Communication device

Abstract

To provide a communication device capable of shortening the time from when communication with another communication device via a narrow area communication unit becomes possible until communication of service data becomes possible.SOLUTION: A communication device includes a wide area communication unit 2 configured to be able to perform wireless communication with another communication device, a narrow area communication unit 3 configured to be able to perform wireless communication with another communication device and having a shorter communication distance than the wide area communication unit, and a communication control unit 1 that performs processing to communicate service data with the other communication device using the narrow area communication unit. The communication control unit is configured to perform at least part of authentication for starting narrow area service communication, which is communication of service data using the narrow area communication unit, using the wide area communication unit.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] TECHNICAL FIELD The disclosure herein relates to communication devices. [Background technology]

[0002] Patent Document 1 discloses a communication device that performs communication using two communication devices, a short-range communication device and a wide-area communication device, and identifies the positional relationship between vehicles based on the communication results. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-081123 Summary of the Invention [Problem to be solved by the invention]

[0004] Some communication standards require authentication before starting actual data communication (hereinafter also referred to as service data communication), such as transmitting images, audio, files, etc. In such communication standards, service data cannot be transmitted or received until authentication is complete. If the short-range communication device of Patent Document 1 uses a communication standard that requires authentication, authentication must first be performed when the device enters the range where the short-range communication device can communicate. Therefore, even if the device enters the range where the short-range communication device can communicate, it will take some time before communication of service data can begin.

[0005] One disclosed object is to provide a communication device that can shorten the time from when communication with another communication device via a short-range communication unit becomes possible to when communication of service data becomes possible. [Means for solving the problem]

[0006] The communication device disclosed herein is a communication device mounted on a vehicle, a wide-area communication unit (2) configured to be able to perform wireless communication with other communication devices; a narrow-area communication unit (3) configured to be capable of wireless communication with other communication devices and having a shorter communication range than the wide-area communication unit; a communication control unit (1) that performs processing for communicating service data with other communication devices using a short-range communication unit; The communication control unit The wide area communication unit is configured to perform at least a part of the authentication for starting short-range service communication, which is communication of service data using the short-range communication unit.

[0007] The wide-area communication unit performs at least part of the authentication for performing service data communication. The wide-area communication unit has a longer communication distance than the narrow-area communication unit. Therefore, the wide-area communication unit can perform at least part of the authentication before the other communication device enters the communication range of the narrow-area communication unit. This reduces the time from when communication with the other communication device via the narrow-area communication unit becomes possible until service data communication can be performed. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a block diagram illustrating an overview of a communication device. [Figure 2] FIG. 2 is a block diagram illustrating a configuration of a short-range communication unit. [Figure 3] FIG. 1 is a diagram illustrating an outline of a communication sequence. [Figure 4] FIG. 2 is a diagram illustrating a communication range of a communication device. [Figure 5] FIG. 2 is a diagram illustrating a communication range of a communication device. [Figure 6] FIG. 2 is a diagram illustrating a communication range of a communication device. [Figure 7] 1 is a flowchart of communication. [Figure 8] 10 is a flowchart of a connection process. [Figure 9] 10 is a flowchart of authentication. [Figure 10] FIG. 10 is a diagram illustrating an outline of a communication sequence in a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0009] In the following description, components having the same function may be given the same reference numerals, and a detailed description thereof may be omitted. Also, components having the same function may be given the same or similar names, and a detailed description thereof may be omitted. When only a portion of the configuration is mentioned, the description given elsewhere may apply to the other portions.

[0010] <Embodiment> The communication device 100 of the present disclosure is a device for communicating with another communication device 200 provided in another vehicle, a roadside device, or the like. The communication device 100 is mounted on a vehicle 7, which is any one vehicle. For convenience, the vehicle 7 on which the communication device 100 is mounted is also referred to as the host vehicle. The vehicle 7 may be a four-wheeled vehicle, a two-wheeled vehicle, a three-wheeled vehicle, or the like. Two-wheeled vehicles also include motorized bicycles. Communication between the communication device 100 and the other communication device 200 may be referred to as vehicle-to-vehicle communication or road-to-vehicle communication. The other communication device 200 may be mounted on another vehicle M, which is a vehicle other than the host vehicle, or on a roadside device installed on the roadside.

[0011] <Communication Device> First, a schematic configuration of the communication device 100 will be described with reference to Fig. 1. As shown in Fig. 1, the communication device 100 includes a communication control unit 1, a wide-area communication unit 2, and a short-range communication unit 3. The wide-area communication unit 2 and the short-range communication unit 3 are each connected to the communication control unit 1 so as to be able to communicate with each other. The communication device 100 is also connected to a sensor 4 and a driving assistance ECU 5 mounted on the vehicle so as to be able to communicate bidirectionally / unidirectionally via a communication network established within the vehicle.

[0012] The sensors 4 are various sensors for detecting information about the vehicle 7. The information about the vehicle 7 is, for example, information about the traveling speed, yaw rate, steering angle, acceleration, shift position, operation state of the turn signal, braking, etc. In other words, the sensors 4 include a speed sensor that detects the traveling speed, a yaw rate sensor that detects the yaw rate, a steering angle sensor that detects the steering angle, an acceleration sensor that detects the acceleration acting on the vehicle, a shift position sensor, a turn signal switch, a brake sensor, etc. The sensors 4 may also include a locator, which will be described next.

[0013] The locator is a device that sequentially calculates (in other words, identifies) the position of the vehicle. For example, the locator includes a GNSS receiver that receives positioning signals transmitted by positioning satellites that make up the GNSS (Global Navigation Satellite System), and calculates the position using the positioning signals received by the GNSS receiver. Position information indicating the current position of the vehicle identified by the locator is also included in the information of the vehicle 7. The information of the vehicle 7 is also referred to as information about the vehicle.

[0014] The detection results of the sensors 4 (information on the vehicle 7) are sequentially provided to the communication device 100 via a communication network. Note that the detection results of the various sensors 4 may be provided to the communication device 100 via any electronic control unit (ECU) or the like. The sensors that fall under the category of sensors 4 are not limited to those described above. Also, it is not necessary to have all of the sensors described above. The types of sensors 4 may be designed as appropriate.

[0015] The driving assistance ECU 5 has at least one of a driving assistance function that assists the driver in driving operations and a driving substitute function that can perform some or all of the driver's driving operations. The driving assistance ECU 5 may be an autonomous driving ECU that provides an autonomous driving function. The driving assistance ECU 5 performs the driving assistance function by having a processor execute a predetermined vehicle control program stored in an internal memory.

[0016] <Wide Area Communications Department> The wide-area communication unit 2 is a component configured to be able to perform wireless communication with other communication devices 200. Wireless communication between the wide-area communication unit 2 and other communication devices 200 is called wide-area communication. The communication range of the wide-area communication unit 2 is set to be wider than the communication range of the narrow-area communication unit 3. In other words, the communication distance of the wide-area communication unit 2 is set to be longer than the communication range of the narrow-area communication unit 3. The wide-area communication unit 2 includes a wide-area antenna 21 and a wide-area transmission / reception circuit (not shown).

[0017] Here, as an example, wide area communication is performed in accordance with the Wi-Fi HaLow (Wi-Fi is a registered trademark) communication standard. Wide area communication is realized using radio waves in the 920 MHz band. The communication standard and frequency band used for wide area communication may be set arbitrarily.

[0018] The wide area antenna 21 is an antenna for transmitting and receiving radio waves in a predetermined frequency band. The wide area communication unit 2 is configured to be able to perform wireless communication with other communication devices 200 using the wide area antenna 21. Here, the wide area antenna 21 is an omnidirectional antenna that is omnidirectional when viewed from above. Omnidirectional antennas include monopole antennas, bowtie arrays, inverted-F antennas, zero-order metamaterial antennas, etc. The wide area antenna 21 may be any other antenna.

[0019] The wide area transmission / reception circuit demodulates a signal received by the wide area antenna 21 and provides it to the communication control unit 1. The wide area transmission / reception circuit modulates data input from the communication control unit 1 and outputs it to the wide area antenna 21 for wireless transmission. The wide area communication unit 2 outputs the received data to the communication control unit 1, and also modulates data input from the communication control unit 1 and transmits it to other communication devices 200, etc.

[0020] <Narrow-area communication section> The short-range communication unit 3 is a component configured to be able to perform wireless communication with other communication devices 200. Wireless communication between the short-range communication unit 3 and other communication devices 200 is called short-range communication. The communication range of the short-range communication unit 3 is set to be narrower than the communication range of the wide-area communication unit 2. In other words, the communication distance of the short-range communication unit 3 is set to be shorter than the communication range of the wide-area communication unit 2.

[0021] Here, as an example, wide-area communication is performed in accordance with the Wi-Fi 6E communication standard. Wide-area communication may be realized using radio waves in the 2.4 GHz, 5 GHz, or 6 GHz band. The communication standard and frequency band used for wide-area communication may be set arbitrarily. As described above, wide-area communication uses the 920 MHz band, and narrow-area communication uses the 2.4 GHz, 5 GHz, or 6 GHz band. The frequency band used by narrow-area communication unit 3 for wireless communication may be set to have a wider bandwidth than the frequency band used by wide-area communication unit 2 for wireless communication.

[0022] The communication distance varies depending on the frequency band and output power used. If the output power of the short-range communication unit 3 and the wide-area communication unit 2 is the same, the communication distance will be longer if the frequency band is lower. Also, if the frequency band of the short-range communication unit 3 and the wide-area communication unit 2 is the same, the communication distance will be longer if the output power is higher.

[0023] The output power of the wide-area communication unit 2 and the narrow-area communication unit 3 may be adjustable by the communication control unit 1, which will be described later. Here, the output power of the wide-area communication unit 2 and the narrow-area communication unit 3 is set to be approximately the same. On the other hand, the wide-area communication unit 2 uses a lower frequency band than the narrow-area communication unit 3. Therefore, the communication distance of the wide-area communication unit 2 is longer than the communication distance of the narrow-area communication unit 3.

[0024] The short-range communication unit 3 includes a directional antenna 31 capable of changing the direction of directivity, and a short-range transmission / reception circuit 30. The directional antenna 31 is an antenna for transmitting and receiving radio waves in a frequency band used for short-range communication. The directional antenna 31 is an antenna having directionality and is an antenna other than an omnidirectional antenna. The short-range communication unit 3 is configured to be able to perform wireless communication with another communication device 200 using the directional antenna 31.

[0025] The directional antenna 31 is made up of a plurality of omnidirectional antennas 311. Here, as an example, it is made up of four omnidirectional antennas 311. The number of omnidirectional antennas 311 making up the directional antenna 31 may be any number. Furthermore, the directional antenna 31 may be made up of antennas other than omnidirectional antennas.

[0026] The multiple omnidirectional antennas 311 are arranged in a row or matrix at predetermined intervals to function as an array antenna A31. The omnidirectional antennas that make up the directional antenna 31 are hereinafter referred to as array elements. Note that the multiple array elements do not necessarily need to be regularly arranged in a single row or multiple rows, and the spacing and element shapes may vary.

[0027] The short-range transmission / reception circuit 30 demodulates a signal received by the array antenna A31 and provides it to the communication control unit 1. The short-range transmission / reception circuit 30 modulates data input from the communication control unit 1 and outputs it to the array antenna A31 for wireless transmission. The short-range communication unit 3 outputs the received data to the communication control unit 1, and modulates data input from the communication control unit 1 and transmits it to other communication devices 200, etc.

[0028] 2, the short-range transceiver circuit 30 may include an analog-to-digital converter E1, an analog signal processor E2, a distribution / coupling circuit E3, and a phase shifter E4. The analog-to-digital converter E1 is configured to convert between digital signals and analog signals. In other words, the analog-to-digital converter E1 functions as a D / A (Digital to Analog) converter and an A / D (Analog to Digital) converter.

[0029] The analog signal processing unit E2 is a group of circuits that perform various predetermined signal processing on analog signals, such as frequency conversion between baseband analog signals and RF band analog signals, shaping, amplification, etc. The distribution / coupling circuit E3 includes a circuit that distributes the analog signal as the transmission signal to each array element, and a circuit that combines the analog signals input from each array element and inputs the combined signals to the analog signal processing unit E2.

[0030] The phase shifter E4 is configured to multiply or add an analog signal by a weighting coefficient (analog weight) specified by the communication control unit 1 and output the result. The phase shifter E4 changes the amplitude and phase of the analog signal according to the weighting coefficient. A set of phase shifters E4 connected to each array element controls the directivity of the array antenna A31 by multiplying each analog signal by a weighting coefficient. In other words, the set of phase shifters E4 achieves beamforming based on the weighting coefficient set for each phase shifter E4. The weighting coefficient set for each phase shifter E4 is controlled by the communication control unit 1, which will be described later. The directional antenna 31 is thus configured to be able to change the direction of its directivity (beam). Note that the short-range transceiver circuit 30 may be configured without the phase shifter E4. The short-range transceiver circuit 30 may be configured to perform digital beamforming, which achieves beamforming using digital signal processing.

[0031] <Communication control unit> The communication control unit 1 includes a CPU 11, memories such as a RAM 12 or a ROM 13, an I / O 14, and a bus connecting these, and performs various processes by executing control programs stored in the ROM 13. Some or all of the functions performed by the communication control unit 1 may be realized using hardware such as one or more ICs.

[0032] The communication control unit 1 acquires information about the vehicle 7 from a sensor 4 mounted on the vehicle 7. The communication control unit 1 acquires information about another vehicle M mounted with another communication device 200 using the wide area communication unit 2 or the short area communication unit 3. In the following, the term "other vehicle M" may be appropriately read as "other communication device 200" or "other vehicle M in which another communication device 200 is mounted." The term "other communication device 200" may be appropriately read as "other vehicle M" or "other vehicle M in which another communication device 200 is mounted."

[0033] The information on the other vehicle M includes information on the traveling speed, yaw rate, steering angle, acceleration, shift position, turn signal operation state, brakes, etc. of the other vehicle M. The information on the other vehicle M also includes location information indicating the current location of the other vehicle M.

[0034] The communication control unit 1 performs processing for communicating service data with other communication devices 200 using the short-range communication unit 3. Service data is data for executing an application. The application may be software that is installed in the vehicle and can be operated, viewed, and used by the user in the vehicle. The application may be an application used in the vehicle related to autonomous driving or driving assistance of the vehicle. The application may be software that provides a route guidance function, or software that displays or provides audio guidance of signs, features, and obstacles related to autonomous driving or driving assistance. The application may also be a call or chat app.

[0035] The service data may be data related to automated driving or driving assistance, data related to route guidance, or data on signs, features, or obstacles. In one aspect, communication of service data may be interpreted as communication at the application layer. In another aspect, service data may be interpreted as content data related to the provision of functions / services. Service data may be rephrased as content data. Service data may actually be video, images, audio, text, program code, map data, etc. Service data may be encrypted data, and in one embodiment, communication of service data may be rephrased as encrypted communication.

[0036] In this disclosure, communication of service data using the short-range communication unit 3 (in other words, transmission and reception) is also referred to as short-range service communication. Short-range service communication becomes executable after authentication of the communication partner is completed.

[0037] The communication control unit 1 is configured to perform at least a part of the authentication for starting short-range service communication using the wide-area communication unit 2. In other words, the authentication for starting short-range service communication is also a preliminary preparation for starting short-range service communication. The authentication is a communication for obtaining information necessary for starting short-range service communication, such as ID exchange, key exchange, and IP address exchange.

[0038] The communication control unit 1 determines the priority of the other communication device 200 to be authenticated (hereinafter also referred to as authentication priority) using information about the host vehicle and information about the other vehicle M linked to the other communication device 200. The other vehicle M linked to the other communication device 200 is the other vehicle M in which the other communication device 200 is installed. There are many possible situations in which a plurality of other vehicles M (i.e., other communication devices 200) exist around the host vehicle. The authentication priority is an index for determining the order in which the other communication devices 200 to be authenticated are to be authenticated among the plurality of other communication devices 200 existing around the host vehicle.

[0039] The authentication priority may be determined based on the relative position. The authentication priority of another communication device 200 whose relative position (in other words, distance) is close may be set to be high. When there are multiple other communication devices 200 at approximately the same distance from the host vehicle, the authentication priority of another communication device 200 associated with another vehicle M traveling in the opposite lane may be set to be relatively low. When another vehicle M (i.e., a preceding vehicle) immediately ahead of the host vehicle applies the brakes, the authentication priority of another communication device 200 associated with the preceding vehicle may be set to be high. When the other vehicle M turns on its turn signal and moves in a different direction from the host vehicle, the authentication priority of another communication device 200 associated with the other vehicle M may be set to be low. The authentication priority of another communication device 200 associated with another vehicle M whose acceleration or deceleration is large may be set to be high even if the relative position is far away. The authentication priority determination rule may be designed according to the content, purpose, or objective of the short-range service communication. The communication control unit 1 may determine the authentication priority for each of the other communication devices 200 in accordance with a rule set in advance.

[0040] The communication control unit 1 may predict the future situations of the subject vehicle and the other vehicle M using information about the subject vehicle and information about the other vehicle M. The communication control unit 1 determines the priority (authentication priority) of the other vehicle M to be authenticated based on the prediction result. For example, the communication control unit 1 may predict a future positional relationship (e.g., distance) using information about the subject vehicle and information about the other vehicle M, and determine the authentication priority based on the prediction. The communication control unit 1 may set a higher authentication priority for the other communication device 200 associated with the other vehicle M whose relative distance is expected to become less than a predetermined value within a predetermined time, even if it is currently far away, based on the acceleration of the other vehicle, the operating state of its turn signal, etc. Conversely, the communication control unit 1 may set a lower authentication priority for the other communication device 200 associated with the other vehicle M whose relative distance is expected to become a predetermined value or more within a predetermined time, even if it is currently close.

[0041] The communication control unit 1 selects another communication device 200 to be authenticated based on the authentication priority. The communication control unit 1 authenticates the other communication device 200 in descending order of authentication priority.

[0042] The communication control unit 1 may be configured to determine a priority of the other vehicle M performing short-range service communication (hereinafter also referred to as a narrow-area priority) using information about the host vehicle and information about the other vehicle M. The narrow-area priority is an index used to determine the priority of the other communication devices 200 performing short-range service communication among the other communication devices 200 around the host vehicle. The process of determining the narrow-area priority may be performed after authentication has been performed.

[0043] The narrow area priority may be determined based on the same criteria as the authentication priority. In other embodiments, the narrow area priority may be determined based on criteria different from the authentication priority. The communication control unit 1 selects another communication device 200 with which to perform narrow area service communication based on the narrow area priority. The communication control unit 1 preferentially performs narrow area service communication with another communication device 200 with a high authentication priority.

[0044] The communication control unit 1 determines the direction in which the directivity is to be directed based on the position information of the host vehicle and the position information of the other vehicle M. Specifically, the communication control unit 1 identifies the direction in which the other vehicle M is located. Then, the communication control unit 1 determines the direction in which the other vehicle M is located as the direction in which the directivity is to be directed. The communication control unit 1 performs control so that the directivity is directed in the direction in which the other vehicle M is located.

[0045] <Communication sequence> The processing performed by the communication control unit 1 in this embodiment will be described with reference to Figures 3, 4, 5, and 6. Figure 3 shows the flow of communication between the host vehicle and another communication device 200 mounted on another vehicle M. Figure 3 assumes a situation in which the host vehicle approaches and overtakes another vehicle M as shown in the order of Figures 4, 5, and 6. The horizontal axis in Figure 3 represents time.

[0046] Fig. 4 is a diagram showing the positional relationship between the host vehicle and another vehicle M at time t1 in Fig. 3. Fig. 5 is a diagram showing the positional relationship between the host vehicle and another vehicle M at time t2 in Fig. 3. Fig. 6 is a diagram showing the positional relationship between the host vehicle and another vehicle M at time t3 in Fig. 3.

[0047] Time t1 in Fig. 3 indicates the timing when another vehicle M enters a range in which wide-area communication is possible by the wide-area communication unit 2. The range in which wide-area communication is possible by the wide-area communication unit 2 is also referred to as wide-area range R1 below. In Figs. 4, 5, and 6, wide-area range R1 is indicated by a solid line. The communication device 100 detects that the other communication device 200 has entered wide-area range R1 based on the wide-area communication unit 2 receiving a beacon signal from the other communication device 200. In other words, time t1 corresponds to the timing when the wide-area communication unit 2 receives a beacon signal.

[0048] Note that a beacon signal is transmitted periodically from another communication device 200. A beacon signal may be a signal for periodically announcing one's own presence. A beacon signal is transmitted in both wide-area communication and short-range communication. A beacon signal transmitted in wide-area communication and a beacon signal transmitted in short-range communication are different signals with different frequencies or communication methods. For convenience, a beacon signal in wide-area communication will be referred to as a wide-area beacon signal, and a beacon signal in short-range communication will be referred to as a short-area beacon signal.

[0049] When the communication control unit 1 receives the wide-area beacon signal, it performs connection processing with another vehicle M using the wide-area communication unit 2. The connection processing is a process of establishing a connection to perform wireless communication with another communication device 200 using the wide-area communication unit 2. Details of the connection processing will be described later. After the connection processing, the wide-area communication unit 2 and the other communication device 200 perform data communication. The data communication performed between the wide-area communication unit 2 and the other communication device 200 is referred to as wide-area data communication.

[0050] In wide-area data communication, information about each vehicle is transmitted and received. The vehicle transmits information about the vehicle to the other communication device 200 using the wide-area communication unit 2. The vehicle receives information about the other vehicle M from the other communication device 200 using the wide-area communication unit 2.

[0051] After the connection process, wide-area data communication can be performed while the other communication device 200 is present within the communication distance of the wide-area communication unit 2. In Fig. 3, the period during which wide-area communication is possible is indicated by hatching. The start of the period during which wide-area communication can be started may be the time when the connection process is completed. The end of the period may correspond to, for example, the time when the other vehicle M leaves the wide-area range R1.

[0052] In this embodiment, vehicle information is exchanged after wide-area communication is established, but this is not limited to this. Vehicle information may be transmitted and received by broadcast. Authentication in wide-area communication is an optional element and may be omitted. Here, vehicle information may be interpreted as information about the subject vehicle and information about the other vehicle M. Vehicle information may also be transmitted and received using the short-range communication unit 3. The subject vehicle and the other vehicle M may be configured to broadcast information about the vehicle in which they are installed using the wide-area communication unit 2 and the short-range communication unit 3. The communication device 100 may receive information about the other vehicle M broadcast from the other vehicle M by short-range communication using the short-range communication unit 3.

[0053] The communication control unit 1 uses information about the other vehicle M to evaluate the possibility of connection with another communication device 200 used in the other vehicle M. Here, the possibility of connection means the possibility of performing actual data communication by short-range communication, that is, the possibility of performing short-range service communication. The evaluation (in other words, the determination) of the possibility of connection may be performed when the other communication device 200 is present in the wide area range R1 and the distance to the other communication device 200 is equal to or less than a predetermined value. The determination of the possibility of connection is performed periodically. The information about the other vehicle M used to determine the possibility of connection may be received by the wide area communication unit 2 or the short-range communication unit 3.

[0054] The possibility of connection is determined based on whether the situation allows the expected application to be executed within the communication distance of the wide area communication unit 2. For example, a case can be considered in which the vehicle is equipped with an application that is executed within a distance of 100 m from another communication device 200. In this case, when the vehicle and the other communication device 200 are within a distance of 100 m, the situation is one in which the application can be executed.

[0055] An example of a situation where the possibility of connection is low is when the other vehicle M makes a right or left turn and the distance between the other communication device 200 and the own vehicle starts to increase. The possibility of connection may be determined based on the direction of change in distance, such as whether the other vehicle M and the own vehicle are approaching each other or moving away from each other.

[0056] The connectability may be determined based on any other conditions. The situation in which an application can be executed may simply include the distance between the vehicle and the other communication device 200 being equal to or less than a predetermined value.

[0057] 3 indicates the timing when the communication control unit 1 determines that the possibility of connection to the other vehicle M is high. In this way, when the communication control unit 1 determines that the possibility of connection to the other vehicle M is high, the communication control unit 1 performs at least a part of the authentication for starting the short-range service communication using the wide-area communication unit 2.

[0058] Time t2 in FIG. 3 indicates the timing when another communication device 200 enters within a short-range communication distance from the vehicle. Hereinafter, the short-range communication distance is also referred to as a short-range range R2. In FIGS. 4, 5, and 6, the short-range range R2 is indicated by a dashed line. If authentication for short-range service communication using the wide-area communication unit 2 has not been completed at time t2, the remaining part of the authentication is continued using the short-range communication unit 3 instead of the wide-area communication unit 2. The remaining part of the authentication refers to an incomplete part of the entire authentication procedure (communication). In this way, the communication means used for authentication for short-range service communication may be switched from wide-area communication to short-range communication upon receiving a short-range beacon. Note that entry of another vehicle M (another communication device 200) into the short-range range R2 may be detected based on reception of a short-range beacon signal emitted from the other vehicle M.

[0059] 3 indicates the timing at which authentication using the short-range communication unit 3 is completed. When authentication is completed at time t23, short-range service communication becomes possible between the communication device 100 and the other communication device 200. The period during which short-range service communication is possible is indicated by hatching with a relatively dense dot pattern.

[0060] At time t3, when the other communication device 200 moves out of the narrow area range R2, it becomes impossible for the communication device 100 to perform narrow area communication with the other communication device 200. In other words, time t3 represents the time when narrow area communication with the other communication device 200 becomes impossible.

[0061] <Communication flow> 7, the communication flow performed by the communication control unit 1 will be described. The communication flow starts when the ignition switch of the vehicle 7 is turned on. S11 of the communication flow may be repeated until the ignition switch is turned off.

[0062] In S11, the communication control unit 1 determines whether the wide-area communication unit 2 has received a beacon signal (i.e., a wide-area beacon signal). Here, the vehicle (wide-area communication unit 2) receives the wide-area beacon signal, but the vehicle (wide-area communication unit 2) also periodically transmits the wide-area beacon signal. The wide-area beacon signal includes an ID such as an SSID that can identify the sender.

[0063] In S12, the communication control unit 1 performs connection processing for wide area communication using the wide area communication unit 2. The connection processing for wide area communication may include S31 to S36, as shown in FIG. 8. In S31, the communication control unit 1 transmits a connection request to the other communication device 200 using the wide area communication unit 2. The connection request is a signal requesting a connection. The connection request may be a signal requesting information about the other communication device 200 necessary for the connection. The connection request may be a signal including information about itself (i.e., the communication device 100) necessary for the connection. The other communication device 200 that has received the connection request transmits a connection response. The connection response is a signal responding to the connection request. The following describes a case where the other communication device 200 returns a positive response (so-called Ack) in response to various requests from the communication device 100. In S32, the communication control unit 1 receives the connection response from the wide area communication unit 2.

[0064] In the connection request and the connection response, information about the communication device 200 and the other communication device 200, such as a MAC address, may be transmitted and received. In the connection request and the connection response, information necessary for identifying a communication group group, such as an association ID, may be transmitted and received. In the connection request and the connection response, an encryption key or information necessary for key generation may be transmitted and received. The series of processes for transmitting and receiving the connection request and the connection response is a process for identifying the other party to associate with. Association may mean that the communication device 100 connects to another communication device 200. In S33, the communication control unit 1 transmits an authentication request to the other communication device 200 using the wide area communication unit 2. The other communication device 200 that has received the authentication request transmits an authentication response. In S34, the communication control unit 1 receives the authentication response via the wide area communication unit 2. The authentication request and the authentication response are processes for performing open system authentication or shared key authentication.

[0065] In S35, the communication control unit 1 transmits an association request to the other communication device 200 using the wide area communication unit 2. The association request is a signal requesting association to the other communication device 200. The association request in S35 is a signal requesting connection with the other communication device 200 via wide area communication. The other communication device 200 that receives the association request transmits an association response. The association response is a signal that responds to the association request. In S36, the communication control unit 1 receives the association response from the wide area communication unit 2. This completes the connection process with the other communication device 200 by the wide area communication unit 2.

[0066] In S13 of FIG. 7, the communication control unit 1 determines whether it is time to update. The update timing refers to the timing at which the position information of each communication device is updated. The update timing may be the timing when a certain time has elapsed since the previous update. In S14, the communication control unit 1 acquires the position information of the host vehicle and the other vehicle M. For example, in S14, the communication control unit 1 acquires information about the host vehicle from the sensor 4. Furthermore, the communication control unit 1 receives information about the other vehicle M (including the position information of the other vehicle M) from the other communication device 200 using the wide-area communication unit 2. In S14, the communication control unit 1 may transmit information about the host vehicle (including the position information of the host vehicle) to the other communication device 200 using the wide-area communication unit 2.

[0067] In S15, the communication control unit 1 calculates the relative position. In S16, the communication control unit 1 determines whether connection is possible. Then, it determines whether connection with another communication device 200 is expected. If NO in S15, the process returns to S13. In this way, after the connection process, the communication control unit 1 and the other communication device 200 periodically exchange position information with each other.

[0068] In S17, the communication control unit 1 determines an authentication priority. The communication control unit 1 extracts other vehicles M that are determined to have connection potential, and determines an authentication priority for the extracted other vehicles M. In S18, the communication control unit 1 selects another communication device 200 associated with the other vehicle M with a high authentication priority, and starts authentication using the wide area communication unit 2 to start short-range service communication using the short-range communication unit 3.

[0069] In S19, the communication control unit 1 determines whether the short-range communication unit 3 has received a short-range beacon signal. Note that the vehicle (short-range communication unit 3) also periodically transmits a short-range beacon signal. In S20, if the authentication by the wide-area communication unit 2 has not been completed, the remaining authentication sequence is continued using the short-range communication unit 3 instead of the wide-area communication unit 2.

[0070] Details of authentication from S18 to S20 will be explained using FIG. 9. Authentication for short-range service communication may include S41 to S45 shown in FIG. 9. S18 described above includes the processes of S41 and S42. S19 includes the process of S43. S20 includes the processes of S44 and S45. In S41, the communication control unit 1 transmits authentication information to the other communication device 200 using the wide-area communication unit 2. In S42, the communication control unit 1 receives authentication information from the other communication device 200 using the wide-area communication unit 2.

[0071] The authentication information may include information about the communication device 200 and other communication devices 200, such as a MAC address, information necessary for identifying communication groups, such as an association ID, an encryption key, or information necessary for key generation.

[0072] In S44, the communication control unit 1 uses the short range communication unit 3 to transmit an association request to the other communication device 200. The association request in S44 is a signal requesting connection with the other communication device 200 via short range communication. The other communication device 200 that has received the association request transmits an association response. In S45, the communication control unit 1 receives the association response via the short range communication unit 3. This completes authentication. In other words, a short range communication connection between the short range communication unit 3 and the other communication device 200 is established.

[0073] 7, the narrow area priority is determined. The communication control unit 1 extracts other vehicles M for which authentication has been completed, and determines the narrow area priority for the extracted other vehicles M. The processing of S21 is performed periodically. The communication control unit 1 selects another communication device 200 associated with the other vehicle M having a high narrow area priority, and performs narrow area service communication using the narrow area communication unit 3.

[0074] In S20, authentication is continued using the short range communication unit 3 instead of the wide range communication unit 2, but in S18 the wide range communication unit 2 may perform all of the authentication. In that case, the process of S20 is omitted.

[0075] In S21, if the authentication by the wide area communication unit 2 has not been completed when wireless communication between the short range communication unit 3 and the other communication device 200 becomes possible, the remaining part of the authentication is continued using the short range communication unit 3 instead of the wide area communication unit 2, but this is not necessarily limited to this. The wide area communication unit 2 may continue to perform the authentication. In S21, the communication control unit 1 determines the short range priority, but the authentication priority may be set as the short range priority as is.

[0076] <Summary of the embodiment> The effects of this embodiment will be described with reference to a comparative example shown in Fig. 10. In this comparative example, the possibility of connection is not determined, and at least a part of the authentication for starting short-range service communication is not performed using the wide-area communication unit 2. In other words, in the comparative example, authentication for short-range service communication starts after the other vehicle M enters the short-range range R2.

[0077] Time t2 shown in Fig. 10 indicates the timing when another communication device 200 enters within the communication distance of the short-range communication unit 3. In the comparative example, as described above, authentication using the short-range communication unit 3 starts after the other communication device 200 enters the short-range range R2. Time t23a in Fig. 10 indicates the timing when authentication in the short-range communication layer is completed. In the comparative example, authentication starts after the other communication device 200 enters within the communication distance of the short-range communication unit 3, so the time until short-range service communication can be performed (time t2 to t23a) is long. The time from t2 to t23a essentially corresponds to the time required for authentication.

[0078] In contrast to the comparative example, in this embodiment, part or all of the authentication for short-range service communication is performed in advance by wide-area communication. Therefore, in this embodiment, compared to the comparative example, the time from when communication with another communication device 200 via the short-range communication unit 3 becomes possible to when short-range service communication can actually be performed can be shortened.

[0079] The communication device 100 of this embodiment determines the authentication priority based on the information of its own vehicle and the information of the other vehicle M, and selects the other communication device 200 to perform authentication based on the authentication priority, thereby enabling authentication to be performed in an appropriate order.

[0080] The communication device 100 of this embodiment determines narrow-area priority based on information about its own vehicle and information about the other vehicle M, and selects another communication device 200 that will perform narrow-area service communication based on the narrow-area priority. This allows narrow-area service communication to be performed in an appropriate order.

[0081] In one embodiment, the above-described communication device 100 predicts future situations of the subject vehicle and the other vehicle M based on information about the subject vehicle and information about the other vehicle M, and determines an authentication priority of the other vehicle M based on the predicted result. Then, the communication device 100 selects another communication device 200 to perform authentication based on the priority taking into account the future situation. This allows authentication to be performed in an order according to the future situation.

[0082] In the communication device 100 of this embodiment, the information about the host vehicle is information about one of the position information, speed, acceleration, steering angle, turn indicator, and brake of the host vehicle. Also, the information about the other vehicle M is information about one of the position information, speed, acceleration, steering angle, turn indicator, and brake of the other vehicle M. As a result, at least one of the authentication priority, narrow-area priority, and future priority can be determined by the information about one of the position information, speed, acceleration, steering angle, turn indicator, and brake of the host vehicle and the information about one of the position information, speed, acceleration, steering angle, turn indicator, and brake of the other vehicle M.

[0083] In the communication device 100 of this embodiment, the short-range communication unit 3 has a directional antenna 31 and is configured to be able to perform wireless communication with another communication device 200 using the directional antenna 31. This allows communication over a longer distance than when the short-range communication unit 3 uses an omnidirectional antenna.

[0084] In the communication device 100 of this embodiment, the short-range communication unit 3 has a directional antenna 31 whose direction of directivity can be changed. The communication control unit 1 determines the direction of the directivity based on the position information of the vehicle 7 and the position information of the other vehicle M. This allows the directivity of the directional antenna 31 to be directed in an appropriate direction.

[0085] In the communication device 100 of this embodiment, the frequency band used by the short-range communication unit 3 for wireless communication has a wider bandwidth than the frequency band used by the wide-area communication unit 2 for wireless communication. If authentication by the wide-area communication unit 2 has not been completed when wireless communication between the short-range communication unit 3 and another communication device 200 is possible, the communication control unit 1 continues authentication using the short-range communication unit 3. The frequency band used by the short-range communication unit 3 has a wider bandwidth than the frequency used by the wide-area communication unit 2. Therefore, the communication speed of the short-range communication unit 3 is faster than that of the wide-area communication unit 2. Therefore, if authentication has not been completed when communication between the short-range communication unit 3 and another communication device 200 is possible, authentication is continued using the short-range communication unit 3, so that authentication can be completed earlier. This makes it possible to speed up the start of short-range service communication.

[0086] <Modification> The short-range communication unit 3 and the wide-area communication unit 2 may use the same frequency band. In this case, the output power of the short-range communication unit 3 is set to be smaller than that of the wide-area communication unit 2. This makes the communication distance of the short-range communication unit 3 shorter than that of the wide-area communication unit 2.

[0087] The directional antenna 31 may be configured by a single directional antenna. In this case, the orientation of the single directional antenna may be changed by physically moving the attitude of the single directional antenna using an actuator such as a motor.

[0088] The short-range communication unit 3 may be configured to be able to perform wireless communication with other communication devices 200 using an omnidirectional antenna instead of the directional antenna 31. The beam control of the short-range communication unit 3 is an optional element and may be omitted. [Explanation of symbols]

[0089] 1 Communication control unit, 2 Wide area communication unit, 21 Wide area antenna, 3 Short range communication unit, 31 Directional antenna, 4 Sensor, 5 Driving assistance ECU

Claims

1. A communication device mounted on a vehicle, a wide-area communication unit (2) configured to be able to perform wireless communication with other communication devices; a narrow-area communication unit (3) configured to be able to perform wireless communication with the other communication device and having a shorter communication range than the wide-area communication unit; a communication control unit (1) that performs processing for communicating service data with the other communication device using the short-range communication unit; The communication control unit A communication device configured to use the wide area communication unit to perform at least a part of authentication for starting short-range service communication, which is communication of the service data using the short-range communication unit.

2. the other communication device is a communication device mounted on another vehicle, The communication control unit Acquiring information about the vehicle from a sensor mounted on the vehicle; acquiring information about the other vehicle equipped with the other communication device using the wide-area communication unit or the short-range communication unit; determining a priority of the other communication device that performs the authentication using information about the vehicle and information about the other vehicle that is linked to the other communication device; The communication device according to claim 1 , wherein the other communication device to perform the authentication is selected based on the priority.

3. the other communication device is a communication device mounted on another vehicle, The communication control unit Acquiring information about the vehicle from a sensor mounted on the vehicle; acquiring information about the other vehicle equipped with the other communication device using the wide-area communication unit or the short-range communication unit; determining a priority of the other vehicle that performs the short-range service communication using information about the vehicle and information about the other vehicle; The communication device according to claim 1 , wherein the other communication device for performing the short-range service communication is selected based on the priority.

4. the other communication device is a communication device mounted on another vehicle, The communication control unit Acquiring information about the vehicle from a sensor mounted on the vehicle; acquiring information about the other vehicle equipped with the other communication device using the wide-area communication unit or the short-range communication unit; predicting future situations of the vehicle and the other vehicle using information about the vehicle and information about the other vehicle; determining a priority of the other vehicle to be authenticated based on the predicted result; The communication device according to claim 1 , wherein the other communication device to perform the authentication is selected based on the priority.

5. The vehicle information is information regarding at least one of a position, a speed, an acceleration, a steering angle, a turn signal, and a brake of the vehicle, 5. The communication device according to claim 2, wherein the information about the other vehicle is information about at least one of a position, a speed, an acceleration, a steering angle, a turn signal, and / or a brake of the other vehicle.

6. The short-range communication unit A directional antenna (31) is provided, The communication device according to claim 1 , wherein the communication device is configured to be capable of performing wireless communication with the other communication device using the directional antenna.

7. The short-range communication unit A directional antenna (31) whose direction of directivity can be changed, a communication device configured to be able to perform wireless communication with the other communication device using the directional antenna; The communication control unit acquiring position information of the vehicle from a sensor mounted on the vehicle as information about the vehicle; acquiring position information of the other vehicle as the information of the other vehicle using the wide-area communication unit or the short-range communication unit; The communication device according to claim 2 , wherein a direction to which the directivity is to be directed is determined based on position information of the vehicle and position information of the other vehicle.

8. a frequency band used by the short-range communication unit for wireless communication has a wider bandwidth than a frequency band used by the wide-area communication unit for wireless communication; 5. The communication device according to claim 1, wherein the communication control unit continues to perform the authentication using the narrow-area communication unit if the authentication using the wide-area communication unit has not been completed when wireless communication between the narrow-area communication unit and the other communication device becomes possible.

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