JP2007214986A - Communications equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently and stably transfer packets to a transmitting destination in a network for making communication between vehicles feasible. <P>SOLUTION: An in-vehicle system of each vehicle constituting the network determines a path along a road from own vehicle position to the center of a packet transmitting destination area as a transmission path of the packets (S150), when there is an input of data transmission instruction. In addition, the transfer area of the packets is determined from the self-vehicle position to the direction of a terminal point of the transmission path according to the transmission path, in an area where own vehicle can perform radio communication and the packet in the header information of which the content and the transmitting destination area are described is transmitted to the network. The in-vehicle system within the transfer area which receives the packet determines the transfer area of the packet, according to the transmission path from the self-vehicle position to the direction of the terminal point of the transmission path in the area, where the self-vehicle can perform radio communication and generates a transfer packet in the header information of which the transfer area, is described. In the present invention, the packets are transferred sequentially to the transmitting destination area, in this way. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vehicle-mounted communication device.

  Conventionally, as inter-vehicle communication, a method is known in which an ad hoc network is configured by a wireless communication device mounted on each vehicle to perform communication. In addition, as an ad hoc network, each node periodically acquires position information of nodes existing in the vicinity, and forwards a packet to a node located in the same direction as the final destination point, thereby Is known that forwards packets to the final destination point (for example, see Patent Document 1).

  Further, as this type of network, there is also known a network that transfers a packet to a final destination point without acquiring position information of nodes existing in the vicinity. Specifically, the packet transmission area (transmission angle) is set in the vector direction extending from the transmission source point to the final transmission destination point at the transmission source node, and the packet reception node automatically starts from the transmission source point. When the vector extending to the current location of the device and the vector extending from the current location of the device to the final destination location are both within the transmission area, the packet is transferred to the final transmission from the source. One that transfers a packet to a destination point is known (see, for example, Patent Document 2).

As another network, a source node searches for a route along a road from a source point to a final destination point, and based on a vector of each link constituting the route, a packet transmission area ( A transmission angle is set, and packets are sequentially transferred from a transmission source to a final transmission destination point (see, for example, Patent Document 2).
JP 2004-310484 A JP 2005-045340 A

  However, conventionally, in a network that communicates between nodes that move at high speed, such as automobiles, even if it tries to periodically acquire the position information of the nodes existing in the vicinity and transfer the packet from the transmission source to the final transmission destination point In some cases, it is difficult to accurately grasp the current position of each node that moves at high speed, and packets cannot be forwarded to an appropriate node. That is, there is a case where the packet cannot be appropriately transferred because the position information acquired in advance is different from the current position of each node.

  In addition, as a conventional technique, there is known a network that realizes packet transfer without periodically acquiring position information of nodes existing in the vicinity. In this type of network, a packet is transmitted at a transmission source node. The transmission area (transmission angle) is set and the packet is forwarded in the direction that matches the final destination point according to this setting, so the road does not extend in the direction where the final destination point exists. When there are radio wave obstacles such as high-rise buildings and hills, packets may not be transferred properly.

  Further, as a conventional technique, the above problem is solved by searching a route along the road from the transmission source point to the final transmission destination point, and expanding the transmission area based on the vector of each link constituting the route. A technique for solving the problem is known. However, when such a technique is adopted, there is a problem in that useless packet transfer is increased because a transmission area (angle) is widened.

  The present invention has been made in view of these problems, and an object of the present invention is to provide a technique capable of transferring a packet to a destination point more efficiently and stably than in the past.

  The communication device according to claim 1, which has been made to achieve such an object, is a packet storing transmission target data designated by an input source of a data transmission command when a data transmission command is input, A packet in which the destination point designated from the command input source is recorded as attached information is generated by the packet sending means, and the packet is sent to the network via the wireless communication means.

  Specifically, when a data transmission command is input, the packet transmission means transmits the data along the road starting from the current position of the vehicle and ending at the destination point designated from the input source of the data transmission command. In the area where wireless communication means can communicate, determine the route, determine the packet transfer range from the current position of the vehicle to the end point of the data transmission route, and input the data transmission command in accordance with the data transmission route. A packet that stores the transmission target data designated from the beginning and that includes the determined data transmission path and transfer range, and the destination point as auxiliary information is generated.

  Further, when the communication apparatus receives the packet via the wireless communication means, the communication apparatus determines whether the destination determination means is based on the destination location indicated by the received packet and the current position of the vehicle indicated by the current position information acquired by the position information acquisition means. If the received packet is a packet addressed to the own device, and the received packet is determined to be a packet addressed to the own device, the data receiving means determines that the received packet is a packet addressed to the own device. To process.

  In addition, when the communication device receives the packet, the communication device determines whether it is necessary to transfer the received packet based on the current information of the vehicle indicated by the attached information described in the received packet and the acquisition information of the position information acquisition means. When it is determined by the transfer necessity determination unit and it is determined that the transfer of the received packet is necessary, the packet transfer unit generates a transfer packet based on the received packet, and the generated transfer packet is transferred to the wireless communication unit. Via the network.

  Specifically, the transfer necessity determination means determines that the transfer of the received packet is necessary when the own vehicle exists within the transfer range indicated by the received packet and the received packet is not a packet addressed to the own device, When the transfer means determines that the transfer of the received packet is necessary by the transfer necessity determination means, the transfer means determines the current vehicle's current state in accordance with the data transmission path indicated by the received packet in the area where the wireless communication means can communicate. A packet transfer range is determined from the position toward the end point of the data transmission path. Then, the packet transfer means replaces the transfer range indicated by the received packet with the determined transfer range, generates a transfer packet, and sends the generated transfer packet to the network via the wireless communication means.

  In this way, in the present invention, instead of determining the data transmission direction at the packet transmission source device, the data transmission route is determined and described in the packet, and at the transfer destination device, the data transmission route is determined. Based on the above, the transfer range of the packet is determined. Therefore, if the network is configured using the communication apparatus of the present invention, it is possible to suppress the packet transfer from being chained in an unnecessary direction, and to follow the data transmission path determined by the packet transmission source apparatus. Thus, the packet can be efficiently transferred to the destination point. In addition, since the packet is transferred along the data transmission path, in the present invention, it is possible to prevent the obstruction of the transfer of the packet by the radio wave obstacle, rather than transferring the packet linearly in the direction of the destination point. it can. Therefore, according to the present invention, the packet can be transferred to the transmission destination point more efficiently and stably than before, and stable vehicle-to-vehicle communication can be realized.

  An example of a method for determining the packet transfer range in accordance with the data transmission path is a method for determining the packet transfer range so that a part of the data transmission path is included in the transfer range.

  In addition, the packet transfer means can be configured to determine the transfer range of the packet by arranging the farthest point from the current position of the own vehicle on the data transmission path. According to the communication apparatus configured as described above (claim 2), the vehicle exists at a point farthest from the current position of the host vehicle that can transfer the packet most efficiently within the packet transfer range. Since the packet is arranged on a highly likely data transmission path, as a result, the packet can be efficiently transferred. As for the method for determining the packet transfer range, the same method as the packet transfer means may be applied to the packet sending means.

  Further, the packet transfer range may be a fixed shape, and in particular, a circle. If the fixed area is a packet transfer range, the transfer range can be expressed by a simple parameter, and the amount of data related to the transfer range in the packet can be reduced. In addition, it is possible to determine whether or not the current position of the host vehicle is within the transfer range by a simple calculation.

  Further, when the communication apparatus is configured so as to determine the packet transfer range in a circle based on the current position of the host vehicle, the packet transfer means may be configured as follows. That is, the packet transfer means may be configured to determine the packet transfer range by matching the intersection of the current position of the vehicle and the straight line passing through the center point of the circle and the arc on the data transmission path. . According to the communication apparatus configured as described above (claim 3), the farthest end of the circle facing the current position of the host vehicle can be aligned on the data transmission path. Therefore, if a network is configured using this communication apparatus, packets can be efficiently transferred along the data transmission path to the destination point.

  However, if the packet transfer range is determined as described above at a location where the data transmission path is greatly bent, an intersection located at the bending point may not be within the packet transfer range (FIG. 6 ( a)). At intersections and the like, since the vehicle density is high, if such an intersection does not fall within the packet transfer range, the probability of packet transfer failure increases, and the stability of communication is impaired.

  Accordingly, the packet transfer means may be configured as follows. That is, the packet transfer means is configured to determine the transfer range of the packet in a circle with the current position of the vehicle as a base point so that a specific point inside the circle (for example, the center of the circle) is aligned on the data transmission path. The packet transfer range may be determined.

  According to the communication apparatus configured as described above (claim 4), there is a possibility that the number of packet transfers increases when viewed from the whole network. However, as shown in FIG. Since it is possible to prevent an intersection or the like from deviating from the packet transfer range around the inflection point, stable vehicle-to-vehicle communication can be realized.

  In addition, as described in claim 5, the packet transfer means may be configured to determine an area having a predetermined width around the data transmission path as a packet transfer range along the data transmission path. Even when the packet transfer range is determined in this way, the transfer range can be expressed with simple parameters, as in the case of determining the transfer range in a circle, and the amount of data related to the transfer range in the packet can be suppressed. Can do.

  Further, when all the vehicles (communication devices) existing within the packet transfer range execute the packet transfer operation, the load on the network increases. Therefore, the communication device of the present invention is specifically configured as follows. Good.

  That is, the communication device is provided with a setting unit that sets a waiting time according to the current position of the vehicle with respect to the transfer range indicated by the received packet when the packet is received through the wireless communication unit. If it is determined by the refusal determining means that the received packet needs to be transferred, the generated transfer packet is sent to the network via the wireless communication means after the waiting time set by the setting means has elapsed. It is good to be done. In addition, in this communication device, a transfer packet scheduled to be transmitted by the packet transfer unit and a packet whose original packet (original packet) is the same in a period until the standby time set by the setting unit elapses. It is preferable to provide prohibiting means for prohibiting transmission of transfer packets by the packet transfer means when the number of received packets exceeds the upper limit number.

  According to the communication device configured in this way (Claim 6), when a predetermined number of other vehicles transfer the same type of packet, the transfer of the packet is stopped, so that network traffic can be suppressed. it can. In addition, as an original packet here, the packet produced | generated by the transmission origin vehicle and the packet produced | generated by the 1st transfer origin vehicle can be mentioned.

  Further, according to this communication device, since the standby time is set according to the current position of the vehicle with respect to the transfer range indicated by the received packet, the packet is efficiently transmitted to the destination point even if the upper limit is set for the number of transfer packets. Can be transferred. For example, the packet can be efficiently transferred to the transmission destination point by shortening the waiting time of the vehicle near the transmission destination point.

  In the communication apparatus, the packet sending means and the packet transfer means are configured so that the current position of the own vehicle is recorded in the packet as attached information, and the setting means is data corresponding to the position of the transfer source vehicle indicated by the received packet. The distance along the data transmission path from the point on the transmission path to the point on the data transmission path corresponding to the current position of the host vehicle is calculated, and the longer the distance, the shorter the standby time is set. Good.

  If the network is configured using the communication device configured as described above (claim 7), the packet can be preferentially transferred from the communication device close to the destination point within the packet transfer range, and the efficiency Thus, the packet can be transferred to the destination point.

  Further, as set forth in claim 8, the setting means calculates a distance along the data transmission path from the transmission destination point indicated by the received packet to the current position of the host vehicle, and the longer the calculated distance, the longer the standby time. May be configured to be set longer. If a network is configured using a communication device provided with setting means having such a configuration, packets can be preferentially transferred from a communication device close to the transmission destination point in the same manner as the communication device (Claim 7). The packet can be efficiently transferred to the destination point.

  In addition, the setting unit may be configured as follows. That is, the setting means is a distance along a straight line connecting the position of the transfer source vehicle indicated by the received packet and a point within the transfer range indicated by the receive packet farthest from the transfer source vehicle, and the position of the transfer source vehicle The distance from the vehicle to the current position of the vehicle may be calculated, and the longer the distance, the shorter the standby time may be set.

  Even when a network is configured using a communication apparatus having such a configuration means, packets can be preferentially transferred from a communication apparatus close to the transmission destination point, and the packet can be efficiently transmitted to the transmission destination. Can be transferred to a point. Further, in this communication device (claim 9), the distance required for setting the standby time can be obtained with a smaller amount of calculation than the communication device that calculates the distance along the data transmission path.

  In addition, the communication device including the prohibition unit includes a congestion determination unit that determines the vehicle congestion around the host vehicle. The upper limit setting unit determines the prohibition unit based on the determination result of the congestion determination unit. The communication device may be configured to set the upper limit number for the.

  If the network is configured using the communication apparatus configured as described above (claim 10), it is possible to suppress an increase in the load on the network in an area where the vehicle density is high. Further, in an area where the vehicle density is low, stable inter-vehicle communication can be realized by increasing the upper limit number.

  Further, in order to suppress the load on the network, the packet transfer range may be determined to a size corresponding to the vehicle congestion around the host vehicle. By using the communication device configured as described above (claim 11), the transfer range is reduced in an area where the vehicle density is high, and the transfer range is increased in an area where the vehicle density is low. The number of vehicles that fall within the range can be adjusted, and stable inter-vehicle communication can be realized while suppressing an increase in the network load.

  In addition, the transfer necessity judgment means may determine whether the own vehicle exists within the transfer range indicated by the received packet even if the own vehicle is not on the data transmission route, and the received packet is not a packet addressed to the own device. It may be configured to determine that the transfer of the received packet is necessary. However, if the transfer necessity determination unit is configured in this way, the possibility that the packet is transferred from a point other than the road increases, There is a high possibility that a packet will be transferred from a place surrounded by the poor communication environment. Such a phenomenon may slightly affect the stability of communication when an upper limit is imposed on the number of transfer packets.

  Therefore, the transfer necessity determination unit may be configured to determine that the transfer of the received packet is not necessary when the vehicle is not present on the data transmission path indicated by the received packet. If the network is configured using the communication device configured as described above (claim 12), the packet is not transferred from a point other than the data transmission path, so that the packet transfer fails due to radio wave interference or the like. The possibility can be sufficiently suppressed.

  However, if the conditions for packet transfer are strict, the number of vehicles that can take over packet transfer is reduced around the transfer source vehicle, and the possibility of packet transfer failure increases. Is preferably provided with a retransmission function of the transfer packet.

  In other words, the above-mentioned communication device has a reception determination for determining whether or not a transfer packet having the same original packet as the transfer packet sent by the packet transfer means has been received from the communication device of another vehicle after sending this transfer packet. If the reception determination unit determines that the transfer packet having the same original packet has not been received from the communication device of another vehicle, the packet transfer unit firstly It may be configured to generate a new transfer packet in place of the transmitted transfer packet and to send it to the network via the wireless communication means. Specifically, the packet transfer means re-determines the packet transfer range in the same manner as the previously transmitted transfer packet, based on the attached information possessed by the received packet that caused the previously transmitted transfer packet to be generated. In accordance with this determination content, a new transfer packet can be generated.

  According to the communication apparatus configured as described above (claim 13), after sending the transfer packet, it is confirmed that the same type of transfer packet is flowing in the network. Since retransmission is performed, packet transfer can be prevented from being interrupted. Therefore, if a network is configured using this communication device, more stable vehicle-to-vehicle communication can be realized.

  In addition, when it is determined that the original packet does not receive the same transfer packet from the communication device of the other vehicle, the packet transfer means has a transfer range wider than the transfer range described in the transfer packet sent earlier. It is preferable that a new transfer packet with the above is generated.

  By configuring the packet transfer means in this way, the transfer range can be reduced during initial packet transfer to reduce the network load, and the packet can be transferred by expanding the transfer range during packet retransmission. It is possible to suppress failure again. That is, according to this communication apparatus (claim 14), the packet can be transferred efficiently and stably.

  In addition, there are vehicles traveling in a direction deviating from the data transmission path within the packet transfer range, and in such vehicles, wireless communication is possible at the time of packet transfer (for example, at the time of retransmission of the transfer packet). There may be no data transmission path in the region. In this case, it is conceivable to determine the packet transfer range in the direction in which the data transmission path is located, but when the transfer range is determined in this way, the packet transfer range is determined regardless of the road installation status. Therefore, the probability that there is no vehicle in the transfer range increases.

  In addition, if the communication device is configured to determine the packet transfer range so that the data transmission path is always included in the transfer range, the packet transfer range can be determined until the vehicle approaches the data transmission path. As a result, the packet cannot be transferred indefinitely.

  Therefore, the above-described packet transfer means may be provided with a function for changing the data transmission path. That is, when there is no data transmission path in the area where the wireless communication means can communicate, the packet transfer means transmits a new route along the road from the current position of the vehicle to the destination point indicated by the received packet. In the area that is determined as the transmission path and can be communicated by the wireless communication means, the packet transfer range is determined from the current position of the own vehicle to the end point of the data transmission path in accordance with the determined data transmission path, and received. The transfer range indicated by the packet may be replaced with the determined transfer range, and the data transmission path indicated by the received packet may be replaced with the determined data transmission path to generate the transfer packet.

  If a network is configured using the communication apparatus configured as described above (claim 15), the probability of packet transfer failure can be further reduced, and more stable vehicle-to-vehicle communication can be realized.

  Further, the packet sending means may be configured to determine, as a data transmission route, a route in which a main road is preferentially selected from routes from the current position of the host vehicle to a destination point. According to the communication device thus configured (claim 16), packets can be transferred from a transmission source point to a transmission destination point along a high-traffic main road, and packets can be stably transmitted. , Can be transferred to the destination point.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1A is an explanatory diagram illustrating the configuration of the in-vehicle system 1 of the first embodiment, and FIG. 1B is an explanatory diagram illustrating the operation of the communication control unit 33 included in the wireless communication device 30. . FIG. 2 is an explanatory diagram showing an ad hoc network realized by a group of vehicles including the in-vehicle system 1.

  As shown in FIG. 1, the in-vehicle system 1 according to the present embodiment has a configuration in which a navigation device 10 and a wireless communication device 30 mounted on a vehicle are connected so as to communicate with each other in the vehicle. The navigation device 10 includes a GPS receiver 11, a map database 13, a display unit 15 including a liquid crystal display and a speaker, a VICS communication unit 17, an operation switch group 19, and a navigation control unit that performs overall control thereof. 21 and an interface unit 23 connected to the wireless communication device 30, and performs route guidance and the like according to instructions from the user (vehicle occupant).

  Specifically, the GPS receiver 11 receives a transmission radio wave from a GPS (Global Positioning System) satellite, detects the current position of the own vehicle, and inputs a detection signal representing the current position to the navigation control unit 21. To do. The map database 13 stores map data and inputs map data to the navigation control unit 21 in accordance with instructions from the navigation control unit 21. The map database 13 includes, as map data, data representing road connection relationships (link and node data), terrain data, facility data, etc., as well as voice data for route guidance.

  In addition, the VICS communication unit 17 exchanges information with a beacon laid on a road, and acquires road traffic information and the like from a VICS (Vehicle Information Communication System) center through the beacon. In addition, traffic information etc. can be mentioned as road traffic information.

  The operation switch group 19 includes a touch panel configured integrally with the display unit 15 and mechanical key switches provided around the display unit 15. In addition, the navigation control unit 21 includes a CPU, a RAM, a ROM, and the like, and executes various programs stored in the ROM, thereby performing overall control of each unit in the apparatus, as well as a map display function, a route search function, a destination A route guidance function is provided.

  For example, the navigation control unit 21 acquires map data around the current location of the vehicle from the map database 13 based on the current location of the vehicle indicated by the detection signal of the GPS receiver 11, and based on the map data, Is displayed on the display unit 15. In addition, when a route search command is input, the navigation control unit 21 functions as the route search unit 21a, and selects an optimal route (route along the road) from the current location of the vehicle to a designated point. A search is performed using a known technique such as a method, and this route information is output to the command input source.

  In addition, when a route guidance command is input from the user through the operation switch group 19, the navigation control unit 21 calculates an optimum route from the current location of the vehicle to the designated destination through the route search unit 21a. This route guidance is performed through the display unit 15. Specifically, the guidance route is displayed with a thick line, etc., overlaid on the map around the current location of the vehicle, and the turning direction of the vehicle near the intersection according to the movement of the vehicle by voice through a speaker. invite.

  In addition, the navigation device 10 according to the present embodiment has various application software for communicating with other vehicles through the wireless communication device 30, and the navigation control unit 21 executes the application software to thereby execute the wireless communication device. Through 30, it communicates with other vehicles. Examples of the application software include application software that transmits a traffic information request command to an area designated by the user and acquires the traffic information from a vehicle in the area.

  The wireless communication device 30 includes a wireless communication unit 31, a communication control unit 33, a timer 35, and an interface unit 37 connected to the navigation device 10. In the wireless communication device 30, the wireless communication unit 31 receives a wireless signal transmitted from the outside, extracts a packet from the received signal, and inputs the packet to the communication control unit 33. The packet input from 33 is converted into a radio signal and output from the antenna.

  The communication control unit 33 includes a CPU, a ROM, a RAM, and the like. When a data transmission command is input through the application software, the communication control unit 33 stores transmission target data designated by the data transmission command input source (application software). Transmission destination area information indicating the transmission destination area designated from the input source of the data transmission command, and transmission path information indicating the transmission path of the packet from the current position of the vehicle to the center Pe of the transmission destination area And a transfer range information indicating the transfer range of the packet is generated, and the packet is transmitted to the network via the wireless communication unit 31.

  In addition, when the communication control unit 33 receives a packet from the outside via the wireless communication unit 31, the received packet is a packet addressed to the own vehicle based on the transmission destination area information included in the received packet and the current position of the own vehicle. If it is determined whether the received packet is a packet addressed to the own vehicle, this packet is output to the corresponding application software.

  In addition, when the communication control unit 33 receives the packet, the communication control unit 33 determines whether or not the vehicle is in the packet transfer range based on the transfer range information described in the received packet. The packet transfer range is determined in the area where the radio signal from the vehicle arrives so as to match the transmission path indicated by the transmission path information described in the received packet, and the transfer packet describing the transfer range is wirelessly communicated. The data is sent to the network via the unit 31.

  In the present embodiment, by the operation of the communication control unit 33 as described above, a packet transmitted from the transmission source vehicle is transmitted through a plurality of vehicles from the transmission source point to the transmission destination area indicated by the packet ( The data is transferred along the thick line shown in FIG. 2, and data is provided from the transmission source vehicle to the vehicle existing in the transmission destination area.

  Below, the detail of operation | movement of this communication control part 33 is demonstrated. FIG. 3 is a flowchart showing packet generation and transmission processing executed by the communication control unit 33 when a data transmission command is input through the application software.

  When the packet generation / transmission process is started, the communication control unit 33 first generates a packet number attached to a newly generated packet (S110). The packet number is a packet-specific number, and the communication control unit 33, for example, combines the individual number of the wireless communication device 30 and the serial number of the packet generated in the packet generation / transmission process as a packet number, A unique number is generated that does not overlap with other packets generated on the network (except for a transfer packet that uses this packet as an original packet).

  When this processing is completed, the communication control unit 33 proceeds to S120, and the transmission destination indicating the position (latitude and longitude) of the center Pe of the transmission destination area designated from the input source of the data transmission command and the area radius r Generate area information. When the processing in S120 is completed, the communication control unit 33 acquires the current position information of the own vehicle from the navigation control unit 21 (S125), and based on this information, the current position (latitude and longitude) of the own vehicle is obtained. The transmission source point information that represents the current position (latitude and longitude) of the host vehicle is generated (S130).

  In addition, when the processing in S130 is completed, the communication control unit 33 proceeds to S140, and displays a route along the road from the current point P0 of the host vehicle to the center Pe of the transmission destination area. The route search unit 21a is caused to search, and route information representing the route between the points P0 and Pe is acquired from the route search unit 21a. Based on this acquired information, transmission path information representing the transmission path of the packet between the points P0 and Pe is generated (S150). The packet transmission path is the same as the path indicated by the path information acquired from the path search unit 21a.

  In addition, when the transmission path information is generated in this way, the communication control unit 33 proceeds to S160, sets the generated transmission path information and transmission destination area information as reference targets, and performs transfer range information generation processing shown in FIG. Execute. FIG. 4 is a flowchart showing transfer range information generation processing executed by the communication control unit 33.

  When the transfer range information generation process is started, the communication control unit 33 searches for a point where a circle with a radius D centered on the current point P0 of the host vehicle intersects the transmission path indicated by the reference transmission path information (S210). ). In addition, the length of the radius D shall be predetermined. Specifically, the length of the radius D is set to a value less than or equal to the maximum value of the radius of the circular area where the radio signal of the radio communication unit 31 can be received at the device design stage.

  If the corresponding point is found as a result of the search in S210 (Yes in S220), the communication control unit 33 proceeds to S230, and the transmission path end point direction of the corresponding points found as a result of the search is a circle. (Ie, the point where the transmission route extends toward the end point Pe toward the outside of the circle), and the distance along the transmission route is the transmission route end point from the current point P0 of the host vehicle. The closest point in the direction is determined as the reference point P1.

  Further, when the reference point P1 is determined in this way, the communication control unit 33 has a radius D / 2 with the center point of the midpoint of the line segment P0P1 connecting the current point P0 of the host vehicle and the reference point P1. The area surrounded by the circle is determined as the packet transfer range (S240). FIGS. 5A, 5B and 6A are explanatory diagrams showing the method for determining the transfer range in S230 to S240. However, in FIGS. 5 and 6, it is assumed that a filled road is set as a packet transmission path, and a region R corresponds to a transfer range.

  When the processing in S240 is completed, the communication control unit 33 proceeds to S250, determines whether or not the own vehicle is located on the transmission route, and if the own vehicle is not located on the transmission route. When the determination is made (No in S250), transfer range information in which the transfer range determined in S240 is described by the position of the center C and the diameter D of the circle is generated (S290), and the transfer range information generation process ends.

  On the other hand, if it is determined that the host vehicle is located on the transmission path (Yes in S250), the communication control unit 33 determines whether a bend point exists in the transmission path from the current point P0 of the host vehicle to the reference point P1. It is determined whether or not (S260). In this embodiment, a point where the route is bent 90 degrees or more is treated as a bending point.

  If it is determined that there is no inflection point in the transmission path from the point P0 to the reference point P1 (No in S260), the communication control unit 33 proceeds to S290 and sets the transfer range determined in S240 to the center C. The transfer range information described by the position and the diameter D of the circle is generated (S290), and then the transfer range information generation process ends.

  On the other hand, when the communication control unit 33 determines that a bending point exists in the transmission path from the point P0 to the reference point P1 (Yes in S260), the communication control unit 33 is a point on the transmission path from the point P0 to the reference point P1. A point that is a straight distance D / 2 away from the point P0 is determined as a reference point P2 (S270), and an area surrounded by a circle with a radius D / 2 centered on the reference point P2 is determined as a packet transfer range. (S280). FIG. 6B is an explanatory diagram showing a method for determining the transfer range in S270 to S280.

  In S240, when the region R shown in FIG. 6A is determined as the transfer range, a part of the periphery of the intersection existing at the inflection point is part of the transfer range because the transmission path has the inflection point. However, if the vicinity of an intersection with a high vehicle density is out of the transfer range, the vehicle density in the transfer range is lowered, which is inconvenient for realizing stable inter-vehicle communication. In S270 to S280, for the purpose of eliminating such inconvenience, the method for determining the packet transfer range is changed so that the vicinity of the intersection is within the transfer range as shown in FIG. 6B. .

  When the processing in S280 is completed, the communication control unit 33 proceeds to S290, and generates transfer range information in which the transfer range determined in S280 is described by the position of the center C and the diameter D of the circle (S290). Then, the transfer range information generation process ends.

  In addition, if the corresponding point is not found as a result of the search in S210 (No in S220), the communication control unit 33 proceeds to S221 and refers to the circle with the radius D centered on the current point P0 of the own vehicle. It is determined whether or not there is an end point Pe of the transmission path indicated by the target transmission path information. If it is determined that the transmission path end point Pe exists within the circle (Yes in S221), a straight line distance D / 2 from the point P0 on the straight line connecting the current point P0 of the vehicle and the transmission path end point Pe. An area surrounded by a circle with a radius D / 2 centered at a distant point is determined as a packet transfer range (S223).

  When this processing is completed, the communication control unit 33 proceeds to S225, and determines whether or not the packet transfer range covers (covers) the transmission destination area indicated by the transmission destination area information to be referred to. If it is determined that the transmission destination area is not covered (No in S225), the process proceeds to S290, where transfer range information describing the transfer range determined in S223 is generated, and then the transfer range information generation process ends.

  On the other hand, if the communication control unit 33 determines in S225 that the transfer range of the packet covers the transmission destination area (Yes in S225), the communication control unit 33 proceeds to S227 and sets this transmission destination area as the transfer range of the packet. decide. Thereafter, the process proceeds to S290, where transfer range information describing the transfer range determined in S227 is generated, and the transfer range information generation process ends.

  If the communication control unit 33 determines in S221 that the end point Pe of the transmission path does not exist within the circle having the radius D centered on the current point P0 of the host vehicle (No in S221), it makes an error determination. (S229), and the transfer range information generation process ends. In the transfer range information generation process performed in S160, it is assumed that no error determination is made in the transfer range information generation process because the current point P0 of the vehicle coincides with the start point of the transmission path.

  In addition, when the transfer range information generation process in S160 is completed in this way, the communication control unit 33, the packet number generated in S110, the transmission destination area information generated in S120, the transmission source point information generated in S130, and A packet in which the transfer source point information, the transmission path information generated in S150, and the transfer range information generated in S160 are described as header information, and the transmission target data designated from the input source of the data transmission command is attached data. Is stored as a packet (S170).

  FIG. 7 is an explanatory diagram showing the configuration of a packet generated by the wireless communication device 30. The transmission target data provided from the input source of the data transmission command takes various forms depending on the protocol used by the input source application software. For example, as the transmission target data, the transmission source address or the transmission destination address is a header. The data which can be mentioned as information can be mentioned.

  In S170, when the packet having such a configuration is generated, the communication control unit 33 proceeds to S180, and transmits the generated packet to the network through the wireless communication unit 31. Thereafter, the packet generation / transmission process is terminated.

  Next, packet reception / transfer processing that is repeatedly executed by the communication control unit 33 during the operation of the wireless communication device 30 will be described. FIG. 8 is a flowchart showing packet reception / transfer processing executed by the communication control unit 33.

  When the packet reception transfer process is started, the communication control unit 33 waits until a packet is received from the outside via the wireless communication unit 31 (S310). When the packet is received (Yes in S310), the communication control unit 33 automatically receives the packet from the navigation control unit 21. The current position information of the vehicle is acquired (S315), and based on this information and the transmission destination area information included in the received packet, it is determined whether or not the own vehicle exists in the transmission destination area (S320).

  If it is determined that the vehicle is present in the transmission destination area (Yes in S320), the received packet is output to the application software executed by the navigation control unit 21, and the received packet is sent to the task of the application software. Process (S325). With such an operation, in the navigation device 10, for example, information (congestion information or the like) indicated by the attached data stored in the received packet is displayed on the display unit 15. When the process in S325 is completed, the communication control unit 33 once ends the packet reception and transfer process, and then waits until the next packet is received (S310).

  On the other hand, if it is determined in S320 that the own vehicle does not exist in the transmission destination area (No in S320), the communication control unit 33 proceeds to S330, and the own vehicle is a packet based on the transfer range information included in the received packet. It is determined whether it exists within the transfer range (S330). If it is determined that the vehicle does not exist within the packet transfer range (No in S330), the packet reception / transfer process is temporarily terminated, and then the process waits until the next packet is received in S310.

  If it is determined in S330 that the vehicle is within the packet transfer range (Yes in S330), the communication control unit 33 proceeds to S340 and executes the time measurement process shown in FIG. FIG. 9 is a flowchart showing time measurement processing executed by the communication control unit 33.

  When starting the time measurement process, the communication control unit 33 first determines in S410 whether or not the transfer source point Pb exists on the transmission path based on the transfer source point information and the transmission path information of the received packet. If it is determined that the transfer source point Pb exists on the transmission path (Yes in S410), the transfer source point Pb is set as the reference point X1 (S420). Thereafter, the process proceeds to S430.

  On the other hand, when the communication control unit 33 determines that the transfer source point Pb does not exist on the transmission path, that is, deviates from the transmission path (No in S410), the communication control unit 33 is on the transmission path within the packet transfer range indicated by the received packet. The point closest to the transmission path start point (packet transmission source point) is set as the reference point X1 (S425). Thereafter, the process proceeds to S430.

  In addition, if it transfers to S430, the communication control part 33 will judge whether the own vehicle exists on a transmission route, and if it judges that the own vehicle exists on a transmission route (Yes in S430), the present vehicle's present condition will be shown. The point P0 is set as the reference point X2 (S440). Thereafter, the process proceeds to S450. On the other hand, if it is determined that the own vehicle does not exist on the transmission path (No in S430), the communication control unit 33 is a contact point Ps between the circle centered on the current point P0 of the own vehicle and the transmission path, The contact point Ps having the shortest straight line distance from the point P0 is set as the reference point X2 (S445). Thereafter, the process proceeds to S450.

  In S450, the communication control unit 33 calculates a distance Z along the transmission path from the reference point X1 to the reference point X2 with a positive value in the transmission path end point direction, and calculates the calculated distance Z. Then, the time T is calculated according to the following equation, and this is set as the timer value T in the timer 35 (S460).

T = A · (M−Z) / M
However, A in the above equation is an arbitrary constant, and M is the length of the transmission path from the reference point X1 to a point on the transmission path within the packet transfer range and closest to the end point Pe. is there. The distance Z is limited to 0 ≦ Z ≦ M. That is, the time T is calculated by setting Z = 0 when the distance Z is a negative value and setting Z = M when the distance Z is M or more. In this way, in S460, the timer value T is set to be smaller as the own vehicle is located closer to the transmission path end point Pe.

  When the processing in S460 is completed, the communication control unit 33 activates the timer 35 to start time measurement (S470), and waits until the timer 35 finishes counting down (time measurement). That is, it waits until the time T elapses (S480). Then, when the countdown (time measurement) is finished by the timer 35 (Yes in S480), the time measurement process is finished.

  In addition, when the time measurement process in S340 is completed in this way, the communication control unit 33 proceeds to S350, a packet having the same packet number as the packet number received in S310, and a packet in S310. In a period from immediately after reception to the present time, it is determined whether or not N or more, which is a predetermined number, has been received. If it is determined that N or more packets have been received (Yes in S350), the packet is received once. The transfer process is terminated, and thereafter, the process waits until the next packet is received in S310.

  On the other hand, if it is determined that N or more packets have not been received (No in S350), the communication control unit 33 proceeds to S360 and executes the transfer packet transmission process shown in FIG. Thereafter, the packet reception transfer process is terminated.

  FIG. 10 is a flowchart showing transfer packet transmission processing executed by the communication control unit 33. When the transfer packet transmission process is started, the communication control unit 33 acquires the current position information of the own vehicle from the navigation control unit 21 (S500), and refers to the transmission route information and the transmission destination area information included in the received packet. Then, the transfer range information generation process (see FIG. 4) is executed (S510).

  When the transfer range information generation process is completed, the process proceeds to S520, where it is determined whether an error determination is made in the transfer range information generation process executed immediately before, and if it is determined that no error determination is made (in S520). No), transfer source point information representing the current position of the vehicle is generated (S530), and then the transfer range information included in the received packet is replaced with the transfer range information generated in S510, and the transfer source point included in the received packet The information is replaced with the transfer source point information generated in S530 to generate a transfer packet corresponding to the received packet (S540), and the generated transfer packet is sent to the network through the wireless communication unit 31 (S590). Thereafter, the transfer packet transmission process is terminated.

  On the other hand, if it is determined in S520 that the error determination has been made (Yes in S520), the communication control unit 33 executes the transmission path information generation process to re-execute the transfer range information generation process, thereby creating new transmission path information. Is generated (S550). FIG. 11 is a flowchart illustrating a transmission path information generation process executed by the communication control unit 33.

  When the transmission route information generation process is started, the communication control unit 33 first selects a point closest to the current point P0 of the vehicle among the points on the transmission route indicated by the transmission route information of the received packet in S551. Pc is determined (see FIG. 12A).

  When this process is completed, the communication control unit 33 proceeds to S553, and causes the route search unit 21a to search for a route from the current location P0 of the vehicle to the determined junction point Pc, and obtains the route information. Obtained from the route search unit 21a. When the processing in S553 is completed, the communication control unit 33 transmits the own vehicle indicated by the route information acquired from the route search unit 21a to the transmission route from the junction point Pc to the end point Pe indicated by the transmission route information of the received packet. The route formed by connecting the route from the current point P0 to the joining point Pc is determined as a transmission route for a new packet, and transmission route information representing this transmission route is generated (S555).

  FIG. 12 is an explanatory diagram showing a transmission path determination method in the transmission path information generation process. For example, when the transmission route information of the received packet indicates the transmission route shown in FIG. 12A, the communication control unit 33 joins the intersection of the road corresponding to the current point P0 of the own vehicle and the transmission route. The route shown in FIG. 12B in which the route from the point P0 to the point Pc and the route from the point Pc to the end point Pe indicated by the received packet are connected to the new transmission route is determined as the point Pc. The transmission path information representing this transmission path is generated.

  In addition, when transmission path information is newly generated in this way, the communication control unit 33 ends the transmission path information generation process. In addition, when the processing in S550 is completed, the communication control unit 33 sets the transmission path information generated in S550 and the transmission destination area information of the received packet as reference targets, and performs transfer range information generation processing (see FIG. 4). By executing, the transfer range of the packet is determined based on the new transmission path, and transfer range information representing this transfer range is generated (S560).

  Then, after completing the process in S560, the communication control unit 33 proceeds to S570, and generates transfer source point information indicating the current position of the host vehicle. Thereafter, the transfer range information included in the received packet is replaced with the transfer range information generated in S560, the transfer source point information included in the received packet is replaced with the transfer source point information generated in S570, and the received packet further includes The transmission path information is replaced with the transmission path information generated in S550 to generate a transfer packet corresponding to the received packet (S580), and the generated transfer packet is sent to the network through the wireless communication unit 31 (S590). Thereafter, the transfer packet transmission process is terminated.

  Although the in-vehicle system 1 of the first embodiment has been described above, in the network configured by the in-vehicle system 1 group of the present embodiment, the packet transmission path is determined in the packet transmission source vehicle, not the packet transmission direction. However, the transfer destination vehicle determines the packet transfer range on the basis of this transmission path, so that the direction in which packet transfer is not required is required compared to conventional networks that transfer packets in a wide range of directions in consideration of radio wave obstructions. The packet can be efficiently transferred to the transmission destination area along the transmission path determined by the packet transmission source vehicle. In addition, according to the present embodiment, since the packet is transferred along the transmission path (road), the packet is transferred by the radio wave obstacle rather than the packet is transferred linearly toward the destination area. Can be prevented from being inhibited.

  In addition, according to the present embodiment, since a method of transferring packets without the position information of surrounding vehicles is adopted, the problem that communication becomes unstable due to an error in the position information of surrounding vehicles is not considered. It will end. Therefore, according to this embodiment, the packet can be transferred to the transmission destination area more efficiently and stably than the conventional network, and stable inter-vehicle communication can be realized in the network.

  Moreover, in the vehicle-mounted system 1 of a present Example, the point farthest from the present position of the own vehicle which is the point where the packet can be transferred most efficiently within the packet transfer range (the opposite side across the center of the circle) ) Is placed on a transmission path where a vehicle is likely to exist, and the packet transfer range is determined, so that packets can be transferred very efficiently. In this embodiment, since the packet transfer range is set in a circle, transfer range information indicating the transfer range can be generated to the extent that the center C and diameter D of the circle are described, and header information contained in the packet The amount of data can be kept low.

  In addition, in the in-vehicle system 1 according to the present embodiment, when there is a bending point in the transmission path from the current point P0 to the point P1 of the own vehicle, the center of the circle is aligned with the transmission route, The packet transfer range is determined to be circular with the position as the base point. Therefore, according to the present embodiment, even if the transmission route is an intersection or the like with a right or left turn, it is possible to suppress the periphery of the intersection with the right or left turn from being out of the packet transfer range. By using the vehicles around the intersection with high height, the transfer packet can be stably transmitted to the transmission destination area.

  In the present embodiment, a short waiting time T is set for a vehicle close to the transmission path end point Pe among vehicles existing within the packet transfer range, and a transfer packet is transmitted from the vehicle after the waiting time T has elapsed. When N vehicles send transfer packets from vehicles close to the transmission path end point Pe, no more transfer packets are transferred from other vehicles. Therefore, according to the present embodiment, it is possible to efficiently transfer packets while suppressing network traffic and to realize efficient and stable vehicle-to-vehicle communication.

  The header information of this embodiment corresponds to the attached information described in “Claims”. In this embodiment, the packet sending means is realized by the packet generation / transmission process shown in FIG. 3, the destination determination means is realized by the process of S320, and the data receiving means is realized by the process of S325. ing. In addition, the transfer necessity determination unit is realized by the process of S330, and the packet transfer unit is realized by the process of S360. The setting means is realized by the process of S340, and the prohibiting means is realized by the process of S350.

  In the time measurement process of the present embodiment, the time T is calculated based on the transfer source point Pb. For example, the time measurement process is configured to calculate the time T based on the end point Pe. (Second embodiment).

  FIG. 13 is a flowchart showing time measurement processing executed by the communication control unit 33 in the in-vehicle system 1 according to the second embodiment. The in-vehicle system 1 of the second embodiment is the one in which the time measurement process (FIG. 9) in the in-vehicle system 1 of the first embodiment is changed to the time measurement process shown in FIG. Therefore, in the following, only the contents of the changed time measurement process will be described as the second embodiment.

  When the time measurement process illustrated in FIG. 13 is started, the communication control unit 33 executes the processes from S410 to S445 as in the first embodiment, and then executes the process of S650 instead of S450.

  In S650, the distance L along the transmission path from the transmission path end point Pe to the reference point X1 is calculated. When this process is finished, the communication control unit 33 proceeds to S655, and calculates the distance Z along the transmission path from the transmission path end point Pe to the reference point X2.

  When the processing in S655 ends, the communication control unit 33 calculates the time T according to the following equation using the calculated distance Z and distance L, and sets this as the timer value T in the timer 35 (S660). ).

T = A · (Z−L + M) / M
However, A in the above equation is an arbitrary constant, and M is the length of the transmission path from the reference point X1 to a point on the transmission path within the packet transfer range and closest to the end point Pe. is there. Further, the distance Z is limited to L−M ≦ Z ≦ L. That is, the time T is calculated by setting Z = LM when the distance Z is less than LM, and setting Z = L when the distance Z is L or more. In this way, in S660, the timer value T is set smaller as the own vehicle is present at a point closer to the transmission path end point Pe.

  When the processing in S660 is completed, the communication control unit 33 activates the timer 35 to start time measurement (S670), and waits until the timer 35 finishes counting down (time measurement). That is, it waits until the time T elapses (S680). When the countdown (time measurement) is finished by the timer 35 (Yes in S680), the time measurement process is finished.

The on-vehicle system 1 of the second embodiment has been described above, but the same effect as that of the first embodiment can be obtained even when the time measurement process is executed as in the second embodiment.
In addition, when calculating the timer value T by calculating the distance along the transmission path, the amount of calculation related to the calculation of the timer value T increases, so the time measurement process does not calculate the distance along the path. The timer value T may be calculated (third embodiment).

  FIG. 14 is a flowchart showing time measurement processing executed by the communication control unit 33 in the in-vehicle system 1 of the third embodiment. The in-vehicle system 1 of the third embodiment is the one in which the time measurement process (FIG. 9) in the in-vehicle system 1 of the first embodiment is changed to the time measurement process shown in FIG. Therefore, hereinafter, only the contents of the changed time measurement process will be described as a third embodiment.

  When the time measurement process shown in FIG. 14 is started, the communication control unit 33 first connects the transfer source point Pb indicated by the received packet and the center C of the packet transfer range (circle) indicated by the received packet in S710. The inner product of the unit vector of the vector PbC and the vector PbP0 connecting the transfer source point Pb and the current point P0 of the host vehicle is the distance from the point Pb to the point P0, and is the most from the transfer source point Pb and the point Pb. The distance Z is calculated as a distance Z along a straight line connecting a point Pa in the remote transfer range.

Z = (distance from the transfer source point Pb to the current point P0 of the vehicle) · cosΘ
However, the angle Θ is an angle formed by the vector PbC and the vector PbP0.
When the processing in S710 is completed, the communication control unit 33 proceeds to S720, calculates the time T according to the following expression using the calculated distance Z, and sets this as the timer value T in the timer 35. (S720).

T = A · (D−Z) / D
However, A in the above equation is an arbitrary constant, and D is the diameter D of the packet transfer range (circle).

  When the processing in S720 is completed, the communication control unit 33 activates the timer 35 to start time measurement (S730), and waits until the timer 35 finishes counting down (time measurement). That is, it waits until the time T elapses (S740). Then, when the countdown (time measurement) is finished by the timer 35 (Yes in S740), the time measurement process is finished.

  The on-vehicle system 1 of the third embodiment has been described above. According to the on-vehicle system 1, the on-vehicle system 1 of the first and second embodiments that calculates the distance along the transmission path and sets the timer value T is described. As a result, the amount of calculation related to the calculation of the timer value T can be suppressed.

  In the first to third embodiments, the in-vehicle system 1 is configured to execute packet transfer even if the vehicle is not located on the transmission path. However, if the vehicle is not located on the transmission path, the packet transfer is performed. It may not be executed (fourth embodiment).

  FIG. 15 is a flowchart showing packet reception / transfer processing executed by the communication control unit 33 in the in-vehicle system 1 according to the fourth embodiment. The in-vehicle system 1 of the fourth embodiment is the one in which the packet reception / transfer processing (see FIG. 8) in the in-vehicle system 1 of the first to third embodiments is changed to the packet reception / transfer processing shown in FIG. Therefore, only the contents of the changed packet reception / transfer process will be described below.

  In the in-vehicle system 1 of the fourth embodiment, the processing from S310 to S360 described above is basically executed and the transfer packet is transmitted, but the processing of S335 is executed in the process of shifting from S330 to S340. To do.

  That is, when the communication control unit 33 receives the packet (Yes in S310), the communication control unit 33 determines whether or not the vehicle exists in the transmission destination area based on the transmission destination area information included in the reception packet (S320). If it is determined that the vehicle does not exist in the transmission destination area (No in S320), it is determined whether or not the vehicle exists in the packet transfer range based on the transfer range information included in the received packet (S330). If it is determined that the vehicle is within the packet transfer range (Yes in S330), the process proceeds to S335.

  When the process proceeds to S335, the communication control unit 33 determines whether or not the own vehicle is located on the transmission path, and determines that the own vehicle is not located on the transmission path (No in S335). The packet reception / transfer process is once completed, and then the process waits until the next packet is received in S310. On the other hand, if it is determined that the host vehicle is located on the transmission path (Yes in S335), the process proceeds to S340, and the processes after S340 described above are executed.

  As described above, the in-vehicle system 1 according to the fourth embodiment has been described. However, according to the in-vehicle system 1, it is not necessary to execute the processes of S425 and S445, so that the time measurement process and the like can be simplified. Also, instead of transferring packets from N vehicles within the packet transfer range, packets are transferred from N vehicles located within the packet transfer range and on the transmission path. Packets can be transferred reliably, and the possibility of packet transfer failure due to radio wave interference or the like can be sufficiently suppressed. In the present embodiment, the transfer necessity determination means is realized by the processing of S330 to S335 (FIG. 15).

  In addition, when the vehicles that transfer packets are limited to vehicles that are located on the transmission path, there are no problems when many vehicles are traveling on the transmission path, but there are no vehicles traveling on the transmission path. When the number is small, there is a possibility that the vehicle that takes over the packet transfer is not in the middle and inconvenience occurs. Therefore, the packet transfer range may be determined as an area having a predetermined width along the transmission path (fifth embodiment).

  FIG. 16 is a flowchart showing transfer range information generation processing executed by the communication control unit 33 in the in-vehicle system 1 according to the fifth embodiment. FIG. 17 is an explanatory diagram showing a method for determining a transfer range in the fifth embodiment. The in-vehicle system 1 of the fifth embodiment is the one in which the transfer range information generation processing (FIG. 4) in the in-vehicle system 1 of the first to fourth embodiments is changed to the transfer range information generation processing shown in FIG. . Accordingly, only the contents of the changed transfer range information generation process will be described below as a fifth embodiment.

  When the transfer range information generation process shown in FIG. 16 is started, the communication control unit 33 determines a point where a circle with a radius D centered on the current point P0 of the host vehicle intersects with the transmission path indicated by the reference transmission path information. Search is performed (S810). In addition, the length of the radius D shall be predetermined. Specifically, the length of the radius D is set to a value less than or equal to the maximum value of the radius of the circular area where the radio signal of the radio communication unit 31 can be received at the device design stage.

  If the corresponding point is found as a result of the search in S810 (Yes in S820), the communication control unit 33 proceeds to S830, and the transmission path end point direction is circle of the corresponding points found as a result of the search. The reference point P1 is determined as a reference point P1 which is a point facing the outside of the vehicle and whose distance along the transmission route is the closest in the direction of the transmission route end point from the current point P0 of the vehicle.

  In addition, when the reference point P1 is determined in this way, the communication control unit 33 proceeds to S840, determines whether or not the own vehicle is located on the transmission route, and the own vehicle is located on the transmission route. If it is determined that the current position P0 is determined (Yes in S840), the current point P0 of the host vehicle is determined as the reference point X (S850). Thereafter, the process proceeds to S860. On the other hand, if it is determined in S840 that the own vehicle is not located on the transmission path (No in S840), the communication control unit 33 contacts the circle P around the current point P0 of the own vehicle and the contact point Ps between the transmission paths. Then, the contact point Ps having the shortest straight line distance from the current point P0 is set as the reference point X (S855). Thereafter, the process proceeds to S860.

  When the process proceeds to S860, the communication control unit 33, as shown in FIG. 17, is a region R having a predetermined width W on both sides from the center line in the transmission path (shown in FIG. 17) from the reference point X to the reference point P1. Is determined as the packet transfer range. In addition, when the packet transfer range R is determined in this way, the communication control unit 33 generates transfer range information describing the determined packet transfer range R with the positions and widths W of the reference points X and P1. (S890). Thereafter, the transfer range information generation process ends.

  On the other hand, if the corresponding point is not found as a result of the search in S810 (No in S820), the communication control unit 33 proceeds to S870 and refers to the circle with the radius D centered on the current point P0 of the own vehicle. It is determined whether or not there is an end point Pe of the transmission path indicated by the target transmission path information. If it is determined that the end point Pe of the transmission path exists in the circle (Yes in S870), the process proceeds to S880, and the transmission destination area indicated by the transmission destination area information to be referenced is centered on the current point P0 of the own vehicle. If it is determined whether or not the destination area is within the circle (Yes in S880), it is the same as the destination area centered on the end point Pe of the transmission path. The area is determined as the packet transfer range (S881). Then, transfer range information representing the transfer range is generated (S890), and then the transfer range information generation process is terminated.

  In S880, if it is determined that the transmission destination area is not within the circle having the radius D centered on the current point P0 of the own vehicle (No in S880), the communication control unit 33 proceeds to S883, It is determined whether or not the vehicle is located on the transmission path. When it is determined that the host vehicle is located on the transmission path (Yes in S883), the current point P0 of the host vehicle is determined as the reference point X (S885), and the process proceeds to S889. On the other hand, if it is determined in S883 that the own vehicle is not located on the transmission path (No in S883), the communication control unit 33 contacts the circle P around the current point P0 of the own vehicle with the transmission path Ps. Then, the contact point Ps having the shortest linear distance from the current point P0 is set as the reference point X (S887). Thereafter, the process proceeds to S889.

  In S889, the communication control unit 33 determines an area having a predetermined width W on both sides from the center line in the transmission path from the reference point X to the point Pe as a packet transfer range. When the packet transfer range is determined in this way, the communication control unit 33 generates transfer range information in which the determined packet transfer range is described by the positions of the points X and Pe and the width W (S890). ). Thereafter, the transfer range information generation process ends.

  As described above, the in-vehicle system 1 of the fifth embodiment has been described. However, if a network is configured using the in-vehicle system 1, the transfer of the packet is taken over between the vehicle on the transmission path and the vehicle near the transmission path. Therefore, it is possible to suppress the absence of the takeover vehicle as compared with the case where the transfer of the packet is limited to the vehicle on the transmission path and can be taken over. In addition, since the packet can be transferred substantially along the transmission path, the possibility of packet transfer failure due to radio wave interference or the like can be sufficiently suppressed.

  By the way, if the above-mentioned parameter D is set to a constant value without considering the vehicle density around the host vehicle, the number of vehicles that can be accommodated in the packet transfer range is large in areas where the vehicle density is low and areas where the vehicle density is high. To change. If there are many vehicles in the packet transfer range, many vehicles must perform time measurement processing and the like. Furthermore, when a plurality of types of packets are exchanged between these vehicle groups, the load related to communication in each vehicle is greatly increased. Therefore, in the on-vehicle system 1 described above, the value of the parameter D may be changed according to the density of vehicles around the own vehicle (sixth embodiment).

  FIG. 18 is a flowchart showing transfer range information generation processing executed by the communication control unit 33 in the in-vehicle system 1 of the sixth embodiment. Moreover, Fig.19 (a) is explanatory drawing showing the structure of the distance setting table built in ROM of the communication control part 33 in the vehicle-mounted system 1 of 6th Example.

  Hereinafter, the in-vehicle system 1 according to the sixth embodiment will be described. The in-vehicle system 1 according to the sixth embodiment is a transfer range information generation process in the in-vehicle system 1 according to the first to fifth embodiments (FIGS. 4 and 16). The procedure of S200 to S205 is added to the head of the information, and the distance setting table shown in FIG. 19A is recorded in the ROM of the communication control unit 33. Therefore, only the contents of the changed transfer range information generation process and the distance setting table will be described below as the sixth embodiment.

  As shown in FIG. 18, in the in-vehicle system 1 of the sixth embodiment, when the transfer range information generation process is started, the processes of S200 to S205 are executed before the process of S210 or S810 is executed. That is, when the transfer range information generation process is started, the communication control unit 33 first determines the vehicle congestion around the own vehicle in S200. In S200, for example, based on the traffic congestion information around the host vehicle received by the VICS communication unit 17, the vehicle congestion around the host vehicle is determined.

  When the process in S200 is completed, the communication control unit 33 uses the distance corresponding to the determination value of the vehicle congestion around the own vehicle based on the distance setting table stored in the ROM as a parameter used in the subsequent S210 or S810. Set as the value of D. In this embodiment, three levels of levels 1 to 3 are determined as the vehicle congestion, and the distance to be set in the parameter D is described in each level in the distance setting table. .

  Specifically, for level 1 where the vehicle congestion is the lowest, the maximum value of the radius of the circular area where the wireless signal of the wireless communication unit 31 can be received is described as the distance to be set in the parameter D, and the vehicle congestion is For normal level 2, the value that is one step smaller than the above maximum value is described as the distance to be set, and for level 3, where the vehicle congestion is the highest, it is two steps smaller than the maximum value. The value is described as the distance to be set. That is, in this embodiment, as shown in FIG. 19B, the smaller the distance D is set, the greater the vehicle density around the host vehicle.

  When the distance D is set, the communication control unit 33, in S210 or S810, transmits the circle indicated by the circle D having the radius D (the distance D) centered on the current point P0 of the own vehicle and the transmission route information to be referred to. When the point where the route intersects is searched and this processing is completed, the processing after S220 or S820 is executed.

  The on-vehicle system 1 according to the sixth embodiment has been described above. According to the on-vehicle system 1, the value of the radius D of the circle used when obtaining the intersection point in S210 or S810 according to the vehicle congestion around the host vehicle. The size of the transfer range is reduced in an area where the vehicle density is high, and the size of the transfer range is increased in an area where the vehicle density is low. Therefore, according to the present embodiment, it is possible to adjust the number of vehicles that fall within the transfer range, and it is possible to suppress an increase in network load in an area where the vehicle density is high. Note that the density determination means described in “Claims” is implemented in the processing of S200 in this embodiment.

  Further, in the network constituted by the in-vehicle system 1 of the first to sixth embodiments, the packet density is transferred to a certain number (N) of vehicles regardless of the density of the vehicles. In high areas, the network load increases. Therefore, it is more preferable that the in-vehicle system 1 described above is configured to change the value of the parameter N according to the density of the vehicle (seventh embodiment).

  FIG. 20 is a flowchart showing packet reception / transfer processing executed by the communication control unit 33 in the in-vehicle system 1 according to the seventh embodiment. FIG. 21A is an explanatory diagram showing the configuration of the transfer number setting table built in the ROM of the communication control unit 33 in the in-vehicle system 1 of the seventh embodiment. Hereinafter, the in-vehicle system 1 according to the seventh embodiment will be described. The in-vehicle system 1 according to the seventh embodiment includes S340 of the reception transfer process (FIGS. 8 and 15) in the in-vehicle system 1 according to the first to sixth embodiments. The procedure of S343 to S347 is added between S350 and the transfer number setting table shown in FIG. 21A is recorded in the ROM of the communication control unit 33. Therefore, only the contents of the packet reception transfer process and transfer number setting table will be described below as the seventh embodiment.

  As shown in FIG. 20, in the packet reception transfer process of the seventh embodiment, the time measurement process in S340 is executed, and after the measurement of the time T is completed, the process proceeds to S343, and the vehicle congestion around the own vehicle is determined. judge. In S343, for example, based on the traffic congestion information around the own vehicle received by the VICS communication unit 17, the vehicle congestion around the own vehicle is determined.

  When the processing in S343 is completed, the communication control unit 33 uses the parameter N used in the subsequent S350 to calculate a numerical value corresponding to the determination value of the vehicle congestion around the own vehicle based on the transfer number setting table stored in the ROM. (S347).

  In this embodiment, three levels of levels 1 to 3 are determined as the vehicle congestion, and the numerical value to be set in the parameter N is described in each transfer level setting table. Yes. Specifically, the maximum value is described for level 1 with the lowest vehicle density, the minimum value is described for level 3 with the highest vehicle density, and the normal level 2 with vehicle density. For, a value larger than the minimum value and smaller than the maximum value is described. That is, in this embodiment, as shown in FIG. 21B, the smaller the vehicle density, the smaller the parameter N is set.

  When the value of the parameter N is set, the communication control unit 33 proceeds to S350, and from the time immediately after receiving the packet in S310 to the current packet, the packet number indicated by the packet received in S310 is the same. During the period, it is determined whether or not N or more, which is the number set in S347, has been received, and if it is determined that N or more packets have been received (Yes in S350), the packet reception transfer process is temporarily terminated, Then, it waits until it receives the next packet in S310. In contrast, if it is determined that N or more packets have not been received (No in S350), the communication control unit 33 proceeds to S360, executes the transfer packet transmission process, and then performs the packet reception transfer process. finish.

  As described above, the in-vehicle system 1 according to the seventh embodiment has been described. According to the in-vehicle system 1, an increase in the network load can be suppressed in an area where the vehicle congestion is high, and the vehicle congestion is high. In low areas, packets can be transferred to many vehicles, and stable inter-vehicle communication can be realized. In the present embodiment, the density determination unit described in “Claims” is realized by the process of S343, and the upper limit setting unit is realized by the process of S347.

  Further, in the above-described in-vehicle system 1, since it is not determined whether or not the transfer of the transfer packet has been taken over after the transfer packet is sent out, there are fewer vehicles around the transfer source vehicle that can take over the transfer of the packet. The possibility of packet transfer failure increases. Therefore, it is preferable to provide a transfer packet retransmission function for the above-described wireless communication device 30 (eighth embodiment).

  FIG. 22 is a flowchart showing packet generation and transmission processing executed by the communication control unit 33 in the in-vehicle system 1 according to the eighth embodiment. FIG. 23 shows the communication control unit 33 in the in-vehicle system 1 according to the eighth embodiment. It is a flowchart showing the transfer range information generation process to be performed. FIG. 24 is a flowchart showing packet reception and transfer processing executed by the communication control unit 33 in the in-vehicle system 1 of the eighth embodiment. FIG. 25 is a communication control unit in the in-vehicle system 1 of the eighth embodiment. 34 is a flowchart showing transfer packet transmission processing executed by 33.

  Hereinafter, the in-vehicle system 1 according to the eighth embodiment will be described. The in-vehicle system 1 according to the eighth embodiment includes a packet generation transmission process, a transfer range information generation process, and a packet reception in the in-vehicle system 1 according to the first to seventh embodiments. The transfer process and the transfer packet transmission process are changed. Accordingly, only the contents of the changed processes will be described below as an eighth embodiment.

  First, packet generation / transmission processing (FIG. 22) executed by the communication control unit 33 when a data transmission command is input will be described. When the packet generation / transmission process is started, the communication control unit 33 first generates a retransmission flag, sets the retransmission flag to OFF (S900), and then newly generates the same as in the process in S110. A packet number attached to the packet is generated (S910).

  When this processing is completed, the communication control unit 33 proceeds to S920, and generates transmission destination area information indicating the position of the center Pe and the area radius r specified from the input source of the data transmission command. . When the processing in S920 is completed, the communication control unit 33 acquires the current position information of the own vehicle from the navigation control unit 21 (S925), and based on this information, the transmission source point information indicating the current position of the own vehicle. And transfer source point information representing the current position of the vehicle is generated (S930).

  When the processing in S930 ends, the communication control unit 33 proceeds to S940, and the route along the road from the current point P0 of the host vehicle to the center Pe of the transmission destination area is the route of the navigation control unit 21. The search unit 21a is caused to search, and route information representing the route between the points P0 and Pe is acquired from the route search unit 21a. And based on this acquisition information, the communication control part 33 produces | generates the transmission path information showing the transmission path | route of the packet between the points P0-Pe (S950).

  When the transmission path information is generated in this way, the communication control unit 33 proceeds to S960, sets the generated transmission path information and transmission destination area information as reference targets, and performs transfer range information generation processing shown in FIG. Execute. Note that the transfer range information generation process shown in FIG. 23 is performed before the process of S210 in the transfer range information generation process shown in FIG. 4 or before the process of S810 in the transfer range information generation process shown in FIG. The procedure of S1030 is added.

  When the transfer range information generation process shown in FIG. 23 is started, the communication control unit 33 determines whether or not the retransmission flag is set to ON (S1000), and the retransmission flag is not set to ON (ie, If it is determined that it is set to OFF (No in S1000), the process proceeds to S1010, and the vehicle congestion around the own vehicle is determined by the same method as in S200 (see FIG. 18).

  When the processing in S1010 is completed, the communication control unit 33 uses the distance corresponding to the determination value of the vehicle congestion around the host vehicle based on the distance setting table stored in the ROM as a parameter used in the subsequent S210 or S810. It is set as the value of D (S1020). The distance setting table in this embodiment is the same as that in the sixth embodiment.

  Further, when the distance D is set in S1020, the communication control unit 33 proceeds to S210 or S810, and uses the value of the parameter D set in S1020 to set the radius D (distance around the current point P0 of the host vehicle). A point where the circle of D) intersects the transmission path indicated by the transmission path information to be referred to is searched, and when this process is finished, the processes after S220 or S820 are executed.

  On the other hand, if the communication control unit 33 determines that the transmission flag is set to ON (Yes in S1000), the communication control unit 33 proceeds to S1030, and the parameter D is the same as the value set when the vehicle congestion level is level 1. Set the value of. That is, the maximum value is set in the parameter D.

  When the processing in S1030 is completed, the communication control unit 33 proceeds to S210 or S810, and uses the value of the parameter D set in S1030 to set the radius D around the current point P0 of the own vehicle. A point where the circle intersects the transmission path indicated by the transmission path information to be referenced is searched, and when this process is finished, the processes after S220 or S820 are executed.

  In addition, when the transfer range information generation process in S960 is completed in this way, the communication control unit 33 determines whether or not an error determination has been made in the transfer range information generation process (S965). If it is determined that the error has been made (Yes in S965), the process proceeds to S925. If it is determined that no error determination has been made (No in S965), the process proceeds to S970.

  In S970, the communication control unit 33 displays the packet number, transmission destination area information, transmission source point information and transfer source point information, transmission path information, and transfer range information generated in the packet generation and transmission process. Then, a packet described as header information, in which transmission target data designated from the input source of the data transmission command is stored as attached data is generated (S970). Thereafter, this packet is sent to the network through the wireless communication unit 31 (S980). In this embodiment, transfer range information and transmission path information may be generated a plurality of times in a single packet generation / transmission process. In this case, the transfer range information and transmission path information generated last is used. Is described as header information.

  When the processing in S980 is completed, the communication control unit 33 proceeds to S990, and transmits a packet having the same packet number as the packet transmitted in S980 within the predetermined time after the transmission of the packet through the wireless communication unit 31. It is determined whether or not the packet has been received from the outside, and if it is determined that the packet having the same packet number as the packet transmitted in S980 is received from the outside (Yes in S990), it is determined that the packet has been successfully transferred. Exit.

  On the other hand, if the packet having the same packet number as the packet transmitted in S980 cannot be received from the outside within the predetermined time, the communication control unit 33 determines No in S990, proceeds to S991, and retransmits the flag. Set to on. When this process is finished, in S993, the current position information of the own vehicle is acquired from the navigation control unit 21, and based on this information, transmission source point information representing the current position of the own vehicle is generated, and the own vehicle is also generated. The transfer source point information representing the current position of the current position is generated (S995).

  Thereafter, the communication control unit 33 proceeds to S960, and executes transfer range information generation processing based on the current position of the host vehicle indicated by the acquisition information in S993. When this process ends, the process proceeds to S965 to determine whether or not an error determination has been made. Note that if the current position of the vehicle is greatly deviated from the initial position and greatly separated from the transmission path, an error determination is made in the transfer range information generation process in S960, and therefore, Yes in S965. And the process proceeds to S925. In this way, in this embodiment, packet generation and transmission processing is performed.

  Next, packet reception transfer processing that is repeatedly executed by the communication control unit 33 of this embodiment will be described. When the packet reception transfer process (FIG. 24) is started, the communication control unit 33 waits until a packet is received from the outside via the wireless communication unit 31 (S310), and when the packet is received (Yes in S310), navigation control is performed. The current position information of the own vehicle is acquired from the unit 21 (S315), and based on this information and the transmission destination area information included in the received packet, it is determined whether or not the own vehicle exists in the transmission destination area (S320). ).

  If it is determined that the vehicle is present in the transmission destination area (Yes in S320), a response indicating that the received packet has been received by replacing the transfer range information of the received packet with null information (null). The packet is generated as a packet and sent to the network through the wireless communication unit 31 (S321). When this process is finished, the received packet described above is output to the application software executed by the navigation control unit 21, and the task of the application software processes the received packet (S325). Thereafter, the packet reception / transfer process is terminated.

  On the other hand, if it is determined in S320 that the vehicle does not exist in the transmission destination area (No in S320), the communication control unit 33 executes the processes after S330 shown in FIG. 8, FIG. 15, or FIG. Then, the packet reception transfer process is terminated.

  When the transfer packet transmission process is started in S360 of the packet reception transfer process, the communication control unit 33 generates a retransmission flag and sets the retransmission flag to OFF as shown in FIG. 25 (S1100). The current position information of the host vehicle is acquired from the navigation control unit 21 (S1105). When this process is finished, the transmission path information and the transmission destination area information included in the received packet are set as reference targets, and the transfer range information generation process shown in FIG. 23 is executed (S1110).

  When the transfer range information generation process ends, the communication control unit 33 proceeds to S1120, determines whether or not an error determination is made in the transfer range information generation process executed immediately before, and no error determination is made. If it is determined (No in S1120), transfer source point information indicating the current position of the vehicle is generated (S1130), and then the transfer range information included in the received packet is replaced with the transfer range information generated in S1110, and received. The transfer source point information included in the packet is replaced with the transfer source point information generated in S1130 to generate a transfer packet corresponding to the received packet (S1140), and the transfer packet is sent to the network through the wireless communication unit 31. (S1190).

  On the other hand, if it is determined in S1120 that an error determination has been made (Yes in S1120), the communication control unit 33 executes transmission path information generation processing (FIG. 11) to generate new transmission path information (S1150). .

  When the processing in S1150 is completed, the communication control unit 33 sets the transmission path information generated in S1150 and the transmission destination area information of the received packet as reference targets, and executes transfer range information generation processing (FIG. 23). Thus, the transfer range of the packet is determined based on the new transmission path, and transfer range information representing this transfer range is generated (S1160).

  When the processing in S1160 ends, the communication control unit 33 proceeds to S1170 and generates transfer source point information indicating the current position of the host vehicle. Thereafter, the transfer range information included in the received packet is replaced with the transfer range information generated in S1160, the transfer source point information included in the received packet is replaced with the transfer source point information generated in S1170, and the received packet further includes The transmission path information is replaced with the transmission path information generated in S1150 to generate a transfer packet corresponding to the received packet (S1180), and the generated transfer packet is sent to the network through the wireless communication unit 31 (S1190).

  When the processing in S1190 is completed, the communication control unit 33 proceeds to S1200, and after the transmission of the packet in S1190, a packet having the same packet number as the packet transmitted in S1190 is transmitted to the wireless communication unit within a predetermined time. It is determined whether or not a packet having the same packet number has been received from the outside (Yes in S1200), and it is determined that the packet has been successfully transferred. finish.

  On the other hand, if it is determined that a packet having the same packet number could not be received from the outside within a predetermined time (No in S1200), the communication control unit 33 proceeds to S1210 and sets the retransmission flag to ON. When this process is finished, the process proceeds to S1105, where the current position information of the own vehicle is newly acquired. Thereafter, in S1110, based on the current position of the own vehicle indicated by the acquired information, a transfer range information generation process ( FIG. 23) is executed. When this process is finished, the processes after S1120 are executed.

  In the above, the in-vehicle system 1 of the eighth embodiment has been described. According to the in-vehicle system 1, it is confirmed that a transfer packet of the same type is flowing through the network after the transfer packet is transmitted, and is not flowing. Since the transfer packet is retransmitted, the packet transfer can be prevented from being interrupted. Therefore, if this in-vehicle system 1 is used to configure a network, more stable inter-vehicle communication can be realized.

  Further, according to the in-vehicle system 1 of the present embodiment, when the density of the vehicle is high at the time of the first packet transfer, the size of the transfer range is set small according to the density of the vehicle. Since the size of the transfer range is increased at the time of retransmission of the transfer packet, it is possible to prevent the packet transfer from failing again. Therefore, if a network is configured using the in-vehicle system 1, packets can be transferred efficiently and stably. Note that the reception determination means described in “Claims” is realized by the processing of S1200 in this embodiment.

As mentioned above, although the Example of this invention was described, the communication apparatus of this invention is not limited to the said Example, It can take a various aspect.
For example, since the navigation apparatus 10 is widely known to have a function of searching for a route that preferentially selects a main road, the communication control unit 33 uses the function to search the route search unit 21a. Then, by searching for a route preferentially selecting the main road, a route preferentially selecting the main road among the routes from the current position of the vehicle to the center Pe of the transmission destination area is determined as a packet transmission route. It may be configured to be determined. If the wireless communication device 30 is configured in this way, packets can be transferred from a transmission source to a transmission destination along a high-traffic main road, and packets can be stably transferred to the transmission destination. be able to.

1 is a block diagram illustrating a configuration of an in-vehicle system 1. FIG. It is explanatory drawing which shows the network implement | achieved by the vehicle-mounted system 1 group. It is a flowchart showing the packet production | generation transmission process which the communication control part 33 performs. It is a flowchart showing the transfer range information generation process which the communication control part 33 performs. It is explanatory drawing which showed the determination method of the transfer range. It is explanatory drawing which showed the determination method (a) of the transfer range in S230-S240, and the determination method (b) of the transfer range in S270-S280. It is explanatory drawing showing the structure of a packet. It is a flowchart showing the packet reception transfer process which the communication control part 33 performs. It is a flowchart showing the time measurement process which the communication control part 33 performs. It is a flowchart showing the transfer packet transmission process which the communication control part 33 performs. It is a flowchart showing the transmission route information generation process which the communication control part 33 performs. It is explanatory drawing which shows the determination method of the transmission path | route in a transmission path | route information generation process. It is a flowchart showing the time measurement process which the communication control part 33 performs in 2nd Example. It is a flowchart showing the time measurement process which the communication control part 33 performs in a 3rd Example. It is a flowchart showing the packet reception transfer process which the communication control part 33 performs in 4th Example. It is a flowchart showing the transfer range information generation process which the communication control part 33 performs in 5th Example. It is explanatory drawing which showed the determination method of the transfer range in 5th Example. It is a flowchart showing the transfer range information generation process which the communication control part 33 performs in 6th Example. It is explanatory drawing (a) showing the structure of a distance setting table, and the graph (b) which shows the relationship between vehicle congestion and the distance D. FIG. It is a flowchart showing the packet reception transfer process which the communication control part 33 performs in 7th Example. It is explanatory drawing (a) showing the structure of a transfer number setting table, and the graph (b) which shows the relationship between vehicle congestion and the number N. It is a flowchart showing the packet production | generation transmission process which the communication control part 33 performs in 8th Example. It is a flowchart showing the transfer range information generation process which the communication control part 33 performs in 8th Example. It is a flowchart showing the packet reception transfer process which the communication control part 33 performs in 8th Example. It is a flowchart showing the transfer packet transmission process which the communication control part 33 performs in 8th Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Car-mounted system, 10 ... Navigation apparatus, 11 ... GPS receiver, 13 ... Map database, 15 ... Display part, 17 ... VICS communication part, 19 ... Operation switch group, 21 ... Navigation control part, 21a ... Route search part, 23, 37 ... interface unit, 30 ... wireless communication device, 31 ... wireless communication unit, 33 ... communication control unit, 35 ... timer

Claims (16)

A vehicle-mounted communication device provided with wireless communication means,
Position information acquisition means for acquiring current position information of the own vehicle;
When a data transmission command is input, the packet stores transmission target data specified from the input source of the data transmission command, and the transmission destination point specified from the input source of the data transmission command is recorded as attached information. Packet sending means for generating the packet and sending the packet to the network via the wireless communication means;
When receiving a packet through the wireless communication means, based on the destination location indicated by the received packet and the current position of the vehicle indicated by the acquisition information of the position information acquisition means, whether the received packet is a packet addressed to the own device Destination judging means for judging;
When the destination determining means determines that the received packet is a packet destined for the own apparatus, data receiving means for processing the received packet as a packet destined for the own apparatus;
When a packet is received through the wireless communication means, it is determined whether transfer of the received packet is necessary based on the attached information described in the received packet and the current position of the vehicle indicated by the acquisition information of the position information acquisition means Transfer necessity determination means to perform,
When it is determined by the transfer necessity determination means that the received packet needs to be transferred, a transfer packet that is a transfer packet is generated based on the received packet, and the generated transfer packet is transferred to the wireless communication means. A packet transfer means for sending to the network via
With
When a data transmission command is input, the packet sending means starts a data transmission route along a road starting from the current position of the own vehicle and ending at the destination point designated from the input source of the data transmission command. And determining a packet transfer range from the current position of the vehicle toward the end point of the data transmission path in accordance with the determined data transmission path in an area where the wireless communication means can communicate, and transmitting the data A packet storing transmission target data designated from an instruction input source, and configured to generate a packet in which the determined data transmission path and transfer range, and the transmission destination point are described as attached information,
The transfer necessity determination means determines that the received packet needs to be transferred when the vehicle exists within the transfer range indicated by the received packet and the received packet is not a packet addressed to the own device;
When the packet transfer means determines that the transfer of the received packet is necessary by the transfer necessity determination means, in the area where the wireless communication means can communicate, according to the data transmission path indicated by the received packet, Determine the packet transfer range from the current position of the vehicle toward the end point of the data transmission route, replace the transfer range indicated by the received packet with the determined transfer range, generate the transfer packet, and generate the transfer A communication apparatus configured to send a packet to a network via the wireless communication means.   2. The communication apparatus according to claim 1, wherein the packet transfer means is configured to determine a transfer range of the packet by matching a point farthest from the current position of the own vehicle on a data transmission path. .   The packet transfer means is configured to determine the transfer range of the packet in a circle from the current position of the own vehicle as a base point, and to transmit the intersection of the current position of the own vehicle and a straight line passing through the center point of the circle and the arc. 3. The communication apparatus according to claim 1, wherein the communication apparatus is configured to determine a transfer range of the packet so as to match the route.   The packet transfer means is configured to determine the transfer range of the packet in a circle with the current position of the vehicle as a base point, and aligns a specific point inside the circle on the data transmission path so that the transfer range of the packet The communication apparatus according to claim 1, wherein the communication apparatus is configured to determine the value.   2. The communication according to claim 1, wherein the packet transfer means is configured to determine an area having a predetermined width centered on the data transmission path as a transfer range of the packet along the data transmission path. apparatus. When receiving a packet through the wireless communication means, a setting means for setting a waiting time according to the current position of the vehicle with respect to the transfer range indicated by the received packet,
When the packet transfer means determines that transfer of the received packet is necessary by the transfer necessity determination means, the packet transfer means transmits the generated transfer packet after the standby time set by the setting means elapses. Via a means to be sent to the network,
Furthermore, the communication device
In a period until the waiting time set by the setting means elapses, when the transfer packet scheduled to be sent by the packet transfer means and the original packet are received more than the predetermined upper limit number, The communication apparatus according to claim 1, further comprising a prohibiting unit that prohibits transmission of the transfer packet by the packet transfer unit. The packet sending means and the packet transfer means are configured to write the current position of the vehicle in the packet as attached information when generating the packet,
The setting means calculates a distance along the data transmission path from a point on the data transmission path corresponding to the position of the transfer source vehicle indicated by the received packet to a point on the data transmission path corresponding to the current position of the own vehicle. 7. The communication apparatus according to claim 6, wherein the waiting time is set shorter as the distance is calculated.   The setting means is configured to calculate a distance along a data transmission path from the transmission destination point indicated by the received packet to the current position of the vehicle, and to set the standby time longer as the calculated distance is longer. The communication apparatus according to claim 6, wherein: The packet sending means and the packet transfer means are configured to write the current position of the vehicle in the packet as attached information when generating the packet,
The setting means is a distance along a straight line connecting a position of the transfer source vehicle indicated by the received packet and a point in the transfer range indicated by the received packet farthest from the transfer source vehicle, and the transfer source vehicle 7. The communication apparatus according to claim 6, wherein a distance from the vehicle position to the current position of the vehicle is calculated, and the standby time is set shorter as the distance is longer. Density determination means for determining the vehicle density around the vehicle;
Upper limit setting means for setting an upper limit number for the prohibition means based on the determination result of the congestion determination means;
The communication apparatus according to claim 6, further comprising: It is provided with a density determination means for determining the density of vehicles around the own vehicle,
The transfer range of the packet is determined according to the determination result of the congestion determination unit, and the size is determined according to the vehicle congestion around the host vehicle. Communication device.   The transfer necessity determination means is configured to determine that it is not necessary to transfer a received packet when the vehicle is not present on a data transmission route indicated by the received packet. Item 12. The communication device according to any one of Items 11. Receiving determination means for determining whether a transfer packet having the same transfer packet as the transfer packet sent by the packet transfer means is received from a communication device of another vehicle after sending the transfer packet;
The packet transfer means, when the reception determination means determines that the transfer packet having the same original packet is not received from a communication device of another vehicle, the transfer packet sent earlier based on the current position of the own vehicle The communication apparatus according to claim 1, wherein a new transfer packet is generated instead of the packet, and the packet is transmitted to the network via the wireless communication unit.   The packet transfer means, when the reception determination means determines that the transfer packet having the same original packet is not received from a communication device of another vehicle, the packet transfer means has a wider range than the transfer range described in the transfer packet sent earlier. The communication apparatus according to claim 13, wherein the communication apparatus is configured to generate a new transfer packet in which a transfer range is written.   When there is no data transmission route in the area where the wireless communication unit can communicate, the packet transfer unit is configured to transfer a route along the road from the current position of the own vehicle to the destination point indicated by the received packet with new data. Determined as a transmission path, in the area where the wireless communication means can communicate, in accordance with the determined data transmission path, determine the packet transfer range from the current position of the vehicle toward the end point of the data transmission path, The transfer range indicated by the received packet is replaced with the determined transfer range, the data transmission path indicated by the received packet is replaced with the determined data transmission path, and the transfer packet is generated. The communication apparatus according to any one of claims 1 to 14.   The packet transmission means is configured to determine, as a data transmission route, a route in which a main road is preferentially selected from routes from the current position of the host vehicle to a destination point. The communication apparatus according to any one of claims 1 to 15.