 1352. Vehicle 8 judges that it can obtain the requested free space information and transmits a response message 1353. Vehicle 9 receives the response message 1351 from vehicle 7, receives the response message 1352 from vehicle 10, and receives the response message 1353 from vehicle 8, and selects vehicles 7 and 8 as targets for sharing the free space information as a result of the selection. Here, vehicle 9 transmits a result message 1354 indicating that vehicles 7 and 8 have been selected. Vehicle 9 may transmit the result message 1354 by broadcast. Vehicles 7 and 8 recognize that they need to provide free space information to vehicle 9 by receiving the result message 1354. On the other hand, vehicle 10 recognizes that it does not need to provide free space information to vehicle 9 by receiving the result message 1354. Thereafter, vehicle 9 performs communication 1355 with vehicles 7 and 8 using their respective communication devices to share the free space information.

[0055] As in embodiment 6, vehicle 9 transmits result message 1354, and vehicle 10 receives result message 1354, whereby vehicle 10 recognizes that it does not need to provide free space information, thereby making it possible to avoid unnecessary waiting for processing, unnecessary message transmission, etc.

[0056] Embodiment 8 In the above-described third to seventh embodiments, in discovery, capabilities are searched for from an unspecified number of vehicles, but vehicles may be searched for in units of a predefined group. For example, in the case of a group of vehicles such as a platoon, there is a rule that free space information must be provided to the leading vehicle and the trailing vehicle, and if such a rule is known in advance, the vehicle searches for group members that require free space information.

[0057] FIG. 15 is a sequence diagram showing an operation when a vehicle according to the eighth embodiment passively searches for a group member who needs free space information. In FIG. 15, a case is considered in which four vehicles 11 to 14 exist. Here, it is assumed that the vehicle 13 is a vehicle capable of acquiring free space information. The vehicle 13 uses a communication device to groupcast the capability of the free space information that it can provide as a group member notification message 1361. The communication devices of each vehicle are communication devices similar to the communication devices 101 and 201 shown in FIG. 1 described in the first embodiment. It is assumed that the vehicles 11 and 14 are group members for the free space information provided by the vehicle 13. The vehicles 11 and 14 are members of a group that desires the free space information of the vehicle 13, and therefore receive the group member notification message 1361. On the other hand, the vehicle 12, which is not a group member, does not receive the group member notification message 1361. Vehicle 11, which has received group member notification message 1361, detects that vehicle 13 can provide free space information, and uses each other's communication devices to carry out communication 1362 for sharing the free space information. Vehicle 14, which has received group member notification message 1361, detects that vehicle 13 can provide free space information, and uses each other's communication devices to carry out communication 1363 for sharing the free space information.

[0058] In this way, when a vehicle capable of providing free space information knows in advance which vehicle group the free space information should be provided to, it uses the above procedure to not provide the free space information to vehicles that do not require the free space information, such as vehicle 12 in the example of Fig. 15. This allows vehicles capable of providing free space information to avoid communication for sharing unnecessary free space information. In addition, vehicles 12 that do not require free space information do not need to perform processes such as receiving and deciphering messages, thereby reducing unnecessary processing.

[0059] Embodiment 9 In the above eighth embodiment, discovery of group members is performed passively, but similar to the fifth embodiment, discovery of group members may be performed actively.

[0060] FIG. 16 is a sequence diagram showing the operation when a vehicle according to the ninth embodiment actively searches for a group member who needs free space information. In FIG. 16, a case is considered in which four vehicles 11 to 14 exist, as in the eighth embodiment. Here, it is assumed that the vehicle 13 is a vehicle that desires to obtain free space information. The vehicle 13 includes a capability that allows the vehicle 13 to obtain the free space information that the vehicle 13 desires to obtain in a group member request message 1370, and groupcasts the message using a communication device. It is assumed that the vehicles 11 and 12 are members of a group that has the free space information that the vehicle 13 desires. The vehicles 11 and 12 are group members for the free space information of the vehicle 13, and therefore receive the group member request message 1370. On the other hand, the vehicle 14, which is not a group member, does not receive the group member request message 1370.

[0061] Vehicle 11, which has received group member request message 1370, transmits group member response message 1371 to vehicle 13. Vehicle 12, which has received group member request message 1370, transmits group member response message 1372 to vehicle 13. Vehicle 13 receives group member response message 1371 transmitted from vehicle 11, and performs communication 1373 for sharing free space information between vehicles 13 and 11, using their respective communication devices. Vehicle 13 receives group member response message 1372 transmitted from vehicle 12, and performs communication 1373 for sharing free space information between vehicles 13 and 12, using their respective communication devices.

[0062] In this way, when a vehicle capable of providing free space information knows in advance which vehicle group the free space information should be provided to, it uses the above procedure to not provide the free space information to vehicles that do not require the free space information, such as vehicle 14 in the example of Figure 16. This allows vehicles capable of providing free space information to avoid communication for sharing unnecessary free space information. In addition, vehicles 14 that do not require free space information do not need to perform processes such as receiving and deciphering messages, thereby reducing unnecessary processing.

[0063] Embodiment 10 In the above-described first to ninth embodiments, the wireless communication method of the wireless communication unit included in the communication device is not particularly limited. In a tenth embodiment, a case will be described in which C-V2X, which is being standardized by 3GPP (registered trademark) (Third Generation Partnership Project), is used as the wireless communication method of the wireless communication unit.

[0064] FIG. 17 is a diagram showing a configuration example of a communication system 70a according to a tenth embodiment. The communication system 70a includes a vehicle 15 and a vehicle 16. The communication system 70a is a system in which free space information is shared between the vehicle 15 and the vehicle 16. The vehicle 15 includes an application execution unit 300 and a communication device 301. The communication device 301 includes a free space information sharing unit 303 and a C-V2X communication unit 304. The vehicle 16 includes an application execution unit 400 and a communication device 401. The communication device 401 includes a free space information sharing unit 403 and a C-V2X communication unit 404. In the communication system 70a, the vehicle 15 and the vehicle 16 share free space information using C-V2X as a wireless communication method of the communication devices 301 and 401.

[0065] In the following description, the vehicle 15 may be referred to as a first vehicle, the vehicle 16 may be referred to as a second vehicle, the communication device 301 may be referred to as a first communication device, the communication device 401 may be referred to as a second communication device, the free space information generated by the communication device 301 of the vehicle 15 may be referred to as the first free space information, and the free space information generated by the communication device 401 of the vehicle 16 may be referred to as the second free space information. In addition, the free space information sharing unit 303 may be referred to as a first free space information sharing unit, the free space information sharing unit 403 may be referred to as a second free space information sharing unit, the C-V2X communication unit 304 may be referred to as a first communication unit, and the C-V2X communication unit 404 may be referred to as a second communication unit.

[0066] The application execution unit 300 and the application execution unit 400 execute applications such as an automatic driving system and a safe driving support system in each vehicle. Note that the applications executed by the application execution unit 300 and the application execution unit 400 are not limited to these. Also, the number of applications simultaneously executed by the application execution unit 300 and the application execution unit 400 is not limited to one, and may be multiple.

[0067] The communication device 301 and the communication device 401 are communication devices for sharing free space information mounted on each vehicle. The communication device 301 is connected to the application execution unit 300 via the interface 302. The communication device 401 is connected to the application execution unit 400 via the interface 402. In the communication device 301, the free space information sharing unit 303 and the C-V2X communication unit 304 are connected via the interface 305. In the communication device 401, the free space information sharing unit 403 and the C-V2X communication unit 404 are connected via the interface 405. The C-V2X communication unit 304 and the C-V2X communication unit 404 are connected via the PC5 interface 910 in 3GPP.

[0068] The C-V2X communication unit 304 and the C-V2X communication unit 404 are communication units that perform wireless communication between vehicles. As described above, C-V2X is used as the wireless communication method between the C-V2X communication unit 304 and the C-V2X communication unit 404.

[0069] Next, an operation of the communication device 301 when transmitting free space information of the vehicle 15, which is the vehicle itself, to the communication device 401 of the vehicle 16, which is the other vehicle, will be described. The free space information sharing unit 303 is controlled by the application execution unit 300 via the interface 302, and generates and analyzes free space information, and transmits the free space information to the C-V2X communication unit 304 via the interface 305. The C-V2X communication unit 304 transmits the free space information to the C-V2X communication unit 404 via the PC5 interface 910. This transmission is performed by Direct Communication in 3GPP ProSe via the PC5 interface described in "3GPP TS 23.304 V18.3.0 "Proximity based Services (ProSe) in the 5G System (5GS)", and communication is performed in Unicast mode. The C-V2X communication unit 404 transmits the free space information to the free space information sharing unit 403 via the interface 405. The free space information sharing unit 403 provides the free space information to the application execution unit 400 via the interface 402 .

[0070] In this way, by using the C-V2X communication unit 304, vehicles can stably communicate to share free space information even in environments where high-speed movement, multipath propagation, etc. occur, and by utilizing standardized signaling, unnecessary processing in the application execution unit 300 can be reduced.

[0071] Embodiment 11 In the above-described tenth embodiment, the free space information is shared between two vehicles using the C-V2X communication unit 304 as a wireless communication unit, but the free space information may be shared between more vehicles. When the free space information is to be shared simultaneously with an unspecified number of surrounding vehicles, the communication between the C-V2X communication unit 304 and the C-V2X communication unit 404 via the PC5 interface 910 in Fig. 17 may be performed in the Broadcast mode. Also, when it is known in advance that the free space information is to be shared only with a certain group of vehicles, the communication may be performed in the Groupcast mode.

[0072] In this way, by vehicles 15 and 16 utilizing the Broadcast mode, Groupcast mode, etc., vehicles that do not require free space information do not need to perform processes such as receiving and deciphering messages, thereby reducing unnecessary processing.

[0073] Embodiment 12 In the above-described third to ninth embodiments, the wireless communication method of the wireless communication unit is not particularly limited when discovering the capability of the free space information. When the C-V2X communication unit 304 is used as the wireless communication unit, Direct Discovery in 3GPP ProSe may be used. A vehicle that wishes to acquire free space information uses Model A Discovery when discovering a vehicle that passively provides free space information, and uses Model B Discovery when discovering a vehicle that actively provides free space information.

[0074] FIG. 18 is a sequence diagram showing an operation in the case where a vehicle according to the twelfth embodiment uses a C-V2X communication unit as a wireless communication unit and uses Model A Discovery in ProSe Direct Discovery for discovery. In FIG. 18, a case is considered in which four vehicles 17 to 20 exist. The communication devices mounted on each vehicle are the same as the communication devices 301 and 401 shown in FIG. 17 described in the tenth embodiment. Here, it is assumed that the vehicle 19 is a vehicle that desires to obtain free space information. The vehicle 17 broadcasts an Announcement message 1380. In the 3GPP standardization, this Announcement message 1380 includes a Type of Discovery Message, a ProSe Application Code, a ProSe Restricted Code, a Relay Indication, a Security protection element, and the like.

[0075] Capabilities related to free space information may be included in various fields. For example, a code for sharing free space information may be prepared in one of ProSe Application Code, ProSe Restricted Code, etc., to clearly indicate that the vehicle 17 can provide free space information. The capabilities may also be included in a metadata field prepared in addition to various fields, and the available free space information may be expressed by a combination of these. The vehicle 19 that receives the Announcement message 1380 recognizes that the vehicle 17 has capabilities related to the desired free space information, and performs communication for sharing the free space information by ProSe Direct Communication 1381. At this time, the vehicle using the C-V2X communication unit may perform communication in any mode among Broadcast mode, Groupcast mode, and Unicast mode.

[0076] FIG. 19 is a sequence diagram showing an operation in the case where a vehicle according to the twelfth embodiment uses a C-V2X communication unit as a wireless communication unit and uses Model B Discovery in ProSe Direct Discovery for discovery. Consider a case where four vehicles 17 to 20 exist. Here, it is assumed that the vehicle 19 is a vehicle that desires to acquire free space information. The vehicle 19 broadcasts a Solicitation Message 1390 to convey that it desires to acquire free space information. In the 3GPP standardization, the Solicitation Message 1390 includes a Type of Discovery Message, a ProSe Application Code, a ProSe Restricted Code, a Relay Indication, a Security protection element, and the like.

[0077] For example, by preparing a code for sharing free space information as one of the ProSe Application Code, ProSe Restricted Code, etc., it is possible to clearly indicate that the vehicle 19 wishes to obtain free space information. The vehicle 17 that receives the Solicitation Message 1390 transmits a Response Message 1391. In the 3GPP standardization, the Response Message 1391 includes a Type of Discovery Message, a ProSe Response Code, a Relay Indication, a Security protection element, etc.

[0078] The capability for the free space information may be included in various fields. For example, by preparing a code for sharing the free space information in one of the ProSe Response Codes, it is possible to clearly indicate that the vehicle 17 can provide the free space information. Also, the capability may be included in a metadata field prepared in addition to various fields, and the available free space information may be expressed by a combination of these. The vehicle 19 that receives the Response Message 1391 recognizes that the vehicle 17 can provide the free space information, and performs communication for sharing the free space information by the ProSe Direct Communication 1392. At this time, the vehicle using the C-V2X communication unit may perform communication in any mode among the Broadcast mode, the Groupcast mode, and the Unicast mode.

[0079] In this way, even when a vehicle uses a C-V2X communication unit, it can obtain the same effects as when a vehicle uses a wireless communication unit that is not limited by the wireless communication method.

[0080] Taking into account the contents of embodiment 12, and explaining using the communication device 301 shown in FIG. 17, it can be said that the C-V2X communication unit 304 can actively or passively search for the capability of the second free space information that it wishes to acquire by ProSe Direct Discovery, and receive the second free space information that it wishes to acquire by ProSe Direct Communication.

[0081] Embodiment 13 In the above-described embodiment 12, discovery is performed to search for capabilities from an unspecified number of vehicles. However, as in embodiment 8, Group Member Discovery in 3GPP ProSe may also be used to search for vehicles in predefined group units.

[0082] FIG. 20 is a sequence diagram showing an operation in a case where a vehicle according to the thirteenth embodiment uses a C-V2X communication unit as a wireless communication unit and uses Model A Discovery in Group Member Discovery for discovery. In FIG. 20, a case is considered where four vehicles 21 to 24 exist. The communication devices mounted on each vehicle are the same as the communication devices 301 and 401 shown in FIG. 17 described in the tenth embodiment. Here, it is assumed that the vehicle 23 is a vehicle capable of providing free space information. The vehicle 23 transmits a Group member discovery announcement message 1400 to clearly indicate that the vehicle is capable of providing free space information. In the 3GPP standardization, the Group member discovery announcement message 1400 includes a Type of Discovery Message, Announcer Info, and Application Layer Group ID. For example, by including a capability in the Announcer Info, it is possible to clearly indicate that the vehicle 23 is capable of providing free space information.

[0083] Vehicle 21 and vehicle 24 that have received Group member discovery announcement message 1400 recognize that vehicle 23 is capable of providing free space information. Vehicle 23 communicates with vehicle 21 via ProSe Direct Communication 1401 to share the free space information, and communicates with vehicle 24 via ProSe Direct Communication 1402 to share the free space information. At this time, communication may be performed in any mode among Broadcast mode, Groupcast mode, and Unicast mode.

[0084] FIG. 21 is a sequence diagram showing an operation in a case where a vehicle according to the thirteenth embodiment uses a C-V2X communication unit as a wireless communication unit and uses Model B Discovery in Group Member Discovery for discovery. In FIG. 21, a case is considered where four vehicles 21 to 24 exist. Here, it is assumed that the vehicle 23 is a vehicle that desires to acquire free space information. The vehicle 23 transmits a Group member discovery solicitation message 1410 to clearly indicate that it desires to acquire free space information. In the 3GPP standardization, the Group member discovery solicitation message 1410 includes a Type of Discovery Message, Discoverer Info, Application Layer Group ID, and Target Info. For example, by including a capability to be acquired in the Discoverer Info, it is possible to clearly indicate that the vehicle 23 desires to acquire free space information.

[0085] Vehicle 21 and vehicle 22 receive Group member discovery solicitation message 1410. Vehicle 21 transmits Group member discovery response message 1411. Vehicle 22 transmits Group member discovery response message 1412. In 3GPP standardization, Group member discovery response messages 1411 and 1412 include Type of Discovery Message, Discovery Info, and Application Layer Group ID. For example, by including capability in Discovery Info, it is possible to clearly indicate that vehicles 21 and 22 can provide free space information desired by vehicle 23.

[0086] The vehicle 23 receives the Group member discovery response messages 1411 and 1412, recognizes that the vehicles 21 and 22 are capable of providing free space information, and performs communication for sharing the free space information between the vehicles 21 and 22 via ProSe Direct Communication 1413. At this time, the communication may be performed in any mode among the Broadcast mode, the Groupcast mode, and the Unicast mode.

[0087] In this way, even when vehicles use a C-V2X communication unit to search for vehicles on a group basis, the same effect can be obtained as when vehicles are searched for on a group basis using a wireless communication unit that is not limited by the wireless communication method.

[0088] Embodiment 14 In the above embodiments 1 to 13, communication between a vehicle requesting free space information and a vehicle providing the free space information is single-hop communication, but it may also be multi-hop communication via a relay vehicle in between.

[0089] Fig. 22 is a sequence diagram showing an operation in a case where communication between a vehicle requesting free space information and a vehicle providing free space information in a vehicle according to the fourteenth embodiment is multi-hop. In Fig. 22, there are four vehicles, vehicles 25 to 28, where vehicle 25 is a vehicle providing free space information, vehicle 28 is a vehicle requesting free space information, and vehicles 26 and 27 are relay vehicles. The communication devices mounted on each vehicle are the same as the communication devices 101 and 201 shown in Fig. 1 described in the first embodiment. When the free space information provided by vehicle 25 is relayed through vehicle 26 and provided to vehicle 28, communication 1420 for sharing the free space information is performed between vehicle 25 and vehicle 26, and then communication 1421 for sharing the free space information is performed between vehicle 26 and vehicle 28. The communications between vehicles 25 and 26 and between vehicles 26 and 28 may be performed alternately, as in communications 1420 and 1421, or, as in communications 1422 and 1423, if the relaying vehicle 26 has the ability to retain data, a certain amount of buffering may be performed, and communication 1423 may be performed after communication 1422 is completed.

[0090] The number of relay vehicles may be increased. For example, when relaying both the vehicle 26 and the vehicle 27, the vehicle 25 may provide the free space information to the vehicle 28 by performing multi-stage relay such as communication 1424 between the vehicle 25 and the vehicle 26, communication 1425 between the vehicle 26 and the vehicle 27, and communication 1426 between the vehicle 27 and the vehicle 28. The vehicle 25 may use a vehicle specified in advance as the relay vehicle, or may select from an unspecified number of vehicles. Unlike discovery of the capability of the free space information, the relay vehicle does not necessarily have to be a vehicle that can obtain the free space information. For example, even if a vehicle does not have an on-board sensor or a function to acquire its own position, it can be used as a relay vehicle as long as it is capable of communication.

[0091] FIG. 23 is a sequence diagram showing an operation when a relay vehicle is selected in a vehicle according to the fourteenth embodiment. In FIG. 23, it is assumed that there are four vehicles, vehicles 25 to 28, and vehicle 27 is a vehicle having a relay function. Vehicle 27 broadcasts a relay notification message 1430 to clearly indicate that it is a vehicle capable of relay transmission. By receiving the relay notification message 1430, vehicle 25 recognizes that vehicle 27 is a vehicle having a relay function, and performs communication for sharing free space information toward vehicle 28 via vehicle 27. Specifically, communication between vehicle 25 and vehicle 28 is performed by communication 1431 between vehicle 25 and vehicle 27, and communication 1432 between vehicle 27 and vehicle 28.

[0092] In this way, by combining relay transmission by relay vehicles, vehicles can share free space information between vehicles in environments where direct communication is difficult.

[0093] Embodiment 15 In the above fourteenth embodiment, the relay vehicle is passively selected in multi-hop communication for sharing free space information, but the relay vehicle may be actively selected.

[0094] FIG. 24 is a sequence diagram showing an operation when a relay vehicle is actively selected in a vehicle according to the fifteenth embodiment. In FIG. 24, it is assumed that there are four vehicles, vehicles 25 to 28, vehicles 26 and 27 are vehicles having a relay function, and vehicles 25 and 28 are vehicles that share free space information. When vehicle 25 cannot directly communicate with vehicle 28, it broadcasts a relay request message 1440 to search for a relay vehicle. Vehicle 27 that has received the relay request message 1440 has a relay function and requests vehicle 28 to perform relay transmission from vehicle 25 by transmitting a relay request message 1441. Vehicle 26 that has received the relay request message 1440 has a relay function and requests vehicle 28 to perform relay transmission from vehicle 25 by transmitting a relay request message 1442.

[0095] Vehicle 28 receives relay request message 1441 from vehicle 27 and transmits relay response message 1443 in response thereto. Vehicle 28 also receives relay request message 1442 from vehicle 26 and transmits relay response message 1444 in response thereto. Vehicle 27, having received relay response message 1443, transmits relay response message 1445 to vehicle 25 to indicate that relay transmission to vehicle 28 is possible. Vehicle 26, having received relay response message 1444, transmits relay response message 1446 to vehicle 25 to indicate that relay transmission to vehicle 28 is possible.

[0096] By receiving relay response message 1445 and relay response message 1446, vehicle 25 can recognize that relay transmission to vehicle 28 via vehicles 26 and 27 is possible, and can communicate to share free space information via multi-hop communication via vehicles 26 and 27.

[0097] Embodiment 16 In the above-described fourteenth and fifteenth embodiments, the wireless communication method of the wireless communication unit is not particularly limited, but the vehicle may use a C-V2X communication unit capable of C-V2X communication standardized by 3GPP as the wireless communication unit. In this case, the multi-hop communication may be realized by ProSe UE-to-UE Layer 3 Relay or ProSe UE-to-UE Layer 2 Relay. In addition, the selection of the relay vehicle may be realized by ProSe UE-to-UE Relay Discovery.

[0098] FIG. 25 is a sequence diagram showing an operation when a vehicle according to the sixteenth embodiment uses ProSe UE-to-UE Relay Model A Discovery in selecting a relay vehicle. In FIG. 25, it is assumed that there are four vehicles, vehicles 25 to 28, and vehicle 27 is a vehicle having a relay function. The communication devices mounted on each vehicle are the same as the communication devices 301 and 401 shown in FIG. 17 described in the tenth embodiment. Vehicle 27 broadcasts a UE-to-UE Relay Discovery Announcement message 1450 to clearly indicate that it is a vehicle capable of relay transmission. In the 3GPP standardization, the UE-to-UE Relay Discovery Announcement message 1450 includes a Type of Discovery Message, a User Info ID of the relay vehicle, a Relay Service Code (RSC), and a list of User Info IDs of terminal vehicles corresponding to the RSC. In the example of FIG. 25, the terminal vehicle is vehicle 28. Vehicles for relaying free space information are managed by the RSC and a User Info ID list linked to the RSC.

[0099] Vehicle 25 recognizes that vehicle 27 is a vehicle having a relay function by receiving UE-to-UE Relay Discovery Announcement message 1450. Vehicle 25 performs communication by ProSe Direct Communication for sharing free space information toward vehicle 28 via vehicle 27, specifically, communication 1451 between vehicle 25 and vehicle 27, and communication 1452 between vehicle 27 and vehicle 28.

[0100] Embodiment 17 In the above-described sixteenth embodiment, a relay vehicle is passively selected by ProSe UE-to-UE Relay Model A Discovery, but a relay vehicle may be actively selected by using ProSe UE-to-UE Relay Model B Discovery.

[0101] FIG. 26 is a sequence diagram showing an operation when a vehicle according to the seventeenth embodiment actively selects a relay vehicle using ProSe UE-to-UE Relay Model B Discovery in selecting a relay vehicle. In FIG. 26, it is assumed that there are four vehicles, vehicles 25 to 28, vehicles 26 and 27 are vehicles having a relay function, and vehicles 25 and 28 are vehicles that share free space information. When vehicle 25 cannot directly communicate with vehicle 28, it broadcasts UE-to-UE Relay Discovery Solicitation message 1460 to search for a relay vehicle. In 3GPP standardization, UE-to-UE Relay Discovery Solicitation message 1460 includes Type of Discovery Message, its own User Info ID, RSC, and a list of User Info IDs of the terminating vehicle. In the example of FIG. 26, the terminating vehicle is vehicle 28. Vehicles for relaying free space information are managed by RSC and User Info ID list.

[0102] Vehicle 27 that has received UE-to-UE Relay Discovery Solicitation message 1460 has a relay function and requests vehicle 28 to relay transmission from vehicle 25 by transmitting UE-to-UE Relay Discovery Solicitation message 1461. Vehicle 26 that has received UE-to-UE Relay Discovery Solicitation message 1460 has a relay function and requests vehicle 28 to relay transmission from vehicle 25 by transmitting UE-to-UE Relay Discovery Solicitation message 1462. In 3GPP standardization, UE-to-UE Relay Discovery Solicitation messages 1461 and 1462 include a Type of Discovery Message, User Info IDs of a vehicle that wishes to obtain free space information and a vehicle that provides free space information, and a User Info ID of a relay vehicle.

[0103] Vehicle 28 receives UE-to-UE Relay Discovery Solicitation message 1461 from vehicle 27, and in response transmits UE-to-UE Relay Discovery Response message 1463. Vehicle 28 also receives UE-to-UE Relay Discovery Solicitation message 1462 from vehicle 26, and in response transmits UE-to-UE Relay Discovery Response message 1464. In 3GPP standardization, UE-to-UE Relay Discovery Response messages 1463 and 1464 include the Type of Discovery Message, RSC, and User Info IDs of the vehicle that wishes to obtain free space information and the vehicle that provides free space information.

[0104] Vehicle 27, which has received UE-to-UE Relay Discovery Response message 1463, transmits UE-to-UE Relay Discovery Response message 1465 to vehicle 25 to indicate that relay transmission to vehicle 28 is possible. Vehicle 26, which has received UE-to-UE Relay Discovery Response message 1464, transmits UE-to-UE Relay Discovery Response message 1466 to vehicle 25 to indicate that relay transmission to vehicle 28 is possible. In 3GPP standardization, the UE-to-UE Relay Discovery Response messages 1465 and 1466 include the Type of Discovery Message, the User Info ID of the relay vehicle, the RSC, and the User Info ID of the terminating vehicle.

[0105] By receiving the UE-to-UE Relay Discovery Response messages 1465 and 1466, vehicle 25 recognizes that relay transmission to vehicle 28 via vehicles 26 and 27 is possible, and is able to communicate to share free space information via multi-hop communication via vehicles 26 and 27.

[0106] Taking into account the contents of embodiment 16 to embodiment 17, to explain using the communication device 301 shown in FIG. 17, it can be said that the C-V2X communication unit 304 can actively or passively search for the capability of the second free space information that it wishes to acquire by ProSe UE-to-UE Relay Discovery, and receive the second free space information that it wishes to acquire by multi-hop of ProSe Direct Communication.

[0107] Embodiment 18 In the above-described first to seventeenth embodiments, the free space information is shared among a plurality of vehicles by single communication or multi-hop communication, but when a conflict occurs regarding the contents of the free space information as a result of sharing the free space information, the vehicles may resolve the conflict. As described in the first embodiment, in the example of the first embodiment, the conflict resolution in the vehicle is performed by the free space information analysis unit 131 provided in the free space information sharing unit 103.

[0108] 3 and 4, the free space information generated from the information obtained by the self-location information collecting unit 133 and the other person's location information collecting unit 134 included in the free space information generating unit 130 is analyzed by the free space information analyzing unit 131. Since the free space information is based on the results obtained by the free space information generating unit 130 of each vehicle, the content of the free space information may differ even for the same location due to differences in the capabilities of the on-board sensors, differences in measurement conditions, etc. Therefore, when multiple vehicles share free space information and multiple pieces of free space information are obtained for overlapping locations, the content may conflict with each other.

[0109] Fig. 27 is a diagram showing an example in which a conflict occurs in free space information shared by a plurality of vehicles according to the eighteenth embodiment. In Fig. 27, free space information 1510-1512 is free space information for the same location of vehicles A-C, respectively. Comparing information elements 1513-1515 of the free space information 1510-1512, at the same location, vehicle A sets information element 1513 as object presence space 1303, vehicle C sets information element 1515 as object presence space 1303, while vehicle B sets information element 1514 as uncertain space 1304. Also, comparing information elements 1516-1518 of the free space information 1510-1512, vehicle A sets information element 1516 as object presence space 1303, vehicle B sets information element 1517 as free space 1302, and vehicle C sets information element 1518 as free space 1302.

[0110] As a solution to the case where a conflict occurs in the free space information between vehicles, it is possible to adopt the result with the greater number of judgments. For example, in the case of information elements 1513 to 1515, it is possible to adopt the result of the object presence space 1303 with the greater number of judgments. In this method, the higher the degree of overlap of the free space information shared between vehicles, the greater the diversity obtained and the higher the reliability. Therefore, it is important to consider this overlap in the discovery of capabilities when selecting vehicles with which to share free space information. On the other hand, if more vehicles try to share free space information, communication resources will be consumed, and there is a trade-off between these two, so by setting a policy in advance, it is possible to avoid acquiring more overlaps than necessary.

[0111] As a result of receiving a notification message, a response message, etc. obtained in discovery, the redundancy of free space information for the desired area can be calculated. Here, when free space information is obtained from N vehicles for a certain point, the redundancy is calculated as N. For example, when information is obtained from only one vehicle, the redundancy is 1, and when information is obtained from two vehicles, the redundancy is 2. When information is not obtained from any vehicle, the redundancy is set to 0. For example, a pre-defined policy may be set as a requirement that the redundancy of the information elements of the obtained free space information is at least 1. All combinations of free space information that can be obtained are investigated, and the redundancy of the information elements is calculated. At this time, it is important for the vehicle to select a combination of free space information that reduces the number of information elements with a redundancy of 0 in the desired area. For example, the vehicle selects a combination that minimizes the cost function, where "cost function = number of information elements with a redundancy of 0".

[0112] Fig. 28 is a diagram showing an example of a result of a vehicle according to the eighteenth embodiment combining a plurality of pieces of free space information. In the case where there are three free space information combination patterns 1523 to 1525 as shown in Fig. 28, when the vehicle calculates a cost function, the cost function becomes 3 for the free space information combination pattern 1523, the cost function becomes 0 for the free space information combination pattern 1524, and the cost function becomes 2 for the free space information combination pattern 1525. Therefore, in the example shown in Fig. 28, the vehicle selects the free space information combination pattern 1524.

[0113] The vehicle can also select a combination based on the average value of the overlapping degree. For example, the vehicle sets "cost function = sum of overlapping degrees of information elements / number of information elements". In the case of this cost function, the combination pattern 1523 of the free space information has a cost function of about 1.83, the combination pattern 1524 of the free space information has a cost function of about 3.92, and the combination pattern 1525 of the free space information has a cost function of 2.5. If the average value of the target overlapping degree is 3, the combination pattern 1524 of the free space information is slightly excessive, and the combination pattern 1525 of the free space information is below the average value but does not generate a surplus, so that the vehicle selects the combination pattern 1525 of the free space information when it is desired to restrict communication resources, for example.

[0114] The above-mentioned cost function and selection criteria are merely examples, and various methods can be considered depending on the application, the requirements, and the like. This embodiment is not limited to the above-mentioned method, and it is sufficient if an optimal combination can be selected from the obtained free space information by some method. For example, if the fail-safe concept is followed, it is also possible to consider treating the free space information of the part where even one conflict has occurred as the uncertain space 1304. In this case, when the application execution units 100 and 200 shown in FIG. 1 and the application execution units 300 and 400 shown in FIG. 17 acquire free space information in which the conflict has been resolved from the free space information analysis unit provided in the connected communication device, the application execution units 100 and 200 shown in FIG. 1 and the application execution units 300 and 400 shown in FIG. 17 advance only to the free space 1302 when the vehicle changes lanes, enters an intersection, merges, leaves, and the like, and does not advance to the object existence space 1303 and the uncertain space 1304.

[0115] As described above, by taking into account the degree of overlap of free space information at the discovery stage, vehicles can share free space information with an appropriate level of accuracy for the required conditions, while also reducing the consumption of communication resources.

[0116] Embodiment 19 In the above-described embodiment 18, the free space information is shared with an appropriate overlapping degree, taking into consideration the possibility of a conflict occurring when sharing the free space information, but when a conflict actually occurs, the conflict may be resolved by having other vehicles provide additional free space information. Here, when free space information is provided from a certain vehicle and a conflict occurs as a result of integrating the provided free space information, if the discovery stage is performed again from the time when the conflict occurred to obtain new free space information from other vehicles, a large delay occurs before new free space information is obtained. Therefore, an embodiment for quickly selecting a vehicle that can provide new free space information when a conflict occurs will be described.

[0117] FIG. 29 is a first sequence diagram showing an operation of selecting a vehicle to be provided with new free space information quickly when a conflict occurs during sharing of free space information in the vehicles according to the nineteenth embodiment. In FIG. 29, six vehicles, vehicles 29 to 34, are present, vehicle 29 is a vehicle that desires to obtain free space information, and among vehicles 30 to 34, vehicles 30 to 33 are vehicles that can provide free space information. The communication devices mounted on each vehicle are the same as the communication devices 101 and 201 shown in FIG. 1 described in the first embodiment. First, vehicle 29 includes a capability that allows it to obtain the free space information it desires to obtain in a request message 1470 and broadcasts it using the communication device. Each vehicle checks its own capability in response to the request message 1470 received by the communication device, and transmits a response message 1471 if it determines that it can obtain the requested free space information. In FIG. 29, vehicles 30 to 33 determine that they can provide the free space information requested by vehicle 29, and transmit a response message 1471 to vehicle 29.

[0118] Vehicle 29, which has received response message 1471 by its communication device, recognizes that vehicles 30 to 33 are vehicles that can provide the desired free space information, and as a result of comparing the capabilities of these vehicles, selects vehicles 30 and 31 as primary response vehicles, and selects vehicles 32 and 33 as secondary response vehicles. Here, the primary response vehicles are vehicles that share free space information the first time. The secondary response vehicles are vehicles that share free space information the second time in order to resolve a conflict that occurred in the first sharing of free space information. Vehicle 29 transmits result message 1472 to specify that vehicles 30 and 31 are primary response vehicles and vehicles 32 and 33 are secondary response vehicles.

[0119] The vehicles 30 to 33 that have received the result message 1472 each recognize whether they are the primary response vehicle or the secondary response vehicle. After that, communication 1473 for sharing free space information is performed between the vehicles 30 and 31, which are the primary response vehicles, and the vehicle 29. If the vehicle 29 determines as a result of the communication 1473 that there is no conflict in the shared free space information and that further sharing of free space information is unnecessary, it transmits a solution message 1476 to notify the vehicles 32 and 33, which are the secondary response vehicles, that sharing of free space information is unnecessary. By receiving the solution message 1476, the vehicles 32 and 33 recognize that they do not need to provide free space information to the vehicle 29. By this operation, the vehicles 32 and 33 do not need to hold the free space information to be provided for the vehicle 29 for an unnecessarily long period of time.

[0120] On the other hand, if a conflict occurs in the free space information of the vehicles 30 and 31 as a result of the communication 1473, the vehicle 29 transmits a conflict message 1474 to request the vehicles 32 and 33, which are secondary response vehicles, to share the free space information, as shown in FIG. 30. FIG. 30 is a second sequence diagram showing the operation of selecting a vehicle to be provided with new free space information quickly when a conflict occurs during sharing of free space information in the vehicle according to the nineteenth embodiment. In FIG. 30, the operation from the broadcast of the request message 1470 by the vehicle 29 to the communication 1473 for sharing the free space information between the vehicles 30 and 31, which are primary response vehicles, and the vehicle 29 is the same as the operation shown in FIG. 29. The vehicles 32 and 33, which are secondary response vehicles, recognize that they need to share their free space information by receiving the conflict message 1474, and perform communication 1475 for sharing the free space information between the vehicles 32 and 33 and the vehicle 29. When the conflict is resolved through communication 1475, vehicle 29 broadcasts a resolution message 1476 to notify surrounding vehicles that the conflict in sharing free space information has been resolved.

[0121] In this way, by setting the secondary response vehicle in advance in discovery, the vehicle can quickly share the free space information a second time even if a conflict occurs in the first sharing of the free space information. Although the transmission of messages such as notification messages, request messages, response messages, result messages, conflict messages, and resolution messages is performed by broadcasting, if the destination is determined, the vehicle may transmit the messages by unicast communication or groupcast communication.

[0122] Embodiment 20. In the above-mentioned embodiment 19, the second response vehicle is set as the response vehicle when the conflict occurs, and the conflict is resolved. However, if the conflict cannot be resolved even by the second response vehicle and information on more vehicles is required, the number of response vehicles may be increased to the third response vehicle, the fourth response vehicle, and so on. For example, it is assumed that the Nth response vehicle can be set. The result message 1472 shown in FIG. 30 includes information on the Nth response vehicle, and each vehicle recognizes what response vehicle it is. The conflict message 1474 includes a content requesting the nth response vehicle to provide free space information. In addition, the resolution message 1476 includes a content indicating that the mth or later response vehicles do not need to provide free space information to the vehicle 29. Note that N is an integer of 2 or more, n is an integer of 2 or more and N or less, and m is an integer of 2 or more, greater than n, and less than N.

[0123] In this way, by being able to flexibly change the degree of response, if it is estimated from the capability included in the response message from the surrounding vehicles that the information may not be obtained with the desired reliability by sharing the free space information only once, the reliability of the free space information can be improved by sharing the free space information multiple times, and these processes can be performed quickly. Although the transmission of messages such as notification messages, request messages, response messages, result messages, conflict messages, and resolution messages is performed by broadcasting, if the destination is determined, the vehicle may transmit the messages by unicast communication or groupcast communication.

[0124] Embodiment 21. In the above-mentioned embodiment 19 and embodiment 20, the primary response and secondary response are actively performed by the vehicles that wish to obtain free space information, but this may also be performed passively.

[0125] FIG. 31 is a sequence diagram showing an operation of passively selecting a vehicle to be provided with new free space information quickly when a conflict occurs during sharing of free space information in the vehicles according to the twenty-first embodiment. In FIG. 31, it is assumed that the vehicle 29 is a vehicle that desires to acquire free space information, and that the vehicles 30 to 33 among the vehicles 30 to 34 are vehicles that can provide free space information. The vehicles 30 to 33 broadcast a notification message 1480 including capabilities related to their own free space information. The vehicle 29 receives the notification message 1480 transmitted by the vehicles 30 to 33, determines a primary response vehicle and a secondary response vehicle from the free space information that it desires to acquire, and notifies the vehicles 30 to 33 by broadcasting a result message 1481 indicating the determined primary response vehicle and secondary response vehicle. Here, it is assumed that the vehicles 30 and 31 are primary response vehicles, and the vehicles 32 and 33 are secondary response vehicles. Vehicles 30 and 31 that receive result message 1481 recognize that they are the primary response vehicles, and perform communication 1482 for sharing free space information between vehicles 30 and 31 and vehicle 29. If no contention occurs here, vehicle 29 broadcasts a resolution message 1485.

[0126] On the other hand, when a conflict occurs, vehicle 29 transmits a conflict message 1483 and requests information provision from vehicles 32 and 33, which are secondary response vehicles. Vehicles 32 and 33 that receive conflict message 1483 perform communication 1484 for sharing free space information between vehicles 32 and 33 and vehicle 29. When the conflict is resolved by communication 1484, vehicle 29 broadcasts a resolution message 1485 to notify that the conflict has been resolved.

[0127] The responding vehicles may be up to N-th responding vehicles. In addition, although the transmission of messages such as notification messages, request messages, response messages, result messages, conflict messages, and resolution messages is performed by broadcasting, unicast communication or groupcast communication may be used if the destination is determined.

[0128] Taking into account the contents of embodiments 18 to 21, and explaining using the communication device 101 shown in Figure 1, it can be said that the wireless communication unit 104 actively or passively searches for the capabilities of the second free space information that it wishes to acquire, receives the second free space information that it wishes to acquire, and if a conflict occurs between the first free space information and the second free space information in the analysis of the free space information sharing unit 103, it can receive the second free space information from the communication device 201 at least once and transmit the first free space information to the communication device 201.

[0129] Embodiment 22. In the above-described embodiments 19 to 21, the wireless communication method of the wireless communication unit was not particularly limited when it came to setting the primary response vehicle, secondary response vehicle, etc. in the event of a conflict. However, the vehicle may use a C-V2X communication unit capable of C-V2X communication, which is being standardized by 3GPP, as the wireless communication unit.

[0130] FIG. 32 is a sequence diagram showing an operation in a case where a C-V2X communication unit is used when a first response vehicle, a second response vehicle, or the like is set in a case where a contention occurs when sharing free space information in a vehicle according to the twenty-second embodiment. In FIG. 32, a vehicle 29 is a vehicle that desires to acquire free space information, and among the vehicles 30 to 34, the vehicles 30 to 33 are vehicles that can provide free space information. The communication devices mounted on each vehicle are the same as the communication devices 301 and 401 shown in FIG. 17 described in the tenth embodiment. The vehicle 29 uses Model B Discovery in ProSe Direct Discovery for discovery and broadcasts a Solicitation message 1490. In the 3GPP standardization, this Solicitation message 1490 includes a Type of Discovery Message, a ProSe Application Code, a ProSe Restricted Code, a Relay Indication, a Security protection element, and the like. For example, by preparing a code for sharing free space information in one of the ProSe Application Code, the ProSe Restricted Code, and the like, it is possible to clearly indicate that the vehicle 29 desires to acquire free space information.

[0131] The vehicles 30 to 33 that have received the Solicitation message 1490 transmit a Response message 1491. In 3GPP standardization, the Response message 1491 includes a Type of Discovery Message, a ProSe Response Code, a relay Indication, and a Security protection element. Capabilities related to free space information may be included in various fields. For example, a code for sharing free space information may be prepared as one of the ProSe Response Codes, thereby making it possible to clearly indicate that the vehicle 29 can provide free space information. In addition, the capabilities may be included in a metadata field that is prepared in addition to various fields, and the available free space information may be expressed by a combination of these.

[0132] Vehicle 29 that has received Response message 1491 recognizes that vehicles 30 to 33 are capable of providing free space information, and notifies by Result message 1492 that the primary response vehicles and secondary response vehicles have been determined. This Result message 1492 may be a signal defined by 3GPP, or may be a newly defined signal. If it is a newly defined signal, the primary response vehicles and secondary response vehicles are specified by including the Layer-2 IDs of the primary response vehicles and secondary response vehicles from the information obtained by Response message 1491, and the Destination Layer-2 ID specifies the Layer-2 IDs of the primary response vehicles and secondary response vehicles, or specifies the Layer-2 ID specified at the time of broadcasting.

[0133] Free space information is shared between vehicle 29 and vehicles 30 and 31, which are the primary response vehicles that received Result message 1492, via ProSe Direct Communication 1493. If no contention exists, vehicle 29 notifies that the contention has been resolved by a Resolution message 1496. This Resolution message 1496 may be a signal specified by 3GPP, or may be a newly specified signal. If it is a newly specified signal, the Destination Layer-2 ID is set to the Layer-2 ID of the secondary response vehicle, or the Layer-2 ID specified at the time of broadcasting.

[0134] On the other hand, if the conflict is not resolved, the vehicle 29 notifies the vehicle 29 of the occurrence of the conflict by a Conflict message 1494. The vehicles 32 and 33 that have received the Conflict message 1494 share free space information between the vehicles 32 and 33 and the vehicle 29 by ProSe Direct Communication 1495. The Conflict message 1494 may be a signal specified by 3GPP or may be a newly specified signal. If it is a newly specified signal, the Destination Layer-2 ID is specified as the Layer-2 ID of the secondary response vehicle or the Layer-2 ID specified at the time of broadcasting. If the conflict is resolved by the ProSe Direct Communication 1495, the vehicle 29 notifies the vehicle 29 of the resolution of the conflict by a Resolution message 1496. The Resolution message 1496 may be a signal specified by 3GPP or may be a newly specified signal. If it is a newly specified signal, the Destination Layer-2 ID is specified as the Layer-2 ID specified at the time of broadcasting.

[0135] In addition, response vehicles of the second or higher order may be set. When the Conflict message 1494 is a newly specified signal, if the vehicle that has shared free space information up to that point is the n-1th order response vehicle, the Destination Layer-2 ID is set to the Layer-2 ID of the nth or higher order response vehicle, or the Layer-2 ID associated with the group member when grouping them, or the Layer-2 ID specified at the time of broadcasting.

[0136] Taking into account the contents of embodiment 22, to explain using the communication device 301 shown in Figure 17, it can be said that the C-V2X communication unit 304 actively or passively searches for the capability of the second free space information it wishes to acquire by ProSe Direct Discovery, receives the second free space information it wishes to acquire by ProSe Direct Communication, and if a conflict occurs between the first free space information and the second free space information in the analysis of the free space information sharing unit 303, receives the second free space information from the communication device 401 by ProSe Direct Communication at least once and transmits the first free space information to the communication device 401.

[0137] Embodiment 23. In the above-mentioned embodiment 1 to embodiment 22, all vehicles sharing the free space information have their own absolute position information or relative position information, but if a vehicle sharing the free space information does not have its own absolute position information or relative position information, a surrounding vehicle may estimate the absolute position information or relative position information of the vehicle. Hereinafter, the ability of a vehicle to estimate and calculate the absolute position information or relative position information of another vehicle is referred to as "positioning capability."

[0138] FIG. 33 is a sequence diagram showing an operation when a surrounding vehicle estimates absolute position information or relative position information of a vehicle that shares free space information in a vehicle according to the twenty-third embodiment, when the vehicle does not have absolute position information or relative position information of the vehicle. In FIG. 33, there are four vehicles 40 to 43. In FIG. 33, there are four vehicles 40 to 43, the vehicle 40 is a vehicle that can provide free space information and does not have absolute position information or relative position information of the vehicle, the vehicle 41 is a vehicle that can calculate absolute position information or relative position information of the vehicle 40, and the vehicle 42 is a vehicle that wishes to obtain free space information. The communication devices mounted on each vehicle are the same as the communication devices 101 and 201 shown in FIG. 1 described in the first embodiment.

[0139] Each vehicle broadcasts a notification message 1500 including a capability for free space information. At this time, the vehicle 40 indicates, as a capability of the notification message, that the vehicle does not have absolute position information or relative position information of the vehicle in addition to the capability for free space information. Also, the vehicle 41 indicates a capability for positioning the vehicle 40 in addition to the capability for free space information. By receiving the notification message 1500, the vehicle 42 recognizes that the vehicle 40 has the free space information it wishes to obtain, but does not have absolute position information or relative position information of the vehicle in itself, and that the vehicle 41 has a capability for positioning the vehicle 40. As a result, the vehicle 42 recognizes that if the vehicle 41 can calculate the absolute position information or relative position information of the vehicle 40, it can utilize the free space information of the vehicle 40.

[0140] Therefore, first, the vehicle 42 performs communication 1501 for sharing free space information between the vehicle 42 and the vehicle 40. Next, the vehicle 42 transmits a positioning request message 1502 to the vehicle 41, and inquires of the vehicle 41 about absolute position information or relative position information of the vehicle 40. The vehicle 41 that receives the positioning request message 1502 uses a positioning message 1503 to obtain absolute position information or relative position information of the vehicle 40. Thereafter, the vehicle 41 shares the absolute position information or relative position information of the vehicle 40 with the vehicle 42 by a positioning result sharing message 1504. Note that the order of sharing free space information and positioning may be reversed, and the transmission and reception of the positioning request message 1502, the positioning message 1503, and the positioning result sharing message 1504 may be performed before the communication 1501 for sharing free space information.

[0141] In this way, even if there is a vehicle that does not have the absolute position information or relative position information of its own vehicle among the vehicles that share the free space information, it is possible to utilize the free space information of the vehicle that does not have the absolute position information or relative position information of its own vehicle by combining the positioning by the other vehicles. For example, even if there is a vehicle that cannot obtain the absolute position information of its own vehicle in a place where it is difficult to receive a GPS signal, such as inside a tunnel, it is possible to utilize the free space information with the assistance of such surrounding vehicles.

[0142] Embodiment 24. In the above embodiment 23, when surrounding vehicles estimate absolute position information or relative position information of another vehicle, a vehicle that wishes to obtain free space information actively issues a request for positioning, but a vehicle capable of positioning may also passively obtain positioning results by performing positioning voluntarily.

[0143] FIG. 34 is a sequence diagram showing an operation in the case where a vehicle capable of positioning performs positioning voluntarily among vehicles according to the twenty-fourth embodiment, and a vehicle desiring to obtain free space information passively obtains a positioning result. As in the twenty-third embodiment, each vehicle broadcasts a notification message 1500. By transmitting and receiving the notification message 1500, the vehicle 40 and the vehicle 42 perform communication 1501 for sharing free space information. On the other hand, the vehicle 41 detects that the vehicle 40 does not have absolute position information or relative position information of the vehicle itself by receiving the notification message 1500, and recognizes that the vehicle 41 can position the vehicle 40. Therefore, the vehicle 41 estimates the absolute position information or relative position information of the vehicle 40 using the positioning message 1503, and shares it with the vehicle 42 using the positioning result sharing message 1504. The order of sharing free space information and positioning may be reversed, and the positioning message 1503 and the positioning result sharing message 1504 may be transmitted and received before the communication 1501 for sharing free space information.

[0144] In this way, a vehicle capable of positioning autonomously performs positioning, so that messages for positioning requests can be reduced.

[0145] Embodiment 25. In the above-mentioned embodiment 23 and embodiment 24, the absolute position information or relative position information of a vehicle that does not have the absolute position information or relative position information of the own vehicle is estimated by one of the surrounding vehicles, but the absolute position information or relative position information of a vehicle that does not have the absolute position information or relative position information of the own vehicle may be estimated by multiple vehicles. Also, the absolute position information or relative position information of multiple vehicles that do not have the absolute position information or relative position information of the own vehicle may be estimated by one or multiple vehicles. Furthermore, the sharing of free space information may be performed by multiple vehicles.

[0146] Embodiment 26. In the above-mentioned embodiments 23 to 25, when vehicles sharing free space information do not possess absolute or relative position information of their own vehicle and surrounding vehicles estimate the absolute or relative position information of the vehicle, the sharing of free space information is performed passively, but it may also be performed actively by a vehicle that wishes to obtain free space information.

[0147] FIG. 35 is a sequence diagram showing an operation when a vehicle sharing free space information in a vehicle according to the twenty-sixth embodiment does not have absolute position information or relative position information of the vehicle, and a surrounding vehicle estimates absolute position information or relative position information of the vehicle and actively shares the free space information. In FIG. 35, there are four vehicles 44 to 47. In FIG. 35, there are four vehicles 44 to 47, and the vehicle 46 is a vehicle that wishes to obtain free space information, the vehicle 44 is a vehicle that can provide free space information but does not have absolute position information or relative position information of the vehicle, and the vehicle 45 is a vehicle that can estimate absolute position information or relative position information of the vehicle 44. The communication devices mounted on each vehicle are the same as the communication devices 101 and 201 shown in FIG. 1 described in the first embodiment.

[0148] The vehicle 46 transmits a request message 1600 including a capability for the free space information it wishes to obtain. The vehicle 44 that receives the request message 1600 transmits a response message 1601 including a message indicating that it can provide the free space information but does not have the absolute position information or the relative position information of its own vehicle. The vehicle 45 also transmits a response message 1602 indicating that it can estimate the absolute position information or the relative position information of the vehicle 44. The vehicle 46 receives the response message 1601, recognizes that the vehicle 44 can provide the desired free space information, and performs communication 1603 for sharing the free space information between the vehicle 46 and the vehicle 44. The vehicle 46 also receives the response message 1602, recognizes that the vehicle 45 can estimate the absolute position information or the relative position information of the vehicle 44, and transmits a positioning request message 1604 to the vehicle 45. The vehicle 45 that has received the positioning request message 1604 estimates absolute position information or relative position information of the vehicle 44 using a positioning message 1605, and shares the estimation result with the vehicle 46 using a positioning result sharing message 1606. Note that the order of sharing of free space information and positioning may be reversed, and the positioning request message 1604, the positioning message 1605, and the positioning result sharing message 1606 may be transmitted and received before the communication 1603 for sharing free space information.

[0149] In this way, the vehicles can share free space information and positioning results with fewer messages by actively sending and receiving messages.

[0150] Embodiment 27. In the above embodiment 26, when a vehicle wishing to obtain free space information actively performs discovery, surrounding vehicles actively estimate the absolute position information or relative position information of vehicles that do not possess the absolute position information or relative position information of the vehicle itself, but the estimation of the absolute position information or relative position information may also be passive.

[0151] Fig. 36 is a sequence diagram showing an operation in the case where a vehicle that desires to acquire free space information actively performs discovery in a vehicle according to the twenty-seventh embodiment, and a surrounding vehicle passively estimates absolute position information or relative position information of a vehicle that does not have the absolute position information or relative position information of the vehicle itself. In Fig. 36, the process up to communication 1603 for sharing free space information is the same as that of the twenty-sixth embodiment. The vehicle 45 receives a response message 1601 from the vehicle 44 to the vehicle 46, or more precisely, by overhearing, the vehicle 45 recognizes that the vehicle 44 does not have the absolute position information or relative position information of the vehicle itself, estimates the absolute position information or relative position information of the vehicle 44 by a positioning message 1605, and shares the result with the vehicle 46 by a positioning result sharing message 1606.

[0152] In this way, the vehicle can reduce positioning request messages by passively performing positioning.

[0153] Considering the contents of the twenty-third to twenty-seventh embodiments, the wireless communication unit 104 can be described as actively or passively searching for the capability of the second free space information desired to be acquired, receiving the second free space information desired to be acquired, and acquiring the location information of the vehicle 2 from a third vehicle capable of measuring the location information of the vehicle 2 when the vehicle 2 does not have the location information of the vehicle 2. In the twenty-third and twenty-fourth embodiments, the first vehicle is the vehicle 42, the second vehicle is the vehicle 40, and the third vehicle is the vehicle 41. In the twenty-sixth and twenty-seventh embodiments, the first vehicle is the vehicle 46, the second vehicle is the vehicle 44, and the third vehicle is the vehicle 45.

[0154] Embodiment 28. In the above-mentioned embodiment 23 to embodiment 27, the vehicle sharing the free space information does not have the absolute position information or relative position information of the vehicle itself, and when the surrounding vehicles estimate the absolute position information or relative position information of the vehicle, the estimation method is not particularly limited. In embodiment 28, the estimation method may be performed by Ranging / SL Positioning, which is standardized in 3GPP. As shown in "3GPP TS 23.586 V18.1.0 "Ranging based services and Sidelink Positioning", 3GPP standardizes a positioning and ranging technology using direct communication between terminals, that is, a sidelink. Hereinafter, the positioning and ranging technology using a sidelink in 3GPP is called Ranging / SL Positioning. In Ranging / SL Positioning, information such as distance, position, and speed can be obtained as a positioning and ranging result by sidelink communication between terminals.

[0155] FIG. 37 is a sequence diagram showing an operation of a vehicle according to the twenty-eighth embodiment when the vehicle does not have the absolute position information or the relative position information of the vehicle and the surrounding vehicle estimates the absolute position information or the relative position information of the vehicle by the Ranging / SL Positioning. In FIG. 37, there are four vehicles 48 to 51. In FIG. 37, there are four vehicles 48 to 51, the vehicle 50 is a vehicle that wishes to obtain the free space information, the vehicle 48 is a vehicle that can provide the free space information but does not have the absolute position information or the relative position information of the vehicle, and the vehicle 49 is a vehicle that can estimate the absolute position information or the relative position information of the vehicle 48 by the Ranging / SL Positioning. Here, from the viewpoint of the Ranging / SL Positioning, the vehicle 50 is an SL Positioning Client UE, the vehicle 48 is a Target UE, and the vehicle 49 is an SL Reference UE or a Located UE. The communication devices mounted on each vehicle are similar to the communication devices 301 and 401 shown in FIG. 17 and described in the tenth embodiment.

[0156] Each vehicle broadcasts its own capability regarding free space information by transmitting an announcement message 1700. Also, vehicle 49 broadcasts its capability regarding positioning by broadcasting a Ranging / SL Positioning Announcement message 1701. In 3GPP standardization, the Ranging / SL Positioning Announcement message 1701 includes a Type of Discovery Message, a Security protection element, RSPP metadata information, a User Info ID of vehicle 49, and the like.

[0157] By receiving the notification message 1700 from the vehicle 48, the vehicle 50 performs communication 1702 for sharing free space information between the vehicle 50 and the vehicle 48. Furthermore, by receiving a Ranging / SL Positioning Announcement message 1701 from the vehicle 49, the vehicle 48 and the vehicle 50 recognize that the vehicle 49 is capable of performing Ranging / SL Positioning. The vehicle 50, which is an SL Positioning Client UE, transmits a Ranging / SL Positioning service request 1703 to the vehicle 49, which is an SL Reference UE or a Located UE. The vehicle 49 performs communication 1704 for Ranging / SL Positioning with the vehicle 48, which is a Target UE, and acquires the position information of the vehicle 48. Specifically, the communication 1704 follows the procedure of 6.8 of the above-mentioned "3GPP TS 23.586 V18.1.0 "Ranging based services and Sidelink Positioning". The vehicle 49 transmits the acquired position information to the vehicle 50 by a Ranging / SL Positioning Response 1705 .

[0158] In this way, by utilizing Ranging / SL Positioning, a vehicle can acquire and estimate absolute position information or relative position information of a vehicle that does not possess its own absolute position information or relative position information by using positioning and ranging with sidelink communication.

[0159] Embodiment 29. In the above embodiment 28, when a vehicle sharing free space information does not possess absolute or relative position information of its own vehicle and a surrounding vehicle estimates the absolute or relative position information of the vehicle using Ranging / SL Positioning, discovery of the vehicle performing Ranging / SL Positioning is passively performed, but this may also be performed actively.

[0160] Fig. 38 is a sequence diagram showing an operation of a vehicle according to the twenty-ninth embodiment, in which a vehicle sharing free space information does not have absolute position information or relative position information of the vehicle itself, and a surrounding vehicle estimates the absolute position information or relative position information of the vehicle by Ranging / SL Positioning, and actively performs discovery of the vehicle performing Range / SL Positioning. In Fig. 38, a vehicle 50 is a vehicle that desires to obtain free space information, a vehicle 48 is a vehicle that can provide free space information but does not have absolute position information or relative position information of the vehicle itself, and a vehicle 49 is a vehicle that can estimate the absolute position information or relative position information of the vehicle 48 by Ranging / SL Positioning. Here, from the viewpoint of Ranging / SL Positioning, the vehicle 50 is an SL Positioning Client UE, the vehicle 48 is a Target UE, and the vehicle 49 is an SL Reference UE or Located UE.

[0161] Each vehicle transmits a notification message 1800 to broadcast its own capability regarding free space information. By receiving the notification message from the vehicle 48, the vehicle 50 recognizes that the vehicle 48 is a terminal capable of providing free space information, but does not possess absolute position information or relative position information of the vehicle. Therefore, the vehicle 50 transmits a Ranging / SL Positioning Solicitation message 1801. The vehicles 48 and 49 that have received the Ranging / SL Positioning Solicitation message 1801 transmit a Ranging / SL Positioning Response message 1802 in response to the message, since the vehicle 48 is a Target UE and the vehicle 49 is an SL Reference UE or a Located UE. In the 3GPP standardization, the Ranging / SL Positioning Response message 1802 includes a Type of Discovery Message, a Security protection element, its own User Info ID, Target Info, the User Info ID of the vehicle 48 or the vehicle 49, RSPP metadata information, and the like.

[0162] The vehicle 50 that has received the Ranging / SL Positioning Response message 1802 recognizes that the vehicle 49 can acquire the position information of the vehicle 48. By receiving the notification message 1800 of the vehicle 48, the vehicle 50 performs communication 1803 for sharing free space information between the vehicle 50 and the vehicle 48. The vehicle 50, which is an SL Positioning Client UE, transmits a Ranging / SL Positioning service request 1804 to the vehicle 49, which is an SL Reference UE or a Located UE. The vehicle 49 performs communication 1805 for Ranging / SL Positioning with the vehicle 48, which is a Target UE, and acquires the position information of the vehicle 48. Specifically, the communication 1805 follows the procedure of 6.8 of the above-mentioned "3GPP TS 23.586 V18.1.0 "Ranging based services and Sidelink Positioning". The vehicle 49 transmits the acquired position information to the vehicle 50 by a Ranging / SL Positioning Response 1806.

[0163] Considering the contents of the twenty-eighth to twenty-ninth embodiments, the communication device 301 shown in Fig. 17 will be described as follows: the C-V2X communication unit 304 actively or passively searches for the capability of the second free space information desired to be acquired, receives the second free space information desired to be acquired, and when the vehicle 16 does not have the position information of the vehicle 16, a third vehicle capable of measuring the position information of the vehicle 16 measures the position information of the vehicle 16 by Ranging / SL Positioning, and can acquire the position information of the vehicle 16 from the third vehicle. In the case of the twenty-eighth and twenty-ninth embodiments, the first vehicle is the vehicle 50, the second vehicle is the vehicle 48, and the third vehicle is the vehicle 49.

[0164] Embodiment 30. In the above-mentioned embodiment 29, when a vehicle sharing free space information does not have absolute position information or relative position information of its own vehicle and a surrounding vehicle estimates the absolute position information or relative position information of the vehicle by Ranging / SL Positioning, the vehicle performs discovery of the vehicle performing Range / SL Positioning independently. However, when a vehicle group is determined in advance and the vehicle group is used to perform Range / SL Positioning, the Group Member Discovery method described in 6.4.2.2 of the above-mentioned "3GPP TS 23.586 V18.1.0 "Ranging based services and Sidelink Positioning" may be used.

[0165] Embodiment 31. In the above embodiment 29, discovery of capabilities when sharing free space information and discovery for acquiring location information are performed independently, but these may be performed simultaneously. For example, notification messages, response messages, request messages, etc. in discovery of capabilities when sharing free space information and discovery for acquiring location information may be combined. In addition, when ProSe Direct Discovery and ProSe Direct Communication are used with Ranging / SL Positioning, discovery in Range / SL Positioning follows ProSe Direct Discovery, so these may be merged by integrating fields such as Announcement message, Solicitation message, and Response message.

[0166] 17, the C-V2X communication unit 304 can be said to actively or passively search for the capability of the second free space information desired to be acquired, receive the second free space information desired to be acquired, and when the vehicle 16 does not have the position information of the vehicle 16, simultaneously search for the capability of the second free space information and the positioning capability of the vehicle 16 when acquiring the position information of the vehicle 16 from a third vehicle capable of positioning the position information of the vehicle 16. In the case of the embodiment 31, taking the embodiment 29 as an example, the first vehicle is the vehicle 50, the second vehicle is the vehicle 48, and the third vehicle is the vehicle 49.

[0167] Embodiment 32. In the above embodiments 1 to 31, the free space information is defined as including absolute position information or relative position information, but the free space information may also include information such as vehicle speed, vehicle movement direction, and time.

[0168] FIG. 39 is a diagram showing an example of a case where information such as vehicle speed, vehicle movement direction, and time is included in the free space information in the vehicle according to the embodiment 32. In addition to the absolute position information or relative position information 2001 of the vehicle, the free space information 2000 includes the vehicle movement direction 2002, the vehicle movement speed 2003, and the like, and further includes the time information 2004 and flag 2005 of the free space information. The time information 2004 of the free space information indicates that it is free space information at that time. Therefore, for example, it may be not only the time of the moment when the free space information is acquired, but also the past time if it is past free space information, and may be the future time if it is prediction of future free space information. In this case, by using the flag 2005, it is possible to indicate whether the free space information is past, present, or future free space information.

[0169] In this way, by including information such as vehicle speed, vehicle movement direction, and time in the free space information, the vehicle can treat the free space information of a moving vehicle, which changes from moment to moment, as time-series data, and can also treat it as data that takes into account the amount of change in the movement speed, movement direction, etc.

[0170] Embodiment 33. In the above-described embodiments 3 to 32, when discovering the capabilities of free space information, the area range in which free space information can be provided is specified, but information such as vehicle speed, vehicle movement direction, and time may also be specified.

[0171] For example, free space information capabilities are discovered in the form of indicating a desire to obtain free space information at a certain time, indicating a desire to obtain future or past free space information such as N seconds from now or M seconds ago, indicating a desire to obtain free space information for a vehicle moving at a certain vehicle speed, or indicating a desire to obtain free space information for a vehicle moving in a certain direction.

[0172] In this way, by performing discovery based on information such as vehicle speed, vehicle movement direction, and time contained in the free space information, a vehicle can more flexibly acquire and utilize the vehicle's free space information, which changes from moment to moment.

[0173] Embodiment 34. In the above-described first to thirty-third embodiments, the free space information is shared between vehicles, but the subject that shares the free space information does not have to be limited to vehicles. For example, any subject having a function for realizing at least one of the above-described first to thirty-third embodiments may be a pedestrian, a robot, a drone or other mobility, a roadside unit, a building, or the like.

[0174] The configurations shown in the above embodiments are merely examples, and may be combined with other known technologies, or the embodiments may be combined with each other. Also, parts of the configurations may be omitted or modified without departing from the spirit of the invention. [Explanation of symbols]

[0175] 1 to 34, 40 to 51 vehicle, 70, 70a communication system, 90, 93 processing circuit, 91 processor, 92 memory, 100, 200, 300, 400 application execution unit, 101, 201, 301, 401, 501, 601, 701, 801 communication device, 102, 105, 132, 202, 205, 302, 305, 402, 405, 900 interface, 103, 203, 303, 403 free space information sharing unit, 104, 204 wireless communication unit, 130 free space information generation unit, 131 free space information analysis unit, 133 self-location information collection unit, 134 other-location information collection unit, 304, 404 C-V2X communication unit, 910 PC5 interface.

Claims

1. A communication device installed in a vehicle, A free space information sharing unit collects self-location information, which is the vehicle's location information, and other-party location information, which includes the location information of other vehicles and the location information of obstacles, and generates self-vehicle free space information, which is free space information indicating a location where the vehicle, the other vehicles, or the obstacles do not exist. A communication unit that receives free space information generated by the aforementioned other vehicle, which is free space information of another vehicle, and transmits the aforementioned free space information of its own vehicle to the aforementioned other vehicle, Equipped with, The accuracy and granularity of the free space information that each vehicle can provide are defined as capabilities. The communication unit actively or passively searches for the capability of acquiring the other vehicle free space information it wishes to acquire, and receives the other vehicle free space information it wishes to acquire. A communication device characterized by the following features.

2. The communication unit actively or passively searches for the capability of the other vehicle free space information it wishes to acquire using ProSe Direct Discovery, and receives the other vehicle free space information it wishes to acquire using ProSe Direct Communication. The communication device according to feature 1.

3. The communication unit actively or passively searches for the capability of the other vehicle free space information to be acquired by ProSe UE-to-UE Relay Discovery, and receives the other vehicle free space information to be acquired by multi-hop ProSe Direct Communication. The communication device according to feature 1.

4. The communication unit actively or passively searches for the capability of the other vehicle free space information it wishes to acquire, receives the other vehicle free space information it wishes to acquire, and if a conflict occurs between the own vehicle free space information and the other vehicle free space information in the analysis of the free space information sharing unit, it receives the other vehicle free space information from the other vehicle at least once and transmits the own vehicle free space information to the other vehicle. The communication device according to feature 1.

5. The communication unit actively or passively searches for the capability of the other vehicle free space information it wishes to acquire using ProSe Direct Discovery, receives the other vehicle free space information it wishes to acquire using ProSe Direct Communication, and if a conflict occurs between the own vehicle free space information and the other vehicle free space information in the analysis of the free space information sharing unit, it receives the other vehicle free space information from the other vehicle using ProSe Direct Communication one or more times, and transmits the own vehicle free space information to the other vehicle. The communication device according to feature 1.

6. The communication unit actively or passively searches for the capability of the other vehicle free space information to be acquired, receives the other vehicle free space information to be acquired, and if the other vehicle does not possess the location information of the other vehicle, acquires the location information of the other vehicle from a vehicle capable of determining the location of the other vehicle. The communication device according to feature 1.

7. The communication unit actively or passively searches for the capability of the other vehicle free space information to be acquired, receives the other vehicle free space information to be acquired, and if the other vehicle does not possess the other vehicle's location information, a vehicle capable of determining the other vehicle's location information determines the other vehicle's location information by Ranging / SL Positioning, and acquires the other vehicle's location information from the vehicle capable of determining the other vehicle's location information. The communication device according to feature 1.

8. The communication unit actively or passively searches for the capability of acquiring the other vehicle free space information it wishes to acquire, receives the other vehicle free space information it wishes to acquire, and if the other vehicle does not possess its own location information, it acquires the other vehicle's location information from a vehicle capable of positioning the other vehicle, while simultaneously searching for the capability of acquiring the other vehicle free space information and the other vehicle's positioning capability. The communication device according to feature 1.

9. The free space information sharing unit shares the free space information of its own vehicle and the free space information of other vehicles with other vehicles. A communication device according to any one of claims 1 to 8.

10. A communication system comprising a first communication device mounted on a first vehicle and a second communication device mounted on a second vehicle, The first communication device is A first free space information sharing unit collects self-position information, which is the vehicle position information of the first vehicle, and other-party position information, which includes the vehicle position information of other vehicles and the position information of obstacles, and generates first free space information, which is free space information indicating a location where the first vehicle, the other vehicles, or the obstacles do not exist. A first communication unit receives second free space information, which is free space information indicating a location where the second vehicle, other vehicles, or obstacles are not present, transmitted from the second communication device, and transmits the first free space information to the second communication device. Equipped with, The second communication device is A second free space information sharing unit collects self-position information, which is the vehicle position information of the second vehicle, and other-party position information, which includes the vehicle position information of other vehicles and the position information of obstacles, and generates the second free space information. A second communication unit that receives the first free space information transmitted from the first communication device and transmits the second free space information to the first communication device, Equipped with, The accuracy and granularity of the free space information that each vehicle can provide are defined as capabilities. Each communications unit actively or passively searches for the capability to acquire free space information from other vehicles, and receives the free space information from other vehicles. A communication system characterized by the following features.

11. A control circuit for controlling a communication device mounted on a vehicle, The system collects its own location information, which is the vehicle's location information, and other-vehicle location information, which includes the location information of other vehicles and the location information of obstacles, and generates its own vehicle free space information, which is free space information indicating a location where the vehicle, the other vehicles, or the obstacles do not exist. The system receives free space information generated by the aforementioned other vehicle, and transmits the aforementioned free space information of its own vehicle to the aforementioned other vehicle. The communication device is instructed to perform the following: The accuracy and granularity of the free space information that each vehicle can provide are defined as capabilities. In receiving the aforementioned free space information of other vehicles, the capabilities of the aforementioned free space information of other vehicles that are to be acquired are searched for actively or passively, and the aforementioned free space information of other vehicles that are to be acquired is received. A control circuit characterized by causing the communication device to perform the above.

12. A storage medium in which a program for controlling a communication device installed in a vehicle is stored, The aforementioned program, The system collects its own location information, which is the vehicle's location information, and other-vehicle location information, which includes the location information of other vehicles and the location information of obstacles, and generates its own vehicle free space information, which is free space information indicating a location where the vehicle, the other vehicles, or the obstacles do not exist. The system receives free space information generated by the aforementioned other vehicle, and transmits the aforementioned free space information of its own vehicle to the aforementioned other vehicle. The communication device is instructed to perform the following: The accuracy and granularity of the free space information that each vehicle can provide are defined as capabilities. In receiving the aforementioned free space information of other vehicles, the capabilities of the aforementioned free space information of other vehicles that are to be acquired are searched for actively or passively, and the aforementioned free space information of other vehicles that are to be acquired is received. A storage medium characterized by causing the communication device to perform the above.

13. A communication method for a communication device installed in a vehicle, Free space information generation step: The free space information sharing unit collects self-location information, which is the vehicle's location information, and other-party location information, which includes the vehicle's location information of other vehicles and the location information of obstacles, and generates self-vehicle free space information, which is free space information indicating a location where the vehicle, the other vehicles, or the obstacles do not exist. A communication step in which the communication unit receives other vehicle free space information, which is free space information generated by the other vehicle, and transmits the own vehicle free space information to the other vehicle, Includes, The accuracy and granularity of the free space information that each vehicle can provide are defined as capabilities. In the aforementioned communication step, the communication unit actively or passively searches for the capability of the other vehicle free space information it wishes to acquire, and receives the other vehicle free space information it wishes to acquire. A communication method characterized by the following features.

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