Communication system, communication method, and vehicle-mounted device program

Abstract

To speed up connection and authentication in radio communication between an on-vehicle machine and a roadside machine.SOLUTION: A communication system includes: an on-vehicle machine (4) which is mounted in a vehicle (40); a roadside machine (3); and a communication monitoring server (20). The roadside machine transmits first information to be used by the on-vehicle machine during traveling of the vehicle to the on-vehicle machine by first radio communication. The communication monitoring server transmits second information to be used for performing authentication with the roadside machine by the on-vehicle machine to the on-vehicle machine by second radio communication. The second information includes reception state channel information and authentication possible range information. The reception state channel information shows a designated frequency channel in an usable state in the first radio communication with the roadside machine by the on-vehicle machine, of a plurality of frequency channels provided in the roadside machine. The authentication possible range information shows an authentication possible range estimated that the on vehicle machine can perform authentication with the roadside machine. The on-vehicle machine starts authentication with the roadside machine using the designated frequency channel after the vehicle enters the authentication possible range.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a communication system, a communication method, and an on-board device program, which can be suitably used, for example, for communication between an on-board device mounted on a vehicle and a roadside device installed near a route traveled by the vehicle. [Background technology]

[0002] To realize autonomous driving of vehicles, there is a technology that provides information indicating the surrounding conditions of the route the vehicle is traveling on to an onboard device installed in the vehicle via wireless communication.

[0003] The in-vehicle device can send and receive data used for autonomous driving by connecting to servers at the edge of the cloud network via wireless communication using cellular systems such as LTE (Long Term Evolution) and 5G. Furthermore, the in-vehicle device can send and receive data used for autonomous driving at higher speeds by connecting via separate wireless communication to roadside units installed near the route the vehicle will travel.

[0004] Generally, wireless communication with a relatively wide communication range has a relatively slow communication speed, while wireless communication with a relatively fast communication speed has a relatively narrow communication range. Therefore, when an in-vehicle device performs relatively high-speed wireless communication with a roadside device, an authentication procedure may be required between the in-vehicle device and the roadside device to start wireless communication each time a traveling vehicle approaches the roadside device and the in-vehicle device enters the wireless communication range with the roadside device. In particular, in the case of a wireless local area network (WLAN), when a communication terminal attempts authentication with an access point, it may take several seconds or more to scan frequency channels to identify a currently available reception channel from among the multiple frequency channels possessed by the access point.

[0005] Furthermore, the in-vehicle device and the roadside device must complete transmission and reception of the desired data by the time the traveling vehicle moves away from the roadside device and the in-vehicle device moves out of the wireless communication range with the roadside device. Considering the moving speed of the vehicle and the width of the communication range of the roadside device, it is preferable to make the connection and authentication in the wireless communication between the in-vehicle device and the roadside device as fast as possible.

[0006] In relation to the above, Non-Patent Document 1 (S. Tsurumi and T. Fujii, "Reliable vehicle-to-vehicle communication using spectrum environment map," Proc. 2018 ICOIN, Chiang Mai, pp. 310-315, published in 2018) discloses a technology for creating map data representing the distribution of wireless environment parameters in a desired area by statistically analyzing measured values ​​that have been put into a database. [Prior art documents] [Non-patent literature]

[0007] [Non-Patent Document 1] S. Tsurumi and T. Fujii, "Reliable vehicle-to-vehicle communication using spectrum environment map", Proc. 2018 ICOIN, Chiang Mai, pp.310-315, published in 2018. Summary of the Invention [Problem to be solved by the invention]

[0008] In view of the above circumstances, one object of the present disclosure is to provide a communication system, a communication method, and an on-board device program that speed up connection and authentication in wireless communication between an on-board device and a roadside device. Other objects and novel features will become apparent from the description of this specification and the accompanying drawings. [Means for solving the problem]

[0009] The following describes the means for solving the problems using the numbers used in the (Mode for Carrying Out the Invention). These numbers are added to clarify the correspondence between the statements in the (Claims) and the (Mode for Carrying Out the Invention). However, these numbers should not be used to interpret the technical scope of the invention described in the (Claims).

[0010] According to one embodiment, the communication system includes an on-board device (4), a roadside device (3), and a communication management server (20). The on-board device (4) is mounted on a vehicle (40). The roadside device (3) is installed near a route traveled by the vehicle (40) and transmits first information used by the on-board device (4) to the on-board device (4) by first wireless communication while the vehicle (40) is traveling. The communication management server (20) transmits second information used by the on-board device (4) to authenticate the first wireless communication with the roadside device (3) to the on-board device (4) by second wireless communication different from the first wireless communication. The roadside device (3) has multiple frequency channels available for the first wireless communication. The second information includes reception status channel information and authentication range information. The reception status channel information indicates a designated frequency channel available for the on-board device (4) in the first wireless communication with the roadside device (3) among the multiple frequency channels. The authentication range information indicates an authentication range in which the vehicle-mounted device (4) is estimated to be able to authenticate with the roadside device (3). After the vehicle enters the authentication range, the vehicle-mounted device (4) starts authentication with the roadside device (3) using a designated frequency channel.

[0011] According to one embodiment, the communication method includes a step (S03) of the communication management server (20) requesting, from a roadside device (3) installed near a route along which a vehicle (40) carrying the onboard device (4) passes, onboard device authentication information used by the onboard device (4) to authenticate with the roadside device (3), the roadside device (3) transmitting the onboard device authentication information to the communication management server (20), and the onboard device (4) receiving the onboard device authentication information from the communication management server (20) via a first wireless communication. The communication method further includes a step (S09) of the onboard device (4) authenticating with the roadside device (3) using the onboard device authentication information via a second wireless communication different from the first wireless communication when the onboard device (4) reaches an authentication range within which authentication with the roadside device (3) is possible. The authentication information for the vehicle-mounted device includes reception status channel information indicating a designated frequency channel that is available for wireless communication with the vehicle-mounted device (4) among the multiple frequency channels that the roadside device (3) has, and authentication range information indicating the authentication range.

[0012] According to one embodiment, the in-vehicle device program is executed by a computing device 42 of the in-vehicle device 4 mounted on the vehicle 40 to realize processing. The processing includes receiving, from the communication management server 20, via a first wireless communication, in-vehicle device authentication information used to perform authentication with a roadside device 3 installed near a route traveled by the vehicle 40 (S03). The processing further includes, when the in-vehicle device 4 reaches an authentication range where authentication with the roadside device 3 is possible, performing authentication with the roadside device 3 using the in-vehicle device authentication information via a second wireless communication different from the first wireless communication (S09). The in-vehicle device authentication information includes reception status channel information indicating a designated frequency channel available for second wireless communication with the in-vehicle device 4 from among multiple frequency channels possessed by the roadside device 3, and authentication range information indicating the authentication range. [Effects of the Invention]

[0013] According to one embodiment, it is possible to speed up connection and authentication in wireless communication between an in-vehicle device and a roadside device. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a diagram illustrating an example of a configuration of a communication system according to an embodiment. [Figure 2A] FIG. 2A is a block circuit diagram showing an example of the configuration of a communication management server according to an embodiment. [Figure 2B] FIG. 2B is a block circuit diagram showing an example of the configuration of a roadside device according to an embodiment. [Figure 2C] FIG. 2C is a block circuit diagram showing an example of the configuration of the vehicle-mounted device according to one embodiment. [Figure 3A] FIG. 3A is a part of a flowchart showing an example of processing of a communication method according to one embodiment. [Figure 3B] FIG. 3B is a part of a flowchart showing an example of processing of a communication method according to one embodiment. [Figure 4] FIG. 4 is a diagram illustrating a communication range of a roadside device according to an embodiment. [Figure 5] FIG. 5 is a diagram illustrating the radio environment database according to an embodiment. [Figure 6] FIG. 6 is a diagram illustrating a radio environment map according to an embodiment. [Figure 7] FIG. 7 is a part of a flowchart showing an example of processing of a communication method according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A communication system, a communication method, and an in-vehicle program according to the present disclosure will be described below with reference to the accompanying drawings.

[0016] (First embodiment) As shown in FIG. 1, a communication system 1 according to an embodiment includes a server system 2, a roadside device 3, and an in-vehicle device 4. The server system 2 according to an embodiment may be configured as an edge of a network such as a cloud network. The roadside device 3 according to an embodiment may be installed near a route such as a road on which vehicles pass. The roadside device 3 may be integrated with a traffic light at an intersection, for example, or may include digital signage that provides information to pedestrians. The in-vehicle device 4 according to an embodiment may be mounted on a vehicle traveling on a route such as a road.

[0017] The server system 2 includes a communication management server 20 and a wireless environment database 200. The communication management server 20 and the wireless environment database 200 are communicatively connected to each other. Each of the communication management server 20 and the wireless environment database 200 may be connected as an edge to a network such as a cloud network.

[0018] The server system 2 and the roadside device 3 are communicatively connected by a first communication means 91. The first communication means 91 may use a wired network. However, this is merely an example and does not limit the embodiment. Furthermore, the communication means 911 that transmits a signal from the roadside device 3 to the server system 2 and the communication means 912 that transmits a signal from the server system 2 to the roadside device 3 do not necessarily need to use the same network system.

[0019] The server system 2 and the vehicle-mounted device 4 are communicatively connected via a second communication means 92. The second communication means 92 may use a cellular network such as LTE or 5G. However, this is merely an example and does not limit the embodiment. Furthermore, the communication means 921 that transmits a signal from the vehicle-mounted device 4 to the server system 2 and the communication means 922 that transmits a signal from the server system 2 to the vehicle-mounted device 4 do not necessarily need to use the same network system.

[0020] The roadside device 3 and the vehicle-mounted device 4 are communicatively connected via a third communication means 93. The third communication means 93 may use a wireless network such as a wireless LAN. However, this is merely an example and does not limit the embodiment. Furthermore, the communication means 931 that transmits a signal from the vehicle-mounted device 4 to the roadside device 3 and the communication means 932 that transmits a signal from the roadside device 3 to the vehicle-mounted device 4 do not necessarily need to use the same network system.

[0021] 2A, the communication management server 20 may be configured as a so-called computer. The communication management server 20 includes, for example, a bus 21, a calculation device 22, a storage device 23, a first communication device 24, a second communication device 25, a third communication device 26, and an input / output device 27. The bus 21 is configured to connect the calculation device 22, the storage device 23, the first communication device 24, the second communication device 25, the third communication device 26, and the input / output device 27 so that they can communicate with each other.

[0022] The arithmetic device 22 includes a communication unit 221, a management unit 222, and a database control unit 223. The storage device 23 includes a server program storage unit 231 that stores a server program. The arithmetic device 22 executes the server program to realize the processes of the communication unit 221, the management unit 222, and the database control unit 223. The communication unit 221, the management unit 222, and the database control unit 223 are each a virtual function block that realizes the process through cooperation between the arithmetic device 22 and the storage device 23. The processes realized by the communication unit 221, the management unit 222, and the database control unit 223 will be described in detail below.

[0023] The server program may be read from the recording medium 230 and stored in the server program storage unit 231. The recording medium 230 may be a non-transitory and tangible medium.

[0024] The first communication device 24 communicates with the roadside device 3. The second communication device 25 communicates with the vehicle-mounted device 4. The third communication device 26 communicates with the radio environment database 200. The communication management server 20 may further include another communication device. The terminal program may be acquired from outside the communication management server 20 via one of these communication devices and stored in the server program storage unit 231.

[0025] The input / output device 27 outputs information to the user and accepts operations input by the user. As an example, the input / output device 27 includes a display device that outputs images, a keyboard that accepts key input operations, a touch panel that accepts touch operations and outputs images, etc.

[0026] 2B, the roadside unit 3 may be configured as a computer that functions as a wireless communication access point. The roadside unit 3 includes, for example, a bus 31, a calculation unit 32, a storage device 33, an observation device 34, a first communication device 35, a second communication device 36, and an input / output device 37. The bus 31 is configured to connect the calculation unit 32, the storage device 33, the observation device 34, the first communication device 35, the second communication device 36, and the input / output device 37 so that they can communicate with each other.

[0027] The arithmetic device 32 includes an observation unit 321, a communication unit 322, and a management unit 323. The storage device 33 includes a roadside device program storage unit 331 that stores a roadside device program. The arithmetic device 32 executes the roadside device program to realize the processes of the observation unit 321, the communication unit 322, and the management unit 323. The observation unit 321, the communication unit 322, and the management unit 323 are each a virtual function block that realizes the process through cooperation between the arithmetic device 32 and the storage device 33. The processes realized by the observation unit 321, the communication unit 322, and the management unit 323 will be described in detail below.

[0028] The roadside device program may be read from the recording medium 330 and stored in the roadside device program storage unit 331. The recording medium 330 may be a non-transitory and tangible medium.

[0029] The observation device 34 uses a sensor that measures desired parameters to observe the situation in the vicinity of the roadside device 3. This sensor may include a camera that takes pictures of the vicinity of the roadside device 3, or a LiDAR (Light Detection and Ranging) that measures the distance from the roadside device 3 to vehicles, pedestrians, etc. that are present in the vicinity.

[0030] The first communication device 35 communicates with the communication management server 20. The second communication device 36 communicates with the in-vehicle device 4. The roadside device 3 may further include another communication device. The roadside device program may be acquired from outside the roadside device 3 via one of these communication devices and stored in the roadside device program storage unit 331.

[0031] The input / output device 37 outputs information to the user and accepts operations input by the user. As an example, the input / output device 37 includes a lamp that outputs light, a speaker that outputs sound, and a button that accepts a press operation.

[0032] 2C, the in-vehicle device 4 may be configured as a so-called computer. The in-vehicle device 4 includes, for example, a bus 41, an arithmetic unit 42, a storage device 43, a positioning device 44, a first communication device 45, a second communication device 46, and an input / output device 47. The bus 41 is configured to connect the arithmetic unit 42, the storage device 43, the positioning device 44, the first communication device 45, the second communication device 46, and the input / output device 47 so that they can communicate with each other.

[0033] The arithmetic device 42 includes a positioning unit 421, a communication unit 422, an estimation unit 423, and a determination unit 424. The storage device 43 includes an in-vehicle device program storage unit 431 that stores an in-vehicle device program, and a roadside device information storage unit 432 that stores roadside device information indicating the position of the roadside device 3, etc. The arithmetic device 42 executes the in-vehicle device program to realize the processes of the positioning unit 421, the communication unit 422, the estimation unit 423, and the determination unit 424. The positioning unit 421, the communication unit 422, the estimation unit 423, and the determination unit 424 are virtual functional blocks that realize processes through cooperation between the arithmetic device 42 and the storage device 43. Details of the processes realized by the positioning unit 421, the communication unit 422, the estimation unit 423, and the determination unit 424 will be described later.

[0034] The in-vehicle device program may be read from the recording medium 430 and stored in the in-vehicle device program storage unit 431. Similarly, the roadside device information may be read from the recording medium 430 and stored in the roadside device information storage unit 432. The recording medium 430 may be a non-transitory and tangible medium.

[0035] The positioning device 44 measures the position of the vehicle using a GNSS (Global Navigation Satellite System) or the like. Strictly speaking, the position measured by the positioning device 44 is the position of an antenna that receives GNSS signals, but when this antenna is fixed to the on-board device 4 and the on-board device 4 is mounted on the vehicle, the positioning device 44 essentially measures the position of the vehicle.

[0036] The first communication device 45 communicates with the communication management server 20. The second communication device 46 communicates with the roadside device 3. The vehicle-mounted device 4 may further include another communication device. The vehicle-mounted device program and roadside device information may be acquired from outside the vehicle-mounted device 4 via one of these communication devices and stored in the vehicle-mounted device program storage unit 431 or the roadside device information storage unit 432, respectively.

[0037] The input / output device 47 outputs information to the user and accepts operations input by the user. For example, the input / output device 47 includes a display device that outputs images, a speaker that outputs audio, a microphone that accepts audio input, buttons that accept press operations, a keyboard that accepts key input operations, a touch panel that accepts touch operations and outputs images, etc.

[0038] An example of the configuration of the processing of the communication method according to one embodiment will be described with reference to the flowcharts of Figures 3A and 3B. Here, attention is particularly focused on the operation of the vehicle-mounted device 4. The flowcharts of Figures 3A and 3B show an example of the configuration of the processing of the vehicle-mounted device program.

[0039] When the on-vehicle device 4 starts operation, step S01 in Fig. 3A is executed. In step S01, the determination unit 424 of the on-vehicle device 4 determines whether or not a roadside device 3 is present near the vehicle. Here, the positioning unit 421 of the on-vehicle device 4 controls the positioning device 44 to measure the position of the vehicle. Positioning by the positioning unit 421 may be performed periodically. The determination unit 424 reads roadside device information from the roadside device information storage unit 432, and extracts information about the roadside device 3 that is present in the traveling direction of the vehicle and is closest to the vehicle.

[0040] In the example of Fig. 4, vehicle 40A equipped with on-board device 4 extracts information about the roadside device 3 that is closest to it before it reaches a communication range that includes the location of vehicle 40B. Fig. 4 shows how the same vehicle 40A continues to move and sequentially arrives at the locations of vehicles 40B, 40C, and 40D. Hereinafter, when there is no need to distinguish between the locations of vehicle 40A, vehicle 40B, vehicle 40C, or vehicle 40D, they will be referred to as vehicle 40.

[0041] The determination unit 424 may calculate the traveling direction of the vehicle 40 based on position information obtained by measuring the position of the vehicle 40 at multiple times, or may estimate the traveling direction based on this position information and the driving plan information. The driving plan information is information that indicates the route that the vehicle 40 is scheduled to travel, and is stored in the storage device 43.

[0042] The determination unit 424 reads information indicating a communication range in which wireless communication with the roadside unit 3 of interest is possible from the roadside unit information. The determination unit 424 also calculates a communication available time when wireless communication with the roadside unit 3 of interest will be possible, based on the communication range, the position information of the vehicle 40, and the current speed of the vehicle 40. If the time from the current time to the communication available time is shorter than a predetermined threshold, the determination unit 424 determines that a roadside unit 3 is present near the vehicle 40 (Yes), and the process proceeds to step S02 in FIG. 3A. Conversely, if the time from the current time to the communication available time is equal to or greater than the predetermined threshold, the determination unit 424 determines that a roadside unit 3 is not present near the vehicle 40 (No), and the process returns to step S01 in FIG. 3A. The current speed of the vehicle 40 may be calculated from the position information of the vehicle 40.

[0043] 3A, the communication unit 422 requests information about the roadside unit 3 of interest from the communication management server 20. Here, the communication unit 422 controls the first communication device 45 to perform wireless communication with the communication management server 20, and transmits to the communication management server 20 in association with the vehicle-mounted unit 4 identification information for identifying the roadside unit 3 of interest.

[0044] The communication unit 221 of the communication management server 20 controls the second communication device 25 to receive the vehicle-mounted device identification information and the roadside device identification information from the vehicle-mounted device 4. Here, the wireless communication between the vehicle-mounted device 4 and the communication management server 20 may start when the vehicle-mounted device 4 starts operation, or may continue until the vehicle-mounted device 4 ends operation.

[0045] The database control unit 223 of the communication management server 20 controls the third communication device 26 to access the radio environment database 200 and acquire information about the roadside unit 3 corresponding to the roadside unit identification information. Here, the information about the roadside unit 3 may include server authentication information such as an ID (identifier) ​​and a password used by the communication management server 20 to communicate with the roadside unit 3. The information about the roadside unit 3 may further include radio environment map information that indicates the distribution of radio environment parameters in the vicinity of the roadside unit 3. The radio environment map information will be described in detail later.

[0046] The communication unit 221 controls the first communication device 24 to communicate with the roadside unit 3 corresponding to the roadside unit identification information, and transmits to the roadside unit 3 a request signal requesting authentication information for the vehicle-mounted unit 4 used by the vehicle-mounted unit 4 to communicate wirelessly with the roadside unit 3, in association with the vehicle-mounted unit identification information of the vehicle-mounted unit 4.

[0047] The communication unit 322 of the roadside device 3 controls the first communication device 35 to receive a request signal and on-board device identification information from the communication management server 20. The management unit 323 of the roadside device 3 generates on-board device authentication information in response to the request signal. The on-board device authentication information includes reception status channel information indicating currently available reception status channels among multiple frequency channels prepared for the second communication device 36 of the roadside device 3 to communicate with the on-board device 4. The reception status channels include, for example, active channels through which the roadside device 3 transmits beacons. The on-board device authentication information may also include an ID and password used by the on-board device 4 to authenticate itself with the roadside device 3. The on-board device authentication information may also include data volume information indicating the volume of data to be transmitted from the roadside device 3 to the on-board device 4. This data may include, for example, observation data including desired parameters representing the situation in the vicinity of the roadside device 3, which is acquired by the observation unit 321 of the roadside device 3 controlling the observation device 34, or image data captured of the vicinity of the roadside device 3. The communication unit 322 of the roadside device 3 controls the first communication device 35 to associate the on-vehicle device authentication information with the on-vehicle device identification information of the on-vehicle device 4 and transmit them to the communication management server 20.

[0048] The communication unit 221 of the communication management server 20 controls the first communication device 24 to receive on-board device authentication information and on-board device identification information of the on-board device 4 from the roadside device 3. The communication unit 221 of the communication management server 20 controls the second communication device 25 to transmit information of the roadside device 3 to the on-board device 4 identified by the on-board device identification information received from the roadside device 3. Here, the information of the roadside device 3 includes the on-board device authentication information received from the roadside device 3. The information of the roadside device 3 may further include radio environment map information of the roadside device 3, which the communication management server 20 acquires from the radio environment database 200.

[0049] The radio environment map information will be described with reference to Figures 5 and 6. The radio environment map information represents a radio environment map 8 obtained by dividing the area near the roadside unit 3 into a mesh and measuring and statisticizing the values ​​of radio environment parameters in each mesh. Here, the radio environment parameters include at least one of received power, authentication time, latency, error rate, etc.

[0050] As shown in Fig. 5, each of the multiple observation terminals 5A, 5B, and 5C measures a predetermined radio environment parameter, associates the measured value of the radio environment parameter with location information indicating the location where the measurement was performed, and transmits the associated data to the radio environment database 200. The measured value collected in the radio environment database 200 is statistically analyzed for each mesh including the measurement location indicated by the location information. As a result, radio environment map information representing a radio environment map 8 as shown in Fig. 6 is generated. The radio environment map information may be generated before the flowcharts of Figs. 3A and 3B start, or may be updated after the flowcharts start. The vehicle-mounted device 4 may operate as the observation terminals 5A, 5B, and 5C.

[0051] In the example of Fig. 6, statistical values ​​based on the measured values ​​of the wireless environment parameters are registered for each of the meshes 82 other than the transmission mesh 81, which is the mesh that includes the roadside unit 3. Generally, as can be seen from the legend 80, the closer the mesh 82 is to the transmission mesh 81, the higher the received power, the shorter the latency, and the lower the error rate. However, this tendency differs depending on the presence of obstructions such as buildings near the roadside unit 3.

[0052] The management unit 222 of the communication management server 20 may estimate an authentication range in which the in-vehicle device 4 can authenticate with the roadside device 3, based on the communication range of the roadside device 3 and the radio environment map 8. As an example, the authentication range is a range within the communication range that is included in a mesh 82 in which radio environment parameters in the radio environment map 8 satisfy predetermined conditions. Here, the conditions satisfied by the radio environment parameters include, for example, received power being higher than a predetermined threshold, authentication time being shorter than a predetermined threshold, latency being less than a predetermined threshold, and error rate being lower than a predetermined threshold. The management unit 222 may generate authentication range information that indicates the authentication range. The information about the roadside device 3 transmitted from the communication unit 221 of the communication management server 20 to the in-vehicle device 4 may further include authentication range information.

[0053] 3A is executed. In step S03, the communication unit 422 of the in-vehicle device 4 controls the first communication device 45 to receive information about the roadside device 3 from the communication management server 20. Hereinafter, a case will be described in which the information about the roadside device 3 received by the communication unit 422 includes in-vehicle device authentication information used by the in-vehicle device 4 to perform wireless communication with the roadside device 3, authentication range information of the roadside device 3, and radio environment map information of the roadside device 3.

[0054] After step S03, step S04 in FIG. 3A is executed. In step S04, the estimation unit 423 of the on-vehicle device 4 estimates a communication available time with the roadside device 3. Here, based on the driving plan information of the vehicle 40, the position of the vehicle 40, the speed of the vehicle 40, the authentication range of the roadside device 3, and the radio environment map 8, the estimation unit 423 estimates a point and / or time at which the on-vehicle device 4 can start an authentication procedure for wireless communication with the roadside device 3, a point and / or time at which the on-vehicle device 4 can start wireless communication with the roadside device 3 after the authentication procedure is completed, and a point and / or time at which the vehicle 40 leaves the communication range and becomes unable to communicate wirelessly with the roadside device 3. Based on these results, the estimation unit 423 estimates a communication available time during which the vehicle 40 will stay inside the communication range where communication with the roadside device 3 can be performed.

[0055] After step S04, step S05 in FIG. 3A is executed. In step S05, the determination unit 424 of the onboard device 4 determines whether the expected data can be transmitted and received while the vehicle 40 is within the communication range of the roadside device 3. First, the estimation unit 423 of the onboard device 4 estimates the required communication time required for the onboard device 4 to receive the expected data from the roadside device 3 based on data volume information indicating the amount of expected data and the radio environment map information. Next, the determination unit 424 compares the required communication time with the available communication time estimated in step S04. If the required communication time is longer than the available communication time, the determination unit 424 determines that the expected data cannot be transmitted and received (No), and the process proceeds to step S06 in FIG. 3A. Conversely, if the required communication time is shorter than the available communication time, the determination unit 424 determines that the expected data can be transmitted and received (Yes), and the process proceeds to step S07 in FIG. 3B.

[0056] In step S06 of FIG. 3A, the communication unit 422 of the vehicle-mounted device 4 transmits and receives data to and from a roadside device 3 other than the roadside device 3 of interest or the communication management server 20.

[0057] Here, if data is to be transmitted or received with another roadside unit 3, the processing of the flowcharts shown in Figures 3A and 3B is terminated and restarted, and step S01 is executed again, and if another roadside unit 3 is nearby, step S02 and subsequent steps are executed again for this other roadside unit 3.

[0058] Alternatively, when transmitting and receiving data to and from the communication management server 20, the communication management server 20 relays the data from the roadside device 3 to the vehicle-mounted device 4. When this data transmission and reception is completed, the processing of the flowcharts shown in Figures 3A and 3B ends.

[0059] 3B, the communication unit 422 of the in-vehicle device 4 registers authentication parameters of the roadside device 3. Here, the authentication parameters include reception condition channel information of the roadside device 3, and an ID and password used for performing an authentication procedure with the roadside device 3.

[0060] After step S07, step S08 in Fig. 3B is executed. In step S08, the determination unit 424 of the on-vehicle device 4 determines whether or not the on-vehicle device 4 has entered the authentication range based on the position information obtained by measuring the current position of the vehicle 40 and the authentication range information of the road-side device 3. If it is determined that the on-vehicle device 4 has not entered the authentication range (No), the process repeats step S08 in Fig. 3B. Conversely, if it is determined that the on-vehicle device 4 has entered the authentication range (Yes), the process proceeds to step S09 in Fig. 3B.

[0061] 3B, the communication unit 422 of the in-vehicle device 4 connects to the roadside device 3. Here, the communication unit 422 controls the second communication device 46 to perform an authentication procedure with the roadside device 3 using the authentication information registered in step S07.

[0062] At this time, the vehicle-mounted device 4 performs the authentication procedure using a reception status channel previously specified by the roadside device 3, so it is important to note that the process of scanning the multiple frequency channels of the roadside device 3 to find a reception status channel can be omitted. In an experiment conducted by the inventors, when performing a wireless LAN authentication procedure including frequency channel scanning, the authentication time required was approximately 6 seconds, but when the authentication procedure was performed under the same conditions except for omitting the frequency channel scanning, the authentication time could be reduced to approximately 0.5 seconds. When the authentication time is shortened, more communication time can be secured, so the vehicle-mounted device 4 can receive more data from the roadside device 3 than when frequency channel scanning is required.

[0063] After step S09, step S10 in Fig. 3B is executed. In step S10, the communication unit 422 of the vehicle-mounted device 4 controls the second communication device 36 to transmit and receive data to and from the road-side device 3.

[0064] After step S10, step S11 in Fig. 3B is executed. In step S11, the communication unit 422 of the vehicle-mounted device 4 disconnects the connection with the road-side device 3. At this time, the communication unit 422 may discard the authentication information registered in step S07.

[0065] 3A and 3B ends when step S11 is completed. After that, the process of the same flowchart may be restarted to communicate with the next roadside device 3.

[0066] As described above, the communication system 1, communication method, and communication program according to one embodiment can speed up connection and authentication in wireless communication between an onboard device 4 mounted on a traveling vehicle 40 and a roadside device 3 installed near the route traveled by the vehicle 40.

[0067] The communication management server 20 may transmit, in addition to the information from the roadside device 3, the latest information on traffic conditions near the current location of the vehicle 40 to the vehicle-mounted device 4 at an appropriate timing.

[0068] (Second embodiment) In the first embodiment, a configuration was described in which roadside device information indicating the location of the roadside device 3 and the like is stored in the roadside device information storage unit 432 of the vehicle-mounted device 4. In the present embodiment, a configuration will be described in which the vehicle-mounted device 4 does not have roadside device information. The vehicle-mounted device 4 according to this embodiment may be configured similarly to the vehicle-mounted device 4 according to the first embodiment shown in Fig. 2C, but the roadside device information storage unit 432 can be omitted.

[0069] A communication method according to this embodiment will be described with reference to the flowchart of Fig. 7. The flowchart of Fig. 7 is obtained by replacing steps S01 to S03 in the flowchart of Fig. 3A with steps S21 and S22.

[0070] In this embodiment, when the on-board device 4 starts operating, step S21 in FIG. 7 is executed. In step S21, the communication unit 422 of the on-board device 4 transmits location information indicating the location of the vehicle 40 to the communication management server 20. Here, the location information of the vehicle 40 is obtained by the positioning unit 421 of the on-board device 4 measuring the location of the vehicle 40, as in the case of step S01 in FIG. 3A. The communication unit 422 of the on-board device 4 controls the first communication device 45 to perform wireless communication with the communication management server 20, and associates the location information of the vehicle 40 with the on-board device identification information of the on-board device 4 and transmits them to the communication management server 20. The communication unit 422 of the on-board device 4 may transmit the location information and the on-board device identification information to the communication management server 20 multiple times or periodically.

[0071] The communication unit 221 of the communication management server 20 controls the second communication device 25 to receive the location information and the vehicle-mounted device identification information from the vehicle-mounted device 4. In this embodiment, similar to the first embodiment, the wireless communication between the vehicle-mounted device 4 and the communication management server 20 may start when the vehicle-mounted device 4 starts operation, or may continue until the vehicle-mounted device 4 ends operation.

[0072] The database control unit 223 of the communication management server 20 controls the third communication device 26 to access the radio environment database 200 and extracts information about the roadside unit 3 that is located in the traveling direction of the vehicle 40 and is closest to the vehicle 40. Here, the traveling direction of the vehicle 40 is obtained, for example, by the management unit 222 of the communication management server 20, by calculation based on multiple pieces of position information of the vehicle 40.

[0073] The communication unit 221 of the communication management server 20 transmits the extracted information of the roadside unit 3 to the vehicle-mounted unit 4, similar to step S02 of FIG. 3A in the first embodiment. At this time, the information of the roadside unit 3 includes vehicle-mounted unit authentication information received from the roadside unit 3, authenticable range information of the roadside unit 3, and radio environment map information of the roadside unit 3. Here, the vehicle-mounted unit authentication information is generated by the roadside unit 3 in response to a request from the communication management server 20, similar to the first embodiment. Furthermore, the authenticable range information is generated by the management unit 222 of the communication management server 20, similar to the first embodiment. Furthermore, the radio environment map information is acquired from the radio environment database 200, similar to the first embodiment.

[0074] After step S21, step S22 in Fig. 7 is executed. In step S22, the determination unit 424 of the on-vehicle device 4 determines whether or not the information on the roadside device 3 has been received from the communication management server 20. If the communication unit 422 of the on-vehicle device 4 has received the information on the roadside device 3 from the communication management server 20 (Yes), the determination unit 424 determines that the information has been received, and the process proceeds to step S04 in Fig. 3A. Conversely, if the communication unit 422 of the on-vehicle device 4 has not received the information on the roadside device 3 from the communication management server 20 (No), the determination unit 424 determines that the information has not been received, and the process returns to step S21 in Fig. 7. The process of the on-vehicle device 4 repeats steps S21 and S22 in Fig. 7 until the information on the roadside device 3 is received from the communication management server 20.

[0075] Steps S04 to S06 in the flowchart of Fig. 7 are the same as those in the flowchart of Fig. 3A. Furthermore, the processing that follows the processing in the flowchart of Fig. 7 is the same as the processing in the flowchart of Fig. 3B.

[0076] As described above, the communication system 1, communication method, and communication program according to this embodiment can speed up connection and authentication in wireless communication with roadside units 3 installed near the route taken by the vehicle 40, just as in the first embodiment, by acquiring the location information of the roadside units 3 from the communication management server 20, even if the vehicle-mounted unit 4 mounted on the traveling vehicle 40 does not have the location information of the roadside units 3.

[0077] (Variation 1) Although the description of the autonomous driving of the vehicle 40 has been omitted up to this point, it goes without saying that the in-vehicle device 4 may be provided with a configuration for realizing autonomous driving. For example, the in-vehicle device 4 may further include a communication device for transmitting and receiving various signals to and from the vehicle 40, and the arithmetic device 42 of the in-vehicle device 4 may further include a control unit for controlling the driving of the vehicle 40.

[0078] (Variation 2) In the above embodiment, a configuration has been described in which the current speed of the vehicle 40 can be calculated from the position information of the vehicle 40. As a variation of this configuration, the in-vehicle device 4 may acquire information indicating the speed of the vehicle 40 from a speedometer of the vehicle 40. In this case, when the in-vehicle device 4 transmits the position information of the vehicle 40 to the communication management server 20 in step S21 of FIG. 7, the in-vehicle device 4 may also transmit speed information indicating the speed of the vehicle 40 to the communication management server 20. In this case, the communication management server 20 may extract the road-side device 3 based on the speed information received from the in-vehicle device 4.

[0079] (Variation 3) In the above embodiment, the configuration has been described in which the management unit 222 of the communication management server 20 estimates the authenticatable range of the roadside device 3. As a variation of this configuration, the estimation unit 423 of the vehicle-mounted device 4 may calculate the authenticatable range of the roadside device 3. In this case, in step S03 of Fig. 3A and step S22 of Fig. 7, the authenticatable range information may be omitted from the information about the roadside device 3 that the vehicle-mounted device 4 receives from the communication management server 20. In addition, in step S22 of Fig. 7, the information about the roadside device 3 that the vehicle-mounted device 4 receives from the communication management server 20 may further include communication range information that indicates the communication range of the roadside device 3.

[0080] The invention made by the inventor has been specifically described above based on the embodiments, but it goes without saying that the present invention is not limited to the embodiments and can be modified in various ways without departing from the spirit of the invention. Furthermore, the features described in the embodiments can be freely combined within the scope of technical compatibility. [Explanation of symbols]

[0081] 1. Communication Systems 2. Server System 20. Communication Management Server 21 Bus 22 Arithmetic unit 221 Communications Department 222 Management Department 223 Database Control Unit 23 storage device 230 Recording Media 231 Server program storage unit 24 First communication device 25 Second communication device 26 Third communication device 27 Input / Output Devices 200 Radio Environment Database 3 Roadside unit 31 Bus 32 Arithmetic unit 321 Observation Department 322 Communications Department 323 Management Department 33 Storage device 330 Recording Media 331 Roadside unit program memory unit 34 Observation equipment 35 First communication device 36 Second communication device 37 Input / Output Devices 4 Onboard equipment 40, 40A, 40B, 40C, 40D vehicles 41 Bus 42 Arithmetic unit 421 Positioning Unit 422 Communications Department 423 Estimation Department 424 Judgment section 43 Storage device 430 Recording Media 431 On-board device program memory unit 432 Roadside machine information storage unit 44 Positioning Device 45 First communication device 46 Second communication device 47 Input / Output Devices 5A, 5B, 5C observation terminals 8 Radio environment map 80 Legend 81 Transmission Mesh 82 mesh 91 First means of communication 911, 912 Communication Methods 92 Secondary means of communication 921, 922 Communication means 93 Third means of communication 931, 932 Communication means

Claims

1. an on-board device mounted on a vehicle; a roadside device that is installed near a route along which the vehicle travels and that transmits first information to the on-board device via first wireless communication while the vehicle is traveling; a communication management server that transmits second information used by the vehicle-mounted device to authenticate the first wireless communication with the roadside device to the vehicle-mounted device via a second wireless communication different from the first wireless communication; Equipped with The roadside unit a plurality of frequency channels available for the first wireless communication; and The second information is reception status channel information indicating a designated frequency channel that is available for use by the vehicle-mounted device in the first wireless communication with the roadside device, among the plurality of frequency channels; authentication range information indicating an authentication range in which the vehicle-mounted device is estimated to be able to perform authentication with the roadside device; Including, The vehicle-mounted device starts authentication with the roadside device using the designated frequency channel after the vehicle enters the authentication range. Communication system.

2. 2. The communication system according to claim 1, The roadside unit an observation device that observes the situation in the vicinity of the roadside device, which is represented by the first information; a first roadside communication device that performs the first wireless communication with the vehicle-mounted device; a second roadside communication device that transmits information representing the designated frequency channel to the communication management server; Equipped with Communication system.

3. 3. The communication system according to claim 1, the authentication range information includes radio environment map information representing a radio environment in the vicinity of the roadside device, The radio environment map information represents a distribution of at least one of a received power, an authentication time, a latency, and an error rate in the first wireless communication in a vicinity of the roadside device. Communication system.

4. In the communication system according to any one of claims 1 to 3, The vehicle-mounted device is an on-board device storage device that stores travel plan information indicating a route that the vehicle is scheduled to travel; a positioning device for measuring position information of the vehicle; an estimation unit that estimates a required communication time required to receive the first information from the roadside device through the first wireless communication and a communication available time during which the vehicle will stay inside a communication available range where the first wireless communication with the roadside device can be performed, based on the second information, the travel plan information, and the position information; Equipped with The vehicle-mounted device performs the first wireless communication with the roadside device when the required communication time is shorter than the available communication time. Communication system.

5. 5. The communication system according to claim 4, The vehicle-mounted device is a roadside device information storage unit that stores roadside device information indicating the positions of the plurality of roadside devices; Furthermore, the on-vehicle device transmits, to the communication management server, roadside device identification information for identifying the roadside device located near the vehicle, based on the roadside device information and the location information; The communication management server transmits the second information corresponding to the roadside device indicated by the roadside device identification information to the vehicle-mounted device. Communication system.

6. 5. The communication system according to claim 4, The vehicle-mounted device transmits the location information to the communication management server, The communication management server transmits the second information corresponding to the roadside device located near the vehicle to the vehicle-mounted device based on the location information. Communication system.

7. The communication system according to any one of claims 1 to 6, the in-vehicle device and the roadside device perform the first wireless communication using a wireless LAN (Local Area Network); The in-vehicle device and the communication management server perform the second wireless communication using a cellular network. Communication system.

8. a communication management server requests authentication information for an on-board device, which is used by the on-board device to authenticate itself with the roadside device, from a roadside device installed near a route along which the vehicle carrying the on-board device passes; the roadside device transmitting the in-vehicle device authentication information to the communication management server; the in-vehicle device receiving the in-vehicle device authentication information from the communication management server via first wireless communication; When the in-vehicle device reaches an authentication range where authentication with the roadside device is possible, the in-vehicle device performs authentication with the roadside device by using the authentication information for the in-vehicle device through second wireless communication different from the first wireless communication. Including, The authentication information for the vehicle-mounted device is reception status channel information indicating a designated frequency channel that is available for use in the second wireless communication with the vehicle-mounted device, among a plurality of frequency channels that the roadside device has; Authentication range information representing the authentication range; Contains Communication method.

9. An in-vehicle device program for realizing processing by causing a computing device of an in-vehicle device mounted on a vehicle to execute the program, The process comprises: receiving, from a communication management server via a first wireless communication, authentication information for an in-vehicle device used for performing authentication with a roadside device installed near a route along which the vehicle passes; When the in-vehicle device reaches an authentication range where authentication with the roadside device is possible, authentication with the roadside device is performed by second wireless communication different from the first wireless communication using the authentication information for the in-vehicle device. Including, The authentication information for the vehicle-mounted device is reception status channel information indicating a designated frequency channel that is available for use in the second wireless communication with the vehicle-mounted device, among a plurality of frequency channels that the roadside device has; Authentication range information representing the authentication range; Contains In-vehicle program.

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