JP6979359B2 - On-board unit, communication system, and communication method - Google Patents

Description

The present invention relates to an on-board unit that wirelessly communicates with a roadside unit provided on the roadside, a communication system that wirelessly communicates between the on-board unit and the roadside unit, and a communication method.

Electronic toll collection system (ETC) that allows a vehicle to pass through a tollhouse by wirelessly communicating information on toll collection between a roadside unit installed at a tollhouse on a highway and an on-board unit mounted on the vehicle. Collection System) is widespread. In addition, with the spread of ITS (Intelligent Transport Systems), roadside machines have been installed not only in tollhouses but also in highway parking areas, general roads, parking lots, etc., and vehicles pass by these roadside machines. During the period, traffic information, information on surrounding facilities, etc. are provided to the in-vehicle device by wireless communication.

The on-board unit is provided with operation buttons used for volume adjustment, history confirmation, etc. (see, for example, Patent Document 1). If an operation button is operated and a command signal is given to the control unit of the on-board unit during wireless communication with the roadside unit, this command processing may affect the communication processing with the roadside unit. Therefore, some conventional on-board units prohibit button operations during wireless communication.

Japanese Unexamined Patent Publication No. 2002-74433

However, the above-mentioned conventional on-board unit cannot perform an external input operation such as a button operation during wireless communication with the roadside unit, which is inconvenient for the user.

The present invention has been made in view of such circumstances, and a main object thereof is to provide an in-vehicle device, a communication system, and a communication method capable of solving the above-mentioned problems.

In order to solve the above-mentioned problems, the in-vehicle device according to one aspect of the present invention has a wireless communication unit that transmits / receives a radio signal to and from a roadside unit, and receives an input from the outside based on the received input. The external input unit that generates a command signal, the command signal processing unit that executes command signal processing according to the command signal, and the command signal processing unit of the command signal processing unit are restricted according to the modulation method of the radio signal. It is equipped with a control unit.

Further, the communication system of another aspect of the present invention includes the vehicle-mounted device of the above-described aspect and a roadside device capable of wireless communication with the vehicle-mounted device.

Further, in the communication method of another aspect of the present invention, a radio signal is transmitted / received between the vehicle-mounted device and the roadside device, an input from the outside is received, and a command signal is generated based on the received input. The command signal processing corresponding to the command signal is executed, and the command signal processing is restricted according to the modulation method of the radio signal in the execution of the command signal processing.

According to the present invention, it is possible to suppress restrictions on external input operations such as button operations during wireless communication with a roadside unit, and improve user convenience.

The schematic diagram which shows the structure of the communication system which concerns on Embodiment 1. The functional block diagram which shows the functional structure of the vehicle-mounted device which concerns on Embodiment 1. FIG. The block diagram which shows an example of the hardware composition of the vehicle-mounted device which concerns on Embodiment 1. FIG. The block diagram which shows an example of the hardware composition of the roadside machine which concerns on Embodiment 1. The schematic diagram which shows the frame structure in DSRC wireless communication. The flowchart which shows the procedure of the wireless communication processing by the communication system which concerns on Embodiment 1. The flowchart which shows the procedure of the command acceptance restriction processing in the vehicle-mounted device which concerns on Embodiment 1. The flowchart which shows the procedure of the modification of the command acceptance restriction processing in the vehicle-mounted device which concerns on Embodiment 1. The block diagram which shows an example of the hardware composition of the vehicle-mounted device which concerns on Embodiment 2. The flowchart which shows the procedure of the wireless communication processing by the communication system which concerns on Embodiment 2. The flowchart which shows the procedure of the command acceptance restriction processing in the vehicle-mounted device 200 which concerns on Embodiment 2. The functional block diagram which shows the functional structure of the vehicle-mounted device which concerns on Embodiment 3. FIG. The flowchart which shows the procedure of the wireless communication processing by the communication system which concerns on Embodiment 3. The flowchart which shows the procedure of the command acceptance restriction processing in the vehicle-mounted device which concerns on Embodiment 3. The functional block diagram which shows the functional configuration of the vehicle-mounted device which concerns on Embodiment 4. FIG. The flowchart which shows the procedure of the command acceptance restriction processing in the vehicle-mounted device which concerns on Embodiment 4. The flowchart which shows the procedure of the command acceptance restriction processing in the vehicle-mounted device which concerns on Embodiment 5.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. It should be noted that each embodiment shown below exemplifies a method and an apparatus for embodying the technical idea of the present invention, and the technical idea of the present invention is not limited to the following. No. The technical idea of the present invention may be modified in various ways within the technical scope described in the claims.

(Embodiment 1)
In the present embodiment, the in-vehicle device mounted on the vehicle performs command signal processing of a command signal related to an external input when wireless communication is performed by transmitting and receiving a wireless signal to and from a roadside unit. It is limited according to the modulation method of. The in-vehicle device can change the limitation according to the modulation method. For example, when the modulation method of wireless communication is the ASK (amplitude-shift keying) method, the command signal processing is limited and wireless. When the signal modulation method is the QPSK (Quadrature Phase Shift Keying) method, the restriction on command signal processing is released. As the QPSK method, for example, there is a π / 4 shift QPSK method. More specifically, the on-board unit determines, for example, the modulation method of the radio signal according to whether or not the demodulation of the radio signal is possible, and limits the command signal processing according to the modulation method as described above. Alternatively, the vehicle-mounted device determines the modulation method of the radio signal from the modulation information of the radio signal, and limits the command signal processing according to the determined modulation method.

<Communication system configuration>
FIG. 1 is a schematic diagram showing a configuration of a communication system according to the present embodiment. As shown in FIG. 1, the communication system 100 includes an on-board unit 200 and a roadside unit 300. The on-board unit 200 is mounted on the vehicle 290, and the roadside unit 300 is installed at a tollhouse on a highway, a parking area, a general road, an entrance / exit gate of a parking lot, and the like. Wireless communication by DSRC is possible between the on-board unit 200 and the roadside unit 300. The roadside unit 300 performs wireless communication with the vehicle-mounted device 200 while the vehicle passes through the wireless communication area.

FIG. 2 is a functional block diagram showing a functional configuration of the vehicle-mounted device 200 according to the present embodiment. The on-board unit 200 is an ETC (Electronic Toll Collection System) on-board unit and has a DSRC communication function. As shown in FIG. 2, the on-board unit 200 has each functional block of a wireless communication unit 201, an external input unit 202, a command signal processing unit 204, an output unit 205, and a control unit 206. The wireless communication unit 201 is capable of wireless communication with the roadside unit 300 by DSRC. The external input unit 202 receives an input from the outside and generates a command signal based on the received input. The configuration of the external input unit 202 is not particularly limited as long as it can accept input from the outside, and is, for example, an operation unit such as a button switch, a slide switch, or an operation controller that can be operated by the user. May be good. Such an operation unit generates various command signals related to operations such as volume adjustment, history confirmation, and setting change. Further, the external input unit 202 may be a communication unit connected to an external device such as a navigation device or a mobile terminal (a mobile phone such as a smartphone). Such a communication unit performs data communication with an external device, receives an external signal from the external device, and generates a command signal. The command signal processing unit 204 receives the command signal generated by the external input unit 202. The output unit 205 outputs information to which an output instruction is given by a command signal. In the present embodiment, the output unit 205 is a speaker and outputs sound. However, the output unit 205 is not limited to the speaker, and may be a display unit that outputs, for example, an image or light (for example, LED light). The control unit 206 determines whether the modulation method of the wireless communication by the wireless communication unit 201 is the ASK method or the QPSK method, and when the modulation method is the ASK method, the command signal by the command signal processing unit 204 Restrict the reception of.

FIG. 3 is a block diagram showing an example of a specific hardware configuration of the vehicle-mounted device 200. The on-board unit 200 includes an information processing unit 210, a wireless communication unit 220, a card reading unit 230, an operation button 240, a communication unit 250, and an output unit 260. Needless to say, the operation button 240 and the communication unit 250 correspond to the external input unit 202 of FIG.

The information processing unit 210 has a CPU 211 and a memory 212, and controls each unit of the vehicle-mounted device 200. The vehicle-mounted device program 213, which is a computer program for the vehicle-mounted device, is stored in the memory 212, and the CPU 211 executes the vehicle-mounted device program 213 to enable operations as described later. The command signal processing unit 204 and the control unit 206 described above are realized by the information processing unit 210.

The wireless communication unit 220 is a communication device that enables wireless communication with the roadside unit 300 by a wireless signal, receives the wireless signal from the roadside unit 300, and transmits the wireless signal to the roadside unit 300. The wireless communication unit 220 has an antenna 221 and a data demodulator 222. The data demodulator 222 demodulates the data modulated by the ASK method or the QPSK method. Although not shown, the wireless communication unit 220 also has a data modulation unit that modulates the data by the ASK method or the QPSK method. The wireless communication unit 201 described above is realized by the wireless communication unit 220. Further, in the DSRC wireless communication by the wireless communication unit 220, the CPU 211 executes the function of the SAM (Secure Application Module) and performs the encryption / decryption processing necessary for the communication.

The card reading unit 230 is an ETC card reading device, and when an ETC card is inserted, it reads out the ETC card information stored in the card. Also in reading the ETC card by the card reading unit 230, the CPU 211 executes the SAM function and performs the encrypted communication necessary for reading the ETC card.

The operation button 240 is a button switch that can be operated by the user, the communication unit 250 is a communication module that performs data communication with the external device 400, and the output unit 260 is a speaker capable of voice output. The external input unit 202 described above is realized by at least one of the operation button 240 and the communication unit 250, and the output unit 205 is realized by the output unit 260.

FIG. 4 is a block diagram showing an example of the hardware configuration of the roadside machine 300. The roadside machine 300 is an ETC roadside machine and has a DSRC communication function. The roadside machine 300 includes an information processing unit 310 and a wireless communication unit 320.

The information processing unit 310 has a CPU 311 and a memory 312, and the memory 312 stores a roadside machine program 313 for communicating with the vehicle-mounted device 200. The information processing unit 310 controls each unit of the roadside machine 300 and executes the roadside machine program 313 to execute communication processing with the vehicle-mounted device 200 as described later.

The wireless communication unit 320 has an antenna 321 for wireless communication and a data modulator 322. The data modulator 322 modulates the data by the ASK method or the QPSK method. The modulated data is transmitted from the antenna 321. Although not shown, the wireless communication unit 320 also has a data demodulator that demodulates the data modulated by the ASK method or the QPSK method.

<Operation of communication system>
Next, the operation of the communication system according to the present embodiment will be described. The roadside unit 300 radiates radio waves from the antenna 321 to form a wireless communication area. DSRC wireless communication by the TDMA (Time Division Multiple Access) method is performed between the roadside unit 300 and the on-board unit 200 in the wireless communication area. FIG. 5 is a schematic diagram showing a frame configuration in DSRC wireless communication. The frame transmitted by the DSRC wireless communication includes slots such as FCMS (Flame Control Message Slot), MDS (Message Data Slot), WCNS (Wireless Call Number Slot), and ACTS (Activation Slot). As shown in FIG. 5, the downlink is composed of FCMS and a plurality of MDSs. The FCMS is a slot for transmitting FCMC including frame control information and slot allocation information, and is positioned at the beginning of a frame. The MDS is a slot for data transmission. The uplink selectively includes MDS, ACTS, WCNS and the like. The ACTS is a slot for transmitting an ACTC (Activation Channel) which is a connection request signal to the roadside machine 300, and the WCNS is a slot for transmitting a WCN (Wireless Call Number).

FIG. 6 is a flowchart showing a procedure of wireless communication processing by the communication system according to the present embodiment. The CPU 311 of the roadside machine 300 periodically transmits the FCMC by the wireless communication unit 320 (step S101). The CPU 211 of the on-board unit 200 mounted on the vehicle 290 sets the reception frequency (channel) of the wireless communication unit 220 (step S102), and whether or not a radio signal is detected in this channel (specifically, a predetermined value or more). (Whether or not the radio wave strength of the above is detected) is determined (step S103). In the series of processes of steps S102 to S103, the radio signal is transmitted (that is, the state in which the channel is used; hereinafter referred to as "busy state") or is not transmitted in the set channel (that is, the state in which the radio signal is used). That is, it is a carrier sense process for determining whether the channel is not being used. Hereinafter, it is referred to as an “idle state”). In other words, the carrier sense process is a process of determining whether or not the vehicle-mounted device 200 has entered the wireless communication area of the roadside unit 300. If the radio signal is not detected (NO in step S103), the CPU 211 determines that it is in an idle state, returns the process to step S102, sets another channel, and executes the carrier sense process again. If the wireless signal is detected (YES in step S103), the CPU 211 determines that it is in a busy state, and shifts the process to step S104.

The CPU 211 receives the FCMC on that channel (step S104). Next, the CPU 211 transmits the ACTC by the wireless communication unit 220 (step S105), and the roadside machine 300 receives it (step S106). After that, the roadside unit 300 transmits the BST (Beacon Service Table) to the on-board unit 200, the on-board unit 200 transmits the VST (Vehicle Service Table) to the roadside unit 300, and the like, and then the roadside unit 300 performs necessary communication. CPU 311 transmits data to the vehicle-mounted device 200 (step S107). This data is WCN request data, message data, and the like. When the CPU 211 of the vehicle-mounted device 200 receives the data (step S108), the response data to the data is transmitted (step S109), and the roadside unit 300 receives the data (step S110). The response data is WCN, ACK, etc. of the own device. Hereinafter, the wireless communication process between the roadside unit 300 and the on-board unit 200 is continued. The above wireless communication processing is performed by any of the ASK method and the QPSK method. The modulation method is selected to match the roadside machine 300 of the communication partner.

FIG. 7 is a flowchart showing a procedure of command signal reception restriction processing in the vehicle-mounted device 200 according to the present embodiment. First, the CPU 211 determines whether or not a command signal is input by operating the operation button 240 or by communicating from the external device 400 (step S111). If no command signal has been input (NO in step S111), the CPU 211 re-executes the process of step S111.

When a command signal is input (YES in step S111), the CPU 211 determines whether or not wireless communication is in progress (step S112). When wireless communication is not in progress (NO in step S112), the CPU 211 moves to step S117 and accepts a command signal (step S117). When wireless communication is in progress (YES in step S112), the CPU 211 determines whether the modulation method of wireless communication is the ASK method or the QPSK method (step S113).

When the modulation method is the ASK method (“ASK” in step S113), the CPU 211 starts a limiting period which is a period for limiting the reception of command signals (step S114), and performs a limiting process for limiting the reception of command signals. Execute (step S115). This restriction processing corresponds to the fact that the CPU 211 does not execute any processing when the command signal is generated by the button operation, and when the command signal is generated by the communication from the external device 400, the external device 400 is subjected to this restriction processing. Corresponds to sending NAK (negative response). The time limit is, for example, 100 milliseconds. The CPU 211 determines whether or not the restricted period has elapsed (step S116), and if the restricted period has not elapsed (NO in step S116), returns the process to step S115. If the time limit has elapsed (YES in step S116), the CPU 211 returns the process to step S111.

When the modulation method is the QPSK method (“QPSK” in step S113), the CPU 211 receives the command signal (step S117) and executes the command (step S118). After that, the CPU 211 returns the process to step S111.

The ASK wireless communication is mainly used for communication of information on toll collection at tollhouses on expressways, and the content of the communication is very important. For example, if the ASK wireless communication at the tollhouse gate does not end normally, the toll collection will not be completed, the gate will remain closed and the vehicle will not be able to pass through the tollhouse, such as an accident or traffic jam. It may cause a serious situation. As described above, in the vehicle-mounted device 200 according to the present embodiment, since the reception of the command signal is restricted while the wireless communication is performed by the ASK method, the wireless communication processing may be interrupted by the reception of the command signal. It is prevented and the above-mentioned serious situation is prevented. For example, in the history confirmation of the on-board unit 200, reading to the ETC card occurs, so that the encrypted communication process by the CPU 211 occurs. Therefore, the access to the SAM function in the wireless communication and the access to the SAM function in the ETC card reading may conflict with each other, and the wireless communication may be interrupted. In the vehicle-mounted device 200 according to the present embodiment, such competition for access to the SAM function does not occur, and interruption of wireless communication can be suppressed.

On the other hand, QPSK wireless communication is used to provide traffic information or information on surrounding facilities by roadside machines such as highway parking areas, general roads, and parking lots, and the importance of communication content is relatively low. Even if wireless communication is interrupted, no serious situation such as an accident or traffic jam will occur. Therefore, the on-board unit 200 according to the present embodiment does not limit the reception of command signals while wireless communication is performed by the QPSK method. Thereby, the button operation and the communication with the external device 400 can be performed during the wireless communication by the QPSK method, and the inconvenience of the user can be reduced. Further, the wireless communication area in the QPSK method is larger than the wireless communication area in the ASK method, and even if the wireless communication is interrupted once, there is a possibility that the wireless communication can be restarted after the command execution is completed. Is high. Therefore, the influence of the command signal reception restriction on the user is small.

In the present embodiment, the vehicle-mounted device determines the modulation method of the radio signal from the modulation information of the radio signal, but the modulation method of the radio signal may be determined depending on whether or not the demodulation of the radio signal is possible. That is, the radio signal can be given to the data demodulator 222 to execute the demodulation process, and the modulation method can be determined depending on whether or not the demodulation is normally performed. For example, when the demodulation by the ASK method can be performed correctly, it is determined that the modulation method is the ASK method, and when the demodulation by the ASK method cannot be performed correctly, it is determined that the modulation method is not the ASK method (the QPSK method). Can be done.

Further, in the present embodiment, in the command signal reception restriction processing, when the modulation method of the radio signal is the ASK method, the restriction of the command signal processing is started, but the modulation method is the ASK method and the roadside machine 300 When the roadside machine ID is received from, the restriction of command signal processing may be started. FIG. 8 is a flowchart showing a procedure of a modification of the command signal reception restriction process in the vehicle-mounted device 200. In this modification, the CPU 211 determines whether or not the roadside machine ID has been received from the roadside machine 300 in the case of the ASK method (“ASK” in step S113) as a result of determining the radio signal modulation method in step S113. (Step S120). When the roadside machine ID is not received (NO in step S120), the CPU 211 receives the command signal (step S117) and executes the command signal processing (step S118). On the other hand, when the roadside machine ID is received (YES in step S120), the CPU 211 executes the processes of steps S114 to S116 and starts limiting the command signal processing. As a result, the restriction of command signal processing is started at the timing when the roadside machine ID is received.

<Comparison between the on-board unit according to this embodiment and the conventional on-board unit>
Here, the conditions for restricting the acceptance of command signals between the on-board unit 200 and the conventional on-board unit (hereinafter referred to as "conventional technology") according to the present embodiment are compared. The table below is a table comparing the conditions for restricting the reception of command signals between the on-board unit 200 according to the present embodiment and the prior art. In the prior art, the reception of command signals is restricted even when radio waves other than radio signals are received as well as radio signals. That is, regardless of the modulation method and the content of the telegram, when the on-board unit receives some radio wave, the reception of the command signal is restricted. On the other hand, in the vehicle-mounted device 200 according to the present embodiment, when the wireless communication processing in the ASK system is being performed, that is, the wireless signal in the ASK system is received and the response data is transmitted in response to the signal. Sometimes the acceptance of command signals is restricted.

(Embodiment 2)
In the present embodiment, after the command signal acceptance restriction is started, when the wireless communication between the roadside unit and the on-board unit by the ASK method is completed, the command signal acceptance restriction is released and the same roadside unit and the same roadside unit are used. When the wireless communication of is restarted, the state where the command signal reception restriction is released is maintained.

<Communication system configuration>
FIG. 9 is a block diagram showing an example of a specific hardware configuration of the vehicle-mounted device 200 according to the present embodiment. The on-board unit 200 has a roadside machine ID area 212a for storing the roadside machine ID and a target exclusion ID area 212b for storing the roadside machine ID excluded from the command signal reception restriction in the memory 212. It is provided. Since the other configurations of the communication system according to the present embodiment are the same as the configurations of the communication system 100 according to the first embodiment, the same components are designated by the same reference numerals and the description thereof will be omitted.

<Operation of communication system>
The operation of the communication system 100 according to the present embodiment will be described. FIG. 10 is a flowchart showing a procedure of wireless communication processing by the communication system according to the present embodiment. Since the processes of steps S101 to S106 are the same as those described in the first embodiment, the description thereof will be omitted.

After the roadside unit 300 transmits the BST to the on-board unit 200, the on-board unit 200 transmits the VST to the roadside unit 300, and other necessary communications, the CPU 311 of the roadside unit 300 sends the roadside unit to the on-board unit 200. The ID is transmitted (step S201). When the CPU 211 of the vehicle-mounted device 200 receives the roadside unit ID (step S202), it transmits an ACK (step S203), and the roadside unit 300 receives this (step S204). Further, the CPU 211 of the vehicle-mounted device 200 stores the received roadside machine ID in the roadside machine ID area 212a of the memory 212 (step S205). Even if the roadside machine ID is already stored in the roadside machine ID area 212a, the latest roadside machine ID is overwritten. That is, the roadside machine ID area 212a always stores the latest communication partner roadside machine ID. After the storage of the roadside unit ID is completed, other data is transmitted / received between the roadside unit 300 and the vehicle-mounted device 200 (steps S107 to).

FIG. 11 is a flowchart showing a procedure of command signal reception restriction processing in the vehicle-mounted device 200 according to the present embodiment. Since the processes of steps S111 to S113 are the same as those described in the first embodiment, the description thereof will be omitted.

When the modulation method is the ASK method (“ASK” in step S113), the CPU 211 compares the roadside machine ID stored in the roadside machine ID area 212a with the information stored in the target exclusion ID area 212b. , It is determined whether or not the current wireless communication partner (roadside machine 300 specified by the roadside machine ID stored in the roadside machine ID area 212a) is excluded from the target of the command signal acceptance restriction (step S211). .. When the current wireless communication partner is excluded from the target of command signal acceptance restriction, that is, the roadside machine ID stored in the roadside machine ID area 212a and the information stored in the target exclusion ID area 212b are If they match (YES in step S211), the CPU 211 moves to step S117, receives a command signal (step S117), and executes the command (step S118).

On the other hand, when the current wireless communication partner is not excluded from the command signal reception restriction, that is, the roadside machine ID stored in the roadside machine ID area 212a and the information stored in the target exclusion ID area 212b. If the above does not match, or if the information is not stored in the target exclusion ID area 212b (NO in step S211), the CPU 211 starts the restriction period (step S114) and restricts the reception of the command signal. The process is executed (step S115). The CPU 211 determines whether or not the limited period has elapsed (step S116), and if the limited period has not elapsed (NO in step S116), the process of step S115 is executed again. When the time limit has elapsed (YES in step S116), the CPU 211 determines whether or not the wireless communication in the wireless communication unit 220 is completed (step S212). If the wireless communication is not completed (NO in step S212), the CPU 211 returns the process to step S111. On the other hand, when the wireless communication is completed (YES in step S212), the CPU 211 stores the roadside machine ID stored in the roadside machine ID area 212a in the target exclusion ID area 212b, and performs the current wireless communication. Exclude the other party from the target of command signal acceptance restriction (step S213). After that, the CPU 211 returns the process to step S111.

When the modulation method is the QPSK method (“QPSK” in step S113), the CPU 211 receives the command signal (step S117) and executes the command (step S118). After that, the CPU 211 returns the process to step S111.

With the above configuration, when wireless communication is restarted with the roadside machine 300 once the wireless communication has been completed, the roadside machine 300 is excluded from the target of the command signal acceptance restriction. Therefore, once the wireless communication is completed, the restriction on accepting the command signal is released, and after that, the state in which the command signal can be accepted is maintained, so that the user operates a button or the external device 400 communicates with the in-vehicle device 200. It becomes possible to perform the above, and the inconvenience of the user is further reduced. For example, when a roadside machine 300 is provided at the exit of an expressway and wireless communication related to a toll refund is performed, a traffic jam occurs near the exit and the vehicle 290 stops for a long time in the wireless communication area of the roadside machine 300. There are times. Once wireless communication is completed in such a situation, it is unnecessary even if wireless communication occurs thereafter. In the vehicle-mounted device 200 according to the present embodiment, the input of the command signal is not restricted while such unnecessary wireless communication is occurring, and the convenience of the user is improved.

(Embodiment 3)
In the present embodiment, when the on-board unit is performing QPSK wireless communication with the roadside unit, it is determined whether or not the device authentication is completed, and when the device authentication is not completed, the command signal is accepted. Restrict.

<Communication system configuration>
FIG. 12 is a functional block diagram showing a functional configuration of the vehicle-mounted device according to the present embodiment. The on-board unit 200 according to the present embodiment has a device authentication status determination unit 208 in addition to a wireless communication unit 201, an external input unit 202, a command signal processing unit 204, an output unit 205, and a control unit 206. The device authentication status determination unit 208 determines whether or not the device authentication performed with the roadside machine 300 has been completed in the case of wireless communication in the QPSK system. The device authentication status determination unit 208 is realized by the information processing unit 210 shown in FIG.

Further, in the present embodiment, when the device authentication status determination unit 208 determines that the device authentication has not been completed, the control unit 206 starts the command signal acceptance restriction. Further, the control unit 206 releases the command signal acceptance restriction when it is determined by the device authentication status determination unit 208 that the device authentication is completed after the command signal acceptance restriction is started. Since the other configurations of the communication system according to the present embodiment are the same as the configurations of the communication system 100 according to the second embodiment, the same components are designated by the same reference numerals and the description thereof will be omitted.

<Operation of communication system>
The operation of the communication system 100 according to the present embodiment will be described. FIG. 13 is a flowchart showing a procedure of wireless communication processing by the communication system according to the present embodiment. Since the processes of steps S101 to S106 are the same as those described in the first embodiment, the description thereof will be omitted.

After the roadside unit 300 transmits the BST to the on-board unit 200 and the on-board unit 200 transmits the VST to the roadside unit 300 and other necessary communications, device authentication is performed between the roadside unit 300 and the on-board unit 200. Will be. Device authentication refers to exchanging security keys between a roadside device and an in-vehicle device to perform mutual authentication. The details of device authentication are omitted here, but for example, security key exchange associated with device authentication. May be performed based on the structure of DSRC-SPF (Security PlatForum) defined by "ITS_FORUM_RC-400", or may be performed by the following procedure. First, the CPU 311 of the roadside unit 300 transmits a WCN request signal requesting WCN to the vehicle-mounted device 200 (step S301). When the CPU 211 of the vehicle-mounted device 200 receives the WCN request signal (step S302), the WCN of the own device is transmitted to the roadside unit 300 (step S303), and the roadside unit 300 receives this (step S304). Although the configuration for transmitting and receiving WCN has been described here, the configuration may be such that the device number assigned to the vehicle-mounted device 200 and other identification information are transmitted and received. Since the processes of steps S201 to S205 are the same as those described in the second embodiment, the description thereof will be omitted. When the roadside machine ID is stored in the roadside machine ID area 212a, the device authentication is completed. After the device authentication, other data is transmitted / received between the roadside device 300 and the on-board unit 200 (steps S107 to S110).

FIG. 14 is a flowchart showing a procedure of command signal reception restriction processing in the vehicle-mounted device 200 according to the present embodiment. Since the processes of steps S111 to S116 are the same as those described in the first embodiment, the description thereof will be omitted.

When the modulation method is the QPSK method (“QPSK” in step S113), the CPU 211 compares the roadside machine ID stored in the roadside machine ID area 212a with the information stored in the target exclusion ID area 212b. , It is determined whether or not the current wireless communication partner (roadside machine 300 specified by the roadside machine ID stored in the roadside machine ID area 212a) is excluded from the target of the command signal acceptance restriction (step S311). .. When the current wireless communication partner is excluded from the target of command signal acceptance restriction, that is, the roadside machine ID stored in the roadside machine ID area 212a and the information stored in the target exclusion ID area 212b are If they match (YES in step S311), the CPU 211 moves to step S117, receives a command signal (step S117), executes a command (step S118), and then returns to step S111.

On the other hand, when the current wireless communication partner is not excluded from the command signal reception restriction, that is, the roadside machine ID stored in the roadside machine ID area 212a and the information stored in the target exclusion ID area 212b. If the above does not match, or if the information is not stored in the target exclusion ID area 212b (NO in step S311), the CPU 211 determines whether or not device authentication has been started (step S312). If device authentication has not been started (NO in step S312), the CPU 211 moves to step S117, receives a command signal (step S117), executes a command (step S118), and then returns to step S111. As a result, when the device authentication is not performed, the command signal can be input to the on-board unit 200.

When the device authentication is started (YES in step S312), the CPU 211 starts the command signal acceptance restriction (step S313), and restricts the subsequent command signal acceptance. Next, the CPU 211 determines whether or not the device authentication is completed (step S314), and if the device authentication is not completed (NO in step S314), the process of step S314 is executed again. When the device authentication is completed (YES in step S314), the CPU 211 releases the command signal acceptance restriction (step S315), and the roadside machine ID stored in the roadside machine ID area 212a is set to the target exclusion ID area 212b. It is stored and the current wireless communication partner is excluded from the target of the command signal acceptance restriction (step S316). After that, the CPU 211 returns the process to step S111.

In the above-mentioned QPSK wireless communication, after device authentication is performed, contents (messages) such as traffic information and peripheral facility information are transmitted from the roadside unit 300 to the in-vehicle device 200 and output in the in-vehicle device 200. .. Therefore, if the device authentication is interrupted, the content will not be provided to the user. With the configuration as described above, the on-board unit 200 according to the present embodiment is restricted from accepting command signals during device authentication when QPSK wireless communication is performed. Therefore, it is possible to prevent the wireless communication from being interrupted by receiving the command signal during the device authentication.

(Embodiment 4)
In the present embodiment, when the on-board unit is performing QPSK wireless communication with the roadside unit, command signal reception is restricted while information having a priority higher than a predetermined value is output.

<Communication system configuration>
FIG. 15 is a functional block diagram showing a functional configuration of the vehicle-mounted device according to the present embodiment. The on-board unit 200 according to this embodiment has a priority determination unit 209 in addition to a wireless communication unit 201, an external input unit 202, a command signal processing unit 204, an output unit 205, a control unit 206, and a device authentication status determination unit 208. Has. The priority determination unit 209 has a priority of the content (message) provided from the roadside machine 300 of a predetermined value or higher (specifically, "priority information" or higher) in the case of wireless communication of the QPSK method. Judge whether or not. The priority determination unit 209 is realized by the information processing unit 210 shown in FIG.

Further, in the present embodiment, the control unit 206 starts the command signal acceptance restriction when the priority determination unit 209 determines that the priority is equal to or higher than a predetermined value. Further, the control unit 206 releases the command signal acceptance restriction when the output of the message having the predetermined priority or higher is completed after the command signal acceptance restriction is started. Since the other configurations of the communication system according to the present embodiment are the same as the configurations of the communication system 100 according to the third embodiment, the same components are designated by the same reference numerals and the description thereof will be omitted.

<Operation of communication system>
The operation of the communication system 100 according to the present embodiment will be described. After the device authentication is completed, the roadside machine 300 transmits a message such as traffic information and peripheral facility information to the vehicle-mounted device 200. The priority is specified in this message, and the data for the roadside machine 300 to provide the message includes the priority information. There are three priorities, for example, "highest priority", "priority", and "general" in order from high priority to low priority. In this embodiment, the priority is "highest priority" and "priority" messages. The reception of command signals is restricted during the output of, and the reception of command signals is not restricted during the output of messages having a priority of "general".

FIG. 16 is a flowchart showing a procedure of command signal reception restriction processing in the vehicle-mounted device 200 according to the present embodiment. Since the processes of steps S111 to S118 and steps S311 to S314 are the same as those described in the first and third embodiments, the description thereof will be omitted.

When the device authentication is completed (YES in step S314), the CPU 211 determines whether or not the priority of the data received from the roadside machine 300 is "priority" or higher (step S411). When the priority is less than "priority" (that is, when the priority is "general". NO in step S411), the CPU 211 moves to step S315 and cancels the command signal acceptance restriction (step S315).

On the other hand, when the priority is "priority" or higher (that is, when the priority is "highest priority" or "priority"; YES in step S411), whether or not the message is being output by the output unit 260 is determined. Determination (step S412). If the message is being output (YES in step S412), the CPU 211 re-executes the process of step S412 and waits until the message output is completed. When the output of the message is completed (NO in step S412), the CPU 211 shifts the process to step S315 and cancels the command signal acceptance restriction (step S315).

In many on-board units, when the volume adjustment or history confirmation command is executed, the volume adjustment confirmation sound or the history confirmation sound is output. If the voice output generated by the reception of such a command signal is generated in the middle of the voice output of the message, the voice output generated by the reception of the command signal has priority and the voice output of the message may be stopped. The vehicle-mounted device 200 according to the present embodiment has the above configuration, and limits the reception of command signals while a message having a priority higher than a predetermined value is output. Therefore, it is possible to prevent the output of this message from being stopped by receiving a command signal while an important message having a high priority is being output.

(Embodiment 5)
In the present embodiment, when it is determined in the carrier sense processing that a radio signal has been received, the command signal reception restriction is started, and when it is determined that the modulation method is the ASK method, the command signal reception is restricted. When it is determined that the QPSK method is used, the command signal acceptance restriction is released. This realizes a function of limiting the reception of command signals when it is determined that the modulation method is the ASK method.

<Communication system configuration>
Since the configuration of the communication system according to the present embodiment is the same as the configuration of the communication system 100 according to the first embodiment, the same components are designated by the same reference numerals and the description thereof will be omitted.

<Operation of communication system>
FIG. 17 is a flowchart showing a procedure of command signal reception restriction processing in the vehicle-mounted device 200 according to the present embodiment. First, the CPU 211 determines whether or not the radio signal is detected in the carrier sense processing, that is, whether or not the carrier is detected (step S511). If no carrier is detected (NO in step S511), the CPU 211 re-executes the process of step S511. When the carrier is detected (YES in step S511), the CPU 211 starts the restriction period and starts the command signal reception restriction (step S512).

Next, the CPU 211 determines whether or not wireless communication is in progress (step S513). When wireless communication is not in progress (NO in step S513), the CPU 211 shifts the process to step S517, cancels the restriction period, and thereby cancels the command signal reception restriction (step S517). After that, the CPU 211 returns the process to step S511. When wireless communication is in progress (YES in step S513), the CPU 211 determines whether the modulation method of wireless communication is the ASK method or the QPSK method (step S514).

When the modulation method is the ASK method (“ASK” in step S514), the CPU 211 does not release the limited period, limits the reception of command signals (step S515), and determines whether or not the limited period has elapsed. (Step S516). That is, in this case, the state in which the reception of the command signal is restricted is maintained. If the time limit has not elapsed (NO in step S516), the CPU 211 returns to step S515 and limits the reception of command signals. On the other hand, when the restriction period has elapsed (YES in step S516), the CPU 211 returns the process to step S511.

When the modulation method is the QPSK method (“QPSK” in step S514), the CPU 211 cancels the restriction period (step S517), thereby canceling the command signal reception restriction. After that, the CPU 211 returns the process to step S511.

Even if the on-board unit 200 performs the above operation, the reception of the command signal is restricted when the modulation method of the wireless communication is the ASK method, and the reception of the command signal is restricted, and the wireless communication is performed when the modulation method is the QPSK method. If not, the reception of command signals is not restricted. Therefore, it is possible to suppress the influence on the wireless communication due to the command signal reception occurring during the wireless communication by the ASK method.

(Other embodiments)
In the above-described embodiments 1 to 5, the ASK method and the QPSK method have been described as the modulation methods, but the modulation method is not limited thereto. In addition to the ASK method and the QPSK method, an OFDM (Orthogonal Frequency-Division Multiplexing) method or a QAM (Quadrature Amplitude Modulation) method can be used for wireless communication, and it is determined that the modulation method is, for example, ASK, OFDM, or QAM. If this is the case, the configuration may be such that the reception of command signals is restricted.

Further, in the above-described embodiments 1 to 5, when the command signal reception is restricted, the configuration in which the restriction target is all command signals is described, but the restriction is not limited to this. It is also possible to restrict the reception of some command signals. For example, in the first to third embodiments, only the command signal that causes access to the SAM function, such as the command signal that causes ETC card reading, may be restricted from being accepted.

Further, in the above-described embodiments 1 to 5, the configuration for limiting the reception of command signals when the modulation method of the received radio signal is the ASK method has been described, but the present invention is not limited to this. .. The term "command signal processing" as used herein includes not only processing for receiving command signals but also processing for which execution is instructed by a command signal. That is, after receiving the command signal, the configuration may be such that the execution of the process instructed by the command signal is restricted.

Further, in the above-described embodiments 1 to 5, the configuration in which the CPU 211 executes the on-board unit program 213, which is software, has been described, but the present invention is not limited thereto. The on-board unit may be equipped with hardware such as an ASIC (Application Specific Integrated Circuit) and an FPGA (Field Programmable Gate Array) that can execute the same processing as the on-board unit program 213.

The on-board unit, communication system, and communication method of the present invention are useful as an on-board unit that wirelessly communicates with a roadside unit provided on the roadside, a communication system that wirelessly communicates between the on-board unit and the roadside unit, and a communication method.

100 Communication system 200 On-board unit 201 Wireless communication unit 202 External input unit 204 Command signal processing unit 205 Output unit 206 Control unit 208 Device authentication status determination unit 209 Priority determination unit 210 Information processing unit 211 CPU
212 Memory 213 On-board unit program 220 Wireless communication unit 290 Vehicle 300 Roadside unit 400 External device

Claims (23)

A wireless communication unit that sends and receives wireless signals to and from the roadside unit,
An external input unit that accepts input from the outside and generates a command signal based on the received input,
A command signal processing unit that executes command signal processing according to the command signal, and
A control unit that determines whether or not the command signal is input, and if the command signal is input , limits the command signal processing of the command signal processing unit according to the modulation method of the radio signal. Prepare, prepare
On-board unit. The control unit limits the command signal processing when the modulation method of the radio signal is the ASK modulation method.
The on-board unit according to claim 1. The control unit releases the restriction on the command signal processing when the modulation method of the radio signal is the QPSK modulation method.
The on-board unit according to claim 1 or 2. The vehicle-mounted device according to any one of claims 1 to 3, wherein the control unit determines a modulation method of the radio signal according to whether or not the demodulation of the radio signal is possible, and limits the command signal processing. The control unit determines the modulation method of the radio signal from the modulation information of the radio signal, and limits the command signal processing according to the determined modulation method.
The vehicle-mounted device according to any one of claims 1 to 4. When the control unit determines the modulation method, the control unit causes the command signal processing unit to start limiting the command signal processing.
The vehicle-mounted device according to any one of claims 1 to 5. The control unit releases the restriction on the command signal processing to the command signal processing unit when the wireless communication processing by the wireless communication unit is completed after the restriction on the command signal processing by the command signal processing unit is started. Let, let
The vehicle-mounted device according to any one of claims 1 to 6. After the wireless communication processing by the wireless communication unit is completed, the control unit causes the command signal processing unit to process the command signal when the wireless communication unit starts the wireless communication processing with the same roadside unit. Keep the restrictions lifted,
The vehicle-mounted device according to claim 7. The control unit determines whether the modulation method of the radio signal is the first modulation method or the second modulation method different from the first modulation method.
When the control unit determines that the modulation method is the first modulation method, the control unit causes the command signal processing unit to limit the command signal processing.
The on-board unit according to claim 1. The control unit determines whether the modulation method of the radio signal is the first modulation method or the second modulation method different from the first modulation method.
When the control unit determines that the modulation method is the second modulation method, the control unit further includes a device authentication status determination unit for determining the device authentication status with the roadside machine.
When the device authentication status determination unit determines that the device authentication has not been completed, the control unit causes the command signal processing unit to limit the command signal processing.
The on-board unit according to claim 1. The control unit causes the command signal processing unit to release the restriction on the command signal processing from the start of the wireless communication processing by the wireless communication unit to the start of the device authentication.
The vehicle-mounted device according to claim 10. When the device authentication status determination unit determines that the device authentication is completed after the command signal processing restriction is started, the control unit releases the command signal processing restriction to the command signal processing unit. Let, let
The vehicle-mounted device according to claim 10 or 11. After the wireless communication processing with the roadside unit and the device authentication are completed, the control unit with the roadside unit when the wireless communication processing with the same roadside unit is restarted by the wireless communication unit. During the wireless communication processing of the above, the command signal processing unit is made to maintain the release of the restriction on the command signal processing.
The vehicle-mounted device according to any one of claims 10 to 12. The wireless communication unit receives a wireless signal whose priority is defined in the communication in the second modulation method, and receives the wireless signal.
Further, a priority determination unit for determining whether or not the priority specified for the wireless signal received by the wireless communication unit is equal to or higher than a predetermined value is provided.
When the priority determination unit determines that the priority is equal to or higher than a predetermined value, the control unit causes the command signal processing unit to limit the command signal processing.
The vehicle-mounted device according to any one of claims 10 to 13. Further, an output unit for outputting information to which an output instruction is given by the command signal is provided.
After the restriction of the command signal processing is started, the control unit sends the command signal processing unit to the command signal processing unit when the output of the information contained in the radio signal having the predetermined priority or higher is completed by the output unit. The restriction on command signal processing is lifted.
The vehicle-mounted device according to claim 14. The first modulation method is an ASK modulation method, and the second modulation method is a QPSK modulation method.
The vehicle-mounted device according to any one of claims 9 to 15. The control unit causes the command signal processing unit to start limiting the command signal processing when the modulation method is the first modulation method by the control unit and the roadside device identification information is received from the roadside machine.
The vehicle-mounted device according to any one of claims 9 to 16. Wherein, when it is determined that the radio signal is received in the carrier sense processing determines whether the radio signal is received by the wireless communication unit at a predetermined frequency, and starts to limit said command signal processing When the modulation method of the radio signal is the ASK modulation method, the limitation of the command signal processing is maintained, and when the modulation method of the radio signal is the QPSK modulation method, the limitation of the command signal processing is released.
The vehicle-mounted device according to any one of claims 1 to 17. Equipped with an operable operation unit
The command signal is generated by operating the operation unit.
The vehicle-mounted device according to any one of claims 1 to 18. The command signal is given by communication from an external device.
The vehicle-mounted device according to any one of claims 1 to 19. The communication by the wireless communication unit is by DSRC.
The vehicle-mounted device according to any one of claims 1 to 20. The on-board unit according to any one of claims 1 to 21 and the vehicle-mounted device.
It is equipped with the on-board unit and a roadside unit capable of wireless communication.
Communications system. The wireless communication unit sends and receives wireless signals between the on-board unit and the roadside unit.
The external input unit receives an input from the outside and generates a command signal based on the received input.
The command signal processing unit executes command signal processing according to the command signal.
The control unit determines whether or not the command signal is input, and if the command signal is input, the command signal processing is restricted according to the modulation method of the radio signal in the execution of the command signal processing. do,
Communication method.

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