JP2009276845A - Mobile communication apparatus and mobile communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly versatile mobile communication apparatus and a mobile communication system which increases the possibility of establishing an inter-vehicle communication when it is difficult to establish the inter-vehicle communication with another vehicle due to the existence of an obstacle. <P>SOLUTION: When a support control ECU 12 decides that a communication condition with another vehicle is deteriorated , the transmission cycle of inter-vehicle communication information to be transmitted from a radio unit 11 to the other vehicle is made shorter than a normal transmission cycle, so that it is possible to increase the possibility of inter-vehicle communication when the inter-vehicle communication with the other vehicle is difficult due to the existence of an obstacle. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a mobile communication device and a mobile communication system that are mounted on a vehicle and used for bidirectional communication between vehicles.

  2. Description of the Related Art Conventionally, a technique is known in which each vehicle exchanges information such as vehicle status through bidirectional communication (hereinafter referred to as “vehicle-to-vehicle communication”) performed between the vehicles. As a method of using this vehicle-to-vehicle communication, it is well known to use an accident prevention technique for preventing collision accidents at intersections by exchanging information such as vehicle status between vehicles.

  In addition, when using vehicle-to-vehicle communication for such accident prevention technology, it is important to maintain the communication efficiency of vehicle-to-vehicle communication. In recent years, there are several technologies for maintaining the communication efficiency of vehicle-to-vehicle communication. Or has been proposed. For example, Patent Documents 1 and 2 disclose techniques for maintaining the communication efficiency of inter-vehicle communication by changing the transmission frequency of information transmitted from the host vehicle in accordance with information such as the vehicle status received from another vehicle. Has been.

  However, the above-described accident prevention technology and the technology disclosed in Patent Documents 1 and 2 are vehicles with other vehicles, such as a time period in which information from other vehicles cannot be received due to the presence of an obstacle continues. In the situation where inter-vehicle communication is difficult, there is a problem that the effect is not exhibited.

Therefore, as means for solving this problem, for example, in Patent Documents 3 to 5, a vehicle capable of directly communicating with the own vehicle (hereinafter referred to as a relay vehicle) is relayed to the vehicle directly with the own vehicle. A technique for performing communication with a vehicle that cannot perform inter-vehicle communication is disclosed.
JP 2000-90396 A JP 2000-311294 A JP 2000-357298 A JP 2004-246458 A JP 2005-141324 A JP 2000-31129 A JP 2000-90395 A JP 2006-202061 A

  However, in the technologies disclosed in Patent Documents 3 to 5, when the above-described relay vehicle does not exist, it is not possible to improve the situation in which inter-vehicle communication with another vehicle is difficult due to the presence of an obstacle. That is, the techniques of Patent Documents 3 to 5 have a problem of lacking versatility.

  The present invention has been made in view of the above-described conventional problems, and the object of the present invention is to enable vehicle-to-vehicle communication in situations where it is difficult to perform vehicle-to-vehicle communication with other vehicles due to the presence of obstacles. An object of the present invention is to provide a mobile communication device and a mobile communication system having higher versatility and higher versatility.

  In order to solve the above-mentioned problem, the mobile communication device according to claim 1 is a mobile communication device that is mounted on a vehicle and used for bidirectional communication between vehicles, from the vehicle to a partner vehicle. A transmission unit for transmitting the information at a predetermined transmission cycle, a communication status determination unit for determining whether or not a communication status with the counterpart vehicle has deteriorated, and a communication status with the counterpart vehicle by the communication status determination unit When it is determined that the transmission period has deteriorated, the transmission means includes a transmission cycle control unit that makes a transmission cycle of information transmitted from the transmission unit to the opponent vehicle shorter than the predetermined transmission cycle.

  According to the configuration of claim 1, when the communication status with the counterpart vehicle deteriorates, that is, when it becomes difficult to perform inter-vehicle communication with the counterpart vehicle, the transmission cycle of information to be sent to the counterpart vehicle is set. The transmission cycle will be shorter than the previous transmission cycle, so even in situations where it is difficult to perform inter-vehicle communication with the other vehicle, the probability that information can be transmitted at a timing or point where the communication status is temporarily improved is increased. be able to. Therefore, in the situation where inter-vehicle communication with other vehicles is difficult due to the presence of an obstacle, the possibility of performing inter-vehicle communication can be further increased. Furthermore, since the above-described effect can be obtained only by including the mobile device of claim 1 without depending on the presence or absence of a vehicle that relays inter-vehicle communication, the configuration using a vehicle that relays inter-vehicle communication. Compared with higher versatility.

  Further, in the mobile communication device according to claim 2, communication traffic that is a parameter that represents a risk level that is a parameter indicating a risk level of collision between the vehicle and the counterpart vehicle and a congestion level of the inter-vehicle communication. Level determination means for determining the level of the status parameter that is at least one of the quantities, and the transmission cycle control means shortens the transmission cycle according to the level of the status parameter determined by the level determination means. It is characterized by changing the degree to be changed.

  According to this, it becomes possible to change the degree of shortening the transmission cycle of the information transmitted to the counterpart vehicle in accordance with the high necessity of performing vehicle-to-vehicle communication. For example, it is necessary to increase the degree of shortening the transmission cycle of information to be transmitted to the partner vehicle as the level of risk of collision with the partner vehicle increases, and to perform inter-vehicle communication such as when the level of risk of collision with the partner vehicle is high The higher the performance, the higher the possibility that vehicle-to-vehicle communication can be performed. In addition, when the risk of collision with the other vehicle is low, the congestion level of the communication path is suppressed by decreasing the degree of shortening the transmission cycle of information transmitted to the other vehicle as the level of inter-vehicle communication congestion increases. It is also possible to suppress a decrease in information transmission efficiency in inter-vehicle communication.

  The mobile communication device according to claim 3 further includes a table storage unit that stores a table in which the level of the status parameter and the value of the transmission cycle are associated with each other in advance. By referring to the table stored in the table storage unit based on the status parameter level determined by the level determination means, the value of the transmission cycle corresponding to the status parameter level is obtained and obtained. The degree of shortening the transmission cycle is changed according to the value of the transmission cycle.

  Even in the case of claim 3, in a situation where it is difficult to perform inter-vehicle communication with other vehicles due to the presence of obstacles, etc., the possibility of performing inter-vehicle communication is further increased, and movement with higher versatility is achieved. A body communication device can be realized.

  The mobile communication device according to claim 4 further includes a risk determination unit that determines a risk that is a parameter representing a level of a risk of collision between the vehicle and the opponent vehicle, and the transmission cycle control unit includes: Even if it is determined that the communication status with the opponent vehicle has deteriorated by the communication status determination means, if the risk level determined by the risk determination means is lower than a predetermined level, The transmission period of the information transmitted from the transmission means to the opponent vehicle is not changed.

  According to this, even if it is determined that the communication status with the opponent vehicle has deteriorated, if the risk of collision with the opponent vehicle is low, a process of shortening the transmission cycle of information to be transmitted to the opponent vehicle is performed. By not doing so, it is possible to suppress congestion of the communication path and to suppress a decrease in information transmission efficiency in inter-vehicle communication.

  According to a fifth aspect of the present invention, there is provided a mobile communication system including a plurality of vehicles including any one of the mobile communication devices.

  According to this, when the situation of vehicle-to-vehicle communication between vehicles equipped with any one of the above mobile communication devices deteriorates, the transmission cycle of information to be transmitted to the counterpart vehicle in the mobile communication device of each other's vehicle Will be shorter than the previous transmission cycle, so even in situations where inter-vehicle communication with the other vehicle is difficult, the probability that information can be transmitted at a timing or point where the communication status is temporarily improved Can be further enhanced. Therefore, it is possible to further increase the possibility that the vehicle-to-vehicle communication can be performed in a situation where the vehicle-to-vehicle communication with another vehicle is difficult due to the presence of an obstacle.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of a mobile communication device 1 to which the present invention is applied. A mobile communication device 1 shown in FIG. 1 is mounted on a vehicle, and includes a wireless device 11 and a support control ECU (electronic control unit) 12. The mobile communication device 1 is connected to the navigation ECU 2, the engine ECU 3, the brake ECU 4, the display device 5, and the audio output device 6 so that electronic information can be exchanged. The ECU 2, the engine ECU 3, and the brake ECU 4 are connected by an in-vehicle LAN 7 that complies with a communication protocol such as CAN (controller area network). Hereinafter, a vehicle equipped with the mobile communication device 1 is referred to as a host vehicle.

  The navigation ECU 2 is composed of a known computer, and processes as various navigation functions based on the current position and traveling direction of the vehicle detected by the position detector 21 described later and map data read from the map data input device 22 described later. (For example, map scale change processing, menu display selection processing, destination setting processing, route search execution processing, route guidance start processing, current position correction processing, display screen change processing, volume adjustment processing, etc.) are executed. Various displays such as route guidance maps are performed on the display device 5 described later, and various voice guidance is performed on the voice output device 6 described later.

  The position detector 21 is a geomagnetic sensor that detects geomagnetism, a gyro sensor that detects an angular velocity around the vertical direction of the host vehicle, a distance sensor that detects a moving distance of the host vehicle, and a current position of the vehicle based on radio waves from a satellite. A GPS receiver for GPS (global positioning system) is detected. Since these sensors have errors of different properties, they are configured to be used while being complemented by a plurality of sensors. Depending on the accuracy of each sensor, the position detector 21 may be configured as a part of the above.

  The map data input device 22 is mounted with a storage medium (not shown), and various data including so-called map matching data, map data, and landmark data for improving the accuracy of position detection stored in the storage medium. Is a device for inputting. The map data includes link data indicating roads and node data. A link is a link between nodes when the roads on the map are divided by a plurality of nodes such as intersections, branches, and merge points, and roads are configured by connecting the links. . Link data includes a unique number (link ID) that identifies the link, link length indicating the link length, link start and end node coordinates (latitude / longitude), road name, road type, road width, number of lanes, right turn -Consists of data such as the presence or absence of a left turn lane, the number of lanes, speed limit, etc. On the other hand, the node data includes a node ID, a node coordinate, a node name, and a link ID of a link connected to the node, each node having a unique number for each node where roads on the map intersect, merge and branch. It consists of each data such as ID and intersection type. The storage medium also stores various facility types, names, address data, and the like, and these data are used for destination setting for route search. Note that a CD-ROM or DVD-ROM, a memory card, an HDD, or the like is used as the storage medium.

  The engine ECU 3 generates an injector in accordance with information on the accelerator pedal opening (that is, information on the degree of depression of the pedal) output from an accelerator opening sensor 31 described later and vehicle speed information output from a vehicle speed sensor 32 described later. By controlling the operation of the engine and the igniter, the engine speed is controlled by manipulating the fuel injection amount to the engine and the ignition interval of the engine. The accelerator opening sensor 31 is a sensor that detects the opening of the accelerator pedal (that is, the amount of depression of the accelerator pedal), and outputs information on the detected opening of the accelerator pedal to the engine ECU 3. The vehicle speed sensor 32 is a sensor that detects the vehicle speed of the host vehicle, and outputs information on the detected vehicle speed to the engine ECU 3.

  The brake ECU 4 controls the steering angle information output from the steering sensor 41 described later and the yaw rate output from the yaw rate sensor 42 described later so that a good deceleration feeling can be obtained when the driver performs a brake operation. Assist control of the braking force of the brake device is performed according to the information. The steering sensor 41 is a sensor that detects the steering angle of the steering of the host vehicle, and outputs information on the detected steering angle to the brake ECU 4. The yaw rate sensor 42 is a sensor that detects an angular velocity of the vehicle amount around the vertical direction, and outputs information on the detected yaw rate to the brake ECU 4.

  The wireless device 11 of the mobile communication device 1 includes a transmission / reception antenna and does not pass through a telephone network with another vehicle (hereinafter referred to as a partner vehicle) existing within a range of several hundred meters around the position of the host vehicle. In addition, information on the own vehicle and information on the other vehicle are received by wireless communication (that is, two-way communication between vehicles). Therefore, the wireless device 11 functions as a transmission unit in the claims. Note that information transmitted and received in this two-way communication between vehicles (hereinafter referred to as vehicle-to-vehicle communication) identifies, for example, vehicle status information indicating the vehicle's current position, speed, braking and other driving conditions, and the vehicle. It is assumed that it is identification information such as an ID (hereinafter, vehicle status information and identification information are referred to as inter-vehicle communication information). Vehicle status information transmitted from the wireless device 11 to the opponent vehicle is obtained from the position detector 21, accelerator opening sensor 31, vehicle speed sensor 32, steering sensor 41, and yaw rate sensor 42 via the navigation ECU 2, engine ECU 3, and brake ECU 4. And In addition, the wireless device 11 sends communication log data in this vehicle-to-vehicle communication and vehicle-to-vehicle communication information received from the counterpart vehicle to the support control ECU 12 described later. Further, the wireless device 11 changes the transmission cycle for transmitting information in accordance with an instruction from the support control ECU 12. The wireless device 11 has the same configuration as, for example, a known infrared communication device or a DSRC (dedicated short range communication) wireless module, except that the transmission cycle is changed in accordance with an instruction from the support control ECU 12.

  The support control ECU 12 of the mobile communication device 1 calculates a basic transmission cycle (hereinafter referred to as a normal transmission cycle). Then, the wireless device 11 is instructed to transmit the inter-vehicle communication information at this normal transmission cycle. In addition, the normal transmission cycle said here represents the transmission cycle in the state in which the communication condition of vehicle-to-vehicle communication has not deteriorated. The timing for calculating the normal transmission cycle is determined based on the travel distance of the host vehicle, the elapsed time since the previous determination of the normal transmission cycle, the deceleration of the host vehicle, and the like. The transmission cycle is newly calculated (that is, updated). A known method can be used for calculating the normal transmission cycle. For example, the calculation of the normal transmission cycle may be performed based on situation data such as the arrival time to the intersection, as disclosed in Patent Document 6, or as disclosed in Patent Document 7, The structure performed according to the vehicle speed of the own vehicle may be sufficient. The normal transmission cycle is set in the range of 400 to 1200 msec, for example.

  Further, the support control ECU 12 includes communication log data sent from the wireless device 11, sensors included in the position detector 21, accelerator opening sensor 31, vehicle speed sensor 32, steering sensor 41, yaw rate sensor 42, and the like. Based on information output from the sensor (hereinafter referred to as own vehicle sensor information), it is determined whether or not the communication status of inter-vehicle communication has deteriorated. The communication log data includes information related to vehicle-to-vehicle communication such as the presence or absence of packet loss, success or failure of reception of vehicle-to-vehicle communication information, congestion status in vehicle-to-vehicle communication, and usage rate of communication band in vehicle-to-vehicle communication. It shall be. In addition, when the support control ECU 12 determines that the communication status of inter-vehicle communication has deteriorated, the transmission cycle such as determination as to whether or not to shorten the transmission cycle than the normal transmission cycle and determination of the degree to shorten the transmission cycle. Perform resetting process. When the degree of shortening the transmission cycle is determined, the wireless device 11 is instructed to transmit the vehicle-to-vehicle communication information at a transmission cycle set shorter than the normal transmission cycle according to the determined degree. . Details of the transmission cycle resetting process will be described later.

  The display device 5 displays a map for guiding the traveling of the vehicle, a destination selection screen, a warning screen described later, and the like in accordance with instructions from the navigation ECU 2 and the support control ECU 12. The display device 5 is capable of full color display, for example, and can be configured using a liquid crystal display, an organic EL display, a plasma display, or the like.

  The voice output device 6 includes a speaker and outputs a guidance voice at the time of route guidance, a guidance voice of parking space information, a warning sound to be described later, and the like according to instructions from the navigation ECU 2 and the support control ECU 12.

  The position detector 21 may be configured to perform position detection using information output from the steering sensor 41, the vehicle speed sensor 32, and the like.

  Next, an operation flow in the mobile communication device 1 will be described with reference to FIG. FIG. 2 is a flowchart showing an operation flow in the mobile communication device 1. This flow is started when the ignition switch of the host vehicle is turned on.

  First, in step S1, the support control ECU 12 calculates a normal transmission cycle, causes the wireless device 11 to start transmission of inter-vehicle communication information in this normal transmission cycle, and proceeds to step S2. Therefore, the processing in step S1 corresponds to the transmission means in the claims. In addition, transmission of the vehicle-to-vehicle communication information from the wireless device 11 is continuously transmitted according to this normal transmission cycle in the range of several hundred meters around the position of the own vehicle regardless of the presence or absence of the partner vehicle. Thereafter, the normal transmission cycle is updated at the timing described above.

  In step S2, when the wireless device 11 receives the inter-vehicle communication information transmitted from the partner vehicle (Yes in step S2), the process proceeds to step S3. In addition, when the wireless device 11 has not received the opponent vehicle transmission information (No in step S2), the flow of step S2 is repeated.

  In step S3, the support control ECU 12 determines whether or not the communication status of the inter-vehicle communication has deteriorated. And when it determines with the communication condition of vehicle-to-vehicle communication having deteriorated (it is Yes at step S3), it moves to step S4. If it is not determined that the communication status of inter-vehicle communication has deteriorated (No in step S3), the flow returns to step S2 and the flow is repeated. Therefore, the processing in step S3 corresponds to communication status determination means in the claims.

  Here, a description will be given of a criterion by which the support control ECU 12 determines that the communication status has deteriorated. As a criterion for determining that the communication status has deteriorated (hereinafter referred to as a deterioration determination criterion), for example, the deterioration determination criterion is that the error rate of the inter-vehicle communication information received by the wireless device 11 is equal to or higher than a predetermined ratio. It is good also as a structure which makes it a deterioration judgment reference | standard that there was a packet loss of the vehicle-to-vehicle communication information received with the radio | wireless machine 11. In this case, the wireless device 11 may be configured to send the error rate and packet information of the inter-vehicle communication information to the support control ECU 12. The predetermined ratio mentioned here is a value that can be arbitrarily set, for example, 20%.

  Moreover, it is good also as a structure used as a deterioration judgment reference | standard that the next reception was not able to be performed during the period more than predetermined time after receiving the vehicle-vehicle communication information with the radio | wireless machine 11. FIG. Here, the period of time equal to or longer than the predetermined time is a period several times the transmission cycle of the vehicle-to-vehicle communication information transmitted from the partner vehicle, for example, the vehicle-to-vehicle communication information transmitted from the partner vehicle. This is a period four times the transmission cycle. In addition, when the vehicle-to-vehicle communication information transmitted from the partner vehicle includes information on the cumulative number of transmissions that the partner vehicle tried to transmit the vehicle-to-vehicle communication information to the host vehicle, this cumulative number of transmissions It is good also as a structure which makes deterioration judgment reference | standard that was more than predetermined number of times. The predetermined number of times referred to here is a number of times that can be arbitrarily set, for example, four times.

  In addition, map data (hereinafter referred to as a communication status deterioration map) indicating information on a point where the communication status of inter-vehicle communication deteriorates is stored in advance in a storage medium attached to the map data input device 22 of the own vehicle. If the communication status deterioration map can be acquired via the wireless device 11 due to the case or VICS (vehicle information and communication system), the current position of the host vehicle is the communication status of inter-vehicle communication on the communication status deterioration map. It is good also as a structure which makes it a deterioration judgment standard to hit the point which deteriorates. In addition, when information on a point where the communication status of vehicle-to-vehicle communication deteriorates (hereinafter referred to as “communication deterioration point”) is received in advance from the other vehicle by inter-vehicle communication, the current position of the host vehicle is the communication deterioration point. It is good also as a structure which makes deterioration judgment criteria to hit.

  In step S4, a transmission cycle resetting process is performed, and the process proceeds to step S5. Here, an outline of the transmission cycle resetting process will be described using the flowchart of FIG.

  First, in step S41, the support control ECU 12 determines the type of deterioration in the communication status of the inter-vehicle communication (hereinafter referred to as the communication status deterioration type) based on the communication log data of the wireless device 11, and the process proceeds to step S42. . As a type of communication status deterioration, a state where reception of incomplete vehicle-to-vehicle communication information such as packet loss continues for a predetermined time or longer in the wireless device 11 (hereinafter referred to as an information loss state) or vehicle-to-vehicle communication information can be received. There is a “communication failure state” such as a state in which a situation in which a user cannot or cannot perform continues for a predetermined time or longer (hereinafter referred to as an intermittent communication state). In addition, there is a “communication disabled state” in which a situation in which vehicle-to-vehicle communication information cannot be received from the partner vehicle continues for a predetermined period or longer. Note that the period longer than the predetermined time mentioned here is a period that is several times the transmission cycle of the inter-vehicle communication information transmitted from the counterpart vehicle, as described above, and is transmitted from the counterpart vehicle, for example. This is a period that is four times the transmission cycle of the inter-vehicle communication information.

  In the present embodiment, the configuration in which the support control ECU 12 determines the communication status deterioration type based on the communication log data of the host vehicle is shown, but the present invention is not necessarily limited thereto. For example, the communication log data of the partner vehicle when the partner vehicle is located at the current position of the host vehicle is received by the wireless device 11 by inter-vehicle communication from the partner vehicle, and the support control ECU 12 determines the communication status based on this The structure which determines a deterioration kind may be sufficient.

  In step S42, the amount of communication traffic, which is a parameter representing the level of congestion of the vehicle-to-vehicle communication, is determined based on the communication log data, and the process proceeds to step S43. Specifically, the amount of communication traffic is determined according to the congestion state in the vehicle-to-vehicle communication in the communication log data, the utilization rate of the communication band, and the like. For example, if the congestion level is greater than or equal to a predetermined level, or if the usage rate of this communication band is greater than or equal to a predetermined rate, the communication traffic volume is determined to be “large” and The amount of communication traffic is determined to be “small” when the degree of congestion is not equal to or greater than a predetermined degree of congestion or when the utilization rate of this communication band is not equal to or greater than a predetermined rate. Note that the predetermined degree of congestion and the predetermined ratio here are values that can be arbitrarily set. For example, the predetermined degree of congestion is 20% as a frequency of occurrence of congestion, and the predetermined ratio is 40%. is there.

  In the present embodiment, the configuration in which the level of communication traffic is determined in two stages of “high” and “low” is shown, but the present invention is not limited to this. For example, the configuration may be such that the level of communication traffic volume is determined in more stages than two stages. In this case, a configuration in which a plurality of threshold values such as the above-described predetermined degree of congestion and a predetermined ratio are provided may be employed.

In step S43, based on the own vehicle sensor information and the inter-vehicle communication information obtained from the opponent vehicle, a risk level, which is a parameter representing the level of risk of collision between the own vehicle and the opponent vehicle, is determined, and step S44. Move on. Specifically, the degree of risk is determined according to the remaining time until the collision with the opponent vehicle, the deceleration necessary to avoid the collision with the opponent vehicle, and the like. For example, if you are already passing by the opponent vehicle, if the remaining time until the predicted collision time is more than a predetermined time, or if the deceleration required to avoid a collision is less than a predetermined value, When it is estimated that there is no danger of colliding with the opponent vehicle, it is determined that there is no danger. The predetermined time and the predetermined value mentioned here are values that can be arbitrarily set. For example, the predetermined time is 12 seconds and the predetermined value is 1.0 m / s ² .

In addition, when it is estimated that there is a risk of collision with the opponent vehicle, if the remaining time until the predicted collision time is less than or equal to a predetermined time or the deceleration required to avoid the collision is predetermined It is a case where it is estimated that there is a risk of collision with the opponent vehicle, and the remaining time until the predicted collision time is less than a predetermined time. If it is not present, or if the deceleration required to avoid a collision is not equal to or greater than a predetermined value, it is determined as “low risk”. Therefore, the processing in step S43 corresponds to the risk determination means in the claims, and the processing in steps S42 and S43 corresponds to the level determination means in the claims. Note that the predetermined time and the predetermined value here are values that can be arbitrarily set, for example, the predetermined time is 4 seconds, and the predetermined value is 3.0 m / s ² .

  In the present embodiment, the risk level is determined in three stages of “no risk”, “low risk”, and “high risk”. However, the present invention is not limited to this. For example, the configuration may be such that the risk level is determined in more stages than three stages. In this case, a configuration may be adopted in which a plurality of threshold values such as the predetermined time and the predetermined value described above are provided. Further, the risk level may be two stages of “hazardous” and “no danger”. In this case, a configuration may be adopted in which threshold values such as the predetermined time and the predetermined value described above are not provided. Further, as disclosed in Patent Document 8, the risk level may be determined based on prediction of the future behavior of the host vehicle.

  In step S44, a transmission cycle is obtained based on the communication status deterioration type determined in step S41, the communication traffic volume determined in step S42, and the risk determined in step S43, and the process proceeds to step S5. Specifically, the support control ECU 12 stores in advance a table (hereinafter referred to as a correspondence table) in which the communication status deterioration type, the communication traffic volume level, the risk level and the transmission cycle value are associated with each other. By referring to the memory, the value of the transmission cycle corresponding to the type of communication status deterioration determined in step S41, the amount of communication traffic determined in step S42, and the risk determined in step S43 (hereinafter referred to as a reset transmission cycle). ) The transmission cycle value associated in the correspondence table is associated with a transmission cycle value shorter than the normal transmission cycle when the communication status deterioration type is “communication failure state”. When the deterioration type is “communication disabled”, the value of the normal transmission cycle is associated. Furthermore, the transmission cycle values associated in the correspondence table are associated with each other so that the values become shorter as the risk level is higher, and the values are made longer as the communication traffic level becomes higher.

  As a specific example, when the communication status deterioration type is “communication failure state”, the communication traffic volume level is “low”, and the danger level is “high risk”, “100 msec” is set as the value of the transmission cycle. It is associated. When “communication traffic volume level” is replaced by “high” or the risk level is replaced by “low risk”, “200 msec” is associated as the transmission cycle value. If the “communication traffic volume level” is replaced with “high” and the risk level is replaced with “low risk”, “300 msec” is associated with the transmission cycle value. In addition, when the communication status deterioration type is “communication disabled” or the risk level is “no danger”, the normal transmission cycle value is associated (that is, the normal transmission cycle value). Is “400 msec”, “400 msec” is associated as the value of the transmission cycle). In addition, the value of the transmission period matched with the correspondence table described here is an example to the last, Comprising: The structure with which another value is matched may be sufficient.

  Further, in the present embodiment, a configuration has been described in which the value of the transmission cycle is obtained by using the correspondence table in the transmission cycle resetting process, but this is not necessarily the case. For example, the transmission cycle value may be obtained by using a function of three parameters such as a communication status deterioration type, a communication traffic level, and a risk level.

  In step S45, transmission of the vehicle-to-vehicle communication information in the reset transmission cycle is started by the wireless device 11, and the process proceeds to step S5.

  Returning to FIG. 2, in step S <b> 5, the support control ECU 12 determines whether or not the communication state of the inter-vehicle communication has been recovered. And when it determines with the communication condition of vehicle-to-vehicle communication having recovered | restored (it is Yes at step S5), it moves to step S7. If it is not determined that the communication status of the inter-vehicle communication has been recovered (No in step S5), the process proceeds to step S6. It should be noted that the determination as to whether or not the communication status of vehicle-to-vehicle communication has been recovered may be configured so as to be performed when the above-described deterioration determination criteria are not met.

  In step S6, the support control ECU 12 determines whether or not a predetermined time has elapsed since the support control ECU 12 determined that the communication status of the inter-vehicle communication has deteriorated. And when it determines with predetermined time having passed (it is Yes at Step S6), it moves to Step S7. If it is not determined that the predetermined time has elapsed (No in step S6), the process returns to step S4 and the flow is repeated. The predetermined time here can be arbitrarily set, for example, 4800 msec.

  In step S7, the value of the transmission cycle is reset to the value of the normal transmission cycle, the transmission of the vehicle-to-vehicle communication information in this normal transmission cycle is started by the radio 11, and the flow is repeated by returning to step S2.

  Note that the flow in FIG. 2 ends even when the ignition switch of the host vehicle is turned off, even in the middle of the flow. In the flow of FIG. 2, when the inter-vehicle communication with the opponent vehicle is completed, the flow returns to the flow of step S2 and repeats the flow even in the middle of the flow.

  If there are multiple opponent vehicles that are estimated to be at risk of collision with the host vehicle, the relative risk rankings of these opponent vehicles are given, and the opponent with the highest risk What is necessary is just to set it as the structure used for the reference of the corresponding | compatible table in a transmission period reset process about the danger level about a vehicle.

  Here, the effect in this invention is demonstrated concretely using FIG. FIG. 4 is a schematic diagram showing a change in communication status between vehicles performing inter-vehicle communication. 4, A1 to A4 are positions of the own vehicle, vehicles B1 to B4 are positions of the opponent vehicle, A1 and B1 are positions of the own vehicle and the opponent vehicle at time t1, and A2 and B2 are the own vehicle at time t2. Further, the positions of the partner vehicle, A3 and B3 are the positions of the host vehicle and the partner vehicle at time t3, and A4 and B4 are the positions of the host vehicle and the partner vehicle at time t4. Further, C in FIG. 4 is an obstacle that hinders vehicle-to-vehicle communication, and a broken line in FIG. 4 schematically shows a communication path of vehicle-to-vehicle communication. Here, it is assumed that both the own vehicle and the opponent vehicle are about to enter the intersection.

  First, since the inter-vehicle communication is not obstructed by the obstacle C between the own vehicle at the position A1 and the counterpart vehicle at the position B1 at time t1, the situation of the inter-vehicle communication is good. Here, as the normal transmission cycle, the inter-vehicle communication information is transmitted from the own vehicle to the partner vehicle, for example, at a transmission cycle of 1200 msec.

  Subsequently, the host vehicle at the position A2 and the counterpart vehicle at the position B2 at time t2 are obstructed by the obstacle C, and the communication status of inter-vehicle communication deteriorates. It is assumed that the communication status deterioration type at this time is “communication failure state”, the communication traffic volume level is “low”, and the danger level is “high risk”. Here, as the transmission cycle shorter than the normal transmission cycle, for example, the inter-vehicle communication information from the own vehicle to the partner vehicle is transmitted at a transmission cycle of 100 msec.

  On the other hand, even if the communication status of inter-vehicle communication deteriorates, each vehicle is temporarily located at a point where the communication status is temporarily improved, such as the host vehicle at position A3 and the counterpart vehicle at position B3 at time t3. When located, vehicle-to-vehicle communication can be performed satisfactorily. Note that the probability of transmitting inter-vehicle communication information from the own vehicle to the partner vehicle at this point is set to 100 msec, which is shorter than the normal transmission cycle, whereas the transmission cycle remains at the normal transmission cycle of 1200 msec. Then it becomes 12 times.

  Then, when the influence of obstruction C is reduced like the own vehicle A4 and the partner vehicle B4 at time t4, the state of inter-vehicle communication is recovered. Here, as the normal transmission cycle, the inter-vehicle communication information is transmitted from the own vehicle to the partner vehicle, for example, at a transmission cycle of 1200 msec.

  As described above, according to the configuration of the present embodiment, when the communication state with the opponent vehicle deteriorates due to the obstacle C, the transmission cycle of the inter-vehicle communication information to be transmitted to the opponent vehicle is the normal transmission up to that time. Probability that vehicle-to-vehicle communication information can be transmitted at the above-mentioned points where the communication status is temporarily improved even in situations where it is difficult to perform vehicle-to-vehicle communication with the opponent vehicle. Can be increased. Therefore, in the situation where the vehicle-to-vehicle communication with the opponent vehicle is difficult due to the presence of the obstacle C, the possibility that the vehicle-to-vehicle communication can be performed can be further increased. Furthermore, since the above-described effect can be obtained only by providing the vehicle with the mobile communication device 1 regardless of the presence or absence of a vehicle that relays vehicle-to-vehicle communication, compared to a configuration using a vehicle that relays vehicle-to-vehicle communication. Higher versatility. Further, when the state of vehicle-to-vehicle communication is recovered, the transmission cycle that has been set shorter than the normal transmission cycle is returned to the normal transmission cycle, so congestion of vehicle-to-vehicle communication can be further suppressed.

  In addition, according to the configuration of the present embodiment, when the risk of collision with the opponent vehicle is low, the transmission cycle of the inter-vehicle communication information transmitted to the opponent vehicle is shortened as the level of the communication traffic amount is higher. Since the degree is weakened, it is possible to suppress the congestion of the communication path of the vehicle-to-vehicle communication and to suppress the decrease in the information transmission efficiency in the vehicle-to-vehicle communication. In addition, the higher the degree of danger, the higher the degree of shortening the transmission cycle of the vehicle-to-vehicle communication information transmitted to the opponent vehicle, so there is a high need for vehicle-to-vehicle communication such as when the level of risk of collision with the opponent vehicle is high From time to time, the possibility of performing vehicle-to-vehicle communication can be further increased.

  Moreover, the structure by which the other party vehicle is equipped with the mobile communication apparatus 1 may be sufficient. According to this, in the mobile communication device 1 of each other's vehicle, the transmission cycle of the information to be transmitted to the other party is made shorter than the previous transmission cycle, so it is difficult to perform inter-vehicle communication with the other vehicle. Even in a situation, it is possible to further increase the probability that vehicle-to-vehicle communication information can be transmitted at a timing or point where the communication situation is temporarily improved. Therefore, it is possible to further increase the possibility that the vehicle-to-vehicle communication can be performed in a situation where the vehicle-to-vehicle communication with another vehicle is difficult due to the presence of an obstacle.

  In the present embodiment, the configuration in which the transmission cycle resetting process is always performed when the support control ECU 12 determines that the communication state has deteriorated is shown, but the present invention is not necessarily limited thereto. For example, even if the support control ECU 12 determines that the communication situation has deteriorated, the risk of the risk determined by the support control ECU 12 is determined when the host vehicle is not located at a point where the risk of a collision is high, such as an intersection. When the level is lower than a predetermined level, the transmission cycle resetting process may not be performed. Note that the predetermined level here is a value that can be arbitrarily set, and is, for example, “low risk”.

  Further, in the present embodiment, when the communication status of the vehicle-to-vehicle communication is recovered as shown in step S5, or when a predetermined time has passed since it was determined that the communication status was deteriorated as shown in step S6. In the above configuration, the transmission cycle is reset to the normal transmission cycle when it is no longer necessary to increase the possibility of vehicle-to-vehicle communication by shortening the transmission cycle to the normal transmission cycle. Not limited to. For example, in the case of a configuration in which the point where the transmission cycle resetting process is performed is limited (for example, a configuration where the point where the transmission cycle resetting process is performed is limited to an intersection), when the point is passed, the transmission cycle May be reset to the normal transmission cycle.

  In the present embodiment, the correspondence table shows the configuration in which the communication status deterioration type, the communication traffic volume level, the risk level, and the transmission cycle value are associated with each other, but the present invention is not limited to this. For example, a configuration in which the communication status deterioration type is not associated with the value of the transmission period in the correspondence table may be used. In this case, the support control ECU 12 may be configured not to determine the communication status deterioration type. Further, only one of the risk level and the communication traffic volume level may be associated with the transmission cycle value in the correspondence table. In this case, the support control ECU 12 may be configured to determine only one of the risk level and the communication traffic level.

  In the present embodiment, when the risk level is “no danger”, the configuration in which the value of the normal transmission period is associated as the value of the transmission period of the correspondence table is shown. Not limited to this. For example, when the level of danger is “no danger”, the value of the transmission period when the level of risk is “low risk” is associated as the value of the transmission period of the correspondence table. It may be a configuration.

  Further, in the present embodiment, when the support control ECU 12 determines that the communication status of inter-vehicle communication has deteriorated, the value of the transmission cycle is determined based on the communication status deterioration type, the communication traffic level, and the risk level. However, the present invention is not limited to this, although the wireless device 11 starts transmitting the vehicle-to-vehicle communication information in this transmission cycle. For example, when the support control ECU 12 determines that the communication status of the inter-vehicle communication has deteriorated, a predetermined transmission cycle (for example, 100 msec) shorter than the normal transmission cycle is set, and the inter-vehicle communication information in this transmission cycle is set. The configuration may be such that the wireless device 11 starts transmission. The predetermined transmission cycle here is a value that can be arbitrarily set. In this case, the support control ECU 12 may be configured not to determine the communication status deterioration type, the communication traffic level, and the risk level.

  In the present embodiment, the configuration in which the transmission cycle is set shorter than the normal transmission cycle is shown, but the present invention is not necessarily limited thereto. For example, when the normal transmission cycle is set to the shortest transmission cycle (here, 100 msec) in the specified transmission cycle (for example, 100 to 1200 msec), the same transmission cycle (here, 100 msec) ) May be set.

  In the present embodiment, the configuration in which the information on the current position of the opponent vehicle is obtained by the wireless device 11 by inter-vehicle communication is shown, but the present invention is not necessarily limited thereto. For example, the configuration may be such that information on the current position of the opponent vehicle is detected by a millimeter wave radar mounted on the host vehicle.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and the technical means disclosed in different embodiments can be appropriately combined. Such embodiments are also included in the technical scope of the present invention.

1 is a block diagram showing a schematic configuration of a mobile communication device 1. FIG. 3 is a flowchart showing an operation flow in the mobile communication device 1; It is a flowchart which shows the operation | movement flow in a transmission period reset process. It is a schematic diagram which shows the change of the communication condition of the vehicles which are performing vehicle-to-vehicle communication.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mobile communication apparatus, 2 Navigation ECU, 3 Engine ECU, 4 Brake ECU, 5 Display apparatus, 6 Voice output apparatus, 7 Car interior LAN, 11 Radio | wireless machine (transmission means), 12 Support control ECU (Communication status determination means, Transmission) (Cycle control means, level determination means, table storage unit, risk determination means), 21 position detector, 22 map data input device, 31 accelerator opening sensor, 32 vehicle speed sensor, 41 steering sensor, 42 yaw rate sensor

Claims (5)

A mobile communication device mounted on a vehicle and used for two-way communication between vehicles,
Transmitting means for transmitting information from the vehicle to the opponent vehicle at a predetermined transmission cycle;
Communication status determination means for determining whether the communication status with the opponent vehicle has deteriorated;
When the communication status determining means determines that the communication status with the counterpart vehicle has deteriorated, a transmission cycle control for making a transmission cycle of information transmitted from the transmission means to the counterpart vehicle shorter than the predetermined transmission cycle And a mobile communication device. A situation parameter that is at least one of a risk that is a parameter that represents a level of risk of collision between the vehicle and the opponent vehicle and a traffic that is a parameter that represents a level of congestion in the inter-vehicle communication. Further comprising level judging means for judging the level;
The mobile communication apparatus according to claim 1, wherein the transmission cycle control unit changes a degree of shortening the transmission cycle in accordance with the level of the status parameter determined by the level determination unit. A table storage unit for storing a table in which the level of the status parameter and the value of the transmission cycle are associated in advance;
The transmission cycle control unit refers to the table stored in the table storage unit based on the level of the situation parameter determined by the level determination unit, thereby determining the transmission cycle corresponding to the level of the situation parameter. The mobile communication device according to claim 2, wherein a value is obtained and a degree of shortening the transmission cycle is changed according to the obtained value of the transmission cycle. A risk determination means for determining a risk that is a parameter representing a level of risk of collision between the vehicle and the opponent vehicle;
Even if the transmission cycle control means determines that the communication status with the opponent vehicle has deteriorated by the communication status determination means, the risk level determined by the risk determination means is lower than a predetermined level. The mobile communication device according to claim 1, wherein when it is low, a transmission cycle of information transmitted from the transmission unit to the opponent vehicle is not changed.   A mobile communication system comprising a plurality of vehicles including the mobile communication device according to claim 1.

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