WO2015133184A1 - Communication apparatus, congestion control method, and program - Google Patents

Abstract

A receiver (3) receives first congestion degree information indicating a plurality of first congestion degrees, each indicating the degree of congestion in a corresponding one of a plurality of first wireless channels, and determines a plurality of second congestion degrees, each indicating the degree of congestion in a corresponding one of a plurality of second wireless channels. A generator (2) generates a message to be transmitted over any of the plurality of second wireless channels. A controller (4) transmits second congestion degree information indicating the plurality of second congestion degrees and selects, on the basis of the first congestion degree information, a wireless channel to be used to transmit the message among the plurality of second wireless channels.

Description

Communication apparatus, congestion control method, and program

The present invention relates to a communication device, a congestion control method, and a program, and more particularly, to a communication device, a congestion control method, and a program for controlling congestion.

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 communicates with a road-side communication device installed on the roadside are attracting attention.

In inter-vehicle communication systems and road-to-vehicle communication systems, messages exchanged between in-vehicle communication devices or between in-vehicle communication devices and roadside communication devices include, for example, DENM (Decentralized Environmental Notification Message) and CAM. (Cooperative Awareness Message) is used.

DENM is a message for informing a communication device within a predetermined range of occurrence of a predetermined event (for example, sudden braking or hazard lamp lighting), and CAM is for informing the surrounding communication devices of the position and speed of the vehicle. Message.

The wireless channel for transmitting each message is determined in advance according to the importance and urgency of the application program that transmits the message. The in-vehicle communication device and the roadside communication device are in accordance with the congestion level of the wireless channel. Thus, congestion control of the wireless channel is performed for each wireless channel.

However, in the above congestion control, only the congestion control of the radio channel is performed for each radio channel, and therefore, the degree of congestion of each radio channel may be biased and a plurality of radio channels may not be used effectively. .

On the other hand, Patent Document 1 describes a road-to-vehicle communication method capable of reducing the unevenness of the congestion degree of each wireless channel. In the road-to-vehicle communication method described in Patent Document 1, a roadside station that is a roadside communication device periodically reports the degree of congestion of each radio channel to a mobile station that is an in-vehicle communication device, and the mobile station is notified. Based on the degree of congestion, a connection desired channel, which is a radio channel actually used for communication, is selected.

Therefore, since it becomes possible to select a wireless channel to be used according to the congestion level of each wireless channel, it is possible to reduce the unevenness of the congestion level of each wireless channel.

JP 2007-174120 A

In the road-to-vehicle communication method described in Patent Document 1, in order to select an appropriate radio channel according to the congestion degree of each radio channel, the congestion degree of a radio channel such as a roadside station is set separately from the in-vehicle communication device. There was a problem that a special device for identifying was required.

An object of the present invention is to provide a communication device, a congestion control method, and a program that can solve the above-described problems.

A communication device according to the present invention comprises:
A generating unit that generates a target message to be transmitted using any one of a plurality of target wireless channels;
Receiving first congestion degree information indicating a first congestion degree that is at least one congestion degree of the plurality of target wireless channels, and determining a second congestion degree that is at least one congestion degree of the plurality of target wireless channels; A receiver to identify;
Based on the transmission operation for transmitting the second congestion degree information indicating the second congestion degree, and the first congestion degree and the second congestion degree, it is used for transmitting the target message from among the plurality of target wireless channels. And a control unit that performs a selection operation for selecting a radio channel.

Further, the congestion control method according to the present invention includes:
Generate a target message to send using one of multiple target wireless channels,
Receiving first congestion degree information indicating a first congestion degree that is at least one congestion degree of the plurality of target wireless channels;
Identifying a second congestion level that is at least one congestion level of the plurality of target wireless channels;
Based on the transmission operation for transmitting the second congestion degree information indicating the second congestion degree, and the first congestion degree and the second congestion degree, it is used for transmitting the target message from among the plurality of target wireless channels. A selection operation for selecting a radio channel is performed.

The program of the present invention is
Generating a target message to be transmitted using one of a plurality of target wireless channels;
Receiving a first congestion degree information indicating a first congestion degree that is at least one congestion degree of the plurality of target wireless channels;
Identifying a second congestion level that is at least one congestion level of the plurality of target radio channels;
Based on the transmission operation for transmitting the second congestion degree information indicating the second congestion degree, and the first congestion degree and the second congestion degree, it is used for transmitting the target message from among the plurality of target wireless channels. And a procedure for performing a selection operation for selecting a radio channel.

According to the present invention, it is possible to select an appropriate radio channel according to the degree of congestion of each radio channel without a special device for specifying the degree of congestion of the radio channel.

It is a block diagram which shows the structure of the communication apparatus of the 1st Embodiment of this invention. It is a flowchart for demonstrating an example of operation | movement of the communication apparatus of the 1st Embodiment of this invention. It is a flowchart for demonstrating the other example of operation | movement of the communication apparatus of the 1st Embodiment of this invention. It is a block diagram which shows the structure of the communication apparatus of the 2nd Embodiment of this invention. It is a flowchart for demonstrating an example of operation | movement of the communication apparatus of the 2nd Embodiment of this invention. It is a flowchart for demonstrating the other example of operation | movement of the communication apparatus of the 2nd Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, components having the same function may be denoted by the same reference numerals and description thereof may be omitted.

(First embodiment)
FIG. 1 is a block diagram illustrating a configuration of a communication apparatus according to a first embodiment of this invention. In FIG. 1, the communication device 1 includes a generation unit 2, a reception unit 3, and a control unit 4.

The generation unit 2 generates a target message to be transmitted using any one of a plurality of target wireless channels.

The receiving unit 3 receives first congestion degree information indicating a first congestion degree that is at least one congestion degree of a plurality of target wireless channels. In addition, the receiving unit 3 specifies a second congestion level that is at least one congestion level of the plurality of target radio channels.

The control unit 4 performs a transmission operation of transmitting second congestion level information indicating the second congestion level specified by the reception unit 3. In addition, the control unit 4 selects a medium among a plurality of target radio channels based on the first congestion level indicated by the first congestion level information received by the reception unit 3 and the second congestion level specified by the reception unit 3. Then, a selection operation for selecting a radio channel used for transmission of the target message generated by the generation unit 2 is performed.

FIGS. 2 and 3 are flowcharts for explaining an example of the operation of the communication apparatus 1.

First, the operation when the second congestion degree is specified will be described with reference to FIG.

The receiving unit 3 specifies the second congestion level, which is at least one congestion level of the specific radio channel, and notifies the control unit 4 of the specified second congestion level (step S1).

The control unit 4 generates and transmits second congestion degree information indicating the notified second congestion degree (step S2).

Next, the operation when the first congestion degree information is received will be described with reference to FIG.

When receiving the first congestion level information, the reception unit 3 outputs the first congestion level information to the control unit 4 (step S3).

When the control unit 4 receives the first congestion degree information, the control unit 4 determines whether the target wireless channel is based on the first congestion degree indicated by the first congestion degree information and the second congestion degree notified in step S1 of FIG. To select a wireless channel to be used for transmitting the target message (step S4).

As described above, according to the present embodiment, the generation unit 2 generates a target message to be transmitted using any one of a plurality of target wireless channels. The receiving unit 3 receives first congestion degree information indicating a first congestion degree that is at least one congestion degree of a plurality of target wireless channels. In addition, the receiving unit 3 specifies a second congestion level that is at least one congestion level of the plurality of target radio channels. The control unit 4 performs a transmission operation of transmitting second congestion level information indicating the second congestion level specified by the reception unit 3. Further, the control unit 4 performs a selection operation of selecting a radio channel used for transmission of the target message from the plurality of target radio channels based on the first congestion level and the second congestion level. For this reason, the degree of congestion of the target wireless channel for transmitting the target message can be mutually notified with the communication partner, so even if there is no special device for specifying the degree of congestion of the wireless channel, each It is possible to select an appropriate radio channel according to the degree of congestion of the radio channel.

(Second Embodiment)
FIG. 4 is a block diagram showing the configuration of the communication apparatus according to the second embodiment of the present invention. A communication device 10 shown in FIG. 4 is an in-vehicle communication device mounted on a vehicle, and at least performs inter-vehicle communication with other in-vehicle communication devices.

In inter-vehicle communication, the communication device 10 transmits and receives messages to and from other communication devices (other in-vehicle communication devices). Examples of the message include a DENM, a CAM, and a unicast message that is a message used in one-to-one communication.

DENM and unicast messages are target messages that are transmitted / received using any of a plurality of target wireless channels. In the present embodiment, the plurality of target radio channels correspond to a plurality of SCHs (Service Channels) having different frequencies.

CAM is a message different from the target message, and is a message transmitted / received using a predetermined radio channel different from the target radio channel. In the present embodiment, the predetermined radio channel corresponds to CCH (Common Channel).

The communication device 10 includes an application unit 11, a reception unit 12, and a control unit 13.

The application unit 11 is realized by executing an application program on a computer, and functions as a generation unit that generates a message.

For example, the application unit 11 periodically generates a CAM indicating the position and speed of the vehicle, when a predetermined event (for example, sudden braking or a hazard lamp is lit), or when one-to-one communication is executed. Or a target message such as a DENM message or a unicast message.

In addition, the application unit 11 notifies the control unit 13 of the type of the generated message (DENM, CAM, unicast message, etc.), a transmission condition according to a predetermined event, and the like. The transmission condition is a condition relating to the transmission of the message, and is, for example, a required communication distance, an acceptable delay time, or the like. Since the CAM is a message not accompanied by a transmission condition, the transmission condition is not notified when the message type is CAM.

The receiving unit 12 receives a message wirelessly transmitted from another communication device. For example, the receiving unit 12 receives first congestion level information transmitted as a CAM. The first congestion degree information indicates a first congestion degree that is at least one congestion degree of the SCH that is the target wireless channel.

Also, the receiving unit 12 specifies the CAM congestion level and the second congestion level, which is at least one congestion level of the SCH that is the target radio channel, based on the communication status of messages using the CAM or SCH.

Note that a radio channel used to receive a message is set in the receiving unit 12. The receiving unit 12 receives a message using the set radio channel and specifies the degree of congestion of the radio channel. In the present embodiment, it is assumed that at least one of CCH and SCH is set in the receiving unit 12.

The control unit 13 performs a transmission operation of transmitting the second congestion degree information indicating the second congestion degree specified by the reception unit 12 to another communication device. The control unit 13 is a target radio channel based on the first congestion level indicated by the first congestion level information received by the reception unit 12 and the second congestion level specified by the reception unit 12. A selection operation for selecting a radio channel to be used for transmission of the target message from the SCH is performed.

Specifically, the control unit 13 includes a radio channel setting unit 21, a control information setting unit 22, a congestion control unit 23, and a transmission unit 24.

In the radio channel setting unit 21, a transmission channel that is a radio channel used for transmitting a message generated by the application unit 11 is set.

In the control information setting unit 22, transmission control information is set according to the transmission condition of the message generated by the application unit 11, the degree of congestion of the wireless channel used for message transmission, and the like. The transmission control information is information for controlling message transmission, and indicates, for example, a transmission cycle, transmission power, transmission speed, and the like.

The congestion control unit 23 sets the CCH and at least one SCH as transmission channels in the radio channel setting unit 21.

Specifically, the congestion control unit 23 first sets a predetermined corresponding radio channel among the CCH and the SCH that is the target radio channel. Note that the corresponding wireless channel is determined in advance according to the importance or urgency of an application program that implements the application unit 11 that generates a message.

When the message type is notified from the application unit 11, the congestion control unit 23 determines whether or not the message type is a target message.

When the message type is not the target message, the congestion control unit 23 maintains the transmission channel set in the wireless channel setting unit 21 as it is.

On the other hand, when the message type is the target message, the congestion control unit 23 selects a radio channel used for transmission of the target message from the SCH that is the target radio channel based on the first congestion level and the second congestion level. Perform the selection operation. Then, the congestion control unit 23 sets the selected radio channel as a transmission channel in the radio channel setting unit 21.

In the selection operation, for example, the congestion control unit 23 selects the SCH having the lowest congestion degree from the first congestion degree and the second congestion degree from the SCHs. In addition, when the congestion level of the corresponding wireless channel is less than a predetermined threshold, the congestion control unit 23 may select the corresponding wireless channel without performing the selection operation.

Further, the congestion control unit 23 sets transmission control information according to the transmission condition notified from the application unit 11 and the degree of congestion of the wireless channel used for message transmission in the control information setting unit 22.

For example, the congestion control unit 23 holds a lookup table indicating the correspondence between the transmission condition and the degree of congestion and the transmission control information for each wireless channel, and refers to the lookup table according to the degree of congestion and the transmission condition. The transmission control information is set in the control information setting unit 22. Thereby, congestion in each wireless channel is controlled.

Moreover, the congestion control unit 23 generates second congestion degree information indicating the second congestion degree specified by the reception unit 12 as a CAM. Note that the second congestion degree information may indicate the specified second congestion degree itself, or may indicate a statistical value of the second congestion degree specified multiple times. Examples of the statistical value of the second congestion degree include an average value, a maximum value, and a minimum value of the second congestion degree.

The transmission unit 24 transmits the message generated by the application unit 11 and the CAM (second congestion degree information) generated by the congestion control unit 23 to the transmission channel set in the wireless channel setting unit 21 and the control information setting unit 22. Wireless transmission is performed in accordance with the transmission control information set in. Thereby, the control part 13 can transmit 2nd congestion degree information using CAM which is a message different from an object message.

Next, the operation will be described.

FIGS. 5 and 6 are flowcharts for explaining an example of the operation of the communication apparatus 10.

First, the operation when a message is received will be described with reference to FIG.

In the reception process, the congestion control unit 23 sets a reception channel, which is a radio channel used for message reception, in the reception unit 12 (step S101). The receiving unit 12 receives a message wirelessly transmitted from another communication device using the reception channel set in step S101 (step S102).

And the receiving part 12 confirms whether the received message is 1st congestion degree information (step S103).

If the message is not the first congestion level information, the receiving unit 12 outputs the message to the application unit 11. Upon receiving the message, the application unit 11 performs application processing according to the message (step S104).

On the other hand, when the message is the first congestion degree information, the receiving unit 12 outputs the first congestion degree information that is the message to the congestion control unit 23. When receiving the first congestion level information, the congestion control unit 23 holds the first congestion level information (step S105).

Upon completion of step S104 or S105, the receiving unit 12 measures the communication status of the set reception channel and specifies the congestion level of the reception channel based on the communication status. Then, the receiving unit 12 notifies the congestion control unit 23 of the specified degree of congestion (step S106). The congestion level includes the CCH congestion level and the second congestion level.

When the congestion control unit 23 accepts the congestion level, the congestion control unit 23 holds the congestion level and performs a congestion control process for setting the transmission control information corresponding to the CCH congestion level included in the congestion level in the control information setting unit 22 (step). S107).

Then, the congestion control unit 23 generates second congestion level information indicating the second congestion level included in the congestion level as a CAM, and outputs it to the transmission unit 24. Upon receiving the CAM, the transmission unit 24 transmits the CAM to another communication device according to the CCH that is the reception channel set in the radio channel setting unit 21 and the transmission control information set in the control information setting unit 22 ( Step S108) and the process returns to Step S101.

Next, the operation when a message is transmitted will be described with reference to FIG.

When the message transmission timing comes, the application unit 11 outputs the message to the transmission unit 24 and notifies the congestion control unit 23 of the message type and transmission conditions (step S201). When the message is CAM, the application unit 11 does not notify the transmission condition.

When the message type and the transmission condition are notified, the congestion control unit 23 determines whether or not the message type indicates the target message (step S202).

When the message type does not indicate the target message, the congestion control unit 23 performs a congestion control process for setting transmission control information corresponding to the CCH congestion level for transmitting and receiving the CAM in the control information setting unit 22 (step S203). ). If the CCH congestion level has not been notified yet, the congestion control unit 23 sets predetermined transmission control information in the control information setting unit 22, for example.

On the other hand, when the message type indicates the target message, the congestion control unit 23 selects a radio channel from the target radio channels based on the first congestion degree and the second congestion degree, and transmits the selected radio channel to the transmission channel. Is set in the wireless channel setting unit 21 (step S204). When the first congestion degree and the second congestion degree are not yet grasped, the congestion control unit 23 sets a corresponding wireless channel in the wireless channel setting unit 21, for example.

When the transmission channel is set, the congestion control unit 23 generates transmission control information according to the congestion degree of the transmission channel and the transmission condition, and performs a congestion control process for setting the transmission control information in the control information setting unit 22 ( Step S205).

Then, when receiving a message from the application unit 11, the transmission unit 24 wirelessly transmits the message according to the transmission channel set in the wireless channel setting unit 21 and the transmission control information set in the control information setting unit 22. (Step S206).

As described above, even in this embodiment, there is a special device for specifying the degree of congestion of the radio channel because the degree of congestion of the radio channel for transmitting the target message can be mutually notified with the communication partner. Even without this, it is possible to select an appropriate radio channel according to the congestion level of each radio channel.

In the present embodiment, since the control unit 13 selects the radio channel with the lowest congestion level, the radio channel can be selected more appropriately.

In this embodiment, when the congestion level of the corresponding wireless channel is less than the threshold, the control unit selects the corresponding wireless channel as a wireless channel used for transmitting the target message without performing the selection operation. For this reason, when congestion does not occur, it is possible to transmit the target message through a radio channel according to the importance or urgency of the application program. Therefore, it is possible to select a radio channel more appropriately.

In the present embodiment, since the second congestion degree information is transmitted using the CCH, the second congestion degree can be notified to many communication devices.

In each of the embodiments described above, the illustrated configuration is merely an example, and the present invention is not limited to the configuration.

For example, the functions of the communication devices 1 and 10 are such that a program for realizing the function is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read and executed by the computer. It may be realized.

This application claims priority based on Japanese Patent Application No. 2014-041316 filed on Mar. 4, 2014, the entire disclosure of which is incorporated herein.

1, 10 Communication device 2 Generation unit 3, 11 Reception unit 4, 13 Control unit 12 Application unit 21 Radio channel setting unit 22 Control information setting unit 23 Congestion control unit 24 Transmission unit

Claims (10)

A generating unit that generates a target message to be transmitted using any one of a plurality of target wireless channels;
Receiving first congestion degree information indicating a first congestion degree that is at least one congestion degree of the plurality of target wireless channels, and determining a second congestion degree that is at least one congestion degree of the plurality of target wireless channels; A receiver to identify;
Based on the transmission operation for transmitting the second congestion degree information indicating the second congestion degree, and the first congestion degree and the second congestion degree, it is used for transmitting the target message from among the plurality of target wireless channels. And a control unit that performs a selection operation for selecting a radio channel. 2. The control unit according to claim 1, wherein, in the selection operation, the control unit selects a radio channel with the lowest congestion degree from the plurality of target radio channels, of the first congestion degree and the second congestion degree. Communication device. The control unit selects a corresponding wireless channel as a wireless channel used for transmission of the target message without performing the selection operation when a predetermined degree of congestion of the corresponding wireless channel is less than a threshold value. Or the communication apparatus of 2. The communication device according to any one of claims 1 to 3, wherein the target message includes at least a message used in DENM (Decentralized Environmental Notification Message) or one-to-one communication. The communication device according to any one of claims 1 to 4, wherein the control unit transmits the second congestion degree information using a message different from the target message. The communication apparatus according to claim 5, wherein the another message is a message transmitted using a predetermined radio channel different from the second radio channel. The communication device according to claim 6, wherein the predetermined radio channel is a common channel. The communication apparatus according to any one of claims 5 to 7, wherein the another message is a CAM (Cooperative Awareness Message). Generate a target message to send using one of multiple target wireless channels,
Receiving first congestion degree information indicating a first congestion degree that is at least one congestion degree of the plurality of target wireless channels;
Identifying a second congestion level that is at least one congestion level of the plurality of target wireless channels;
Based on the transmission operation for transmitting the second congestion degree information indicating the second congestion degree, and the first congestion degree and the second congestion degree, it is used for transmitting the target message from among the plurality of target wireless channels. A congestion control method for performing a selection operation for selecting a radio channel. Generating a target message to be transmitted using one of a plurality of target wireless channels;
Receiving a first congestion degree information indicating a first congestion degree that is at least one congestion degree of the plurality of target wireless channels;
Identifying a second congestion level that is at least one congestion level of the plurality of target radio channels;
Based on the transmission operation for transmitting the second congestion level information indicating the second congestion level before and the first congestion level and the second congestion level, the target message is transmitted from the plurality of target wireless channels. The program which makes a computer perform the procedure which performs selection operation | movement which selects the radio channel to be used.

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