WO2015133181A1 - Communication apparatus, communication control method, and recording medium - Google Patents

Communication apparatus, communication control method, and recording medium Download PDF

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Publication number
WO2015133181A1
WO2015133181A1 PCT/JP2015/051035 JP2015051035W WO2015133181A1 WO 2015133181 A1 WO2015133181 A1 WO 2015133181A1 JP 2015051035 W JP2015051035 W JP 2015051035W WO 2015133181 A1 WO2015133181 A1 WO 2015133181A1
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WO
WIPO (PCT)
Prior art keywords
message
transmission
control unit
communication device
representative
Prior art date
Application number
PCT/JP2015/051035
Other languages
French (fr)
Japanese (ja)
Inventor
山本　武志
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日本電気株式会社
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Publication date
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Publication of WO2015133181A1 publication Critical patent/WO2015133181A1/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W28/00—Network traffic management; Network resource management
    • H04W28/02—Traffic management, e.g. flow control or congestion control
    • H04W28/0205—Traffic management, e.g. flow control or congestion control at the air interface
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W4/00—Services specially adapted for wireless communication networks; Facilities therefor
    • H04W4/30—Services specially adapted for particular environments, situations or purposes
    • H04W4/40—Services specially adapted for particular environments, situations or purposes for vehicles, e.g. vehicle-to-pedestrians [V2P]
    • H04W4/44—Services specially adapted for particular environments, situations or purposes for vehicles, e.g. vehicle-to-pedestrians [V2P] for communication between vehicles and infrastructures, e.g. vehicle-to-cloud [V2C] or vehicle-to-home [V2H]
    • G—PHYSICS
    • G08—SIGNALLING
    • G08G—TRAFFIC CONTROL SYSTEMS
    • G08G1/00—Traffic control systems for road vehicles
    • G08G1/01—Detecting movement of traffic to be counted or controlled
    • G08G1/0104—Measuring and analyzing of parameters relative to traffic conditions
    • G08G1/0108—Measuring and analyzing of parameters relative to traffic conditions based on the source of data
    • G08G1/0112—Measuring and analyzing of parameters relative to traffic conditions based on the source of data from the vehicle, e.g. floating car data [FCD]
    • G—PHYSICS
    • G08—SIGNALLING
    • G08G—TRAFFIC CONTROL SYSTEMS
    • G08G1/00—Traffic control systems for road vehicles
    • G08G1/01—Detecting movement of traffic to be counted or controlled
    • G08G1/0104—Measuring and analyzing of parameters relative to traffic conditions
    • G08G1/0125—Traffic data processing
    • G08G1/0133—Traffic data processing for classifying traffic situation
    • G—PHYSICS
    • G08—SIGNALLING
    • G08G—TRAFFIC CONTROL SYSTEMS
    • G08G1/00—Traffic control systems for road vehicles
    • G08G1/09—Arrangements for giving variable traffic instructions
    • G08G1/0962—Arrangements for giving variable traffic instructions having an indicator mounted inside the vehicle, e.g. giving voice messages
    • G08G1/0967—Systems involving transmission of highway information, e.g. weather, speed limits
    • G08G1/096766—Systems involving transmission of highway information, e.g. weather, speed limits where the system is characterised by the origin of the information transmission
    • G08G1/096775—Systems involving transmission of highway information, e.g. weather, speed limits where the system is characterised by the origin of the information transmission where the origin of the information is a central station

Definitions

  • the present invention relates to a communication device, a communication control method, and a program, and more particularly, to a communication device, a communication control method, and a program that control message communication.
  • a vehicle-to-vehicle communication system in which vehicle-mounted communication devices mounted on a vehicle communicate with each other, and a road-to-vehicle communication system in which a vehicle-mounted communication device mounted on a vehicle and a roadside communication device installed on a roadside communicate with each other are known.
  • DENM Decentralized Environmental Notification Message
  • CAM Cooperative Awareness Message
  • DENM is a message for informing a communication device within a predetermined range of occurrence of a predetermined event (for example, sudden braking or lighting of a hazard lamp).
  • the DENM is repeatedly transmitted for a predetermined time as a predetermined event occurs.
  • transmission conditions for example, necessary transmission distance and necessary transmission delay time
  • DENM indicates a transmission source identifier for specifying a DENM transmission source device.
  • the CAM is a message for notifying surrounding communication devices of the position and speed of the vehicle.
  • the CAM is repeatedly transmitted regardless of the occurrence of an event.
  • a transmission condition corresponding to an event such as DENM is not set in the CAM.
  • the CAM also indicates a transmission source identifier for specifying the CAM transmission source device.
  • Patent Document 1 describes an inter-vehicle communication device that widens the communication area of inter-vehicle communication.
  • the vehicle-to-vehicle communication device described in Patent Literature 1 is selected as a relay vehicle by the transmission source vehicle-to-vehicle communication device, the information received from the transmission source vehicle-to-vehicle communication device is transferred to another vehicle-to-vehicle communication device.
  • the vehicle-to-vehicle communication device described in Patent Document 1 is selected as a relay vehicle by separate vehicle-to-vehicle communication devices, and receives the same information (for example, sudden braking information) from these separate vehicle-to-vehicle communication devices, respectively, these same Forward all the messages indicating the information.
  • a plurality of messages indicating the same information are likely to be redundant messages as a whole. For this reason, the inter-vehicle communication device described in Patent Document 1 has a problem that congestion is easily induced by a message indicating the same information that is likely to be a redundant message.
  • An object of the present invention is to provide a communication device, a communication control method, and a program that can solve the above-described problems.
  • the communication device of the present invention A receiving unit for receiving a message indicating information and an identifier of the transmission source device transmitted from the transmission source device; A representative message indicating the same information is transmitted as a representative of a specific message indicating the same information from different transmission source devices specified by different identifiers according to the type of message received by the receiving unit. And a control unit that executes a transmission operation.
  • the communication control method of the present invention includes: Receiving a message transmitted from the transmission source device and indicating the information and the identifier of the transmission source device; Transmission for transmitting a representative message indicating the same information as a representative of a specific message indicating the same information from different transmission source devices specified by different identifiers according to the type of the received message Perform the action.
  • the recording medium of the present invention is On the computer, A reception procedure for receiving a message indicating information and an identifier of the transmission source device transmitted from the transmission source device; A representative message indicating the same information as a representative of a specific message indicating the same information from different transmission source devices specified by different identifiers according to the type of the message received in the reception procedure. It is a computer-readable recording medium which recorded the program which performs the control procedure which performs the transmission operation
  • FIG. 1 It is the figure which showed the communication apparatus 1 of 1st Embodiment of this invention.
  • 4 is a flowchart for explaining the operation of the communication apparatus 1; It is the figure which showed the communication apparatus 11 of 2nd Embodiment of this invention. It is the figure which showed an example of DENM hold
  • 4 is a flowchart for explaining the operation of the communication device 11; It is the figure which showed the vehicle-mounted communication apparatus 30 containing the communication apparatus 11.
  • FIG. 1 is a diagram illustrating a communication device 1 according to a first embodiment of the present invention.
  • control unit 3 operates to transmit a representative message indicating the same information as a representative message (hereinafter referred to as “specific message”) indicating the same information from different in-vehicle communication devices (hereinafter referred to as “transmission operation”). Can be executed).
  • the controller 3 performs a transmission operation according to the type of message received by the receiver 2.
  • the control unit 3 specifies different in-vehicle communication devices using the identifier indicated in the message.
  • there is information on the same event for example, sudden braking or hazard lamp lighting).
  • FIG. 2 is a flowchart for explaining the operation of the communication apparatus 1.
  • the receiving unit 2 When receiving the message transmitted from the in-vehicle communication device (step S1), the receiving unit 2 outputs the message (hereinafter also referred to as “received message”) to the control unit 3.
  • the control unit 3 accepts the received message output from the receiving unit 2. Each time the control unit 3 receives a received message, the control unit 3 holds the received message in association with the reception time of the received message. Then, the control unit 3 refers to the stored reception message and reception time, and performs a transmission operation according to the type of the reception message (step S2).
  • the receiving unit 2 receives a message transmitted from the in-vehicle communication device.
  • the controller 3 performs a transmission operation according to the type of message received by the receiver 2.
  • the transmission operation is an operation of transmitting a representative message indicating the same information as a representative of a specific message indicating the same information from different in-vehicle communication devices specified by different identifiers. For this reason, it is possible to suppress the occurrence of a situation in which congestion is induced by transferring each of a plurality of specific messages indicating the same information that is likely to be a redundant message. Also, a transmission operation is executed according to the message type. For this reason, it is possible to suppress unnecessary representative message transmission operation for a type of message whose necessity of transmitting a representative message is low.
  • FIG. 3 is a diagram illustrating the communication device 11 according to the second embodiment of the present invention.
  • the communication device 11 includes a receiving unit 12 and a control unit 13.
  • the control unit 13 includes an application unit 13a, a radio channel setting unit 13b, a transmission cycle setting unit 13c, a transmission power / transmission rate setting unit 13d, a congestion control unit 13e, and a transmission unit 13f.
  • the application unit 13a includes a DENM aggregation unit 13a1.
  • the communication device 11 uses a CCH (Control Channel) as one of the two radio channels (hereinafter referred to as “radio channel CH1”).
  • the CCH is commonly used in each of the in-vehicle communication devices 101 to 10n that perform road-vehicle communication with the communication device 11.
  • the CCH is an example of a common radio channel set in advance for communication of the communication device 11.
  • CCH is used for CAM communication.
  • CCH may also be used for DENM communications.
  • the communication device 11 uses one of a plurality of SCHs (Service Channels) having different frequencies as the other of the two wireless channels (hereinafter referred to as “wireless channel CH2”).
  • SCHs Service Channels
  • wireless channel CH2 wireless channel
  • Each SCH is used for DENM communication.
  • the frequency of each SCH is different from the frequency of CCH.
  • the number of SCHs may be one or more.
  • the number of wireless channels simultaneously used by the communication device 11 is not limited to “2” and can be changed as appropriate.
  • the radio channel used by the communication device 11 is not limited to CCH and SCH, and can be changed as appropriate.
  • the receiving unit 12 receives a message wirelessly transmitted from each of the in-vehicle communication devices 101 to 10n through the wireless channel CH1.
  • the receiving unit 12 also receives messages wirelessly transmitted from each of the in-vehicle communication devices 101 to 10n through the wireless channel CH2.
  • the receiving unit 12 Upon receiving a message (for example, CAM or DENM) wirelessly transmitted from each of the in-vehicle communication devices 101 to 10n through the wireless channel CH1 or CH2, the receiving unit 12 outputs the message to the application unit 13a.
  • a message for example, CAM or DENM
  • the receiving unit 12 specifies the degree of congestion of each of the radio channels CH1 and CH2 based on the message communication status.
  • the receiving unit 12 notifies the congestion control unit 13e of the degree of congestion of each of the radio channels CH1 and CH2.
  • the control unit 13 controls the communication device 11.
  • the application unit 13a receives a message (CAM or DENM) output from the receiving unit 12.
  • the application unit 13 a controls message transmission according to the message received from the receiving unit 12.
  • the application unit 13a may transmit a transmission condition (for example, a transmission distance or a transmission delay) according to a specific event for each event (hereinafter referred to as a “specific event”) such as sudden braking or hazard lamp lighting indicated by DENM. Time).
  • a specific event for each event (hereinafter referred to as a “specific event”) such as sudden braking or hazard lamp lighting indicated by DENM. Time).
  • the application unit 13a stores a communication distance A1 required for communication and a delay time B1 required for communication as a transmission condition corresponding to “sudden braking” which is an example of a specific event.
  • the application unit 13a stores a communication distance A2 required for communication and a delay time B2 required for communication as transmission conditions corresponding to “hazard lamp lighting” which is an example of a specific event.
  • the delay time required for communication is referred to as “request delay time”.
  • the request delay time is an example of a transmission delay time that is a transmission condition. In the present embodiment, it is assumed that the request delay time is longer than the time indicated by a predetermined shortest transmission cycle.
  • the requested communication distance A1 may be the same as or different from the requested communication distance A2.
  • the request delay time B1 may be the same as or different from the request delay time B2.
  • the DENM aggregation unit 13a1 receives the message (CAM or DENM) output from the reception unit 12. Each time DENM aggregation section 13a1 receives DENM, DENM aggregation section 13a1 holds DENM in association with the reception time.
  • FIG. 4 is a diagram showing an example of DENM held in the DENM aggregation unit 13a1.
  • each DENM is held in association with the reception time.
  • Each DENM includes a transmission source device identifier and event information.
  • the DENM aggregating unit 13a1 refers to the DENM held in the DENM aggregating unit 13a1, and receives the DENM indicating the same event information (hereinafter referred to as “specific DENM”) from different in-vehicle communication devices. Generate an aggregate message that aggregates specific DENM.
  • the specific DENM is an example of a specific message.
  • the DENM aggregation unit 13a1 generates, as an aggregation message, DENM indicating event information (for example, sudden braking) indicated by the specific DENM.
  • the aggregate message is an example of a representative message.
  • a radio channel (hereinafter referred to as “scheduled radio channel to be used”) used to transmit an aggregate message that is a message to be transmitted is set.
  • the transmission cycle of the message to be transmitted is set in the transmission cycle setting unit 13c.
  • the transmission power and transmission speed of the message to be transmitted are set.
  • the congestion control unit 13e determines the transmission of the transmission target message (for example, the transmission cycle, the scheduled wireless channel, the transmission power, the transmission speed) based on the type of the transmission target message and the congestion level notified from the reception unit 12. By controlling, the congestion control operation is executed.
  • the congestion control unit 13e stores a correspondence table indicating a correspondence relationship between transmission power and transmission distance, and a congestion degree threshold value.
  • the transmission power increases as the corresponding transmission distance increases.
  • the transmission unit 13f sets the message to be transmitted in the scheduled use radio channel set in the radio channel setting unit 13b, the transmission cycle set in the transmission cycle setting unit 13c, and the transmission power / transmission rate setting unit 13d. Wireless transmission with the same transmission power and transmission speed.
  • FIG. 5 is a flowchart for explaining the operation of the communication device 11.
  • the reception unit 12 uses the CCH as the radio channel CH1 and uses one of a plurality of SCHs as the radio channel CH2 (for example, default SCH or SCH) set by the user.
  • the receiving unit 12 uses CCH as the radio channel CH1 and uses the scheduled radio channel as the radio channel CH2.
  • the receiving unit 12 specifies the degree of congestion of each of the radio channels CH1 and CH2 based on the communication status of the message through each radio channel.
  • the receiving unit 12 notifies the congestion control unit 13e of the degree of congestion of each of the radio channels CH1 and CH2.
  • the receiving unit 12 When receiving the message through the radio channel CH1 or CH2 (Step 101), the receiving unit 12 outputs the message to the DENM aggregation unit 13a1.
  • the DENM aggregation unit 13a1 When the DENM aggregation unit 13a1 receives a message from the reception unit 12, the DENM aggregation unit 13a1 holds the message in association with the reception time of the message.
  • the DENM aggregation unit 13a1 determines whether the type of message from the reception unit 12 is CAM or DENM (step S102).
  • DENM is an example of a predetermined type.
  • CAM is an example of a type different from the predetermined type.
  • the DENM aggregation unit 13a1 ends the operation.
  • the DENM aggregation unit 13a1 executes Step S103.
  • the DENM aggregation unit 13a1 refers to the message in the DENM aggregation unit 13a1, and when a plurality of specific DENMs are received within a predetermined period immediately before the current time, the DENM aggregation unit 13a1 indicates event information indicated by these specific DENMs.
  • DENM is generated as an aggregate message.
  • the DENM aggregation unit 13a1 ends the operation without generating the aggregate message when the aggregate message corresponding to the specific DENM has been generated within a predetermined period immediately before the current time. Further, when a plurality of specific DENMs are not received within a predetermined period immediately before the current time, the DENM aggregation unit 13a1 ends the operation, for example.
  • the DENM aggregation unit 13a1 When the DENM aggregation unit 13a1 generates an aggregation message (DENM), the transmission condition corresponding to the aggregation message is read from the application unit 13a.
  • DENM aggregation message
  • the DENM aggregating unit 13a1 outputs the aggregated message as a transmission target message to the transmission cycle setting unit 13c, and the message type information indicating the type of the aggregated message (DENM) as the type of the transmission target message is congestion control. To the unit 13e.
  • the DENM aggregation unit 13a1 outputs the transmission condition of the aggregation message to the congestion control unit 13e as the transmission condition of the message to be transmitted. For example, the DENM aggregation unit 13a1 outputs a transmission condition corresponding to the specific event represented by the aggregation message (DENM) to the congestion control unit 13e.
  • DENM aggregation message
  • request communication distance information indicating a request communication distance
  • request delay time information indicating a request delay time
  • the transmission cycle setting unit 13c When the transmission cycle setting unit 13c receives the aggregation message, the transmission period setting unit 13c holds the aggregation message.
  • the congestion control unit 13e refers to the congestion levels of the radio channels CH1 and CH2 and transmission conditions (requested communication distance information and request delay time information) (step S104). ).
  • the congestion control unit 13e determines a scheduled radio channel (Step S105).
  • the congestion control unit 13e determines the corresponding radio channel as a scheduled radio channel.
  • the congestion control unit 13e determines one corresponding radio channel from among the plurality of corresponding radio channels as the scheduled radio channel.
  • priorities are assigned in advance to each of the plurality of SCHs and the CCH.
  • the highest priority is assigned to the CCH, and a priority other than the highest priority is assigned to each SCH.
  • a priority other than the highest priority is assigned to each SCH.
  • the priority assignment is not limited to the above, and can be changed as appropriate.
  • the congestion control unit 13e holds the priority assignment result for the CCH and the plurality of SCHs. Then, the congestion control unit 13e determines the radio channel with the highest priority among the radio channels as the scheduled radio channel.
  • the congestion control unit 13e sets the scheduled radio channel to be used determined in step S105 in the radio channel setting unit 13b.
  • the congestion control unit 13e determines the transmission cycle of the message to be transmitted based on the congestion level of the scheduled radio channel and the transmission condition (step S106).
  • the congestion control unit 13e determines the shortest transmission cycle as the transmission cycle of the message to be transmitted.
  • the congestion control unit 13e firstly has a cycle longer than the transmission cycle currently set in the transmission cycle setting unit 13c (hereinafter referred to as “transmission cycle”). Identified as “candidate”).
  • the congestion control unit 13e sets the transmission cycle candidate as the transmission cycle of the message to be transmitted. decide.
  • the congestion control unit 13e determines the request delay time as the transmission cycle of the message to be transmitted. This means that the maximum value of the transmission cycle is limited by the request delay time.
  • the request delay time, the time represented by the shortest transmission cycle, and the specified time have a relationship of “request delay time”> “time represented by the shortest transmission cycle” + “specified time”.
  • the congestion control unit 13e determines a cycle longer than the shortest transmission cycle by a specified time as the transmission cycle of the message to be transmitted.
  • the congestion control unit 13e sets the transmission cycle determined in step S106 in the transmission cycle setting unit 13c as the transmission cycle of the message to be transmitted.
  • the transmission cycle setting unit 13c copies the held aggregate message at a time interval indicated by the transmission cycle, and copies the aggregate message (hereinafter referred to as “transmission data”). (Step S107).
  • the transmission cycle setting unit 13c outputs the transmission data to the transmission unit 13f.
  • the congestion control unit 13e determines the transmission power of the message to be transmitted based on the congestion level of the scheduled radio channel to be used and the transmission conditions (step S108).
  • the congestion control unit 13e determines the maximum transmission power as the transmission power of the message to be transmitted.
  • the congestion control unit 13e first transmits a transmission power (a predetermined amount smaller than the transmission power currently set in the transmission power / transmission speed setting unit 13d). (Hereinafter referred to as “transmission power candidates”).
  • the congestion control unit 13e refers to the correspondence table and identifies the requested transmission power corresponding to the requested communication distance represented by the requested communication distance information.
  • the congestion control unit 13e determines the transmission power candidate as the transmission power of the message to be transmitted.
  • the congestion control unit 13e determines the requested transmission power as the transmission power of the message to be transmitted. This means that the minimum value of the transmission power is limited by the required communication distance.
  • the required transmission power, the maximum transmission power, and the specified amount have a relationship of “requested transmission power” ⁇ “maximum transmission power” ⁇ “specified amount”.
  • the congestion control unit 13e determines the transmission power obtained by subtracting the specified amount from the maximum transmission power as the transmission power of the message to be transmitted.
  • the congestion control unit 13e sets the transmission power determined in step S108 in the transmission power / transmission rate setting unit 13d as the transmission power of the message to be transmitted.
  • the congestion control unit 13e determines the transmission rate of the message to be transmitted based on the congestion level of the scheduled radio channel (step S109).
  • the congestion control unit 13e sets a predetermined slowest transmission rate (hereinafter referred to as “latest transmission rate”) to the message to be transmitted. Determined as transmission speed.
  • the congestion control unit 13e transmits a transmission rate that is faster than the transmission rate currently set in the transmission power / transmission rate setting unit 13d by a specified value. It is determined as the transmission rate of the target message. Note that, in a situation where the transmission rate is not set in the transmission power / transmission rate setting unit 13d, the congestion control unit 13e determines a transmission rate that is faster than the latest transmission rate by a specified value as the transmission rate of the message to be transmitted. .
  • the congestion control unit 13e sets the transmission rate determined in step S109 as the transmission rate of the transmission target message in the transmission power / transmission rate setting unit 13d.
  • the transmission unit 13f Upon receiving the transmission data from the transmission cycle setting unit 13c, the transmission unit 13f uses the transmission data set in the transmission power / transmission rate setting unit 13d using the scheduled radio channel set in the radio channel setting unit 13b. Transmission is performed at power and transmission speed (step S110).
  • the transmission unit 13f outputs a transmission notification to the congestion control unit 13e.
  • the congestion control unit 13e determines whether the elapsed time after receiving the message type information exceeds a predetermined transmission duration (step S111).
  • step S111 If the elapsed time does not exceed the transmission duration time in step S111, the congestion control unit 13e returns the process to step S104.
  • the congestion control unit 13e deletes the aggregate message held by the transmission cycle setting unit 13c. Subsequently, the congestion control unit 13e deletes the transmission cycle, transmission power, and transmission rate set in the transmission cycle setting unit 13c and the transmission power / transmission rate setting unit 13d, and ends the operation.
  • the control unit 13 performs a transmission operation when the type of the message received by the receiving unit 12 is DENM.
  • the transmission operation is an operation of transmitting an aggregate message in which specific DENMs indicating information on the same event from different in-vehicle communication devices are aggregated. For this reason, it is possible to suppress congestion from being induced by transferring each of a plurality of specific DENMs that are likely to be redundant messages.
  • a transmission operation is executed when the message type is DENM. For this reason, it is possible to suppress unnecessary aggregation message transmission processing for a type of message (for example, CAM) that is less necessary to transmit the aggregation message.
  • the control unit 13 controls transmission of the aggregate message in the scheduled radio channel based on the congestion level of the scheduled radio channel and the transmission condition. For this reason, it is possible to control congestion by performing transmission control in consideration of transmission conditions for the aggregate message.
  • both the transmission distance and the transmission delay time are used as the transmission conditions.
  • the transmission condition may be any one of the transmission distance and the transmission delay time, and can be changed as appropriate.
  • the order of determining the transmission cycle, determining the transmission power, and determining the transmission rate can be changed as appropriate.
  • transmission rate control may be omitted. Further, in order to simplify the transmission operation, either or both of the transmission cycle control and the transmission power control may be omitted.
  • the DENM aggregation unit 13a1 may use one of the specific DENMs received by the reception unit 12 (for example, the specific DENM received by the reception unit 12) instead of the aggregation message.
  • the specific DENM used instead of the aggregate message is an example of the representative message.
  • the control unit 13 may transmit a stop message for instructing to stop further transmission of the specific DENM to a separate transmission source device that is a transmission source of the specific DENM, along with the transmission operation.
  • the DENM aggregation unit 13a1 outputs a DENM cancellation message to the congestion control unit 13e following the output of the aggregation message.
  • the congestion control unit 13e Upon receiving the DENM cancellation message, the congestion control unit 13e causes the transmission unit 13f to transmit the DENM cancellation message.
  • further transmission of the specific DENM is canceled by the cancellation message, it becomes possible to avoid congestion caused by the specific DENM.
  • the DENM aggregation unit 13a1 may specify the transition of the position of each in-vehicle communication device using a CAM (message indicating the position of the in-vehicle communication device) transmitted in time series from each in-vehicle communication device.
  • a CAM messages indicating the position of the in-vehicle communication device
  • the DENM aggregation unit 13a1 may specify the moving direction of each in-vehicle communication device based on the transition of the position of each in-vehicle communication device.
  • the control unit 13 executes the transmission operation by outputting the aggregation message in a situation where the reception unit 12 receives the specific DENM from different in-vehicle communication devices moving in the same direction, the DENM aggregation unit 13a1. Good.
  • the DENM aggregation unit 13a1 transmits an aggregation message in a situation where the reception unit 12 receives a specific DENM from different in-vehicle communication devices moving in the same direction within a predetermined area, so that the control unit 13 performs a transmission operation. May be executed.
  • control unit 13 may execute the transmission operation by transmitting the aggregation message in a situation where the DENM aggregation unit 13a1 receives the specific DENM from different in-vehicle communication devices in the predetermined area.
  • the control unit 13 may transfer the CAM without performing the transmission operation described above for the CAM. Further, the control unit 13 may control congestion by controlling the transmission of the CAM based on the congestion degree of the radio channel used for the CAM transfer.
  • the CAM is an example of a predetermined message.
  • the communication device 11 may be included in the in-vehicle communication device instead of the roadside communication device.
  • FIG. 6 is a diagram showing the in-vehicle communication device 30 including the communication device 11.
  • a vehicle on which the in-vehicle communication device 30 is mounted a vehicle that manages a road, an emergency vehicle, or a highly public bus can be cited.
  • the vehicle on which the in-vehicle communication device 30 is mounted is not limited to the vehicle described above, and can be changed as appropriate.
  • the following modified technique may be used instead of the technique using priority.
  • the congestion control unit 13e determines the radio channel with the lowest congestion level among the plurality of radio channels as the scheduled radio channel.
  • the congestion control unit 13e confirms the radio channel used by the receiving unit 12.
  • the congestion control unit 13e causes the transmission unit 13f to transmit radio channel information indicating the radio channel used by the reception unit 12.
  • the congestion control unit 13e receives radio channel information indicating a radio channel used by another communication device.
  • the radio channel information is transmitted from another communication device, for example.
  • the congestion control unit 13e determines a radio channel used by another communication device among a plurality of corresponding radio channels as a scheduled radio channel. In this case, since the radio channel used by another communication device is used as the scheduled radio channel, communication with the other communication device can be executed with high probability.
  • the congestion control unit 13e When there is no radio channel used by another communication device among the plurality of corresponding radio channels, the congestion control unit 13e refers to the radio channel information and the reception unit 12 currently uses the radio channel CH2. The SCH being used is changed to the SCH used by another communication device. Subsequently, the congestion control unit 13e determines the changed SCH as a use-scheduled radio channel regardless of the degree of congestion of the changed SCH.
  • the congestion control unit 13e selects one of the plurality of radio channels (for example, one selected at random). Is determined as the scheduled radio channel.
  • the congestion control unit 13e may use the above-described priority order. For example, when each of a plurality of radio channels used by other communication devices is a corresponding radio channel, the congestion control unit 13e is assigned a radio channel to which the highest priority is assigned among the plurality of radio channels. Is determined as the scheduled radio channel.
  • the congestion control unit 13e selects a radio channel having the lowest congestion degree among the plurality of radio channels. It is determined as a scheduled radio channel.
  • the communication device may be realized by a computer.
  • the computer reads and executes a program recorded on a recording medium such as a CD-ROM (Compact Disk Read Only Memory) that can be read by the computer, and executes a function of the communication device.
  • a recording medium such as a CD-ROM (Compact Disk Read Only Memory) that can be read by the computer, and executes a function of the communication device.
  • the recording medium is not limited to the CD-ROM and can be changed as appropriate.

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Abstract

A communication apparatus comprises: a reception unit that receives messages transmitted from transmission source apparatuses and indicating information and the identifiers of the respective transmission source apparatuses; and a control unit that executes, in accordance with the types of the messages received by the reception unit, a transmission operation to transmit, as a representative of the particular messages indicating the same information and received from the different transmission source apparatuses identified by the different identifiers, a representative message indicating the same information.

Description

通信装置、通信制御方法および記録媒体COMMUNICATION DEVICE, COMMUNICATION CONTROL METHOD, AND RECORDING MEDIUM
　本発明は、通信装置、通信制御方法およびプログラムに関し、特には、メッセージの通信を制御する通信装置、通信制御方法およびプログラムに関する。 The present invention relates to a communication device, a communication control method, and a program, and more particularly, to a communication device, a communication control method, and a program that control message communication.
　車両に搭載された車載通信装置同士が通信する車々間通信システムや、車両に搭載された車載通信装置と路側に設置された路側通信装置とが通信する路車間通信システムが知られている。 2. Description of the Related Art A vehicle-to-vehicle communication system in which vehicle-mounted communication devices mounted on a vehicle communicate with each other, and a road-to-vehicle communication system in which a vehicle-mounted communication device mounted on a vehicle and a roadside communication device installed on a roadside communicate with each other are known.
　車々間通信システムや路車間通信システムでは、例えば、DENM（Decentralized Environmental Notification Message：分散型環境通知メッセージ）やCAM（Cooperative Awareness Message：協調認識メッセージ）が用いられる。 In the inter-vehicle communication system and the road-to-vehicle communication system, for example, DENM (Decentralized Environmental Notification Message) and CAM (Cooperative Awareness Message) are used.
　DENMは、所定イベント（例えば、急ブレーキやハザードランプの点灯）の発生を所定範囲内の通信装置に知らせるためのメッセージである。DENMは、所定イベントの発生に伴い、所定時間の間繰り返し送信される。DENMには、所定イベントに応じた送信条件（例えば、必要となる送信距離や必要となる送信遅延時間）が設定される。また、DENMには、DENMの送信元の装置を特定するための送信元識別子が示される。 “DENM” is a message for informing a communication device within a predetermined range of occurrence of a predetermined event (for example, sudden braking or lighting of a hazard lamp). The DENM is repeatedly transmitted for a predetermined time as a predetermined event occurs. In DENM, transmission conditions (for example, necessary transmission distance and necessary transmission delay time) according to a predetermined event are set. In addition, DENM indicates a transmission source identifier for specifying a DENM transmission source device.
　一方、CAMは、車両の位置や速度を周囲の通信装置に知らせるためのメッセージである。CAMは、イベントの発生に関わらず繰り返し送信される。CAMには、DENMのようなイベントに応じた送信条件は設定されない。また、CAMにも、CAMの送信元の装置を特定するための送信元識別子が示される。 On the other hand, the CAM is a message for notifying surrounding communication devices of the position and speed of the vehicle. The CAM is repeatedly transmitted regardless of the occurrence of an event. A transmission condition corresponding to an event such as DENM is not set in the CAM. The CAM also indicates a transmission source identifier for specifying the CAM transmission source device.
　特許文献１には、車々間通信の通信領域を広範囲にする車々間通信装置が記載されている。特許文献１に記載の車々間通信装置は、送信元の車々間通信装置にて中継車両として選定された場合、送信元の車々間通信装置から受信した情報を、他の車々間通信装置に転送する。 Patent Document 1 describes an inter-vehicle communication device that widens the communication area of inter-vehicle communication. When the vehicle-to-vehicle communication device described in Patent Literature 1 is selected as a relay vehicle by the transmission source vehicle-to-vehicle communication device, the information received from the transmission source vehicle-to-vehicle communication device is transferred to another vehicle-to-vehicle communication device.
特開２００５－１２５２２号公報JP 2005-12522 A
　特許文献１に記載の車々間通信装置は、別々の車々間通信装置にて中継車両として選定され、それら別々の車々間通信装置から同一の情報（例えば急ブレーキ情報）を示すメッセージをそれぞれ受信すると、これら同一の情報を示すメッセージの全てを転送する。同一の情報を示す複数のメッセージは、複数のメッセージ全体として冗長なメッセージとなる可能性が高い。このため、特許文献１に記載の車々間通信装置では、冗長なメッセージとなる可能性が高い同一の情報を示すメッセージにて、輻輳が誘発されやすくなるという課題があった。 The vehicle-to-vehicle communication device described in Patent Document 1 is selected as a relay vehicle by separate vehicle-to-vehicle communication devices, and receives the same information (for example, sudden braking information) from these separate vehicle-to-vehicle communication devices, respectively, these same Forward all the messages indicating the information. A plurality of messages indicating the same information are likely to be redundant messages as a whole. For this reason, the inter-vehicle communication device described in Patent Document 1 has a problem that congestion is easily induced by a message indicating the same information that is likely to be a redundant message.
　本発明の目的は、上記課題を解決可能な通信装置、通信制御方法およびプログラムを提供することである。 An object of the present invention is to provide a communication device, a communication control method, and a program that can solve the above-described problems.
　本発明の通信装置は、
　送信元装置から送信された、情報と前記送信元装置の識別子とを示すメッセージを受信する受信部と、
　前記受信部が受信したメッセージの種別に応じて、互いに異なる前記識別子にて特定される別々の前記送信元装置からの同一の情報を示す特定メッセージの代表として前記同一の情報を示す代表メッセージを送信する送信動作を実行する制御部と、を含む。 The communication device of the present invention
A receiving unit for receiving a message indicating information and an identifier of the transmission source device transmitted from the transmission source device;
A representative message indicating the same information is transmitted as a representative of a specific message indicating the same information from different transmission source devices specified by different identifiers according to the type of message received by the receiving unit. And a control unit that executes a transmission operation.
　本発明の通信制御方法は、
　送信元装置から送信された、情報と前記送信元装置の識別子とを示すメッセージを受信し、
　前記受信されたメッセージの種別に応じて、互いに異なる前記識別子にて特定される別々の前記送信元装置からの同一の情報を示す特定メッセージの代表として前記同一の情報を示す代表メッセージを送信する送信動作を実行する。 The communication control method of the present invention includes:
Receiving a message transmitted from the transmission source device and indicating the information and the identifier of the transmission source device;
Transmission for transmitting a representative message indicating the same information as a representative of a specific message indicating the same information from different transmission source devices specified by different identifiers according to the type of the received message Perform the action.
　本発明の記録媒体は、
　コンピュータに、
　送信元装置から送信された、情報と前記送信元装置の識別子とを示すメッセージを受信する受信手順と、
　前記受信手順で受信されたメッセージの種別に応じて、互いに異なる前記識別子にて特定される別々の前記送信元装置からの同一の情報を示す特定メッセージの代表として前記同一の情報を示す代表メッセージを送信する送信動作を実行する制御手順と、を実行させるプログラムを記録したコンピュータ読み取り可能な記録媒体である。 The recording medium of the present invention is
On the computer,
A reception procedure for receiving a message indicating information and an identifier of the transmission source device transmitted from the transmission source device;
A representative message indicating the same information as a representative of a specific message indicating the same information from different transmission source devices specified by different identifiers according to the type of the message received in the reception procedure. It is a computer-readable recording medium which recorded the program which performs the control procedure which performs the transmission operation | movement which transmits.
　本発明によれば、同一の情報を示すメッセージにて輻輳が誘発される事態の発生を抑制可能になる。 According to the present invention, it is possible to suppress the occurrence of a situation in which congestion is induced by a message indicating the same information.
本発明の第１実施形態の通信装置１を示した図である。It is the figure which showed the communication apparatus 1 of 1st Embodiment of this invention. 通信装置１の動作を説明するためのフローチャートである。4 is a flowchart for explaining the operation of the communication apparatus 1; 本発明の第２実施形態の通信装置１１を示した図である。It is the figure which showed the communication apparatus 11 of 2nd Embodiment of this invention. DENM集約部１３ａ１に保持されたDENMの一例を示した図である。It is the figure which showed an example of DENM hold | maintained at DENM aggregation part 13a1. 通信装置１１の動作を説明するためのフローチャートである。4 is a flowchart for explaining the operation of the communication device 11; 通信装置１１を含む車載通信装置３０を示した図である。It is the figure which showed the vehicle-mounted communication apparatus 30 containing the communication apparatus 11. FIG.
　以下、本発明の実施形態について図面を参照して説明する。 Hereinafter, embodiments of the present invention will be described with reference to the drawings.
　（第１実施形態）
　図１は、本発明の第１実施形態の通信装置１を示した図である。 (First embodiment)
FIG. 1 is a diagram illustrating a communication device 1 according to a first embodiment of the present invention.
　図１において、通信装置１は、受信部２と制御部３とを含む。通信装置１は、例えば、路側通信装置に含まれる。通信装置１は、CAMやDENMを送信する車載通信装置の各々（不図示）と路車間通信を実行する。受信部２は、送信元装置である各車載通信装置から送信されたメッセージ（CAMやDENM）を受信する。各車載通信装置から送信されたメッセージは、情報と送信元装置（車載通信装置）の識別子とを示す。制御部３は、通信装置１を制御する。例えば、制御部３は、別々の車載通信装置からの同一の情報を示すメッセージ（以下「特定メッセージ」と称する）の代表として該同一の情報を示す代表メッセージを送信する動作（以下「送信動作」と称する）を実行可能である。制御部３は、受信部２が受信したメッセージの種別に応じて送信動作を実行する。制御部３は、メッセージに示された識別子を用いて別々の車載通信装置を特定する。同一の情報の一例としては、同一のイベント（例えば、急ブレーキまたはハザードランプ点灯）の情報が挙げられる。 1, the communication device 1 includes a receiving unit 2 and a control unit 3. The communication device 1 is included in, for example, a roadside communication device. The communication device 1 executes road-to-vehicle communication with each of the in-vehicle communication devices (not shown) that transmit CAM and DENM. The receiving unit 2 receives a message (CAM or DENM) transmitted from each in-vehicle communication device that is a transmission source device. The message transmitted from each in-vehicle communication device indicates information and an identifier of the transmission source device (in-vehicle communication device). The control unit 3 controls the communication device 1. For example, the control unit 3 operates to transmit a representative message indicating the same information as a representative message (hereinafter referred to as “specific message”) indicating the same information from different in-vehicle communication devices (hereinafter referred to as “transmission operation”). Can be executed). The controller 3 performs a transmission operation according to the type of message received by the receiver 2. The control unit 3 specifies different in-vehicle communication devices using the identifier indicated in the message. As an example of the same information, there is information on the same event (for example, sudden braking or hazard lamp lighting).
　図２は、通信装置１の動作を説明するためのフローチャートである。 FIG. 2 is a flowchart for explaining the operation of the communication apparatus 1.
　受信部２は、車載通信装置から送信されたメッセージを受信すると（ステップＳ１）、そのメッセージ（以下「受信メッセージ」とも称する）を制御部３に出力する。 When receiving the message transmitted from the in-vehicle communication device (step S1), the receiving unit 2 outputs the message (hereinafter also referred to as “received message”) to the control unit 3.
　制御部３は、受信部２から出力された受信メッセージを受け付ける。制御部３は、受信メッセージを受け付けるごとに、受信メッセージをその受信メッセージの受信時刻と関連づけて保持する。そして、制御部３は、保持されている受信メッセージおよび受信時刻を参照し、受信メッセージの種別に応じて送信動作を実行する（ステップＳ２）。 The control unit 3 accepts the received message output from the receiving unit 2. Each time the control unit 3 receives a received message, the control unit 3 holds the received message in association with the reception time of the received message. Then, the control unit 3 refers to the stored reception message and reception time, and performs a transmission operation according to the type of the reception message (step S2).
　次に、本実施形態の効果を説明する。 Next, the effect of this embodiment will be described.
　受信部２は、車載通信装置から送信されたメッセージを受信する。制御部３は、受信部２が受信したメッセージの種別に応じて送信動作を実行する。送信動作は、互いに異なる識別子にて特定される別々の車載通信装置からの同一の情報を示す特定メッセージの代表として、その同一の情報を示す代表メッセージを送信する動作である。このため、冗長なメッセージとなる可能性が高い同一の情報を示す複数の特定メッセージの各々を転送することで輻輳が誘発される事態の発生を抑制可能になる。また、メッセージの種別に応じて送信動作が実行される。このため、代表メッセージを送信する必要性が低い種別のメッセージについて、不要な代表メッセージの送信動作を行うことを抑制可能になる。 The receiving unit 2 receives a message transmitted from the in-vehicle communication device. The controller 3 performs a transmission operation according to the type of message received by the receiver 2. The transmission operation is an operation of transmitting a representative message indicating the same information as a representative of a specific message indicating the same information from different in-vehicle communication devices specified by different identifiers. For this reason, it is possible to suppress the occurrence of a situation in which congestion is induced by transferring each of a plurality of specific messages indicating the same information that is likely to be a redundant message. Also, a transmission operation is executed according to the message type. For this reason, it is possible to suppress unnecessary representative message transmission operation for a type of message whose necessity of transmitting a representative message is low.
　（第２実施形態）
　図３は、本発明の第２実施形態の通信装置１１を示した図である。 (Second Embodiment)
FIG. 3 is a diagram illustrating the communication device 11 according to the second embodiment of the present invention.
　図３において、通信装置１１は、受信部１２と、制御部１３と、を含む。制御部１３は、アプリケーション部１３ａと、無線チャネル設定部１３ｂと、送信周期設定部１３ｃと、送信電力／伝送速度設定部１３ｄと、輻輳制御部１３ｅと、送信部１３ｆと、を含む。アプリケーション部１３ａは、DENM集約部１３ａ１を含む。 3, the communication device 11 includes a receiving unit 12 and a control unit 13. The control unit 13 includes an application unit 13a, a radio channel setting unit 13b, a transmission cycle setting unit 13c, a transmission power / transmission rate setting unit 13d, a congestion control unit 13e, and a transmission unit 13f. The application unit 13a includes a DENM aggregation unit 13a1.
　通信装置１１は、路側通信装置２０に含まれる。通信装置１１は、CAMやDENMを送信する車載通信装置１０１～１０ｎ（ｎは２以上の整数）の各々と路車間通信を実行する。車載通信装置１０１～１０ｎの各々は、送信元装置の一例である。 The communication device 11 is included in the roadside communication device 20. The communication device 11 performs road-to-vehicle communication with each of the in-vehicle communication devices 101 to 10n (n is an integer of 2 or more) that transmits CAM and DENM. Each of the in-vehicle communication devices 101 to 10n is an example of a transmission source device.
　通信装置１１は、２つの無線チャネルを同時に使用して路車間通信を実行する。 The communication device 11 executes road-to-vehicle communication using two wireless channels simultaneously.
　通信装置１１は、CCH（Control Channel：制御チャネル）を、２つの無線チャネルのうちの一方の無線チャネル（以下「無線チャネルCH1」と称する）として用いる。CCHは、通信装置１１と路車間通信を行う車載通信装置１０１～１０ｎの各々にて共通に使用される。CCHは、通信装置１１の通信に対して予め設定された共通無線チャネルの一例である。CCHは、CAMの通信に使用される。CCHは、DENMの通信に使用されることもある。 The communication device 11 uses a CCH (Control Channel) as one of the two radio channels (hereinafter referred to as “radio channel CH1”). The CCH is commonly used in each of the in-vehicle communication devices 101 to 10n that perform road-vehicle communication with the communication device 11. The CCH is an example of a common radio channel set in advance for communication of the communication device 11. CCH is used for CAM communication. CCH may also be used for DENM communications.
　通信装置１１は、２つの無線チャネルのうちの他方の無線チャネル（以下「無線チャネルCH2」と称する）として、互いに周波数が異なる複数のSCH（Service Channel）のいずれかを用いる。各SCHは、DENMの通信に使用される。各SCHの周波数は、CCHの周波数と異なる。SCHの数は１以上であればよい。 The communication device 11 uses one of a plurality of SCHs (Service Channels) having different frequencies as the other of the two wireless channels (hereinafter referred to as “wireless channel CH2”). Each SCH is used for DENM communication. The frequency of each SCH is different from the frequency of CCH. The number of SCHs may be one or more.
　通信装置１１が同時に使用する無線チャネルの数は「２」に限らず適宜変更可能である。通信装置１１が使用する無線チャネルは、CCHやSCHに限らず適宜変更可能である。 The number of wireless channels simultaneously used by the communication device 11 is not limited to “2” and can be changed as appropriate. The radio channel used by the communication device 11 is not limited to CCH and SCH, and can be changed as appropriate.
　受信部１２は、無線チャネルCH1を通じて車載通信装置１０１～１０ｎの各々から無線送信されたメッセージを受信する。また、受信部１２は、無線チャネルCH2を通じて車載通信装置１０１～１０ｎの各々から無線送信されたメッセージも受信する。 The receiving unit 12 receives a message wirelessly transmitted from each of the in-vehicle communication devices 101 to 10n through the wireless channel CH1. The receiving unit 12 also receives messages wirelessly transmitted from each of the in-vehicle communication devices 101 to 10n through the wireless channel CH2.
　受信部１２は、無線チャネルCH1またはCH2を通じて、車載通信装置１０１～１０ｎの各々から無線送信されたメッセージ（例えば、CAMやDENM）を受信すると、そのメッセージを、アプリケーション部１３ａに出力する。 Upon receiving a message (for example, CAM or DENM) wirelessly transmitted from each of the in-vehicle communication devices 101 to 10n through the wireless channel CH1 or CH2, the receiving unit 12 outputs the message to the application unit 13a.
　また、受信部１２は、無線チャネルCH1およびCH2の各々の混雑度をメッセージの通信状況に基づいて特定する。受信部１２は、無線チャネルCH1およびCH2の各々の混雑度を輻輳制御部１３ｅに通知する。 In addition, the receiving unit 12 specifies the degree of congestion of each of the radio channels CH1 and CH2 based on the message communication status. The receiving unit 12 notifies the congestion control unit 13e of the degree of congestion of each of the radio channels CH1 and CH2.
　制御部１３は、通信装置１１を制御する。 The control unit 13 controls the communication device 11.
　アプリケーション部１３ａは、受信部１２から出力されたメッセージ（CAMやDENM）を受け付ける。アプリケーション部１３ａは、受信部１２から受信したメッセージに応じて、メッセージの送信を制御する。 The application unit 13a receives a message (CAM or DENM) output from the receiving unit 12. The application unit 13 a controls message transmission according to the message received from the receiving unit 12.
　また、アプリケーション部１３ａは、例えば、DENMに示される急ブレーキやハザードランプの点灯等のイベント（以下「特定イベント」と称する）ごとに、特定イベントに応じた送信条件（例えば、送信距離や送信遅延時間）を記憶している。 In addition, the application unit 13a may transmit a transmission condition (for example, a transmission distance or a transmission delay) according to a specific event for each event (hereinafter referred to as a “specific event”) such as sudden braking or hazard lamp lighting indicated by DENM. Time).
　例えば、アプリケーション部１３ａは、特定イベントの一例である「急ブレーキ」に応じた送信条件として、通信に要求される通信距離Ａ１および通信に要求される遅延時間Ｂ１を記憶している。また、アプリケーション部１３ａは、特定イベントの一例である「ハザードランプ点灯」に応じた送信条件として、通信に要求される通信距離Ａ２および通信に要求される遅延時間Ｂ２を記憶している。 For example, the application unit 13a stores a communication distance A1 required for communication and a delay time B1 required for communication as a transmission condition corresponding to “sudden braking” which is an example of a specific event. In addition, the application unit 13a stores a communication distance A2 required for communication and a delay time B2 required for communication as transmission conditions corresponding to “hazard lamp lighting” which is an example of a specific event.
　以下、通信に要求される通信距離を「要求通信距離」と称する。要求通信距離は、送信条件となる送信距離の一例である。本実施形態では、要求通信距離に対応する送信電力（以下「要求送信電力」と称する）は、予め定められた最大送信電力よりも小さいものとする。 Hereinafter, the communication distance required for communication is referred to as “requested communication distance”. The requested communication distance is an example of a transmission distance that is a transmission condition. In this embodiment, it is assumed that the transmission power corresponding to the requested communication distance (hereinafter referred to as “requested transmission power”) is smaller than a predetermined maximum transmission power.
　また、通信に要求される遅延時間を「要求遅延時間」と称する。要求遅延時間は、送信条件となる送信遅延時間の一例である。本実施形態では、要求遅延時間は、予め定められた最短送信周期が示す時間よりも長いものとする。 Also, the delay time required for communication is referred to as “request delay time”. The request delay time is an example of a transmission delay time that is a transmission condition. In the present embodiment, it is assumed that the request delay time is longer than the time indicated by a predetermined shortest transmission cycle.
　要求通信距離Ａ１は、要求通信距離Ａ２と同一でもよいし異なってもよい。要求遅延時間Ｂ１は、要求遅延時間Ｂ２と同一でもよいし異なってもよい。 The requested communication distance A1 may be the same as or different from the requested communication distance A2. The request delay time B1 may be the same as or different from the request delay time B2.
　DENM集約部１３ａ１は、受信部１２から出力されたDENMに基づいて、代表メッセージを出力する。代表メッセージは、送信対象のメッセージの一例である。 The DENM aggregation unit 13a1 outputs a representative message based on the DENM output from the reception unit 12. The representative message is an example of a message to be transmitted.
　DENM集約部１３ａ１は、受信部１２から出力されたメッセージ（CAMやDENM）を受信する。DENM集約部１３ａ１は、DENMを受信するごとに、DENMをその受信時刻と関連づけて保持する。 The DENM aggregation unit 13a1 receives the message (CAM or DENM) output from the reception unit 12. Each time DENM aggregation section 13a1 receives DENM, DENM aggregation section 13a1 holds DENM in association with the reception time.
　図４は、DENM集約部１３ａ１に保持されたDENMの一例を示した図である。 FIG. 4 is a diagram showing an example of DENM held in the DENM aggregation unit 13a1.
　図４に示したように、各DENMは、受信時刻と関連づけられて保持される。なお、各DENMは、送信元装置の識別子とイベントの情報とを含む。 As shown in FIG. 4, each DENM is held in association with the reception time. Each DENM includes a transmission source device identifier and event information.
　DENM集約部１３ａ１は、DENM集約部１３ａ１に保持されているDENMを参照し、別々の車載通信装置から、同一のイベントの情報を示すDENM（以下「特定DENM」と称する）を受信した場合、これら特定DENMを集約した集約メッセージを生成する。特定DENMは、特定メッセージの一例である。DENM集約部１３ａ１は、特定DENMが示すイベントの情報（例えば、急ブレーキ）を示すDENMを、集約メッセージとして生成する。集約メッセージは、代表メッセージの一例である。 The DENM aggregating unit 13a1 refers to the DENM held in the DENM aggregating unit 13a1, and receives the DENM indicating the same event information (hereinafter referred to as “specific DENM”) from different in-vehicle communication devices. Generate an aggregate message that aggregates specific DENM. The specific DENM is an example of a specific message. The DENM aggregation unit 13a1 generates, as an aggregation message, DENM indicating event information (for example, sudden braking) indicated by the specific DENM. The aggregate message is an example of a representative message.
　図３に示した無線チャネル設定部１３ｂには、送信対象のメッセージである集約メッセージの送信に用いられる無線チャネル（以下「使用予定無線チャネル」と称する）が設定される。 In the radio channel setting unit 13b shown in FIG. 3, a radio channel (hereinafter referred to as “scheduled radio channel to be used”) used to transmit an aggregate message that is a message to be transmitted is set.
　送信周期設定部１３ｃには、送信対象のメッセージの送信周期が設定される。 The transmission cycle of the message to be transmitted is set in the transmission cycle setting unit 13c.
　送信電力／伝送速度設定部１３ｄには、送信対象のメッセージの送信電力および伝送速度が設定される。 In the transmission power / transmission speed setting unit 13d, the transmission power and transmission speed of the message to be transmitted are set.
　輻輳制御部１３ｅは、送信対象のメッセージの種別と受信部１２から通知された混雑度とに基づいて送信対象のメッセージの送信（例えば、送信周期、使用予定無線チャネル、送信電力、伝送速度）を制御することで、輻輳制御動作を実行する。 The congestion control unit 13e determines the transmission of the transmission target message (for example, the transmission cycle, the scheduled wireless channel, the transmission power, the transmission speed) based on the type of the transmission target message and the congestion level notified from the reception unit 12. By controlling, the congestion control operation is executed.
　また、輻輳制御部１３ｅは、送信電力と送信距離との対応関係を示す対応テーブルと、混雑度閾値と、を記憶している。対応テーブルでは、送信電力は、対応する送信距離が長くなるほど大きくなる。 Further, the congestion control unit 13e stores a correspondence table indicating a correspondence relationship between transmission power and transmission distance, and a congestion degree threshold value. In the correspondence table, the transmission power increases as the corresponding transmission distance increases.
　送信部１３ｆは、送信対象のメッセージを、無線チャネル設定部１３ｂに設定された使用予定無線チャネル、送信周期設定部１３ｃに設定された送信周期、および、送信電力／伝送速度設定部１３ｄに設定された送信電力および伝送速度で、無線送信する。 The transmission unit 13f sets the message to be transmitted in the scheduled use radio channel set in the radio channel setting unit 13b, the transmission cycle set in the transmission cycle setting unit 13c, and the transmission power / transmission rate setting unit 13d. Wireless transmission with the same transmission power and transmission speed.
　次に、動作を説明する。 Next, the operation will be described.
　図５は、通信装置１１の動作を説明するためのフローチャートである。 FIG. 5 is a flowchart for explaining the operation of the communication device 11.
　受信部１２は、無線チャネル設定部１３ｂに設定された使用予定無線チャネルがCCHである場合、無線チャネルCH1としてCCHを使用し、無線チャネルCH2として複数のSCHのいずれか（例えば、デフォルトのSCHや、ユーザが設定したSCH）を使用する。 When the scheduled radio channel to be used set in the radio channel setting unit 13b is CCH, the reception unit 12 uses the CCH as the radio channel CH1 and uses one of a plurality of SCHs as the radio channel CH2 (for example, default SCH or SCH) set by the user.
　一方、無線チャネル設定部１３ｂに設定された使用予定無線チャネルがCCHでない場合、受信部１２は、無線チャネルCH1としてCCHを使用し、無線チャネルCH2として使用予定無線チャネルを使用する。 On the other hand, when the scheduled radio channel set in the radio channel setting unit 13b is not CCH, the receiving unit 12 uses CCH as the radio channel CH1 and uses the scheduled radio channel as the radio channel CH2.
　受信部１２は、無線チャネルCH1およびCH2の各々の混雑度を、各無線チャネルを通じたメッセージの通信状況に基づいて特定する。受信部１２は、無線チャネルCH1およびCH2の各々の混雑度を輻輳制御部１３ｅに通知する。 The receiving unit 12 specifies the degree of congestion of each of the radio channels CH1 and CH2 based on the communication status of the message through each radio channel. The receiving unit 12 notifies the congestion control unit 13e of the degree of congestion of each of the radio channels CH1 and CH2.
　受信部１２は、無線チャネルCH1またはCH2を通じてメッセージを受信すると（ステップ１０１）、そのメッセージをDENM集約部１３ａ１に出力する。 When receiving the message through the radio channel CH1 or CH2 (Step 101), the receiving unit 12 outputs the message to the DENM aggregation unit 13a1.
　DENM集約部１３ａ１は、受信部１２からメッセージを受信すると、そのメッセージをそのメッセージの受信時刻に関連づけて保持する。 When the DENM aggregation unit 13a1 receives a message from the reception unit 12, the DENM aggregation unit 13a1 holds the message in association with the reception time of the message.
　続いて、DENM集約部１３ａ１は、受信部１２からのメッセージの種別がCAMであるかDENMであるかを判断する（ステップＳ１０２）。なお、DENMは所定種別の一例である。CAMは、所定種別と異なる種別の一例である。 Subsequently, the DENM aggregation unit 13a1 determines whether the type of message from the reception unit 12 is CAM or DENM (step S102). Note that DENM is an example of a predetermined type. CAM is an example of a type different from the predetermined type.
　メッセージの種別がCAMである場合、DENM集約部１３ａ１は動作を終了する。 If the message type is CAM, the DENM aggregation unit 13a1 ends the operation.
　一方、メッセージの種別がDENMである場合、DENM集約部１３ａ１は、ステップＳ１０３を実行する。 On the other hand, if the message type is DENM, the DENM aggregation unit 13a1 executes Step S103.
　ステップＳ１０３では、DENM集約部１３ａ１は、DENM集約部１３ａ１内のメッセージを参照し、現在時刻の直前の所定期間内に複数の特定DENMが受信された場合、これら特定DENMが示すイベントの情報を示すDENMを、集約メッセージとして生成する。 In step S103, the DENM aggregation unit 13a1 refers to the message in the DENM aggregation unit 13a1, and when a plurality of specific DENMs are received within a predetermined period immediately before the current time, the DENM aggregation unit 13a1 indicates event information indicated by these specific DENMs. DENM is generated as an aggregate message.
　なお、DENM集約部１３ａ１は、特定DENMに対応する集約メッセージを現在時刻の直前の所定期間内に生成済みである場合には、集約メッセージの生成を行わず動作を終了する。また、DENM集約部１３ａ１は、現在時刻の直前の所定期間内に複数の特定DENMが受信されていない場合、例えば動作を終了する。 The DENM aggregation unit 13a1 ends the operation without generating the aggregate message when the aggregate message corresponding to the specific DENM has been generated within a predetermined period immediately before the current time. Further, when a plurality of specific DENMs are not received within a predetermined period immediately before the current time, the DENM aggregation unit 13a1 ends the operation, for example.
　DENM集約部１３ａ１は、集約メッセージ（DENM）を生成すると、集約メッセージに対応する送信条件を、アプリケーション部１３ａから読み出す。 When the DENM aggregation unit 13a1 generates an aggregation message (DENM), the transmission condition corresponding to the aggregation message is read from the application unit 13a.
　続いて、DENM集約部１３ａ１は、集約メッセージを送信対象のメッセージとして送信周期設定部１３ｃに出力し、かつ、集約メッセージの種別（DENM）を送信対象のメッセージの種別として表すメッセージ種別情報を輻輳制御部１３ｅに出力する。 Subsequently, the DENM aggregating unit 13a1 outputs the aggregated message as a transmission target message to the transmission cycle setting unit 13c, and the message type information indicating the type of the aggregated message (DENM) as the type of the transmission target message is congestion control. To the unit 13e.
　DENM集約部１３ａ１は、集約メッセージの送信条件も送信対象のメッセージの送信条件として輻輳制御部１３ｅに出力する。例えば、DENM集約部１３ａ１は、その集約メッセージ（DENM）が表す特定イベントに応じた送信条件を、輻輳制御部１３ｅに出力する。集約メッセージの送信条件としては、要求通信距離を表す要求通信距離情報と、要求遅延時間を表す要求遅延時間情報とが用いられる。 The DENM aggregation unit 13a1 outputs the transmission condition of the aggregation message to the congestion control unit 13e as the transmission condition of the message to be transmitted. For example, the DENM aggregation unit 13a1 outputs a transmission condition corresponding to the specific event represented by the aggregation message (DENM) to the congestion control unit 13e. As transmission conditions for the aggregate message, request communication distance information indicating a request communication distance and request delay time information indicating a request delay time are used.
　送信周期設定部１３ｃは、集約メッセージを受け付けると、その集約メッセージを保持する。 When the transmission cycle setting unit 13c receives the aggregation message, the transmission period setting unit 13c holds the aggregation message.
　輻輳制御部１３ｅは、送信対象のメッセージの種別がDENMであるので、無線チャネルCH1およびCH2の各混雑度と、送信条件（要求通信距離情報と要求遅延時間情報）と、を参照する（ステップＳ１０４）。 Since the type of message to be transmitted is DENM, the congestion control unit 13e refers to the congestion levels of the radio channels CH1 and CH2 and transmission conditions (requested communication distance information and request delay time information) (step S104). ).
　続いて、輻輳制御部１３ｅは、使用予定無線チャネルを決定する（ステップＳ１０５）。 Subsequently, the congestion control unit 13e determines a scheduled radio channel (Step S105).
　例えば、輻輳制御部１３ｅは、まず、無線チャネルCH1およびCH2のうち混雑度が混雑度閾値以下である該当無線チャネルを特定する。なお、無線チャネルCH1およびCH2の各混雑度が、いずれも混雑度閾値を超えていた場合、輻輳制御部１３ｅは、無線チャネルCH1およびCH2のうち最も混雑度が低い無線チャネルを、該当無線チャネルの代わりに用いる。 For example, the congestion control unit 13e first identifies a corresponding radio channel whose congestion level is equal to or less than the congestion level threshold among the radio channels CH1 and CH2. If the congestion levels of the radio channels CH1 and CH2 exceed the congestion level threshold, the congestion control unit 13e selects the radio channel with the lowest congestion level among the radio channels CH1 and CH2 as the corresponding radio channel. Use instead.
　続いて、輻輳制御部１３ｅは、該当無線チャネルの数が１であった場合、その該当無線チャネルを、使用予定無線チャネルとして決定する。 Subsequently, when the number of corresponding radio channels is 1, the congestion control unit 13e determines the corresponding radio channel as a scheduled radio channel.
　一方、該当無線チャネルの数が２以上であった場合、輻輳制御部１３ｅは、複数の該当無線チャネルのうちの１つの該当無線チャネルを、使用予定無線チャネルとして決定する。 On the other hand, when the number of corresponding radio channels is two or more, the congestion control unit 13e determines one corresponding radio channel from among the plurality of corresponding radio channels as the scheduled radio channel.
　ここで、複数の該当無線チャネルから１つの該当無線チャネルを使用予定無線チャネルとして決定する手法の一例を説明する。 Here, an example of a method for determining one corresponding radio channel as a scheduled radio channel from a plurality of corresponding radio channels will be described.
　この例では、複数のSCHの各々とCCHには予め優先順位が割り当てられている。例えば、CCHに最も高い優先順位が割り当てられ、各SCHには最も高い優先順位以外の優先順位が割り当てられる。各SCHに最も高い優先順位以外の優先順位を割り当てる例としては、重要度や使用頻度が高いSCHほど高い優先順位が割り当てられる例が挙げられる。優先順位の割り当ては、上記に限らず適宜変更可能である。輻輳制御部１３ｅは、CCHおよび複数のSCHに対する優先順位の割り当て結果を保持している。そして、輻輳制御部１３ｅは、該当無線チャネルのうち最も優先順位の高い該当無線チャンネルを、使用予定無線チャネルとして決定する。 In this example, priorities are assigned in advance to each of the plurality of SCHs and the CCH. For example, the highest priority is assigned to the CCH, and a priority other than the highest priority is assigned to each SCH. As an example of assigning a priority other than the highest priority to each SCH, an example in which a higher priority is assigned to a SCH having a higher importance or usage frequency can be given. The priority assignment is not limited to the above, and can be changed as appropriate. The congestion control unit 13e holds the priority assignment result for the CCH and the plurality of SCHs. Then, the congestion control unit 13e determines the radio channel with the highest priority among the radio channels as the scheduled radio channel.
　続いて、輻輳制御部１３ｅは、ステップＳ１０５で決定された使用予定無線チャネルを無線チャネル設定部１３ｂに設定する。 Subsequently, the congestion control unit 13e sets the scheduled radio channel to be used determined in step S105 in the radio channel setting unit 13b.
　続いて、輻輳制御部１３ｅは、使用予定無線チャネルの混雑度と送信条件とに基づいて、送信対象のメッセージの送信周期を決定する（ステップＳ１０６）。 Subsequently, the congestion control unit 13e determines the transmission cycle of the message to be transmitted based on the congestion level of the scheduled radio channel and the transmission condition (step S106).
　例えば、使用予定無線チャネルの混雑度が混雑度閾値以下である場合、輻輳制御部１３ｅは、最短送信周期を送信対象のメッセージの送信周期として決定する。 For example, when the congestion level of the scheduled radio channel is equal to or less than the congestion level threshold, the congestion control unit 13e determines the shortest transmission cycle as the transmission cycle of the message to be transmitted.
　一方、使用予定無線チャネルの混雑度が混雑度閾値よりも高い場合、輻輳制御部１３ｅは、まず、送信周期設定部１３ｃに現在設定されている送信周期よりも規定時間長い周期（以下「送信周期候補」と称する）を特定する。 On the other hand, when the congestion level of the scheduled radio channel is higher than the congestion level threshold, the congestion control unit 13e firstly has a cycle longer than the transmission cycle currently set in the transmission cycle setting unit 13c (hereinafter referred to as “transmission cycle”). Identified as "candidate").
　続いて、輻輳制御部１３ｅは、送信周期候補が表す時間（周期）が、要求遅延時間情報にて表された要求遅延時間よりも短い場合、送信周期候補を、送信対象のメッセージの送信周期として決定する。一方、送信周期候補が表す時間（周期）が、要求遅延時間以上である場合、輻輳制御部１３ｅは、要求遅延時間を、送信対象のメッセージの送信周期として決定する。これは、送信周期の最大値が要求遅延時間にて制限されることを意味する。 Subsequently, when the time (cycle) represented by the transmission cycle candidate is shorter than the request delay time represented by the request delay time information, the congestion control unit 13e sets the transmission cycle candidate as the transmission cycle of the message to be transmitted. decide. On the other hand, when the time (cycle) represented by the transmission cycle candidate is equal to or longer than the request delay time, the congestion control unit 13e determines the request delay time as the transmission cycle of the message to be transmitted. This means that the maximum value of the transmission cycle is limited by the request delay time.
　本実施形態では、要求遅延時間と最短送信周期が表す時間と規定時間とは、「要求遅延時間」＞「最短送信周期が表す時間」＋「規定時間」、という関係を有する。 In this embodiment, the request delay time, the time represented by the shortest transmission cycle, and the specified time have a relationship of “request delay time”> “time represented by the shortest transmission cycle” + “specified time”.
　送信周期設定部１３ｃに送信周期が設定されていない状況では、輻輳制御部１３ｅは、最短送信周期よりも規定時間長い周期を、送信対象のメッセージの送信周期として決定する。 In a situation where the transmission cycle is not set in the transmission cycle setting unit 13c, the congestion control unit 13e determines a cycle longer than the shortest transmission cycle by a specified time as the transmission cycle of the message to be transmitted.
　続いて、輻輳制御部１３ｅは、ステップＳ１０６で決定された送信周期を、送信対象のメッセージの送信周期として送信周期設定部１３ｃに設定する。 Subsequently, the congestion control unit 13e sets the transmission cycle determined in step S106 in the transmission cycle setting unit 13c as the transmission cycle of the message to be transmitted.
　送信周期設定部１３ｃは、送信対象のメッセージの送信周期が設定されると、保持済みの集約メッセージを、その送信周期が示す時間間隔でコピーして、集約メッセージの複製（以下「送信データ」と称する）を生成する（ステップＳ１０７）。 When the transmission cycle of the message to be transmitted is set, the transmission cycle setting unit 13c copies the held aggregate message at a time interval indicated by the transmission cycle, and copies the aggregate message (hereinafter referred to as “transmission data”). (Step S107).
　続いて、送信周期設定部１３ｃは、送信データを送信部１３ｆに出力する。 Subsequently, the transmission cycle setting unit 13c outputs the transmission data to the transmission unit 13f.
　輻輳制御部１３ｅは、送信周期を送信周期設定部１３ｃに設定すると、使用予定無線チャネルの混雑度および送信条件に基づいて送信対象のメッセージの送信電力を決定する（ステップＳ１０８）。 When the congestion control unit 13e sets the transmission cycle in the transmission cycle setting unit 13c, the congestion control unit 13e determines the transmission power of the message to be transmitted based on the congestion level of the scheduled radio channel to be used and the transmission conditions (step S108).
　例えば、使用予定無線チャネルの混雑度が混雑度閾値以下である場合、輻輳制御部１３ｅは、最大送信電力を送信対象のメッセージの送信電力として決定する。 For example, when the congestion level of the scheduled radio channel is equal to or less than the congestion level threshold, the congestion control unit 13e determines the maximum transmission power as the transmission power of the message to be transmitted.
　一方、使用予定無線チャネルの混雑度が混雑度閾値よりも高い場合、輻輳制御部１３ｅは、まず、送信電力／伝送速度設定部１３ｄに現在設定されている送信電力よりも規定量小さい送信電力（以下「送信電力候補」と称する）を特定する。 On the other hand, when the congestion level of the wireless channel to be used is higher than the congestion level threshold, the congestion control unit 13e first transmits a transmission power (a predetermined amount smaller than the transmission power currently set in the transmission power / transmission speed setting unit 13d). (Hereinafter referred to as “transmission power candidates”).
　続いて、輻輳制御部１３ｅは、対応テーブルを参照して、要求通信距離情報にて表された要求通信距離に対応する要求送信電力を特定する。 Subsequently, the congestion control unit 13e refers to the correspondence table and identifies the requested transmission power corresponding to the requested communication distance represented by the requested communication distance information.
　続いて、輻輳制御部１３ｅは、送信電力候補が表す送信電力が要求送信電力よりも大きい場合、送信電力候補を、送信対象のメッセージの送信電力として決定する。一方、送信電力候補が表す送信電力が要求送信電力以下である場合、輻輳制御部１３ｅは、要求送信電力を、送信対象のメッセージの送信電力として決定する。これは、送信電力の最小値が要求通信距離にて制限されることを意味する。 Subsequently, when the transmission power represented by the transmission power candidate is larger than the requested transmission power, the congestion control unit 13e determines the transmission power candidate as the transmission power of the message to be transmitted. On the other hand, when the transmission power represented by the transmission power candidate is equal to or less than the requested transmission power, the congestion control unit 13e determines the requested transmission power as the transmission power of the message to be transmitted. This means that the minimum value of the transmission power is limited by the required communication distance.
　本実施形態では、要求送信電力と最大送信電力と規定量とは、「要求送信電力」＜「最大送信電力」－「規定量」、という関係を有する。 In this embodiment, the required transmission power, the maximum transmission power, and the specified amount have a relationship of “requested transmission power” <“maximum transmission power” − “specified amount”.
　送信電力／伝送速度設定部１３ｄに送信電力が設定されていない状況では、輻輳制御部１３ｅは、最大送信電力から規定量を減算した送信電力を、送信対象のメッセージの送信電力として決定する。 In a situation where the transmission power is not set in the transmission power / transmission speed setting unit 13d, the congestion control unit 13e determines the transmission power obtained by subtracting the specified amount from the maximum transmission power as the transmission power of the message to be transmitted.
　続いて、輻輳制御部１３ｅは、ステップＳ１０８で決定された送信電力を、送信対象のメッセージの送信電力として送信電力／伝送速度設定部１３ｄに設定する。 Subsequently, the congestion control unit 13e sets the transmission power determined in step S108 in the transmission power / transmission rate setting unit 13d as the transmission power of the message to be transmitted.
　続いて、輻輳制御部１３ｅは、使用予定無線チャネルの混雑度に基づいて送信対象のメッセージの伝送速度を決定する（ステップＳ１０９）。 Subsequently, the congestion control unit 13e determines the transmission rate of the message to be transmitted based on the congestion level of the scheduled radio channel (step S109).
　例えば、使用予定無線チャネルの混雑度が混雑度閾値以下である場合、輻輳制御部１３ｅは、予め定められた最も遅い伝送速度（以下「最遅伝送速度」と称する」を、送信対象のメッセージの伝送速度として決定する。 For example, when the congestion level of the scheduled wireless channel is less than or equal to the congestion level threshold, the congestion control unit 13e sets a predetermined slowest transmission rate (hereinafter referred to as “latest transmission rate”) to the message to be transmitted. Determined as transmission speed.
　また、使用予定無線チャネルの混雑度が混雑度閾値よりも高い場合、輻輳制御部１３ｅは、送信電力／伝送速度設定部１３ｄに現在設定されている伝送速度よりも規定値速い伝送速度を、送信対象のメッセージの伝送速度として決定する。なお、送信電力／伝送速度設定部１３ｄに伝送速度が設定されていない状況では、輻輳制御部１３ｅは、最遅伝送速度よりも規定値速い伝送速度を、送信対象のメッセージの伝送速度として決定する。 When the congestion level of the scheduled radio channel is higher than the congestion threshold, the congestion control unit 13e transmits a transmission rate that is faster than the transmission rate currently set in the transmission power / transmission rate setting unit 13d by a specified value. It is determined as the transmission rate of the target message. Note that, in a situation where the transmission rate is not set in the transmission power / transmission rate setting unit 13d, the congestion control unit 13e determines a transmission rate that is faster than the latest transmission rate by a specified value as the transmission rate of the message to be transmitted. .
　続いて、輻輳制御部１３ｅは、ステップＳ１０９で決定された伝送速度を、送信対象のメッセージの伝送速度として、送信電力／伝送速度設定部１３ｄに設定する。 Subsequently, the congestion control unit 13e sets the transmission rate determined in step S109 as the transmission rate of the transmission target message in the transmission power / transmission rate setting unit 13d.
　送信部１３ｆは、送信周期設定部１３ｃから送信データを受け付けると、送信データを、無線チャネル設定部１３ｂに設定された使用予定無線チャネルを使い、送信電力／伝送速度設定部１３ｄに設定された送信電力および伝送速度で送信する（ステップＳ１１０）。 Upon receiving the transmission data from the transmission cycle setting unit 13c, the transmission unit 13f uses the transmission data set in the transmission power / transmission rate setting unit 13d using the scheduled radio channel set in the radio channel setting unit 13b. Transmission is performed at power and transmission speed (step S110).
　続いて、送信部１３ｆは、送信通知を輻輳制御部１３ｅに出力する。 Subsequently, the transmission unit 13f outputs a transmission notification to the congestion control unit 13e.
　輻輳制御部１３ｅは、送信通知を受け付けると、メッセージ種別情報を受け付けてからの経過時間が、予め定められた送信継続時間を超えているかを判断する（ステップＳ１１１）。 When the congestion control unit 13e receives the transmission notification, the congestion control unit 13e determines whether the elapsed time after receiving the message type information exceeds a predetermined transmission duration (step S111).
　ステップＳ１１１で経過時間が送信継続時間を超えていないと、輻輳制御部１３ｅは、処理をステップＳ１０４に戻す。 If the elapsed time does not exceed the transmission duration time in step S111, the congestion control unit 13e returns the process to step S104.
　ステップＳ１１１で経過時間が送信継続時間を超えていると、輻輳制御部１３ｅは、送信周期設定部１３ｃが保持している集約メッセージを削除する。続いて、輻輳制御部１３ｅは、送信周期設定部１３ｃ、送信電力／伝送速度設定部１３ｄにそれぞれ設定されている、送信周期、送信電力および伝送速度を削除して動作を終了する。 If the elapsed time exceeds the transmission duration in step S111, the congestion control unit 13e deletes the aggregate message held by the transmission cycle setting unit 13c. Subsequently, the congestion control unit 13e deletes the transmission cycle, transmission power, and transmission rate set in the transmission cycle setting unit 13c and the transmission power / transmission rate setting unit 13d, and ends the operation.
　次に、本実施形態の効果を説明する。 Next, the effect of this embodiment will be described.
　制御部１３は、受信部１２が受信したメッセージの種別がDENMである場合、送信動作を実行する。送信動作は、別々の車載通信装置からの同一のイベントの情報を示す特定DENMを集約した集約メッセージを送信する動作である。このため、冗長なメッセージとなる可能性が高い複数の特定DENMの各々を転送することで輻輳が誘発されることを抑制可能になる。また、メッセージの種別がDENMである場合に送信動作が実行される。このため、集約メッセージを送信する必要性が低い種別のメッセージ（例えばCAM）について、不要な集約メッセージの送信処理を行うことを抑制可能になる。 The control unit 13 performs a transmission operation when the type of the message received by the receiving unit 12 is DENM. The transmission operation is an operation of transmitting an aggregate message in which specific DENMs indicating information on the same event from different in-vehicle communication devices are aggregated. For this reason, it is possible to suppress congestion from being induced by transferring each of a plurality of specific DENMs that are likely to be redundant messages. A transmission operation is executed when the message type is DENM. For this reason, it is possible to suppress unnecessary aggregation message transmission processing for a type of message (for example, CAM) that is less necessary to transmit the aggregation message.
　制御部１３は、使用予定無線チャネルの混雑度と送信条件とに基づいて使用予定無線チャネルでの集約メッセージの送信を制御する。このため、集約メッセージに対して送信条件を考慮した送信制御を行って輻輳を制御することが可能になる。 The control unit 13 controls transmission of the aggregate message in the scheduled radio channel based on the congestion level of the scheduled radio channel and the transmission condition. For this reason, it is possible to control congestion by performing transmission control in consideration of transmission conditions for the aggregate message.
　次に、本実施形態の変形例について説明する。 Next, a modification of this embodiment will be described.
　本実施形態では、送信条件として、送信距離および送信遅延時間の両方が用いられた。しかしながら、送信条件は、送信距離および送信遅延時間のいずれか一方でもよく適宜変更可能である。 In this embodiment, both the transmission distance and the transmission delay time are used as the transmission conditions. However, the transmission condition may be any one of the transmission distance and the transmission delay time, and can be changed as appropriate.
　送信周期の決定と送信電力の決定と伝送速度の決定の順番は、適宜変更可能である。 The order of determining the transmission cycle, determining the transmission power, and determining the transmission rate can be changed as appropriate.
　送信動作の簡略化を図るために、伝送速度の制御が省略されてもよい。また、送信動作の簡略化を図るために、送信周期の制御と送信電力の制御とのいずれか一方または両方が省略されてもよい。 In order to simplify the transmission operation, transmission rate control may be omitted. Further, in order to simplify the transmission operation, either or both of the transmission cycle control and the transmission power control may be omitted.
　DENM集約部１３ａ１は、受信部１２が受信した特定DENMのいずれか（例えば、受信部１２が受信した特定DENM）を集約メッセージの代わりに用いてもよい。この場合、集約メッセージの代わりに用いられる特定DENMが、代表メッセージの一例となる。 The DENM aggregation unit 13a1 may use one of the specific DENMs received by the reception unit 12 (for example, the specific DENM received by the reception unit 12) instead of the aggregation message. In this case, the specific DENM used instead of the aggregate message is an example of the representative message.
　制御部１３は、送信動作に伴って、特定DENMの送信元である別々の送信元装置に対して、特定DENMの更なる送信の中止を指示する中止メッセージを送信してもよい。例えば、DENM集約部１３ａ１が、集約メッセージの出力に続いて、DENMの中止メッセージを輻輳制御部１３ｅに出力する。輻輳制御部１３ｅは、DENMの中止メッセージを受け付けると、DENMの中止メッセージを送信部１３ｆに送信させる。中止メッセージにて特定DENMの更なる送信が中止されると、特定DENMに起因する輻輳を回避することが可能になる。 The control unit 13 may transmit a stop message for instructing to stop further transmission of the specific DENM to a separate transmission source device that is a transmission source of the specific DENM, along with the transmission operation. For example, the DENM aggregation unit 13a1 outputs a DENM cancellation message to the congestion control unit 13e following the output of the aggregation message. Upon receiving the DENM cancellation message, the congestion control unit 13e causes the transmission unit 13f to transmit the DENM cancellation message. When further transmission of the specific DENM is canceled by the cancellation message, it becomes possible to avoid congestion caused by the specific DENM.
　DENM集約部１３ａ１は、各車載通信装置から時系列で送信されるCAM（車載通信装置の位置を示すメッセージ）を用いて、各車載通信装置の位置の遷移を特定してもよい。 The DENM aggregation unit 13a1 may specify the transition of the position of each in-vehicle communication device using a CAM (message indicating the position of the in-vehicle communication device) transmitted in time series from each in-vehicle communication device.
　また、DENM集約部１３ａ１は、各車載通信装置の位置の遷移に基づいて各車載通信装置の移動方向を特定してもよい。 Further, the DENM aggregation unit 13a1 may specify the moving direction of each in-vehicle communication device based on the transition of the position of each in-vehicle communication device.
　また、DENM集約部１３ａ１が、同一方向に移動中の別々の車載通信装置から特定DENMを受信部１２が受信する状況で集約メッセージを出力することで、制御部１３が送信動作を実行してもよい。 Moreover, even if the control unit 13 executes the transmission operation by outputting the aggregation message in a situation where the reception unit 12 receives the specific DENM from different in-vehicle communication devices moving in the same direction, the DENM aggregation unit 13a1. Good.
　また、DENM集約部１３ａ１が、所定領域内で同一方向に移動中の別々の車載通信装置から特定DENMを受信部１２が受信する状況で集約メッセージを送信することで、制御部１３が送信動作を実行してもよい。 In addition, the DENM aggregation unit 13a1 transmits an aggregation message in a situation where the reception unit 12 receives a specific DENM from different in-vehicle communication devices moving in the same direction within a predetermined area, so that the control unit 13 performs a transmission operation. May be executed.
　また、DENM集約部１３ａ１が、所定領域内の別々の車載通信装置から特定DENMを受信部１２が受信する状況で集約メッセージを送信することで、制御部１３が送信動作を実行してもよい。 Further, the control unit 13 may execute the transmission operation by transmitting the aggregation message in a situation where the DENM aggregation unit 13a1 receives the specific DENM from different in-vehicle communication devices in the predetermined area.
　制御部１３は、受信部１２がCAMを受信した場合、CAMについて上述した送信動作を行うことなくCAMを転送してもよい。また、制御部１３は、CAMの転送に使用する無線チャネルの混雑度に基づいてCAMの送信を制御して輻輳を制御してもよい。CAMは、所定メッセージの一例である。 When the receiving unit 12 receives the CAM, the control unit 13 may transfer the CAM without performing the transmission operation described above for the CAM. Further, the control unit 13 may control congestion by controlling the transmission of the CAM based on the congestion degree of the radio channel used for the CAM transfer. The CAM is an example of a predetermined message.
　通信装置１１は、路側通信装置ではなく、車載通信装置に含まれてもよい。図６は、通信装置１１を含む車載通信装置３０を示した図ある。車載通信装置３０が搭載される車両の一例として、道路を管理する車両、緊急車両または公共性の高いバスが挙げられる。なお、車載通信装置３０が搭載される車両は上述した車両に限らず適宜変更可能である。 The communication device 11 may be included in the in-vehicle communication device instead of the roadside communication device. FIG. 6 is a diagram showing the in-vehicle communication device 30 including the communication device 11. As an example of a vehicle on which the in-vehicle communication device 30 is mounted, a vehicle that manages a road, an emergency vehicle, or a highly public bus can be cited. The vehicle on which the in-vehicle communication device 30 is mounted is not limited to the vehicle described above, and can be changed as appropriate.
　複数の該当無線チャネルから１つの該当無線チャネルを使用予定無線チャネルとして決定する手法として、優先順位を用いる手法の代わりに、以下の変形例の手法が用いられてもよい。 As a technique for determining one corresponding radio channel as a scheduled radio channel from a plurality of corresponding radio channels, the following modified technique may be used instead of the technique using priority.
　＜変形例１＞
　輻輳制御部１３ｅは、複数の該当無線チャネルのうち最も混雑度の低い該当無線チャンネルを、使用予定無線チャネルとして決定する。 <Modification 1>
The congestion control unit 13e determines the radio channel with the lowest congestion level among the plurality of radio channels as the scheduled radio channel.
　＜変形例２＞
　輻輳制御部１３ｅは、受信部１２が使用している無線チャネルを確認する。輻輳制御部１３ｅは、受信部１２が使用している無線チャネルを確認すると、受信部１２が使用している無線チャネルを示す無線チャネル情報を、送信部１３ｆに送信させる。 <Modification 2>
The congestion control unit 13e confirms the radio channel used by the receiving unit 12. When the congestion control unit 13e confirms the radio channel used by the reception unit 12, the congestion control unit 13e causes the transmission unit 13f to transmit radio channel information indicating the radio channel used by the reception unit 12.
　また、輻輳制御部１３ｅは、他の通信装置が使用している無線チャネルを示す無線チャネル情報を受信する。無線チャネル情報は、例えば、他の通信装置から送信される。輻輳制御部１３ｅは、複数の該当無線チャネルのうち他の通信装置が使用している無線チャネルを、使用予定無線チャネルとして決定する。この場合、他の通信装置が使用している無線チャネルを使用予定無線チャネルとして使用するので、他の通信装置との通信を高い確率で実行可能となる。 Further, the congestion control unit 13e receives radio channel information indicating a radio channel used by another communication device. The radio channel information is transmitted from another communication device, for example. The congestion control unit 13e determines a radio channel used by another communication device among a plurality of corresponding radio channels as a scheduled radio channel. In this case, since the radio channel used by another communication device is used as the scheduled radio channel, communication with the other communication device can be executed with high probability.
　なお、複数の該当無線チャネルの中に他の通信装置が使用している無線チャネルが無い場合、輻輳制御部１３ｅは、無線チャネル情報を参照して、受信部１２が無線チャネルCH2として現在使用しているSCHを、他の通信装置が使用しているSCHに変更する。続いて、輻輳制御部１３ｅは、変更後のSCHの混雑度に関わらず、変更後のSCHを使用予定無線チャネルとして決定する。 When there is no radio channel used by another communication device among the plurality of corresponding radio channels, the congestion control unit 13e refers to the radio channel information and the reception unit 12 currently uses the radio channel CH2. The SCH being used is changed to the SCH used by another communication device. Subsequently, the congestion control unit 13e determines the changed SCH as a use-scheduled radio channel regardless of the degree of congestion of the changed SCH.
　また、他の通信装置が使用している複数の無線チャネルの各々が該当無線チャネルである場合、輻輳制御部１３ｅは、それら複数の無線チャネルの１つ（例えば、ランダムに選択された１つ）を使用予定無線チャネルとして決定する。 When each of a plurality of radio channels used by other communication devices is a corresponding radio channel, the congestion control unit 13e selects one of the plurality of radio channels (for example, one selected at random). Is determined as the scheduled radio channel.
　＜変形例３＞
　変形例２において、輻輳制御部１３ｅは上述した優先順位を使用してもよい。例えば、他の通信装置が使用している複数の無線チャネルの各々が該当無線チャネルである場合、輻輳制御部１３ｅは、それら複数の無線チャネルの中で最も高い優先順位が割り当てられている無線チャネルを使用予定無線チャネルとして決定する。 <Modification 3>
In the second modification, the congestion control unit 13e may use the above-described priority order. For example, when each of a plurality of radio channels used by other communication devices is a corresponding radio channel, the congestion control unit 13e is assigned a radio channel to which the highest priority is assigned among the plurality of radio channels. Is determined as the scheduled radio channel.
　＜変形例４＞
　変形例２において、他の通信装置が使用している複数の無線チャネルの各々が該当無線チャネルである場合、輻輳制御部１３ｅは、それら複数の無線チャネルの中で混雑度が最も低い無線チャネルを使用予定無線チャネルとして決定する。 <Modification 4>
In the second modification, when each of a plurality of radio channels used by other communication devices is a corresponding radio channel, the congestion control unit 13e selects a radio channel having the lowest congestion degree among the plurality of radio channels. It is determined as a scheduled radio channel.
　上記各実施形態において、通信装置は、コンピュータにて実現されてもよい。この場合、コンピュータは、コンピュータにて読み取り可能なＣＤ－ＲＯＭ（Compact Disk Read Only Memory）のような記録媒体に記録されたプログラムを読込み実行して、通信装置が有する機能を実行する。記録媒体は、ＣＤ－ＲＯＭに限らず適宜変更可能である。 In each of the above embodiments, the communication device may be realized by a computer. In this case, the computer reads and executes a program recorded on a recording medium such as a CD-ROM (Compact Disk Read Only Memory) that can be read by the computer, and executes a function of the communication device. The recording medium is not limited to the CD-ROM and can be changed as appropriate.
　以上説明した各実施形態において、図示した構成は単なる一例であって、本発明はその構成に限定されるものではない。 In each of the embodiments described above, the illustrated configuration is merely an example, and the present invention is not limited to the configuration.
　実施形態を参照して本願発明を説明したが、本願発明は上記実施形態に限定されるものではない。本願発明の構成や詳細には、本願発明のスコープ内で当業者が理解し得る様々な変更をすることができる。この出願は、２０１４年３月４日に出願された日本出願特願２０１４－４１３１３を基礎とする優先権を主張し、その開示の全てをここに取り込む。 Although the present invention has been described with reference to the embodiments, the present invention is not limited to the above-described embodiments. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention. This application claims the priority on the basis of Japanese application Japanese Patent Application No. 2014-41313 for which it applied on March 4, 2014, and takes in those the indications of all here.
　　　１、１１　通信装置
　　　２、１２　受信部
　　　３、１３　制御部
　　　１３ａ　　アプリケーション部
　　　１３ａ１　DENM集約部
　　　１３ｂ　　無線チャネル設定部
　　　１３ｃ　　送信周期設定部
　　　１３ｄ　　送信電力／伝送速度設定部
　　　１３ｅ　　輻輳制御部
　　　１３ｆ　　送信部
　　　２０　　　路側通信装置
　　　３０、１０１～１０ｎ　車載通信装置 DESCRIPTION OF SYMBOLS 1,11 Communication apparatus 2,12 Reception part 3,13 Control part 13a Application part 13a1 DENM aggregation part 13b Radio channel setting part 13c Transmission period setting part 13d Transmission power / transmission speed setting part 13e Congestion control part 13f Transmission part 20 Roadside communication Device 30, 101-10n In-vehicle communication device

Claims (16)

  1. 　送信元装置から送信された、情報と前記送信元装置の識別子とを示すメッセージを受信する受信部と、
    　前記受信部が受信したメッセージの種別に応じて、互いに異なる前記識別子にて特定される別々の前記送信元装置からの同一の情報を示す特定メッセージの代表として前記同一の情報を示す代表メッセージを送信する送信動作を実行する制御部と、を含む通信装置。     A receiving unit for receiving a message indicating information and an identifier of the transmission source device transmitted from the transmission source device;
    A representative message indicating the same information is transmitted as a representative of a specific message indicating the same information from different transmission source devices specified by different identifiers according to the type of message received by the receiving unit. And a control unit that executes a transmission operation.
  2. 　前記制御部は、前記受信部が受信した複数の前記特定メッセージを集約した集約メッセージを、前記代表メッセージとして送信する、請求項１に記載の通信装置。 The communication device according to claim 1, wherein the control unit transmits an aggregation message obtained by aggregating the plurality of specific messages received by the reception unit as the representative message.
  3. 　前記制御部は、前記受信部が受信した前記特定メッセージのいずれかを、前記代表メッセージとして送信する、請求項１に記載の通信装置。 The communication device according to claim 1, wherein the control unit transmits any one of the specific messages received by the receiving unit as the representative message.
  4. 　前記制御部は、前記送信動作に伴って、前記別々の送信元装置に対して前記特定メッセージの更なる送信の中止を指示する、請求項１から３のいずれか１項に記載の通信装置。 The communication device according to any one of claims 1 to 3, wherein the control unit instructs the separate transmission source device to stop further transmission of the specific message in accordance with the transmission operation.
  5. 　前記制御部は、前記受信部が受信したメッセージの種別が所定種別である場合に、前記送信動作を実行する、請求項１から４のいずれか１項に記載の通信装置。 The communication device according to any one of claims 1 to 4, wherein the control unit executes the transmission operation when a message type received by the receiving unit is a predetermined type.
  6. 　前記所定種別は、DENMである、請求項５に記載の通信装置。 The communication device according to claim 5, wherein the predetermined type is DENM.
  7. 　前記制御部は、前記受信部が前記所定種別と異なる種別の所定メッセージを受信した場合、前記送信動作を行うことなく前記所定メッセージを転送する、請求項５または６に記載の通信装置。 The communication device according to claim 5 or 6, wherein when the receiving unit receives a predetermined message of a type different from the predetermined type, the control unit transfers the predetermined message without performing the transmission operation.
  8. 　前記所定種別と異なる種別は、CAMである、請求項７に記載の通信装置。 The communication device according to claim 7, wherein the type different from the predetermined type is CAM.
  9. 　前記情報は、イベントの情報である、請求項１から８のいずれか１項に記載の通信装置。 The communication apparatus according to any one of claims 1 to 8, wherein the information is event information.
  10. 　前記制御部は、
    　　前記送信元装置の位置を時系列で受け付け、
    　　前記位置の遷移に基づいて前記送信元装置の移動方向を特定し、
    　　前記受信部が同一方向に移動中の前記別々の送信元装置から前記特定メッセージを受信する状況または所定領域内で同一方向に移動中の前記別々の送信元装置から前記特定メッセージを受信する状況で前記代表メッセージを送信する動作を、前記送信動作として実行する、請求項１から９のいずれか１項に記載の通信装置。     The controller is
    Receiving the position of the transmission source device in time series,
    Identify the direction of movement of the source device based on the position transition;
    In a situation in which the receiving unit receives the specific message from the different transmission source devices moving in the same direction or in a situation of receiving the specific message from the different transmission source devices moving in the same direction within a predetermined area The communication apparatus according to claim 1, wherein the operation of transmitting the representative message is executed as the transmission operation.
  11. 　前記制御部は、
    　　前記送信元装置の位置を受け付け、
    　　前記受信部が所定領域内の前記別々の送信元装置から前記特定メッセージを受信する状況で前記代表メッセージを送信する動作を、前記送信動作として実行する、請求項１から９のいずれか１項に記載の通信装置。     The controller is
    Accepts the location of the source device;
    10. The operation according to claim 1, wherein an operation of transmitting the representative message in a situation in which the reception unit receives the specific message from the separate transmission source devices within a predetermined area is performed as the transmission operation. The communication device described.
  12. 　前記制御部は、前記受信部が所定時間内に前記別々の送信元装置から前記特定メッセージを受信する状況で前記代表メッセージを送信する動作を、前記送信動作として実行する、請求項１から９のいずれか１項に記載の通信装置。 10. The control unit according to claim 1, wherein the control unit executes, as the transmission operation, an operation of transmitting the representative message in a situation where the reception unit receives the specific message from the different transmission source devices within a predetermined time. The communication apparatus of any one of Claims.
  13. 　前記特定メッセージは、既定の送信条件を有するメッセージであり、
    　前記制御部は、前記代表メッセージの送信に用いる無線チャネルの混雑度と前記送信条件とに基づいて、前記代表メッセージの送信を制御する、請求項１から１２のいずれか１項に記載の通信装置。     The specific message is a message having a predetermined transmission condition;
    The communication device according to claim 1, wherein the control unit controls transmission of the representative message based on a congestion degree of a radio channel used for transmission of the representative message and the transmission condition. .
  14. 　前記受信部は、他の通信装置が使用している無線チャネルを示す無線チャネル情報を受信し、
    　前記制御部は、前記代表メッセージを前記無線チャネル情報が示す無線チャネルを使用して送信する、請求項１から１３のいずれか１項に記載の通信装置。     The receiving unit receives radio channel information indicating a radio channel used by another communication device;
    The communication device according to claim 1, wherein the control unit transmits the representative message using a radio channel indicated by the radio channel information.
  15. 　送信元装置から送信された、情報と前記送信元装置の識別子とを示すメッセージを受信し、
    　前記受信されたメッセージの種別に応じて、互いに異なる前記識別子にて特定される別々の前記送信元装置からの同一の情報を示す特定メッセージの代表として前記同一の情報を示す代表メッセージを送信する送信動作を実行する、通信制御方法。     Receiving a message transmitted from the transmission source device and indicating the information and the identifier of the transmission source device;
    Transmission for transmitting a representative message indicating the same information as a representative of a specific message indicating the same information from different transmission source devices specified by different identifiers according to the type of the received message A communication control method for executing an operation.
  16. 　コンピュータに、
    　送信元装置から送信された、情報と前記送信元装置の識別子とを示すメッセージを受信する受信手順と、
    　前記受信手順で受信されたメッセージの種別に応じて、互いに異なる前記識別子にて特定される別々の前記送信元装置からの同一の情報を示す特定メッセージの代表として前記同一の情報を示す代表メッセージを送信する送信動作を実行する制御手順と、を実行させるためのプログラムを記録したコンピュータ読み取り可能な記録媒体。     On the computer,
    A reception procedure for receiving a message indicating information and an identifier of the transmission source device transmitted from the transmission source device;
    A representative message indicating the same information as a representative of a specific message indicating the same information from different transmission source devices specified by different identifiers according to the type of the message received in the reception procedure. A computer-readable recording medium having recorded thereon a control procedure for executing a transmission operation for transmission.
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