Source: https://patents.google.com/patent/JPWO2012124685A1/en
Timestamp: 2020-01-29 15:29:31
Document Index: 122465855

Matched Legal Cases: ['art 1', 'art 1', 'art 112', 'art 121', 'art 121', 'art 13', 'art 121', 'art 13', 'art 122', 'art 121', 'art 122', 'art 112', 'art 122', 'art 122', 'art 122', 'Application No. 2011', 'art 111', 'art 112', 'art 12', 'art 121', 'art 13', 'art 14', 'art 15', 'art 2']

JPWO2012124685A1 - Wireless communication device, wireless communication system, congestion control method, and recording medium - Google Patents
Wireless communication device, wireless communication system, congestion control method, and recording medium Download PDF
JPWO2012124685A1
JPWO2012124685A1 JP2012056402A JP2013504735A JPWO2012124685A1 JP WO2012124685 A1 JPWO2012124685 A1 JP WO2012124685A1 JP 2012056402 A JP2012056402 A JP 2012056402A JP 2013504735 A JP2013504735 A JP 2013504735A JP WO2012124685 A1 JPWO2012124685 A1 JP WO2012124685A1
JP2012056402A
JP5962649B2 (en
2011-03-14 Priority to JP2011055032 priority Critical
2011-03-14 Priority to JP2011055032 priority
2012-03-13 Application filed by 日本電気株式会社 filed Critical 日本電気株式会社
2012-03-13 Priority to PCT/JP2012/056402 priority patent/WO2012124685A1/en
2014-07-24 Publication of JPWO2012124685A1 publication Critical patent/JPWO2012124685A1/en
2016-08-03 Publication of JP5962649B2 publication Critical patent/JP5962649B2/en
A wireless communication device that communicates with another wireless communication device that is a communication partner includes a first detection unit that detects a movement state of the other wireless communication device, a second detection unit that detects a movement state of the own device, Third detection means for detecting the degree of congestion of communication between the other wireless communication devices or between the other wireless communication devices and the own device, and transmission for transmitting a radio signal from the own device to the other wireless communication device And control means for controlling the transmission of the radio signal performed by the transmission means based on the movement state of the other wireless communication device, the movement state of the own device, and the degree of congestion.
The present invention relates to a wireless communication device, a wireless communication system, a congestion control method, and a recording medium.
An inter-vehicle communication system that performs communication between vehicles is known. In the inter-vehicle communication system, a wireless communication device mounted on a vehicle exchanges information (for example, a current position that is information related to traveling) with a wireless communication device (communication partner) mounted on another vehicle.
In a wireless communication system in which wireless communication devices directly communicate with each other without using a base station, such as an inter-vehicle communication system, the communication status of the wireless communication device changes every moment as the wireless communication device moves. For example, the communication status of a wireless communication device changes from the situation in which there is no communication partner in the communication range of its own device to the situation in which a small number of communication partners exist in the communication range of its own device. It is assumed that the situation changes to a situation where there are many communication partners.
In a situation where there are a large number of communication partners, that is, a large number of wireless communication devices within the communication range of the wireless communication device, the communication between the wireless communication devices is congested, causing congestion and a decrease in throughput. .
A wireless communication device that can cope with this problem is described in Patent Document 1. The wireless communication device described in Patent Document 1 adjusts the size of a communication area by controlling transmission power based on a propagation loss of a signal received from a communication partner. The wireless communication device described in Patent Document 1 can suppress the number of wireless communication devices that are communication partners by adjusting the size of the communication area. Therefore, it is possible to reduce congestion and a decrease in throughput while securing a wireless link with a relatively nearby wireless communication device.
JP 2008-244960 A
The wireless communication device described in Patent Literature 1 controls transmission power, that is, congestion, without considering the traveling state of each vehicle. For this reason, the wireless communication device described in Patent Literature 1 cannot control congestion according to the traveling state of each vehicle.
FIG. 1 shows that a vehicle 200 equipped with an in-vehicle communication device 100, which is a wireless communication device, travels in a lane 300 in which the vehicle is mounted, and vehicles 201-204 equipped with in-vehicle communication devices 101-104 respectively are in a lane 400 in a traffic jam. It is the figure which showed the condition which is drive | working.
In the situation shown in FIG. 1, the in-vehicle communication device 100 on the lane 300 is controlled to suppress congestion in order to ensure communication with other in-vehicle communication devices (not shown) on the lane 300 (for example, It is desirable not to perform control to reduce transmission power as much as possible. On the other hand, since the distance between the in-vehicle communication devices 101 to 104 on the lane 400 and other in-vehicle communication devices on the lane 400 is short, it is desirable to perform control to suppress congestion.
FIG. 2 is a diagram illustrating a situation in which a vehicle 600 that is stopped due to a failure or the like equipped with the in-vehicle communication device 500 and vehicles 601 to 604 that are equipped with the in-vehicle communication devices 501 to 504 are traveling in the lane 700. is there.
In the situation shown in FIG. 2, it is desirable that the in-vehicle communication device 500 does not perform control for suppressing congestion as much as possible in order to prevent a rear-end collision. On the other hand, since the distance between the in-vehicle communication devices 501 to 504 and other in-vehicle communication devices on the lane 700 is short, it is desirable to perform control for suppressing congestion.
As shown in FIGS. 1 and 2, there is a problem that it is desired to control congestion in consideration of the traveling state of each vehicle, that is, the moving state of each wireless communication device.
An object of the present invention is to provide a wireless communication device, a wireless communication system, a congestion control method, and a recording medium that can solve the above-described problems.
The wireless communication device of the present invention is a wireless communication device that communicates with another wireless communication device that is a communication partner, the first detection means for detecting the movement state of the other wireless communication device, and the movement of the own device. Second detection means for detecting a state; third detection means for detecting a degree of communication between the other wireless communication devices or between the other wireless communication devices and the own device; and Radio signal transmission performed by the transmission means based on the transmission means for transmitting a radio signal to the radio communication apparatus, the movement state of the other radio communication apparatus, the movement state of the own apparatus, and the degree of congestion And control means for controlling.
The wireless communication system of the present invention includes a plurality of the wireless communication devices, and the wireless communication devices communicate with each other.
The congestion control method of the present invention is a congestion control method in a wireless communication device that communicates with another wireless communication device that is a communication partner, and includes a first detection step of detecting a movement state of the other wireless communication device. A second detection step for detecting a movement state of the own device; a third detection step for detecting a degree of congestion of communication between the other wireless communication devices or between the other wireless communication devices and the own device; Based on the transmission step of transmitting a radio signal from the device to the other wireless communication device, the movement state of the other wireless communication device, the movement state of the own device, and the degree of congestion. And a control step for controlling transmission.
The recording medium of the present invention includes a first detection procedure for detecting a movement state of another wireless communication device serving as a communication partner, a second detection procedure for detecting the movement state of the computer, and the other wireless communication. A third detection procedure for detecting a degree of congestion in communication between the computers or the other wireless communication device and the computer, a transmission procedure for transmitting a wireless signal from the computer to the other wireless communication device, and the other wireless communication device. A computer-readable recording medium recording a program for executing a control procedure for controlling transmission of the wireless signal based on a moving state of a communication device, a moving state of the computer, and the degree of congestion. .
According to the present invention, it is possible to control congestion in consideration of the movement state of each wireless communication device.
It is the figure which showed an example of the running condition of each vehicle. It is the figure which showed the other example of the driving | running | working condition of each vehicle. It is the block diagram which showed the vehicle-to-vehicle communication system of 1st Embodiment of this invention. It is the block diagram which showed the vehicle-mounted communication apparatus. It is the figure which showed surrounding vehicle information. It is the block diagram which showed the vehicle-mounted communication part 1X. It is the block diagram which showed the vehicle-mounted communication part 1Y.
FIG. 3 is a block diagram showing an inter-vehicle communication system which is a wireless communication system according to the first embodiment of the present invention.
In FIG. 3, the inter-vehicle communication system includes a plurality of in-vehicle communication devices 1 (in-vehicle communication devices 1a and 1b). Although only two in-vehicle communication devices 1 are shown in FIG. 3, the number of in-vehicle communication devices 1 is not limited to two, and may be three or more.
In-vehicle communication devices 1a and 1b can generally be referred to as wireless communication devices. The in-vehicle communication devices 1a and 1b perform direct wireless communication with each other.
The in-vehicle communication device 1a is connected to the in-vehicle application system 2a, and the in-vehicle communication device 1b is connected to the in-vehicle application system 2b.
The in-vehicle application systems 2a and 2b are, for example, a well-known car navigation system or a well-known safe driving support system. The in-vehicle application systems 2a and 2b include a GPS (Global Positioning System) and various in-vehicle sensors.
FIG. 4 is a block diagram showing the in-vehicle communication device 1 used as the in-vehicle communication device 1a and the in-vehicle communication device 1b. In FIG. 4, the in-vehicle communication device 1 includes a wireless unit 11, a processing unit 12, and a transmission power control unit 13.
The wireless unit 11 transmits and receives wireless signals. The radio unit 11 includes a transmission unit 111 and a reception unit 112.
Transmitting section 111 can be generally referred to as transmitting means.
The transmission unit 111 modulates transmission data to be transmitted to other in-vehicle communication devices (hereinafter simply referred to as “other in-vehicle communication devices”) mounted on the surrounding vehicles. The transmission unit 111 transmits the modulated transmission data to another in-vehicle communication device using a radio signal.
The transmission data includes identification information (hereinafter referred to as “ID”) for identifying the own device (the in-vehicle communication device 1), position information indicating the position of the own device, and traveling direction information indicating the traveling direction of the own device. , Including movement speed information indicating the movement speed of the own apparatus, and a transmission power setting value indicating the transmission power of the own apparatus.
Receiving unit 112 can be generally referred to as first detection means.
The receiving unit 112 receives a radio signal transmitted from another in-vehicle communication device. When receiving the wireless signal, the receiving unit 112 measures the reception power of the wireless signal, specifies the reception time, demodulates the wireless signal, and generates reception data.
The received data includes IDs of other in-vehicle communication devices, position information of other in-vehicle communication devices, traveling direction information of other in-vehicle communication devices, movement speed information of other in-vehicle communication devices, and other in-vehicle communication devices. Transmission power setting value. For this reason, the receiving part 112 detects the movement state (traveling direction or moving speed) of another vehicle-mounted communication apparatus by producing | generating reception data.
The receiving unit 112 generates neighboring vehicle information by associating the received data, the measured value of the received power, and the reception time information indicating the reception time.
FIG. 5 is a diagram showing surrounding vehicle information.
In FIG. 5, surrounding vehicle information 301 includes ID 301a, position information 301b, traveling direction information 301c, moving speed information 301d, transmission power setting value 301e, received power measurement value 301f, and reception time information 301g. ,including.
The receiving unit 112 outputs the surrounding vehicle information 301 to the processing unit 12.
The processing unit 12 receives the surrounding vehicle information 301 from the wireless unit 11. Further, the processing unit 12 refers to the position of the vehicle on which the own device is mounted, that is, the position information indicating the position of the own device, from the in-vehicle application system 2 as a predetermined time interval (hereinafter referred to as “specific time interval”). )
The processing unit 12 includes detection units 121 and 122.
Detection unit 121 can generally be referred to as second detection means. The detection unit 121 detects the movement state of the own device. In the present embodiment, the detection unit 121 detects the traveling direction and the moving speed of the own device as the moving state of the own device.
The detection unit 121 detects the traveling direction of the own device based on the position indicated by the position information from the in-vehicle application system 2. For example, each time the position information is acquired, the detection unit 121 holds the position information, and the position information acquired this time indicates the position indicated by the position information acquired before the position information (previous position information). The direction toward the position is detected as the traveling direction of the aircraft. When the previous position information does not exist, the detection unit 121 does not detect the traveling direction of the own device.
Moreover, the detection part 121 detects the moving speed of an own machine based on the position which each positional information from the vehicle-mounted application system 2 shows, and the acquisition time interval (specific time interval) of positional information. For example, each time the position information is acquired, the detection unit 121 obtains a distance from the position indicated by the previous position information to the position indicated by the position information acquired this time, and divides the distance by a specific time interval. Detect the moving speed of When there is no previous position information, the detection unit 121 does not detect the moving speed of the own device.
The detection unit 121 outputs the traveling direction and movement speed of the own device to the transmission power control unit 13 together with the ID of the own device held in the detection unit 121.
Further, the detection unit 121 indicates position information from the in-vehicle application system 2, traveling direction information indicating the traveling direction of the own device, a moving speed indicating the moving speed of the own device, and an ID of the own device. The communication data is output to the transmitter 111.
In addition, the detection part 121 does not need to detect the advancing direction of an own machine, when the transmission power control part 13 does not use a advancing direction in order to set transmission power. In this case, the communication data and the surrounding vehicle information 301 do not have traveling direction information.
Moreover, the detection part 121 does not need to detect the movement speed of an own machine, when the transmission power control part 13 does not use a movement speed in order to set transmission power. In this case, the communication data and the surrounding vehicle information 301 do not have moving speed information.
Detection unit 122 can generally be referred to as third detection means.
The detection unit 122 receives the surrounding vehicle information 301 from the reception unit 112. The detection unit 122 outputs the surrounding vehicle information 301 to the transmission power control unit 13 and the in-vehicle application system 2.
Moreover, the detection part 122 detects the congestion degree of communication with other vehicle-mounted communication apparatuses or another vehicle-mounted communication apparatus, and an own machine. The detection unit 122 detects, as the congestion level, the congestion level of the wireless channel used for communication with other in-vehicle communication devices, or the number or density of other in-vehicle communication devices.
For example, the detection unit 122 uses a well-known carrier sense function or the like to detect the use status of a plurality of wireless channels that can be used in a wireless communication system (vehicle-to-vehicle communication system), or Then, “the degree of congestion of the in-vehicle communication device” indicating the number and density of the in-vehicle communication devices that can communicate with each other using the surrounding vehicle information 301 is detected as the congestion degree.
The detection unit 122 outputs the degree of congestion to the transmission power control unit 13.
Transmission power control unit 13 can be generally referred to as control means.
The transmission power control unit 13 holds surrounding vehicle information 301. When the transmission power control unit 13 newly receives the surrounding vehicle information 301 having the same ID as the ID in the surrounding vehicle information 301 already held, the transmission power control unit 13 has the same ID as the newly received surrounding vehicle information 301. The already held surrounding vehicle information 301 having the above is updated to the newly received surrounding vehicle information 301. The transmission power control unit 13 may delete the surrounding vehicle information 301 that has not been updated for a predetermined time.
The transmission power control unit 13 includes the movement state of other in-vehicle communication devices indicated in the surrounding vehicle information 301, the movement state of the own device detected by the detection unit 121, the degree of communication congestion detected by the detection unit 122, and Based on the above, the transmission of the wireless signal performed by the transmission unit 111 is controlled.
The transmission power control unit 13 controls the transmission power of the radio signal based on the movement state of the other in-vehicle communication device, the movement state of the own device, and the degree of communication congestion.
In the present embodiment, the transmission power control unit 13 is a ratio of the number of wireless communication devices having the same or substantially the same traveling direction as the own device among other wireless communication devices to the number of other in-vehicle communication devices. (Hereinafter referred to as “first ratio”) is equal to or greater than a threshold value. For example, 80% is used as the threshold value. The threshold value is not limited to 80% and can be changed as appropriate. For example, a value of 50% or more is used.
Further, the traveling direction that is the same or substantially the same as the traveling direction of the own aircraft is, for example, a traveling direction in which an angle formed with the traveling direction of the own aircraft is n (n is a number of 0 or more and 45 or less) degrees. Note that n is a number used to detect an in-vehicle communication device existing in the same lane in the same traveling direction as the own device among other in-vehicle communication devices, and n is any number between 0 and 45. It can be changed as appropriate.
When the first ratio is equal to or greater than the threshold value, the transmission power control unit 13 decreases the setting value of the transmission power of the radio signal by a first predetermined value or more when the degree of congestion exceeds the reference value. On the other hand, when the first ratio is less than the threshold value, the transmission power control unit 13 decreases the set value of the transmission power of the radio signal by 0 or more and less than the first predetermined value when the degree of congestion exceeds the reference value. The threshold value, the reference value, and the first predetermined value can be changed as appropriate, and are held in the transmission power control unit 13.
Note that the transmission power control unit 13 may control the transmission power of the radio signal based on the moving speed of the other in-vehicle communication device, the moving speed of the own device, and the degree of communication congestion.
In this case, the transmission power control unit 13 determines the number of in-vehicle communication devices having a moving speed that is within a predetermined range with respect to the number of other in-vehicle communication devices. It is determined whether the ratio (hereinafter referred to as “second ratio”) is equal to or greater than a threshold value. For example, 0 km / h to 50 km / h is used as the predetermined range. The predetermined range is not limited to 0 km / h to 50 km / h and can be changed as appropriate.
When the second ratio is equal to or greater than the threshold value, the transmission power control unit 13 decreases the set value of the transmission power of the radio signal by the first predetermined value or more when the degree of congestion exceeds the reference value. On the other hand, when the second ratio is less than the threshold value, the transmission power control unit 13 decreases the set value of the transmission power of the radio signal by 0 or more and less than the first predetermined value when the degree of congestion exceeds the reference value. Also in this case, the threshold value, the reference value, and the first predetermined value can be changed as appropriate, and are held in the transmission power control unit 13.
The transmission power control unit 13 outputs the transmission power setting value to the transmission unit 111.
The transmission unit 111 generates transmission data by adding a transmission power setting value to the communication data from the detection unit 121, modulates the transmission data, and indicates the modulated transmission data in the transmission power setting value. The transmitted power is transmitted to other in-vehicle communication devices by radio signals.
When receiving a wireless signal transmitted from another in-vehicle communication device, the receiving unit 112 measures the reception power of the wireless signal, specifies the reception time, and demodulates the wireless signal to generate reception data.
The receiving unit 112 associates the received data, the received power measurement value, and the reception time information indicating the reception time with each other to generate the surrounding vehicle information 301 and outputs the surrounding vehicle information 301 to the processing unit 12.
In the processing unit 12, the detection unit 121 detects the traveling direction of the own device based on the position indicated by each position information from the in-vehicle application system 2. Moreover, the detection part 121 detects the moving speed of an own machine based on the position which each positional information from the vehicle-mounted application system 2 shows, and the acquisition time interval (specific time interval) of positional information.
The detection unit 121 outputs the traveling direction information and the moving speed information of the own device to the transmission power control unit 13 together with the ID of the own device held in the detection unit 121. In addition, the detection unit 121 outputs communication data indicating the position information from the in-vehicle application system 2, the traveling direction information and movement speed information of the own device, and the ID of the own device to the transmission unit 111.
Upon receiving the surrounding vehicle information 301 from the receiving unit 112, the detecting unit 122 outputs the surrounding vehicle information 301 to the transmission power control unit 13 and the in-vehicle application system 2.
In addition, the detection unit 122 detects the degree of congestion of communication between the other in-vehicle communication device and the own unit, and outputs the degree of congestion to the transmission power control unit 13.
The transmission power control unit 13 detects the movement state (traveling direction or movement speed) of other in-vehicle communication devices indicated in the surrounding vehicle information 301, the movement state of the own device detected by the detection unit 121, and the detection unit 122 detects The set value of the transmission power of the radio signal is controlled based on the communication congestion level.
For example, when the first ratio is greater than or equal to the threshold value, the transmission power control unit 13 decreases the set value of the transmission power of the radio signal by the first predetermined value or more when the congestion degree exceeds the reference value, When the ratio is less than the threshold, when the degree of congestion exceeds the reference value, the setting value of the transmission power of the radio signal is decreased by 0 or more and less than the first predetermined value.
The transmission power control unit 13 sets the transmission power setting value to a default value when the power is turned on.
Next, an example of transmission power control will be described.
In the inter-vehicle communication system, as already shown in FIG. 1, it is assumed that a plurality of in-vehicle communication devices such as the in-vehicle communication devices 100 to 104 gather at a short distance and the plurality of in-vehicle communication devices transmit and receive radio signals to each other. The In the following description, each of the in-vehicle communication devices 100 to 104 has the same configuration as the in-vehicle communication device 1.
As the number of surrounding vehicles increases, the degree of congestion of the wireless propagation path increases. Each of the in-vehicle communication devices 100 to 104 detects the congestion of the wireless channel by detecting the congestion degree of the wireless channel using carrier sense or the like, or by information on the density of the peripheral in-vehicle communication device obtained from the surrounding vehicle information 301. Detect the degree.
The in-vehicle communication devices 101 to 104 proceed in the same direction, but only the in-vehicle communication device 100 proceeds in the reverse direction.
In this case, even if the degree of congestion of the wireless propagation path is high, the lane 300 in which the in-vehicle communication device 100 travels has a small traffic volume. Therefore, in order for the in-vehicle communication device 100 to communicate with another in-vehicle communication device (not shown) in the same traveling direction as the in-vehicle communication device 100, it is desirable to make the communication distance as long as possible without reducing the transmission power.
For this reason, in the present embodiment, even if the in-vehicle communication devices 101 to 104 reduce the transmission power as the degree of congestion of the wireless propagation path increases, the in-vehicle communication device 100 does not decrease the transmission power or the transmission power decreases. The width is made smaller than the lowered width of the in-vehicle communication devices 101-104.
Further, as already shown in FIG. 2, it is assumed that a plurality of in-vehicle communication devices such as the in-vehicle communication devices 500 to 504 gather in a short distance and the plurality of in-vehicle communication devices transmit and receive radio signals to each other. In the following description, each of the in-vehicle communication devices 500 to 504 has the same configuration as the in-vehicle communication device 1.
The in-vehicle communication devices 501 to 504 are proceeding at the same moving speed, but only the communication device 500 is stopped.
In this case, the in-vehicle communication device 500 has a large speed difference from other in-vehicle communication devices, and the traveling state is different. For this reason, even when the degree of congestion of the wireless propagation path is high, considering, for example, prevention of rear-end collision, it is desirable that the in-vehicle communication device 500 take as long a communication distance as possible without reducing transmission power.
Therefore, in this embodiment, even if the in-vehicle communication devices 501 to 504 decrease the transmission power as the radio propagation path congestion increases, the in-vehicle communication device 500 does not decrease the transmission power or the transmission power decreases. The width is made smaller than the lowered width of the in-vehicle communication devices 101-104.
According to the present embodiment, the receiving unit 112 detects the movement state of other in-vehicle communication devices. The detection unit 121 detects the movement state of the own device. The detection part 122 detects the congestion degree of communication with other radio | wireless communication apparatuses or another vehicle-mounted communication apparatus, and an own machine. Transmitter 111 transmits a radio signal from the own device to another in-vehicle communication device. The transmission power control unit 13 controls the transmission of the radio signal performed by the transmission unit 111 based on the movement state of the other in-vehicle communication device, the movement state of the own device, and the degree of congestion.
For this reason, it becomes possible to control communication congestion in consideration of the movement state of each in-vehicle communication device.
In the present embodiment, the transmission power control unit 13 has a first ratio (a wireless communication device having a traveling direction that is the same as or substantially the same as the traveling direction of its own among other in-vehicle communication devices with respect to the number of other in-vehicle communication devices. It is determined whether the ratio of the number is equal to or greater than a threshold value. When the first ratio is equal to or greater than the threshold value, the transmission power control unit 13 decreases the setting value of the transmission power of the radio signal by a first predetermined value or more when the degree of congestion exceeds the reference value. On the other hand, when the first ratio is less than the threshold value, the transmission power control unit 13 decreases the set value of the transmission power of the radio signal by 0 or more and less than the first predetermined value when the degree of congestion exceeds the reference value.
For this reason, even if a situation where the radio propagation path is congested is detected, if a small number of vehicles are smoothly running on the opposite route to the route in which traffic is congested, they are mounted on the small number of vehicles. In-vehicle communication equipment does not reduce transmission power even if the radio propagation path is congested, or the transmission power reduction range is on a congested route in order to secure a communication distance suitable for smooth running It becomes possible to make it smaller than the reduction | decrease amount of the transmission power of a communication apparatus.
Note that the transmission power control unit 13 has a second rate (the in-vehicle communication device having a moving speed in which the difference from the moving speed of the own device among other in-vehicle communication devices is within a predetermined range with respect to the number of other in-vehicle communication devices. If the congestion degree exceeds the reference value, the set value of the transmission power of the radio signal is decreased by a first predetermined value or more, and the second ratio is less than the threshold. When the degree of congestion exceeds the reference value, the following effects can be obtained when the set value of the transmission power of the radio signal is reduced by 0 or more and less than the first predetermined value.
By utilizing the information on the moving speed, the in-vehicle communication device assumed to have a large speed difference from the moving speeds of a large number of surrounding vehicles and to be in a traveling state or a stopped state different from a large number of traveling vehicles, In order to raise the priority of own information over information from a large number of vehicles, even if the radio propagation path is congested, the transmission power will not be reduced, or the transmission power will be reduced within many other vehicles. It becomes possible to make it smaller than the reduction | decrease amount of the transmission power of a vehicle-mounted communication apparatus.
As described above, by using the information on the moving speed and traveling direction of the in-vehicle communication device, the transmission power is controlled appropriately according to the running state of the vehicle and the surrounding traffic conditions, and the congestion degree of the radio propagation path is reduced. Control can be realized.
The in-vehicle communication device 1 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 the wireless unit 11, the processing unit 12, and the transmission power control unit. 13 functions. The recording medium is not limited to the CD-ROM and can be changed as appropriate.
FIG. 6 is a block diagram showing an in-vehicle communication unit 1X used in an inter-vehicle communication system that is a wireless communication system according to a second embodiment of the present invention.
The in-vehicle communication device 1X illustrated in FIG. 6 is different from the in-vehicle communication device 1 illustrated in FIG. 4 in that it includes a transmission cycle control unit 14 instead of the transmission power control unit 13. Hereinafter, the in-vehicle communication device 1X will be described focusing on differences from the in-vehicle communication device 1.
In FIG. 6, the transmission cycle control unit 14 can be generally referred to as control means.
The transmission cycle control unit 14 receives the surrounding vehicle information 301 from the detection unit 122 and holds the surrounding vehicle information 301. In the present embodiment, the surrounding vehicle information 301 may not include the transmission power setting value 301e. When the transmission cycle control unit 14 newly receives the surrounding vehicle information 301 having the same ID as the ID in the surrounding vehicle information 301 that is already held, the transmission cycle control unit 14 has the same ID as the newly received surrounding vehicle information 301. The already held surrounding vehicle information 301 having the above is updated to the newly received surrounding vehicle information 301. The transmission cycle control unit 14 may delete the surrounding vehicle information 301 that has not been updated for a predetermined time.
The transmission cycle control unit 14 includes the movement state of other in-vehicle communication devices indicated in the surrounding vehicle information 301, the movement state of the own device detected by the detection unit 121, the degree of communication congestion detected by the detection unit 122, and Based on the above, the transmission period of the radio signal performed by the transmission unit 111 is controlled.
In the present embodiment, the transmission cycle control unit 14 determines whether the first ratio is equal to or greater than the threshold, similarly to the transmission power control unit 13.
When the first ratio is equal to or greater than the threshold, the transmission cycle control unit 14 increases the set value of the transmission cycle of the radio signal by a second predetermined value or more when the degree of congestion exceeds the reference value. On the other hand, when the first ratio is less than the threshold, the transmission cycle control unit 14 increases the set value of the transmission cycle by 0 or more and less than the second predetermined value when the degree of congestion exceeds the reference value. The threshold value, the reference value, and the second predetermined value can be changed as appropriate, and are held in the transmission cycle control unit 14.
Note that the transmission cycle control unit 14 may control the transmission cycle of the radio signal based on the moving speed of another in-vehicle communication device, the moving speed of the own device, and the degree of communication congestion.
In this case, the transmission cycle control unit 14 determines whether the second ratio is equal to or greater than a threshold value.
When the second ratio is equal to or greater than the threshold, the transmission cycle control unit 14 increases the set value of the transmission cycle of the radio signal by a second predetermined value or more when the degree of congestion exceeds the reference value. On the other hand, when the second ratio is less than the threshold, the transmission cycle control unit 14 increases the set value of the transmission cycle by 0 or more and less than the second predetermined value when the degree of congestion exceeds the reference value. Also in this case, the threshold value, the reference value, and the second predetermined value can be changed as appropriate, and are held in the transmission cycle control unit 14.
The transmission cycle control unit 14 outputs the set value of the transmission cycle to the transmission unit 111.
The transmission cycle control unit 14 sets the transmission cycle setting value to a default value when the power is turned on.
The transmission unit 111 modulates the communication data from the detection unit 121 as transmission data, and transmits the modulated transmission data to another in-vehicle communication device with a radio signal at the transmission cycle indicated by the setting value of the transmission cycle. .
According to the present embodiment, the transmission cycle control unit 14 uses a radio signal based on the movement state (traveling direction or movement speed) of another in-vehicle communication device, the movement state of the own device, and the degree of communication congestion. Control the transmission cycle. For this reason, it is possible to realize the same congestion control as in the first embodiment.
The in-vehicle communication device 1X may be realized by a computer. In this case, the computer reads and executes a program recorded on a computer-readable recording medium, and functions as the wireless unit 11, the processing unit 12, and the transmission cycle control unit 14.
FIG. 7 is a block diagram showing an in-vehicle communication unit 1Y used in an inter-vehicle communication system that is a wireless communication system according to a third embodiment of the present invention.
The in-vehicle communication device 1Y illustrated in FIG. 7 is different from the in-vehicle communication device 1 illustrated in FIG. 4 in that a transmission rate control unit 15 is provided instead of the transmission power control unit 13. Hereinafter, the in-vehicle communication device 1Y will be described focusing on differences from the in-vehicle communication device 1.
In FIG. 7, the transmission rate control unit 15 can be generally referred to as control means.
The transmission speed control unit 15 receives the surrounding vehicle information 301 from the detection unit 122 and holds the surrounding vehicle information 301. In the present embodiment, the surrounding vehicle information 301 may not include the transmission power setting value 301e. When the transmission speed control unit 15 newly receives the surrounding vehicle information 301 having the same ID as the ID in the surrounding vehicle information 301 that is already held, the transmission speed control unit 15 has the same ID as the newly received surrounding vehicle information 301. The already held surrounding vehicle information 301 having the above is updated to the newly received surrounding vehicle information 301. The transmission speed control unit 15 may delete the surrounding vehicle information 301 that has not been updated for a predetermined time.
The transmission speed control unit 15 includes the movement state of other in-vehicle communication devices indicated in the surrounding vehicle information 301, the movement state of the own device detected by the detection unit 121, the degree of communication congestion detected by the detection unit 122, The transmission unit 111 controls the transmission speed of the radio signal based on the above.
In the present embodiment, the transmission rate control unit 15 determines whether the first ratio is equal to or greater than the threshold, similarly to the transmission power control unit 13.
When the first ratio is equal to or greater than the threshold, the transmission rate control unit 15 increases the set value of the transmission rate of the radio signal by a third predetermined value or more when the degree of congestion exceeds the reference value. On the other hand, when the first ratio is less than the threshold value, the transmission rate control unit 15 increases the set value of the transmission rate by 0 or more and less than the third predetermined value when the degree of congestion exceeds the reference value. The threshold value, the reference value, and the third predetermined value can be changed as appropriate and are held in the transmission rate control unit 15.
Note that the transmission rate control unit 15 may control the transmission rate of the radio signal based on the moving speed of another in-vehicle communication device, the moving speed of the own device, and the degree of communication congestion.
In this case, the transmission rate control unit 15 determines whether the second ratio is equal to or greater than a threshold value.
When the second ratio is equal to or greater than the threshold, the transmission rate control unit 15 increases the set value of the transmission rate of the radio signal by a third predetermined value or more when the degree of congestion exceeds the reference value. On the other hand, when the second ratio is less than the threshold, the transmission rate control unit 15 increases the set value of the transmission rate by 0 or more and less than the third predetermined value when the degree of congestion exceeds the reference value. Also in this case, the threshold value, the reference value, and the third predetermined value can be changed as appropriate, and are held in the transmission rate control unit 15.
The transmission rate control unit 15 outputs the set value of the transmission rate to the transmission unit 111.
The transmission rate control unit 15 sets the transmission rate setting value to a default value when the power is turned on.
The transmission unit 111 modulates the communication data from the detection unit 121 as transmission data, and transmits the modulated transmission data to another in-vehicle communication device with a wireless signal at the transmission rate indicated by the transmission rate setting value. .
According to the present embodiment, the transmission rate control unit 15 transmits a radio signal based on the movement state (traveling direction or movement speed) of another in-vehicle communication device, the movement state of the own device, and the degree of communication congestion. To control the transmission speed. For this reason, it is possible to realize the same congestion control as in the first embodiment.
The in-vehicle communication device 1Y may be realized by a computer. In this case, the computer reads and executes a program recorded on a computer-readable recording medium, and functions as the wireless unit 11, the processing unit 12, and the transmission rate control unit 15.
In each of the above embodiments, the receiving unit 112 demodulates the radio signal to detect the respective traveling directions of the other in-vehicle communication devices. However, the detection unit 122 detects the in-vehicle communication device for each other in-vehicle communication device. The traveling direction of the in-vehicle communication device may be detected based on the respective position information 301b in the corresponding plurality of surrounding vehicle information 301.
For example, when the detection unit 122 receives the surrounding vehicle information 301, the detection unit 122 in the received surrounding vehicle information 301 among the surrounding vehicle information 301 in the transmission power control unit 13, the transmission cycle control unit 14, or the transmission speed control unit 15. The position information 301b is read from the surrounding vehicle information 301 having the same ID as the ID 301a.
Subsequently, the detection unit 122 specifies the direction from the position indicated by the position information 301b to the position indicated by the position information 301b in the received surrounding vehicle information 301 by the ID 301a in the received surrounding vehicle information 301. This is detected as the traveling direction of the in-vehicle communication device.
Subsequently, the detection unit 122 outputs traveling direction information indicating the traveling direction of the in-vehicle communication device to the transmission power control unit 13, the transmission cycle control unit 14, or the transmission rate control unit 15. In this case, the detection unit 122 also functions as a first detection unit.
In this case, the transmission data may not include the traveling direction information.
Moreover, in each said embodiment, although the receiving part 112 detected each moving speed of the other vehicle-mounted communication apparatus by demodulating a radio signal, the detection part 122 carries out the vehicle-mounted communication for every other vehicle-mounted communication apparatus. The moving speed of the in-vehicle communication device may be detected based on the position information 301b in the plurality of surrounding vehicle information 301 corresponding to the machine and the reception time interval of the position information 301b.
For example, when the detection unit 122 receives the surrounding vehicle information 301, the detection unit 122 in the received surrounding vehicle information 301 among the surrounding vehicle information 301 in the transmission power control unit 13, the transmission cycle control unit 14, or the transmission speed control unit 15. The position information 301b is read from the surrounding vehicle information 301 having the same ID as the ID 301a (hereinafter referred to as “previous information”).
Subsequently, the detection unit 122 calculates a distance from the position indicated by the position information 301b to the position indicated by the position information 301b in the received surrounding vehicle information 301.
Subsequently, the detection unit 122 calculates an elapsed time (reception time interval) from the date / time indicated by the reception time information 301g in the previous information to the date / time indicated by the reception time information 301g in the accepted surrounding vehicle information 301.
Subsequently, the detection unit 122 detects the moving speed of the in-vehicle communication device specified by the ID 301a in the received surrounding vehicle information 301 by dividing the calculated distance by the calculated elapsed time.
Subsequently, the detection unit 122 outputs movement speed information indicating the movement speed of the in-vehicle communication device to the transmission power control unit 13, the transmission cycle control unit 14, or the transmission rate control unit 15. In this case, the detection unit 122 also functions as a first detection unit.
In this case, the transmission data may not include the moving speed information.
Moreover, in each said embodiment, although the detection part 122 output the surrounding vehicle information 301 to the vehicle-mounted application system 2, the detection part 122 carries out only the information which the vehicle-mounted application system 2 requests | requires among the surrounding vehicle information 301. You may output to the application system 2. In this case, information that is not required for congestion control and that is not required by the in-vehicle application system 2 can be deleted from the transmission data.
This application claims the priority on the basis of Japanese application Japanese Patent Application No. 2011-055032 for which it applied on March 14, 2011, and takes in those the indications of all here.
DESCRIPTION OF SYMBOLS 1, 1X, 1Y, 1a, 1b Vehicle-mounted communication apparatus 11 Radio | wireless part 111 Transmission part 112 Reception part 12 Processing part 121,122 Detection part 13 Transmission power control part 14 Transmission period control part 15 Transmission rate control part 2, 2a, 2b Application system
A wireless communication device that communicates with another wireless communication device that is a communication partner,
First detecting means for detecting a movement state of the other wireless communication device;
Second detection means for detecting the movement state of the own machine;
Third detection means for detecting a degree of congestion of communication between the other wireless communication devices or between the other wireless communication device and the own device;
Transmitting means for transmitting a wireless signal from the own device to the other wireless communication device;
A wireless communication device comprising: a control unit that controls transmission of a wireless signal performed by the transmission unit based on a movement state of the other wireless communication device, a movement state of the own device, and the degree of congestion.
The moving state is a traveling direction,
The control means is configured such that a ratio of the number of wireless communication devices having the same or substantially the same traveling direction as the own device among the other wireless communication devices to the number of the other wireless communication devices is equal to or greater than a threshold value. If the degree of congestion exceeds a reference value, the transmission power of the radio signal is reduced by a predetermined value or more, and if the ratio is less than the threshold, the degree of congestion exceeds the reference value. The wireless communication device according to claim 1, wherein the transmission power is reduced to 0 or more and less than the predetermined value.
The control means is configured such that a ratio of the number of wireless communication devices having the same or substantially the same traveling direction as the own device among the other wireless communication devices to the number of the other wireless communication devices is equal to or greater than a threshold value. If the degree of congestion exceeds a reference value, the radio signal transmission cycle is increased by a predetermined value or more. If the ratio is less than the threshold, the degree of congestion exceeds the reference value. The wireless communication device according to claim 1, wherein the transmission cycle is increased by 0 or more and less than the predetermined value.
The control means is configured such that a ratio of the number of wireless communication devices having the same or substantially the same traveling direction as the own device among the other wireless communication devices to the number of the other wireless communication devices is equal to or greater than a threshold value. If the degree of congestion exceeds a reference value, the wireless signal transmission speed is increased by a predetermined value or more. If the ratio is less than the threshold, the degree of congestion exceeds the reference value. The wireless communication device according to claim 1, wherein the transmission speed is increased by 0 or more and less than the predetermined value.
The movement state is a movement speed,
The control means is configured such that a ratio of the number of wireless communication devices having a moving speed in which a difference from a moving speed of the own device is within a predetermined range among the other wireless communication devices with respect to the number of the other wireless communication devices. If the degree of congestion exceeds a threshold value when it is equal to or greater than a threshold value, the transmission power of the radio signal is reduced by a predetermined value or more. If the ratio is less than the threshold value, the congestion level is equal to the reference value. 2. The wireless communication device according to claim 1, wherein the transmission power is reduced by 0 or more and less than the predetermined value when exceeding.
The control means is configured such that a ratio of the number of wireless communication devices having a moving speed in which a difference from a moving speed of the own device is within a predetermined range among the other wireless communication devices with respect to the number of the other wireless communication devices. If the degree of congestion exceeds a reference value when it is greater than or equal to a threshold value, the radio signal transmission period is increased by a predetermined value or more. If the ratio is less than the threshold value, the degree of congestion is equal to the reference value. The wireless communication device according to claim 1, wherein if the value is exceeded, the transmission cycle is lengthened by 0 or more and less than the predetermined value.
The control means is configured such that a ratio of the number of wireless communication devices having a moving speed in which a difference from a moving speed of the own device is within a predetermined range among the other wireless communication devices with respect to the number of the other wireless communication devices. When the congestion degree exceeds a reference value when the threshold is greater than or equal to a threshold value, the transmission rate of the wireless signal is increased by a predetermined value or more. When the ratio is less than the threshold value, the congestion degree is the reference value. The wireless communication device according to claim 1, wherein when the value is exceeded, the transmission rate is increased by 0 or more and less than the predetermined value.
The second detection means acquires the position of the own machine a plurality of times, detects a traveling direction of the own machine based on a plurality of the positions of the own machine,
The transmission means transmits position information indicating the position of the own device to the other wireless communication device by the wireless signal every time the position of the own device is acquired,
The first detection means receives a plurality of the position information transmitted from the other wireless communication device, and detects a traveling direction of the other wireless communication device based on the plurality of position information. 5. The wireless communication device according to any one of items 1 to 4.
The transmitting means transmits the traveling direction information indicating the traveling direction of the own device to the other wireless communication device by the wireless signal,
The first detection means receives the traveling direction information transmitted from the other wireless communication device, and detects the traveling direction of the other wireless communication device based on the traveling direction information. The wireless communication device according to any one of the above.
The second detection means acquires the position of the own device a plurality of times, detects the moving speed of the own device based on the plurality of positions of the own device and the acquisition time interval of the position,
The first detection means receives a plurality of the location information transmitted from the other radio communication device, and based on the plurality of location information and a reception time interval of the location information, the other radio The wireless communication device according to any one of claims 5 to 7, wherein a moving speed of the communication device is detected.
The transmission means transmits movement speed information representing the movement speed of the own apparatus to the other radio communication apparatus by the radio signal,
The first detection means receives the moving speed information transmitted from the other wireless communication device, and detects the moving speed of the other wireless communication device based on the moving speed information. The wireless communication device according to any one of the above.
12. The device according to claim 1, wherein the third detection unit detects, as the congestion level, a congestion level of a radio channel with the other wireless communication device, or the number or density of the other wireless communication devices. The wireless communication device according to item 1.
A wireless communication system comprising a plurality of wireless communication devices according to any one of claims 1 to 12, wherein the wireless communication devices communicate with each other.
A congestion control method in a wireless communication device that communicates with another wireless communication device that is a communication partner,
Detecting the movement state of the other wireless communication device,
Detects the movement status of your aircraft,
Detecting the degree of congestion of communication between the other wireless communication devices or between the other wireless communication device and the own device,
Transmitting a wireless signal from the own device to the other wireless communication device;
A congestion control method for controlling transmission of the radio signal based on a movement state of the other wireless communication device, a movement state of the own device, and the congestion degree.
A first detection procedure for detecting a movement state of another wireless communication device as a communication partner;
A second detection procedure for detecting a movement state of the computer;
A third detection procedure for detecting a degree of congestion of communication between the other wireless communication devices or between the other wireless communication device and the computer;
A transmission procedure for transmitting a wireless signal from the computer to the other wireless communication device;
A computer-readable recording of a program for executing a control procedure for controlling the transmission of the radio signal based on the movement state of the other wireless communication device, the movement state of the computer, and the degree of congestion Possible recording media.
JP2013504735A 2011-03-14 2012-03-13 Wireless communication device, wireless communication system, congestion control method, and recording medium Active JP5962649B2 (en)
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PCT/JP2012/056402 WO2012124685A1 (en) 2011-03-14 2012-03-13 Wireless communication apparatus, wireless communication system, congestion control method and recording medium
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JP2013504735A Active JP5962649B2 (en) 2011-03-14 2012-03-13 Wireless communication device, wireless communication system, congestion control method, and recording medium
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