JP6277531B2 - Wireless device - Google Patents

Description

  The present invention relates to communication technology, and more particularly to a terminal device that receives a signal including predetermined information.

  The wireless communication device (terminal device) receives information transmitted from another traveling vehicle. The wireless communication device determines whether driving assistance is necessary based on the received information, and provides driving assistance to the driver (see, for example, Patent Document 1).

JP 2000-348299 A

  If two vehicles traveling on each of the two intersecting roads enter the intersection at close timing, these two vehicles are at risk of collision. The driver should be notified of the danger of a collision with another vehicle. However, if the intersection of the two roads at the intersection is not a plane intersection but a three-dimensional intersection, there is no danger of a collision, so the driver should not be notified. On the other hand, if the wireless communication device holds the map information, it can be recognized by checking the map information whether the intersection is a three-dimensional intersection or a plane intersection, but if the map information is not held, Recognition is difficult.

  This invention is made | formed in view of such a condition, The objective is to provide the technique which suppresses the collision misjudgment in an intersection, without using map information.

  In order to solve the above problems, a wireless device according to an aspect of the present invention is a wireless device that can be mounted on a vehicle, and includes an acquisition unit that acquires position information of the vehicle on which the wireless device is mounted, and another wireless device Included in a packet signal received from a device and a packet signal including position information of another vehicle on which the other wireless device is mounted, and a packet signal received in the past by the receiver. A storage unit that stores at least one of the acquired position information and position information acquired in the past by the acquisition unit as travel history information, and an intersection where at least two roads intersect based on the travel history information stored in the storage unit Based on the estimation unit that estimates the intersection situation at the point, the position information acquired by the acquisition unit, and the position information included in the packet signal received by the reception unit, the vehicle at the intersection And when the intersection of the other vehicle is expected, provided in accordance with the cross situation corresponding to the intersection, a determination unit that determines whether to notify the presence of other vehicles, the.

  It should be noted that any combination of the above-described constituent elements and a conversion of the expression of the present invention between a method, an apparatus, a system, a recording medium, a computer program, etc. are also effective as an aspect of the present invention.

  ADVANTAGE OF THE INVENTION According to this invention, the collision misjudgment in an intersection can be suppressed, without using map information.

It is a figure which shows the structure of the communication system which concerns on the Example of this invention. It is a figure which shows the structure of the base station apparatus of FIG. FIGS. 3A to 3D are diagrams showing frame formats defined in the communication system of FIG. It is a figure which shows the structure of the terminal device of FIG. It is a figure which shows the structure of the data memorize | stored in the memory | storage part of FIG. FIGS. 6A and 6B are diagrams showing an outline of processing in the estimation unit of FIG. It is a figure which shows the encounter collision prevention assistance in the determination part of FIG. It is a flowchart which shows the estimation procedure by the estimation part of FIG. It is a flowchart which shows another estimation procedure by the estimation part of FIG. It is a flowchart which shows another estimation procedure by the estimation part of FIG. It is a flowchart which shows the determination procedure of the assistance by the terminal device of FIG.

  Prior to specific description of the embodiments of the present invention, the underlying knowledge will be described. Embodiments of the present invention relate to a communication system that performs vehicle-to-vehicle communication between terminal devices mounted on a vehicle, and also executes road-to-vehicle communication from a base station device installed at an intersection or the like to a terminal device. Such a communication system is also called ITS (Intelligent Transport Systems). The communication system uses an access control function called CSMA / CA (Carrier Sense Multiple Access Collision Aviation), as well as a wireless LAN (Local Area Network) compliant with a standard such as IEEE 802.11. Therefore, the same radio channel is shared by a plurality of terminal devices. On the other hand, in ITS, it is necessary to transmit information to an unspecified number of terminal devices. In order to efficiently perform such transmission, the communication system broadcasts a packet signal.

  That is, as inter-vehicle communication, the terminal device broadcasts a packet signal that stores information such as the position, speed, and traveling direction of the vehicle. In addition, the other terminal device receives the packet signal and recognizes the approach of the vehicle based on the above-described information. Here, in order to reduce interference between road-vehicle communication and vehicle-to-vehicle communication, the base station apparatus repeatedly defines a frame including a plurality of subframes. The base station apparatus selects any of a plurality of subframes for road-to-vehicle communication, and broadcasts a packet signal in which control information and the like are stored during the period of the head portion of the selected subframe.

  The control information includes information related to a period for the base station apparatus to broadcast the packet signal (hereinafter referred to as “road vehicle transmission period”). The terminal device specifies a road and vehicle transmission period based on the control information, and broadcasts a packet signal by the CSMA method in a period other than the road and vehicle transmission period (hereinafter referred to as “vehicle transmission period”). As a result, road-to-vehicle communication and vehicle-to-vehicle communication are time-division multiplexed. Note that a terminal device that cannot receive control information from the base station device, that is, a terminal device that exists outside the area formed by the base station device transmits a packet signal by the CSMA method regardless of the frame configuration.

  Under such circumstances, the terminal device according to the present embodiment derives the support that satisfies the support generation condition based on the information included in the packet signal received from another terminal device or the base station device. The terminal device and the vehicle on which the terminal device is mounted are collectively referred to as “own vehicle”, and the other terminal device and the vehicle on which the other terminal device is mounted are collectively referred to as “other vehicle”. An example of the information included in the packet signal is information such as the state of the vehicle from another terminal device, such as information such as the state of the vehicle from the base station device, road shape, and signal information. Furthermore, the support is to assist the driver in driving, for example, to notify the presence of another vehicle that is facing the vehicle when the host vehicle turns right.

  There are a plurality of types of such support, and support generation conditions are specified for each support. An example of the support defined by a plurality of types is the encounter collision prevention support by inter-vehicle communication. In the encounter collision prevention support, the road on which the vehicle is traveling intersects with another road at the intersection, and the vehicle and the other vehicle traveling on the other road are in an intersecting relationship. To be executed. For example, a situation in which another vehicle is approaching from the front and side of the traveling vehicle corresponds to a crossing relationship, and therefore, encounter collision prevention support is provided. In that case, the driver is urged to pay attention to other vehicles entering the intersection from other roads. However, there is a case where the intersection at the intersection is not a plane intersection but a three-dimensional intersection. If it is a three-dimensional intersection, it does not collide with other vehicles, so that it is not necessary to support encounter collision prevention. However, if the type of intersection is not identified, the encounter collision prevention support is erroneously performed.

  On the other hand, if the terminal device holds the map information, it is easy to identify whether the intersection is a three-dimensional intersection or a plane intersection. However, holding map information leads to an increase in cost, so the terminal device may not hold map information. Even under such circumstances, it is desired to identify whether the intersection is a three-dimensional intersection or a plane intersection. In order to cope with this, the terminal device according to the present embodiment analyzes the travel information of the vehicle that has passed through the intersection, and the difference between the inflow speed and the exit speed is smaller than the threshold for the vehicle that flows into the intersection. When the difference between the inflow azimuth angle and the exit azimuth angle is smaller than the threshold value, it is determined that the intersection is a three-dimensional intersection.

  FIG. 1 shows a configuration of a communication system 100 according to an embodiment of the present invention. This corresponds to a case where one intersection is viewed from above. The communication system 100 includes a base station device 10, a first vehicle 12a, a second vehicle 12b, a third vehicle 12c, a fourth vehicle 12d, a fifth vehicle 12e, a sixth vehicle 12f, and a seventh vehicle 12g, collectively referred to as a vehicle 12. , The eighth vehicle 12h, and the network 202. Here, only the first vehicle 12 a is shown, but each vehicle 12 is equipped with a terminal device 14. An area 212 is formed around the base station apparatus 10, and an outside area 214 is formed outside the area 212.

  As shown in the drawing, the road that goes in the horizontal direction of the drawing, that is, the left and right direction, intersects the vertical direction of the drawing, that is, the road that goes in the up and down direction, at the central portion. Here, the upper side of the drawing corresponds to the direction “north”, the left side corresponds to the direction “west”, the lower side corresponds to the direction “south”, and the right side corresponds to the direction “east”. An intersection of two roads is an “intersection”. The first vehicle 12a and the second vehicle 12b are traveling from left to right, and the third vehicle 12c and the fourth vehicle 12d are traveling from right to left. Further, the fifth vehicle 12e and the sixth vehicle 12f are traveling from the top to the bottom, and the seventh vehicle 12g and the eighth vehicle 12h are traveling from the bottom to the top.

  In the communication system 100, the base station apparatus 10 is fixedly installed at an intersection. The base station device 10 controls communication between terminal devices. The base station apparatus 10 receives a frame including a plurality of subframes based on a signal received from a GPS (Global Positioning System) satellite (not shown) or a frame formed by another base station apparatus 10 (not shown). Generate repeatedly. Here, the road vehicle transmission period can be set at the head of each subframe.

  The base station apparatus 10 selects a subframe in which the road and vehicle transmission period is not set by another base station apparatus 10 from among a plurality of subframes in the frame. The base station apparatus 10 sets a road and vehicle transmission period at the beginning of the selected subframe. The base station apparatus 10 notifies the packet signal in the set road and vehicle transmission period. In the road and vehicle transmission period, a plurality of packet signals may be notified. The packet signal includes, for example, accident information, traffic jam information, signal information, and the like. Note that the packet signal also includes information related to the timing when the road and vehicle transmission period is set and control information related to the frame.

  As described above, the terminal device 14 is mounted on the vehicle 12 and is movable. When receiving the packet signal from the base station apparatus 10, the terminal apparatus 14 estimates that the terminal apparatus 14 exists in the area 212. When the terminal device 14 exists in the area 212, the terminal device 14 generates a frame based on the control information included in the packet signal, in particular, the information on the timing when the road and vehicle transmission period is set and the information on the frame. As a result, the frame generated in each of the plurality of terminal devices 14 is synchronized with the frame generated in the base station device 10. The terminal device 14 notifies the packet signal in the vehicle transmission period that is a period different from the road and vehicle transmission period. Here, CSMA / CA is executed in the vehicle transmission period. On the other hand, when it is estimated that the terminal apparatus 14 exists outside the area 214, the terminal apparatus 14 notifies the packet signal by executing CSMA / CA regardless of the frame configuration. The terminal device 14 recognizes the approach of the other vehicle 12 on which the other terminal device 14 is mounted based on the packet signal from the other terminal device 14.

  FIG. 2 shows the configuration of the base station apparatus 10. The base station apparatus 10 includes an antenna 20, an RF unit 22, a modem unit 24, a processing unit 26, a control unit 28, and a network communication unit 30. Further, the processing unit 26 includes a frame defining unit 32, a selecting unit 34, and a generating unit 36.

  The RF unit 22 receives a packet signal from a terminal device 14 (not shown) or another base station device 10 by the antenna 20 as a reception process. The RF unit 22 performs frequency conversion on the received radio frequency packet signal to generate a baseband packet signal. Further, the RF unit 22 outputs a baseband packet signal to the modem unit 24. In general, since a baseband packet signal is formed by an in-phase component and a quadrature component, two signal lines should be shown, but here only one signal line is shown for the sake of clarity. Shall be shown. The RF unit 22 includes an LNA (Low Noise Amplifier), a mixer, an AGC, and an A / D conversion unit.

  As a transmission process, the RF unit 22 performs frequency conversion on the baseband packet signal input from the modem unit 24 to generate a radio frequency packet signal. Further, the RF unit 22 transmits a radio frequency packet signal from the antenna 20 during the road-vehicle transmission period. The RF unit 22 also includes a PA (Power Amplifier), a mixer, and a D / A conversion unit.

  The modem unit 24 demodulates the baseband packet signal from the RF unit 22 as a reception process. Further, the modem unit 24 outputs the demodulated result to the processing unit 26. The modem unit 24 also modulates the data from the processing unit 26 as a transmission process. Further, the modem unit 24 outputs the modulated result to the RF unit 22 as a baseband packet signal. Here, since the communication system 100 corresponds to an OFDM (Orthogonal Frequency Division Multiplexing) modulation scheme, the modem unit 24 also performs FFT (Fast Fourier Transform) as reception processing and IFFT (Inverse Fast Forward) as transmission processing. Also execute.

  The frame defining unit 32 receives a signal from a GPS satellite (not shown), and acquires time information based on the received signal. In addition, since a well-known technique should just be used for acquisition of the information of time, description is abbreviate | omitted here. The frame defining unit 32 generates a plurality of frames based on the time information. For example, the frame defining unit 32 generates ten “100 msec” frames by dividing the “1 sec” period into ten on the basis of the timing indicated by the time information. By repeating such processing, the frame is defined to be repeated. The frame defining unit 32 may detect control information from the demodulation result and generate a frame based on the detected control information. Such processing corresponds to generating a frame synchronized with the timing of the frame formed by another base station apparatus 10.

  3A to 3D show frame formats defined in the communication system 100. FIG. FIG. 3A shows the structure of the frame. The frame is formed of N subframes indicated as the first subframe to the Nth subframe. This can be said that the terminal device 14 forms a frame by multiplexing a plurality of subframes that can be used for notification for a plurality of hours. For example, when the frame length is 100 msec and N is 8, a subframe having a length of 12.5 msec is defined. N may be other than 8. The description of FIGS. 3B to 3D will be described later and returns to FIG.

  The selection part 34 selects the sub-frame which should set a road and vehicle transmission period among several sub-frames contained in the flame | frame. More specifically, the selection unit 34 receives a frame defined by the frame defining unit 32. The selection unit 34 receives an instruction regarding the selected subframe via an interface (not shown). The selection unit 34 selects a subframe corresponding to the instruction. Apart from this, the selection unit 34 may automatically select a subframe. At this time, the selection unit 34 inputs a demodulation result from another base station device 10 or the terminal device 14 (not shown) via the RF unit 22 and the modem unit 24. The selection part 34 extracts the demodulation result from the other base station apparatus 10 among the input demodulation results. The selection unit 34 specifies the subframe that has not received the demodulation result by specifying the subframe that has received the demodulation result.

  This corresponds to specifying a subframe in which the road and vehicle transmission period is not set by another base station apparatus 10, that is, an unused subframe. When there are a plurality of unused subframes, the selection unit 34 selects one subframe at random. When there are no unused subframes, that is, when each of a plurality of subframes is used, the selection unit 34 acquires reception power corresponding to the demodulation result, and gives priority to subframes with low reception power. Select

  FIG. 3B shows a configuration of a frame generated by the first base station apparatus 10a (not shown). The first base station apparatus 10a sets a road and vehicle transmission period at the beginning of the first subframe. Moreover, the 1st base station apparatus 10a sets a vehicle transmission period following a road and vehicle transmission period in a 1st sub-frame. The vehicle transmission period is a period during which the terminal device 14 can notify the packet signal. That is, the first base station apparatus 10a can notify the packet signal in the road and vehicle transmission period which is the first period of the first subframe, and the terminal apparatus in the vehicle and vehicle transmission period other than the road and vehicle transmission period in the frame. It is specified that 14 can broadcast the packet signal. Furthermore, the first base station apparatus 10a sets only the vehicle transmission period from the second subframe to the Nth subframe.

  FIG. 3C shows a configuration of a frame generated by the second base station apparatus 10b (not shown). The second base station apparatus 10b sets a road and vehicle transmission period at the beginning of the second subframe. Also, the second base station apparatus 10b sets the vehicle transmission period from the first stage of the road and vehicle transmission period in the second subframe, from the first subframe and the third subframe to the Nth subframe. FIG. 3D shows a configuration of a frame generated by a third base station apparatus 10c (not shown). The third base station apparatus 10c sets a road and vehicle transmission period at the beginning of the third subframe. In addition, the third base station apparatus 10c sets the vehicle transmission period from the first stage of the road and vehicle transmission period in the third subframe, the first subframe, the second subframe, and the fourth subframe to the Nth subframe. As described above, the plurality of base station apparatuses 10 select different subframes, and set the road and vehicle transmission period at the head portion of the selected subframe. Returning to FIG. The selection unit 34 outputs the selected subframe number to the generation unit 36.

  The generation unit 36 receives a subframe number from the selection unit 34. The generation unit 36 sets a road and vehicle transmission period in the subframe of the received subframe number, and generates a packet signal to be notified during the road and vehicle transmission period. When a plurality of packet signals are transmitted in one road and vehicle transmission period, the generation unit 36 generates them. The packet signal is composed of control information and a payload. The control information includes a subframe number in which a road and vehicle transmission period is set. The payload includes, for example, accident information, traffic jam information, signal information, and the like. These data are acquired from the network 202 (not shown) by the network communication unit 30. The processing unit 26 broadcasts the packet signal to the modem unit 24 and the RF unit 22 during the road and vehicle transmission period. The control unit 28 controls processing of the entire base station device 10.

  This configuration can be realized in terms of hardware by a CPU, memory, or other LSI of any computer, and in terms of software, it can be realized by a program loaded in the memory, but here it is realized by their cooperation. Draw functional blocks. Accordingly, those skilled in the art will understand that these functional blocks can be realized in various forms only by hardware, or by a combination of hardware and software.

  FIG. 4 shows the configuration of the terminal device 14. The terminal device 14 includes an antenna 50, an RF unit 52, a modem unit 54, a processing unit 56, and a control unit 58. The processing unit 56 includes a timing specification unit 60, a transfer determination unit 62, an acquisition unit 64, a generation unit 66, a notification unit 70, a storage unit 80, an estimation unit 82, and a determination unit 84. The timing specification unit 60 includes an extraction unit 72. The carrier sense unit 74 is included. The terminal device 14 can be mounted on the vehicle 12 as described above. The antenna 50, the RF unit 52, and the modem unit 54 execute the same processing as the antenna 20, the RF unit 22, and the modem unit 24 in FIG. Here, the difference will be mainly described.

  The modem unit 54 and the processing unit 56 receive a packet signal from another terminal device 14 or the base station device 10 (not shown) in the reception process. As described above, the modem unit 54 and the processing unit 56 receive a packet signal from the base station apparatus 10 during the road-to-vehicle transmission period, and receive packet signals from other terminal apparatuses 14 during the vehicle-to-vehicle transmission period. To do. The packet signal from the other terminal device 14 includes at least the presence position, traveling direction, moving speed, etc. (hereinafter collectively referred to as “position information”) of the other vehicle 12 on which the other terminal device 14 is mounted. It is.

  When the demodulation result from the modem unit 54 is a packet signal from the base station apparatus 10 (not shown), the extraction unit 72 specifies the timing of the subframe in which the road and vehicle transmission period is arranged. In that case, the extraction part 72 estimates that it exists in the area 212 of FIG. The extraction unit 72 generates a frame based on the timing of the subframe and the content of the message header of the packet signal, specifically, the content of the road and vehicle transmission period length. Note that the generation of the frame only needs to be performed in the same manner as the frame defining unit 32 described above, and thus the description thereof is omitted here. As a result, the extraction unit 72 generates a frame synchronized with the frame formed in the base station device 10. When the packet signal notification source is another terminal device 14, the extraction unit 72 omits synchronized frame generation processing, but extracts the position information included in the packet signal and stores the position information in the storage unit 80. And output to the determination unit 84.

  On the other hand, when the extraction unit 72 has not received a packet signal from the base station apparatus 10, the extraction unit 72 estimates that the extraction unit 72 exists outside the area 214 in FIG. When it is estimated that the extraction unit 72 exists in the area 212, the extraction unit 72 selects the vehicle transmission period. When it is estimated that the extraction unit 72 exists outside the area 214, the extraction unit 72 selects a timing unrelated to the frame configuration. When the vehicle transmission period is selected, the extraction unit 72 outputs information on the frame and subframe timing and the vehicle transmission period to the carrier sense unit 74. When selecting the timing unrelated to the frame configuration, the extraction unit 72 instructs the carrier sense unit 74 to execute carrier sense.

  The carrier sense unit 74 receives information about the timing of the frames and subframes and the vehicle transmission period from the extraction unit 72. The carrier sense unit 74 determines the transmission timing by starting CSMA / CA within the vehicle transmission period. On the other hand, when the carrier sense unit 74 is instructed by the extraction unit 72 to execute carrier sense not related to the frame configuration, the carrier sense unit 74 performs transmission timing by executing CSMA / CA without considering the frame configuration. To decide. The carrier sense unit 74 notifies the modem unit 54 and the RF unit 52 of the determined transmission timing, and broadcasts the packet signal.

  The transfer determination unit 62 controls transfer of control information. The transfer determination unit 62 extracts information to be transferred from the control information. The transfer determination unit 62 generates information to be transferred based on the extracted information. Here, the description of this process is omitted. The transfer determination unit 62 outputs information to be transferred, that is, a part of the control information, to the generation unit 66.

  The acquisition unit 64 includes a GPS receiver (not shown), a gyroscope, a vehicle speed sensor, and the like. Based on data supplied from these, the location of the vehicle 12 (not shown), that is, the position of the vehicle 12 on which the terminal device 14 is mounted, the progress The direction, moving speed, etc. (as described above, collectively referred to as “position information”) are acquired. The existence position is indicated by latitude and longitude. The traveling direction is indicated by an azimuth angle, with north as a reference azimuth (0 degree) and clockwise as a positive angle. Since a known technique may be used for these acquisitions, description thereof is omitted here. The traveling direction is also called an azimuth angle. The acquisition unit 64 outputs these pieces of information to the generation unit 66, the storage unit 80, and the determination unit 84.

  The generation unit 66 receives information from the acquisition unit 64 and receives a part of control information from the transfer determination unit 62. The generation unit 66 generates a packet signal including these, and broadcasts the generated packet signal via the modem unit 54, the RF unit 52, and the antenna 50 at the transmission timing determined by the carrier sense unit 74. To do. This corresponds to inter-vehicle communication.

  The storage unit 80 receives position information and the like from the extraction unit 72 and position information and the like from the acquisition unit 64. The storage unit 80 stores at least one of the position information received in the past as travel history information. FIG. 5 shows the configuration of data stored in the storage unit 80. For example, the travel history information includes vehicle identification information, time information acquisition information, position information, speed information, and azimuth. As described above, the position information, the speed information, and the azimuth angle history for one vehicle 12 are stored along with the time change. Such a history is stored for a plurality of vehicles 12. Returning to FIG.

  Based on the travel history information stored in the storage unit 80, the estimation unit 82 determines whether the intersection at the intersection where at least two roads intersect, for example, whether the intersection at the intersection is a plane intersection or a three-dimensional intersection. Estimate if there is. Note that the terminal device 14 does not store information regarding the intersection situation at the intersection or map information.

  In the intersection situation estimation process, the estimation unit 82 first specifies an intersection point to be estimated. The estimation unit 82 extracts a plurality of intersections where two roads intersect from the position information of the vehicle 12 included in the travel history information. The intersection point is set based on the information of the intersection point where the traveling trajectories of the two vehicles 12 traveling in directions intersecting each other intersect. In addition, the estimation unit 82 acquires information related to the expected encounter point when it is determined that the host vehicle and the other vehicle encounter within a predetermined time in the collision prevention support, which will be described later. Here, the expected encounter point indicates an intersection or a point of intersection determined that the host vehicle and another vehicle encounter within a predetermined time. Furthermore, the estimation part 82 specifies the intersection corresponding to an expected encounter point among the extracted plurality of intersections. Following this, the estimation unit 82 estimates the type of intersection for the identified intersection (predicted encounter point). Hereinafter, the process will be described in more detail.

  The estimation unit 82 extracts information on the vehicle 12 passing through the specified intersection from the travel history information stored in the storage unit 80. In general, information for a plurality of vehicles 12 is extracted. More preferably, the information of the vehicle 12 that has passed the intersection from the same direction as the own vehicle and the information of the vehicle 12 that has passed the intersection from the same direction as the other vehicle that is determined to encounter the own vehicle in the determination unit 84 described later, respectively. Extract. Here, the process with respect to the vehicle 12 which passes an intersection is demonstrated using Fig.6 (a)-(b). 6A to 6B show an outline of processing in the estimation unit 82. FIG. In FIG. 6A, the first vehicle 400 travels on one of the two roads that intersect at the intersection, and the second vehicle 402 travels on the other. When the intersection at this intersection is a plane intersection, one of the first vehicle 400 and the second vehicle 402 stops before entering the intersection due to the priority relationship of the traffic signal or the intersection without the traffic signal. In addition, one of the stopped first vehicle 400 and second vehicle 402 starts. On the other hand, when the intersection at this intersection is a three-dimensional intersection, the first vehicle 400 and the second vehicle 402 pass through the intersection while maintaining a constant speed unless there is a traffic jam or the like.

  Based on the extracted information, the estimation unit 82 derives a change in speed when each vehicle 12 travels an intersection. This corresponds to, for example, calculating the difference between the maximum value and the minimum value of the speed of one vehicle 12 in a certain distance range centered on the intersection, for example, 20 m. In addition, the estimation unit 82 compares the change in speed with a threshold value. The threshold value is set to be a speed difference when the vehicle 12 stops before the intersection of the plane intersection, and a speed difference when the vehicle 12 stops after starting to decelerate, or a speed difference when acceleration starts from the stop. Is done. The estimation unit 82 performs such processing on each vehicle 12 to detect the vehicle 12 whose speed change exceeds the threshold value and the vehicle 12 that does not exceed the threshold value. When at least one vehicle 12 whose speed change exceeds a threshold is detected, the estimation unit 82 estimates that the intersection is a plane intersection, and in the case of only the vehicle 12 that does not exceed the threshold, Presume that the intersection is a three-dimensional intersection. More preferably, the estimation unit 82 derives a change in speed when the vehicle 12 travels the intersection based on the information of the vehicle 12 that has passed through the intersection from the same direction as the own vehicle. Based on the information of the vehicle 12 passing through the intersection from the same direction as the other vehicle that is determined to be encountered, a change in speed when the vehicle 12 travels the intersection is derived. The estimation unit 82 determines that the speed change exceeds a threshold value among the vehicle 12 that has passed the intersection from the same direction as the own vehicle and the vehicle 12 that has passed the intersection from the same direction as the other vehicle that is determined to encounter the own vehicle. When at least one vehicle 12 is detected, it is estimated that the intersection is a plane intersection. On the other hand, when the vehicle 12 that has passed the intersection from the same direction as the own vehicle and the vehicle 12 that has passed the intersection from the same direction as the other vehicle determined to encounter the own vehicle are only vehicles 12 that do not exceed the threshold, It is estimated that the point is a three-dimensional intersection.

  In FIG. 6B, the first vehicle 400 enters the intersection. When the intersection at the intersection is a plane intersection, the first vehicle 400 travels on one of the straight route 410, the left turn route 412, and the right turn route 414. On the other hand, when the intersection at this intersection is a three-dimensional intersection, the first vehicle 400 travels only on the straight route 410. Based on the extracted information, the estimation unit 82 derives a change in azimuth angle when each vehicle 12 travels an intersection. This corresponds to, for example, calculating the absolute value of the difference between the azimuth angle when one vehicle 12 enters the intersection and the azimuth angle when leaving the intersection. In addition, the estimation unit 82 compares the change in azimuth angle with a threshold value.

  The threshold value is set to a value that allows the straight path 410 to be identified with respect to the left turn path 412 and the right turn path 414 in FIG. The estimation unit 82 performs such processing on each vehicle 12 to derive the vehicle 12 whose change in azimuth angle exceeds the threshold value and the vehicle 12 that does not exceed the threshold value. When at least one vehicle 12 exceeding the threshold is detected, the estimation unit 82 estimates that the intersection is a plane intersection. When only the vehicle 12 that does not exceed the threshold is detected, the intersection is solid. Presumed to be an intersection. More preferably, the estimation unit 82 derives a change in the azimuth angle when the vehicle 12 travels the intersection based on the information of the vehicle 12 that has passed the intersection from the same direction as the own vehicle. Based on the information of the vehicle 12 passing through the intersection from the same direction as the other vehicle determined to encounter, the change in the azimuth angle when the vehicle 12 travels the intersection is derived. The estimation unit 82 determines whether the change in the azimuth angle has a threshold value among the vehicle 12 that has passed the intersection from the same direction as the host vehicle and the vehicle 12 that has passed the intersection from the same direction as the other vehicle that is determined to encounter the host vehicle. When at least one vehicle 12 that exceeds is detected, it is estimated that the intersection is a plane intersection. On the other hand, when the vehicle 12 that has passed the intersection from the same direction as the own vehicle and the vehicle 12 that has passed the intersection from the same direction as the other vehicle determined to encounter the own vehicle are only vehicles 12 that do not exceed the threshold, It is estimated that the point is a three-dimensional intersection.

  Note that the estimation unit 82 may estimate that it is finally a three-dimensional intersection when it is estimated that a three-dimensional intersection is caused by a change in speed and a three-dimensional intersection is estimated by a change in azimuth angle. On the other hand, when these conditions are not satisfied, it may be finally estimated that the plane intersects. As described above, at the intersection of the plane intersections, the vehicle 12 traveling in one of the lanes intersecting by signal control has a large speed change due to deceleration or acceleration, or a large change in azimuth angle due to a right or left turn or turning. The phenomenon of becoming is seen. On the other hand, if the intersection is a three-dimensional intersection, these changes do not occur, and the vehicle 12 passes through the intersection while maintaining a speed and azimuth within a certain range.

  Further, the estimation unit 82 may use altitude information in order to estimate whether the intersection is a three-dimensional intersection or a plane intersection. In this case, the altitude information acquired by GPS is included in the travel history information. The estimation unit 82 derives an altitude difference between the vehicles 12 traveling on each of the two roads intersecting at the intersection from the travel history information stored in the storage unit 80. The estimation unit 82 may derive one altitude difference by averaging a plurality of altitude differences. The estimation unit 82 compares the altitude difference with a threshold value. Here, the threshold value is set to a value about the vehicle height. The estimation unit 82 estimates that the intersection is a plane intersection when the difference in altitude is smaller than a threshold, and the intersection is a three-dimensional intersection when the difference in altitude is not smaller than the threshold. Estimated.

  Based on the information acquired by the acquisition unit 64 and the information from the extraction unit 72, the determination unit 84 derives the support to be provided from among the multiple types of support. The multiple types of support are, for example, right-turn collision prevention support, left-turn collision prevention support, encounter collision prevention support, and the like. Here, support for encounter collision prevention is the subject of explanation. In the encounter collision prevention support (vehicle-to-vehicle communication), the driver is notified of the presence of an approaching vehicle when another vehicle is approaching so as to intersect when the host vehicle goes straight. FIG. 7 shows encounter collision prevention support in the determination unit 84. The host vehicle 300 moves from the bottom to the top as shown by the arrow, and the other vehicle 302 moves from the right to the left as shown by the arrow. Further, the routes of the own vehicle 300 and the other vehicle 302 intersect at an intersection 310. Here, the determination unit 84 acquires the position / velocity / acceleration / azimuth angle of the host vehicle 300 from GPS or an in-vehicle network, for example, a controller area network (CAN), as information from the host vehicle 300.

  Further, the determination unit 84 acquires the position / velocity / acceleration / azimuth angle of the other vehicle 302 as information from the other vehicle 302. Based on these pieces of information, the determination unit 84 (i) the positional relationship between the own vehicle 300 and the other vehicle 302 is an intersection, and (ii) the own vehicle 300 and the other vehicle 302 meet within a predetermined time. If so, decide to help prevent encounters. The determination unit 84 responds to the intersection when the encounter collision prevention support is determined, that is, when the intersection of the own vehicle 300 (vehicle 12) and the other vehicle 302 (other vehicle 12) is expected at the intersection. Whether to notify the presence of the other vehicle 302 (other vehicle 12) is determined according to the crossed situation. Here, when the estimation unit 82 estimates a plane intersection, notification of the presence of the other vehicle 302 (other vehicle 12) is determined. On the other hand, when the estimation unit 82 estimates a three-dimensional intersection, non-notification of the presence of the other vehicle 302 (other vehicle 12) is determined.

  When the notification is determined by the determination unit 84, the notification unit 70 displays a message for preventing encounter collision, for example, “attention to the vehicle from the side” on a monitor (not shown). Moreover, the notification part 70 may display the map image in a car navigation system. Moreover, in addition to the display by the notification unit 70, notification by voice or the like may be performed together. Note that the notification unit 70 does not display a message when the determination unit 84 determines non notification.

  The operation of the communication system 100 configured as above will be described. FIG. 8 is a flowchart showing an estimation procedure by the estimation unit 82. The estimation unit 82 extracts information about the vehicle 12 that may intersect from the storage unit 80 (S10). The estimation unit 82 derives a speed difference before and after the intersection (S12). If the speed difference is larger than the threshold value (Y in S14), the estimating unit 82 estimates that the intersection is a plane intersection (S16). On the other hand, if the speed difference is not greater than the threshold value (N in S14), the estimating unit 82 estimates that the intersection is a three-dimensional intersection (S18).

  FIG. 9 is a flowchart showing another estimation procedure by the estimation unit 82. The estimation unit 82 extracts information about the vehicle 12 that may intersect from the storage unit 80 (S30). The estimation unit 82 derives the displacement of the azimuth angle before and after the intersection (S32). If the change in azimuth is larger than the threshold value (Y in S34), the estimation unit 82 estimates that the intersection is a plane intersection (S36). On the other hand, if the change in azimuth is not greater than the threshold (N in S34), the estimating unit 82 estimates that the intersection is a three-dimensional intersection (S38).

  FIG. 10 is a flowchart showing still another estimation procedure by the estimation unit 82. The estimation unit 82 extracts information about the vehicle 12 that may intersect from the storage unit 80 (S50). The estimation unit 82 derives an altitude difference at the intersection (S52). If the altitude difference is larger than the threshold value (Y in S54), the estimating unit 82 estimates that the intersection is a three-dimensional intersection (S56). On the other hand, if the altitude difference is not greater than the threshold value (N in S54), the estimation unit 82 estimates that the intersection is a plane intersection (S58).

  FIG. 11 is a flowchart illustrating a procedure for determining support by the terminal device 14. When there is another vehicle with a possibility of crossing (Y in S70) and a plane crossing (Y in S72), the determination unit 84 performs driving support (S74). If there is no other vehicle that may be intersected (N in S70), or if it is not a plane intersection (N in S72), step 74 is skipped.

  According to the embodiment of the present invention, since the intersection situation at the intersection is estimated based on the travel history information, the amount of information used for estimating the intersection situation can be increased. Moreover, since the amount of information used for estimating the intersection situation is increased, the estimation accuracy can be improved. In addition, since it is determined whether to notify the presence of another vehicle according to the intersection situation, it is possible to execute a collision determination according to the intersection situation. Moreover, since the collision determination according to the intersection state is executed, it is possible to suppress the erroneous collision determination at the intersection without using the map information. In addition, if it is estimated that the intersection is a plane intersection, the notification of the presence of another vehicle is determined, so the driver can be informed of the danger. Further, if the intersection situation is estimated as a three-dimensional intersection, non-notification of the presence of another vehicle is determined, so unnecessary notification can be omitted. Moreover, since it is estimated whether it is a plane intersection or a three-dimensional intersection based on the change in speed, collision misjudgment at the intersection can be suppressed without using map information. Moreover, since it is estimated whether it is a plane intersection or a three-dimensional intersection based on the change of an azimuth angle, the erroneous determination of a collision at an intersection can be suppressed without using map information. Moreover, since it is estimated whether it is a plane intersection or a three-dimensional intersection based on the combination of a change in speed and a change in azimuth, estimation accuracy can be improved. Moreover, since it is estimated whether it is a plane intersection or a three-dimensional intersection based on an altitude difference, it is possible to suppress erroneous collision determination at an intersection without using map information.

  In the above, this invention was demonstrated based on the Example. This embodiment is an exemplification, and it will be understood by those skilled in the art that various modifications can be made to each of those constituent elements or combinations of processing processes, and such modifications are also within the scope of the present invention. .

  In this embodiment, position information and the like are included in the packet signal, and traveling history information is formed in the storage unit 80 by accumulating this. However, the present invention is not limited to this. For example, traveling history information may be included in some packet signals. According to this modification, the travel history information stored in the storage unit 80 can be formed early.

  In the present embodiment, when the estimation unit 82 estimates a three-dimensional intersection, the estimation unit 82 outputs only that to the determination unit 84. However, the present invention is not limited to this, and for example, the estimation unit 82 may output the fact to the storage unit 80 and the generation unit 66 when estimating the solid intersection. The information on the solid intersection stored in the storage unit 80 is used when the vehicle 12 next travels in the vicinity of the intersection, so that the estimation process of the estimation unit 82 is omitted. In addition, the generation unit 66 transmits the information of the solid intersection including the packet signal to notify the other terminal devices 14 of the presence of the solid intersection. According to the present modification, the process for estimating the intersection is omitted, so that the process can be simplified.

  In the present embodiment, the estimation unit 82 estimates that the intersection is a plane intersection when detecting at least one vehicle 12 whose speed change exceeds the threshold value. However, the present invention is not limited thereto, and for example, the estimation unit 82 may estimate that the intersection is a plane intersection when two or more vehicles 12 whose speed change exceeds a threshold value are detected. According to this modification, it is possible to reduce the influence of errors included in the speed change.

  In this embodiment, the estimation unit 82 estimates that the intersection is a plane intersection when at least one vehicle 12 whose change exceeds the threshold value is detected. However, the present invention is not limited thereto, and for example, the estimation unit 82 may estimate that the intersection is a plane intersection when two or more vehicles 12 whose azimuth angle changes exceed a threshold value are detected. According to this modification, it is possible to reduce the influence of errors included in the change in azimuth angle.

  The outline of one embodiment of the present invention is as follows. A wireless device according to an aspect of the present invention is a wireless device that can be mounted on a vehicle, an acquisition unit that acquires position information of the vehicle on which the wireless device is mounted, and a packet signal from another wireless device. In addition, a receiving unit that receives a packet signal including position information of another vehicle on which the other wireless device is mounted, a position information included in a packet signal received in the past by the receiving unit, and an acquiring unit A storage unit that stores at least one of position information acquired in the past as travel history information, and an estimation that estimates an intersection situation at an intersection where at least two roads intersect based on the travel history information stored in the storage unit The vehicle and other vehicles are expected to intersect at the intersection based on the position information acquired by the transmission unit, the position information acquired by the acquisition unit, and the position information included in the packet signal received by the reception unit. When it is provided in accordance with the cross situation corresponding to the intersection, a determination unit that determines whether to notify the presence of other vehicles, the.

  According to this aspect, the crossing situation at the crossing point is estimated based on the travel history information, and it is determined whether or not to notify the presence of another vehicle. Therefore, it is possible to execute the collision determination according to the crossing situation.

  The estimation unit estimates whether the intersection is a plane intersection or a three-dimensional intersection, and the determination unit may determine the notification of the presence of another vehicle when the estimation unit estimates that the intersection is a plane intersection. . In this case, since the notification of the presence of another vehicle is determined when it is estimated that the plane is crossed, it is possible to notify the danger, and when it is estimated that it is a three-dimensional intersection, the non-notification of the presence of the other vehicle is determined. Can be omitted.

  The estimation unit estimates from the travel history information stored in the storage unit that the intersection is a plane intersection when the speed of at least one vehicle has changed beyond the threshold at the intersection. Also good. In this case, since it is estimated whether it is a plane intersection or a three-dimensional intersection based on the change in speed, it is possible to suppress erroneous collision determination at the intersection without using map information.

  The estimation unit estimates that the intersection is a plane intersection when the azimuth angle of at least one vehicle has changed beyond the threshold at the intersection from the travel history information stored in the storage unit. May be. In this case, since it is estimated whether it is a plane intersection or a three-dimensional intersection based on the change of the azimuth angle, it is possible to suppress the erroneous collision determination at the intersection without using the map information.

  The estimation unit determines that the intersection is a plane intersection when the difference in altitude between the vehicles traveling on each of the two roads intersecting at the intersection is smaller than the threshold from the travel history information stored in the storage unit. May be estimated. In this case, since it is estimated whether it is a plane intersection or a three-dimensional intersection based on the altitude difference, it is possible to suppress erroneous collision determination at the intersection without using map information.

  10 base station device, 12 vehicle, 14 terminal device, 20 antenna, 22 RF unit, 24 modulation / demodulation unit, 26 processing unit, 28 control unit, 30 network communication unit, 32 frame definition unit, 34 selection unit, 36 generation unit, 50 Antenna, 52 RF unit, 54 modulation / demodulation unit, 56 processing unit, 58 control unit, 60 timing identification unit, 62 transfer determination unit, 64 acquisition unit, 66 generation unit, 70 notification unit, 72 extraction unit, 74 carrier sense unit, 80 A storage unit, 82 estimation unit, 84 determination unit, 100 communication system.

Claims (2)

A wireless device that can be mounted on a vehicle,
Position information of the vehicle to which the present wireless device is mounted, traveling direction, traveling speed, and the acquisition unit for acquiring the altitude information,
Different wireless devices different from each other are mounted on each of the plurality of other vehicles, which are packet signals from the plurality of other wireless devices , and each of the plurality of other wireless devices is mounted. A receiving unit that receives a packet signal including position information , traveling direction, moving speed, altitude information, and identification information of another vehicle;
Position information , travel direction, moving speed, altitude information, identification information included in packet signals from a plurality of other wireless devices received in the past in the reception unit, position information acquired in the past in the acquisition unit, and progress A storage unit for storing direction, moving speed, and altitude information as travel history information;
Based on the travel history information stored in the storage unit, an intersection where at least two roads intersect is extracted, and it is determined that the vehicle and the second vehicle of the other vehicles meet within a predetermined time. It is determined that, with respect to an intersection, information on a plurality of first vehicles among other vehicles that have passed through the intersection from the same direction as the main vehicle out of the travel history information stored in the storage unit and the vehicle is encountered. Based on the information of a plurality of third vehicles among other vehicles that have passed through the intersection from the same direction as the second vehicle of the other vehicles, the intersection is a plane intersection or a three-dimensional intersection An estimation unit for estimating
Based on the positional information , traveling direction, moving speed acquired in the acquiring unit, and positional information , traveling direction, moving speed, identification information included in the packet signal received in the receiving unit, the route of the vehicle At the intersection where the route with the second vehicle intersects, when the vehicle and the second vehicle are expected to encounter within a predetermined time, if the intersection is estimated to be a plane intersection, the estimation unit estimates A decision unit that decides to notify the presence of the second vehicle, and decides not to notify the presence of the second vehicle if the estimation unit estimates that the intersection is a three-dimensional intersection ;
With
The estimation unit is configured to calculate between the plurality of first vehicles and the plurality of third vehicles traveling on each of two roads intersecting at an intersection from the altitude information included in the travel history information stored in the storage unit. A radio apparatus characterized by estimating that the intersection is a plane intersection when the difference in altitude is smaller than a threshold value. A transmission unit that transmits a packet signal including position information of the vehicle on which the wireless device is mounted;
The radio apparatus according to claim 1, wherein the transmission unit includes information on whether the intersection is a plane intersection or a three-dimensional intersection estimated in the estimation unit, and transmits the packet signal. .

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